Thursday, October 31, 2019

#243 - Wednesday, October 30, 2019

We had an extra quantum mechanics lecture this week to make up for the one we lost when PG&E shut off power in the area to help prevent wildfires, and having three days in a row of that 90-minute lecture was brutal!  So I got home late, but got the scope set up as soon as I could.

I figured out pretty quickly what happened to the declination axis last night -- the cable bundle had gotten wrapped around the mount!  I forgot to re-attach one of the cable clips onto the mount when I borrowed the connection for testing my solar imaging rig yesterday.  I detangled it and re-attached it, re-aligned the scope with 2 alignment stars and 3 calibration stars, and started the sequence.  It's a little out of focus at the moment, but it will be in focus for a greater portion of the night at the point that it's at, since it was colder when I set it.  I still haven't heard back from Technical Innovations on the email I sent them asking about what the problem might be with my focus controller, so it might be time for a phone call.

I processed the luminance data from Brian Sheets of NGC 1055 yesterday, and wow did it come out nicely!  Way more detail than in a single frame.  I love when that happens.

Watermark got a little messed up...adding the second line on the left was really rather difficult in Lightroom.
Date: 27 October 2019
Location: Mountainville Observatory (Brian Sheets), Alpine, UT
Object: NGC 1055
Attempt: 1
Camera: SBIG STL-1001e
Telescope: Celestron C14
Accessories: Astrodon LRGB filters
Mount: Software Bisque Paramount MX+
Guide scope: N/A
Guide camera: N/A
Subframes: L: 137x60s (2h17m)
Gain/ISO: N/A
Acquisition method: ACP - DC-3 Dreams
Stacking program: PixInsight 1.8.7
Post-Processing program: PixInsight 1.8.7
Temperature: -25C (chip)

A promising start!  I had to crop the already-small (1024x1024) image quite a bit due to the piling up of tracking errors that ultimately made it wander pretty far through the frame, but it worked out nonetheless.  I did some interpolation in Photoshop to bump up the image size.  I'll re-process it at some point using drizzle processing, which I haven't played with much yet because all of my cameras have rather large pixel arrays (12-24 megapixels).  I was also rather pleased to be able to get some 3D-ness on the galaxy -- you can see it wrap around behind the central bulge a bit.  Yay for contrast enhancement!

When I combed through the frames in the morning, I lost quite a few, as usual -- the Flaming Star Nebula shots all had streaky stars, the Heart and Pacman Nebulae were out of focus because it hadn't gotten cold enough out yet, and M31 lost its guide star several times according to the Sequence Generator Pro error log, as well as failing to settle the guider.  Still not sure what's up with that one.  Oh well...I'll keep trying!

Wednesday, October 30, 2019

#242 - Tuesday, October 29, 2019

Yesterday, I was home in the afternoon, and after struggling with trying to do homework for a while, I decided to go ahead and test my solar imaging rig for the fast-approaching Mercury transit.

I brought my 8-inch Celestron Schmidt-Cassegrain outside on my Celestron NexStar SE alt-az mount and set it up near the back fence in my backyard to catch the sun before it got too far west.

And here's a test shot:

Those aren't sunspots, but bits of dust on the camera or thereabouts.  One nice thing about the Seymour Solar filters is they give you a nice "sun-like" orange color, rather than pink or blue or green or other colors I've seen.  I checked my NASA Space Weather app: nope, no sunspots today.  :(

The front did get quite hot, so I think I'll buy some white gaffers tape and put that on the front instead.

The smoke picked up again last night, so I decided not to image.  But tonight is looking clearer, so I decided to go ahead and see how my images might come out.

I set up, and checked focus on star Alpheratz -- perfect!  Which was crazy, since I took the camera off to image the sun on Sunday, and it's pretty tough to get it back in exactly the same spot.

Along with the camera, I've also now got the correct light pollution filter on!  I had previously been imaging with the Astronomik CLS, which is fine for DSLRs, but doesn't block UV/IR light.  Neither of my ZWO cameras have built-in UV/IR filters (and good thing too -- it opens up more possibilities of imaging, like with an IR-pass filter, which is helpful for planets).  So I sold the CLS filter to help fund the new one -- the Astronomik CLS-CCD filter, which also blocks UV/IR.  Not blocking it was causing problems with my refractor because only optical light is corrected and focused onto the same spot -- IR light can show up as a defocused halo around the star, which is exactly what was happening in images like my recent Eastern Veil Nebula.  This should fix that problem!

I went ahead and left the C8 set up outside on its alt-az mount because I'm hoping to image Uranus here soon on a night with good seeing.  I've tried before, but haven't gotten much, back when I was using my DSLR.  I'm ready for another attempt now, and it's shortly past opposition!  But I need a night of good seeing, and last night was forecast to be only "below average."

I went to bed, and in the morning, peeked out my window to check that the mount had parked itself.  It had not :( It was pointing at my neighbor's garage.  When I got out there, PlateSolve2 was still doing a spiral search on M31!  My guess was that dec had slipped or jumped again for some reason, since pointing at the wall was where it had parked itself, thinking it was the home position.  The mount got lost.  Guess I'll re-align next night!

Monday, October 28, 2019

#241 - Sunday, October 27, 2019 - Collaboration

I got out of church late after chatting with some people, so I skipped the TAIC talk and made dinner (sorry guys!).  Then I played some Borderlands 3 with some of my classmates from school.  But before I started playing, I got the scope set up around 7:15 PM, just about as soon as it was dark.  The atmospheric transparency was forecast to be not great until about 1 AM, and there is still some lingering smoke in the air, but I figured I may as well try, and I can just toss bad exposures later.  Especially since it's so little effort to acquire the images now that I've put all this work into the setup!

The Flaming Star Nebula and M31 Andromeda Galaxy still had tracking issues on the Celestron AVX mount.  I've given M31 plenty of time to get past the meridian before I start imaging to avoid any badness that might be occurring up that high, but it doesn't seem to be helping!

My early morning shots on M42 Orion Nebula were out of focus, thanks to temperature changes.  The Rosette Nebula was too.  I emailed Technical Innovations again yesterday about my Robofocus; hopefully this time I will hear back.

A new project

A new project I've got going is a collaboration with Brian Sheets, an amateur astronomer out in Utah.  He primarily does scientific imaging -- mainly NEO-hunting (near-Earth objects).  He contacted me back in August to ask if I would be interested in doing some 'pretty-picture' astrophotography on his rig -- he was curious to see what it was capable of producing.  I, of course, agreed!  I was working on my move out to California at the time, so I didn't get started on it till this month, but I finally put in a target, and finally got some frames on it last night!

He has a Celestron C14 with a SBIG STL-1001e on a Paramount MX+.  His location in Utah is not particularly dark.  However, I was excited about using his rig primarily for the small FOV -- the native focal length of the C14 is 3910mm, and that camera is only 1024x1024 pixels.  Also, that camera has 24-micron pixels, which is enormous!!  For comparison, my ZWO cameras have 3.8 and 4.6-micron pixels.  Now, you might think, "Why would you want big pixels? Won't that decrease your spatial resolution?"  That is a true statement.  However, a bigger pixel collects more light due to its larger surface area, and it is thus a very sensitive camera.  It's a good thing too, since he doesn't have an autoguider set up on that rig yet, so I'm limited to 2-minute exposures (which is honestly pretty good for such a long focal length and heavy scope!).

I was excited about the small FOV because I have largely been unable to image tiny targets, like most galaxies and planetary nebulae, for the last two years, since my Celestron CGE and CGE Pro mounts have been basically non-functional.  I haven't been able to use my C11 in ages, and when I have tried my C8 on my Celestron AVX mount, I have to use my focal reducer (which drops the focal length to 1280mm), and I can only take like 30s images.  While I looooove shooting nebulae through refractors, I miss imaging galaxies!  So the first target I put in was NGC 1055, a galaxy in the constellation of Cetus that lies about 63 million lightyears away.  It's not quite edge-on, but it's relatively close, so you can see some awesome dust lanes, as well as the bright bulge of the core rising up out of the plane.  Tonight is the first night I've got images coming down -- very exciting!

Solar filter

On Saturday, I finally worked on a project I've been meaning to do for a long time -- a solar filter for my C8!  Just in time for the upcoming Mercury transit.  I looked up some ideas online, and combined a few together.  I ultimately decided to follow some advice I saw several places, which was for telescopes with apertures 8 inches or bigger, an off-axis cell is the best way to go.  You do lose a little resolution that way, but at that size it gets difficult to disperse the heat, especially since the Seymour Solar filter paper I have is absorptive rather than reflective.

I laid out a couple of Blue Apron cardboard boxes I had been holding onto and cut out a long strip, which I wrapped around my Celestron 8-inch SCT's exterior tube at the objective.  I cut it to size, and then cut two more.  I forgot to add the extra length of going around the inner strips of cardboard, however, so they came up a little short.  Some duct tape took care of that.  I used a box cutter to cut a square into the ring so there would be a spot for the dovetail.  After wrapping the entire circle in duct tape and black gaffers tape, I set it aside, and cut out two flat circles larger than the diameter of my scope's objective by about 4 cm.  I used my dew shield to get the size of the outermost metal ring, since it's larger than just the scope's 8-inch aperture.  Next, I used a compass to make a circle for the solar filter, which I cut with a box cutter out on my front porch.  I lined the inner circle with black gaffers tape to smooth it out.  Then, using double-sided tape, I taped the filter onto one of the cardboard circles, and taped the other one to it.  Finally, I used wood glue to attach the circular strips to the front circle with the filter.  (Sorry I didn't take more pictures!)  I used some textbooks and a telescope counterweight to press the pieces together, and let it set overnight.  I used some spare cardboard pieces to protect the filter paper.

Once the glue dried, I covered the rest of the exterior with black gaffers tape.  Then I cut out some cardboard pieces and put Velcro on them to protect the filter paper on both the inside and the outside.

It was too smoky to go test it today, but hopefully I can squeeze it in tomorrow.

Saturday, October 26, 2019

#240 - Friday, October 25, 2019 - Smoked Out, Day 2

The Astropheric forecast, which shows smoke and smoke forecast (based on wind patterns) showed that the Kincaid wildfire smoke might clear out the second half of the night.  So I went ahead and set up, figuring I'd just toss the first half of the night's data.  Since the moon is down, I swapped back to my color camera, my ZWO ASI294MC Pro, with my newly-acquired Astronomik CLS-CCD light pollution filter.  I previous had the regular version of the CLS filter, but I learned that it doesn't block UV/IR, which was fine with my DSLR because it has its own blocking filter, but the 294 does not.  This caused the brighter stars to have weird rings around them, since the IR light doesn't get focused the same way the optical light does in a refractor.

The images that came down were pretty much garbage, as expected.  Darn wildfires!  Stupid climate change!

I went out and re-focused before bed because the temperature had dropped quite a bit, and then went to bed.  In the morning, I looked outside to check on it as I usually do, and it wasn't pointing at the home position!  I looked at the sequence to see what happened, and it was still trying to recover, which was weird.  It was on my last target, the Flaming Star Nebula, and it turns out that when I copied the sequence to make the new one for the color camera, the "end sequence at" time didn't copy.  Whoops!  So I set that and parked the mount and buttoned everything back up.

M31 still had tracking issues, even though I made sure it didn't start until 25 minutes after the meridian.  That should have been enough time for it to settle down.  The Flaming Star Nebula, also west of the meridian, did not have these issues.  More troubleshooting to do...

Friday, October 25, 2019

#239 - Thursday, October 24, 2019 - Smoked Out

Fall in California means wildfire season.  And while none were particularly close to Berkeley, the smoke from the Kincaid fire, among others, was being blown all over the place.  People were preparing for another possible Smokepocalypse, buying masks and planning their transit routes.  The Astrospheric app I used showed some smoke forecasts, and it did not look good for astronomy!

Looking at the scale, purple is off-the-charts bad!

I decided to give it a shot and see how far along I could get before it got too bad.  I set up my DSLR to capture the sky in a timelapse, since it might be hard to see it well in the images.  

The weather was warm and breezy, and it was still nearly 80 degrees when I went out to set up my scope!  The cooler on my camera was running at 79% just to hit -15C.  I started the evening by re-aligning the mount after the clutch slip the previous night.

Things ran smoothly, and I checked my data in the morning. I had added Thor's Helmet to my list as the last target before sunrise, but the sequence didn't get that far for some reason.  The Rosette Nebula didn't run either.  M31, imaged near the meridian, were still having tracking issues, with several frames not having any tracking at all.  I'm still troubleshooting that.  M42 worked this time though!  However, they were out of focus, so I threw them out.

Thursday, October 24, 2019

#238 - Wednesday, October 23, 2019 - More AVX Tweaks

Sometime during the previous night, the dec axis had some kind of issue and ended up losing alignment, which I knew because it wasn't in the home position in the morning, but several degrees off in dec.  Likely, the cable going to the motor housing (why is this not done internally??) got tugged on or something, which makes the mount slew without that motion being encoded, and at a high speed.  After shoving it back into the port, I rebooted the mount to clear the alignment, and then slewed to Vega as the first alignment star.  During the slew, I saw that the RA axis had some serious delay!  It took a few seconds for it to start spinning after I hit the controller button when I tried to move it.  So I popped open the RA casing to see what was going on.  I slewed the mount, and saw that the motor shaft was turning, but the gear wasn't!  Luckily, this was easy to fix -- the set screws holding the gear to the shaft had worked their way loose somehow.  I tightened them with a tiny hex key, and everything was back to normal.

Looking down at the open RA motor housing.  The motor drive gear is the left one; the little gray circles on it are the set screws.

After this 5-minute pause, I was back to alignment.  I re-aligned, and also re-calibrated the autoguiding software PHD2, since I forgot to do that last week when I re-polar-aligned it.  By 8:45 PM, I was off and imaging!  Time to go hang out inside, have some wine, pet my cats, and watch some TV.

On the imaging docket was, with my ZWO ASI1600MM Pro and hydrogen alpha filter:
- Pacman Nebula
- Heart Nebula
- California Nebula
- NGC 2174 "Monkey Head" Nebula
- M31 Andromeda Galaxy
- M42 Orion Nebula
- Rosette Nebula

In the morning, I looked out a back window as I usually do to check that it had indeed returned to the home position -- and it had not!  It was pointing down at the ground!  

I was a little perplexed at how this could happen.  However, it didn't take me long to figure it out -- the clutch had some loose.  Over time, tightening the clutch advanced the position of the knob, and when the mount rotated, it was dragged across the dec motor housing, which loosened it back up.  

Luckily, this was also easy to fix: you simply take out the Philips-head screw that holds the knob to the bolt, rotate it upward, and screw it back in.  Done!  

I looked through my data, and unfortunately it had only gotten through the Heart Nebula before it slipped.  Dang.  Oh well...

Wednesday, October 23, 2019

#237 - Tuesday, October 22, 2019

Man I loooooove having so many clear nights!  My average is going to jump from 50 nights per year to like 200.  Sooooo much data though!

After the Rosette Nebula 10-minute frames went so well last night, I decided to try the same for the Heart Nebula.  And boy oh boy was that a great idea.  Look at this!!

IC 1508 Heart Nebula, single 10-minute subframe in hydrogen-alpha
Takahashi FSQ-106N, ZWO ASI1600MM Pro

Close-up of the Melotte 15 region at the core, and this super-cool spiral structure!

The Heart Nebula is a gorgeous nebula to begin with, but it has an even more fascinating region at the center that has this incredible spiral structure.  It is very often imaged, and I'm excited to finally be taking data on it!  I've been trying to image the Heart for the past two winters, but weather conditions kept me from being able to get much on it.  But now I have much better weather, and many more hours a night since it's all automated now!

When I had just started the sequence and was checking messages on my phone and enjoying the evening weather, I heard a noise from behind me.  I turned on my headlamp and pointed it at the sound, thinking it was a raccoon, but nope, it was a skunk!  Code red!  I grabbed the scope cover (I like to leave it on my porch so that critters don't climb in, and it doesn't get dewy) and dashed inside the house.  Yeeeep!  I watched the first frames come in while hanging out inside using my remote connection on TeamViewer.  

In the morning, I took another video of the moon, which was gorgeous in the clear morning air.  However, the RA axis had some mega-backlash while I was slewing, and something clearly happened last night to throw off dec as well, since the scope came in a bit far from the moon.  

Date: 23 October 2019
UTC: 23 October 2019, 13:34
Location: East Bay area, CA
Object: Moon
Attempt: 33
Camera: ZWO ASI1600MM Pro
Telescope: Takahashi FSQ-106N
Accessories: Astronomik H-alpha 12nm T2 filter
Mount: Celestron AVX
Frames: 1422/2007
FPS: 18 fps
Exposure: 15 ms
ISO/Gain: 139
Stacking program: RegiStax 6
Processing program: Photoshop CC 2019

Things ran well the first half of the night, but got dicey later in the night.  M42 didn't show up in its frame at all, which wound up being a result of me forgetting to re-check the "center" button in Sequence Generator Pro.  The Rosette Nebula and Thor's Helmet didn't even take (I added Thor's Helmet to the extra time in the morning since meridian-flipping on M42 obviously isn't working), which looked like it was the result of a weird error where the PlateSolve2 database saved on my computer wouldn't open.  The file had somehow disappeared, so I copied it back into its place.  Always all these little things!

Tuesday, October 22, 2019

#236 - Monday, October 21, 2019 - Long Exposure

I got outside a little after 8 PM, took the cover off the scope and connected my tablet to the USB hub and to power, and then re-focused after focusing on the Moon in the morning.  (I know it doesn't make a ton of sense because the moon should be at infinity focus as well, same as the stars, but it has been my experience that solar system objects and deep sky objects have different focal points.  I'm not sure why that is.)

Things ran quite smoothly that night.  I set M31 to not start until it was 13 degrees past the meridian, and that seemed to get past the rough patch, I guess.  I still didn't get a chance to take a look inside the mount for the lagging in RA that M42 was doing, so that one didn't turn out.

In addition, NGC 2174, the Monkey Head Nebula, was out of focus due to the focus drift with temperature that Takahashi refractors are known for.  Rawr!

Onnnn the other hand, even though it was out of focus, the 10-minute exposures of the Rosette Nebula I tested that night came out round!  I didn't keep them unfortunately to show, but this is very exciting.  It really opens up the door for more narrowband imaging in the future of a wider variety of targets if I can hit those kind of exposure times.  In addition, it's very promising for putting longer focal length scopes on it and still being able to get 3-5 minute images.  I have my 8-inch Schmidt-Cassegrain that's 2000mm long, compared to 530mm of my Takahashi (although I'll probably be running it with a focal reducer to drop it to 1260mm so that my off-axis guider can find a guide star, and I can take shorter exposures).  I also have my new-to-me Newtonian f/4 astrograph that's 800mm long from my astro-buddy Rikk, which I'm quite excited to use as well.  I'll probably put the C8 on in the springtime for galaxy season.

Another piece of excitement for the night came early in the evening with the Pacman Nebula.  I was watching exposures come in from indoors, and I saw that an airplane had gone through one of my images.  Upon closer inspection, I saw a really cool phenomenon that I hadn't yet caught in one of my own images!

As you've undoubtedly seen on airplanes, there's a strobe that flashes every second or so.  It must be a very fast strobe because it lit up the jet engines for a short enough time to "freeze" it in the frame!  Super super cool. :D  Fortunately, it should process out with pixel rejection and averaging in the stacking process.

Monday, October 21, 2019

#235 - Sunday, October 20, 2019

Another night of hydrogen-alpha imaging on my monochrome ZWO ASI1600MM Pro.  The subframes come out looking so nice!  Things were running smoothly as the evening began, and I monitored progress from inside on my desktop computer during the post-broadcast chat after the weekly The Astro Imaging Channel broadcast.

The Heart Nebula went behind my plum tree a little earlier than I expected, so I moved up the M31 start time, but the mount thought that it was outside my restrictive -5-degree slew limit.  I double-checked the RA limits because it should have been fine -- maybe it needs to be +5 degrees to say how far it's allowed past the meridian?  I changed the M31 start time to be about five degrees on the other side of the meridian to give me some padding, but then I needed another target to fill the gap.  I decided to try the California Nebula, which is much to big to fit even in my relatively wide field-of-view, but I've seen some images of it recently that are just of part of it, and they look really cool.

While slewing around, I think I might have heard the dec axis slipping a few times, which oftentimes the AVX is good at "catching up" and still maintaining its alignment.  But I slewed to Algol to check, and while it was in the frame, it wasn't quite centered.  Then the mount had trouble centering the California Nebula, and PlateSolve2 was doing a spiral search to figure out where it was pointed.  Gosh dangit, I needed to go to bed!  I didn't want to go outside, so I thought maybe I could do the alignment from inside using the NexStar hand controller GUI.  Unfortunately, it needed info I didn't have handy, like the version number of the motor control and hand control firmware.  So I wound up just going outside and doing the alignment.  (I could use the PWI software, but there are advantages to letting the mount save the alignment rather than my computer, and I haven't used it in a while).

I had the mount slew to the home position to see if the alignment was actually off, and sure enough, the index mark on the dec axis did not line back up.  So I power-cycled the mount and re-did the whole alignment.  The RA axis had some crazy backlash pointing far south!  I need to get inside the mount and check on things.  It might be the cause of my M42 bad-tracking problems.

Back inside, it was time for M31, so I watched it slew and center and start imaging, but the dec axis hung up again and went off the rails on PHD.  I nudged the mount in Sequence Generator Pro, and then re-centered M31, but that only worked for one frame in the end.  I finally went to bed at 12:30 AM.

When I went outside in the morning around 6:30 AM, the sky was gorgeous!  Lots of glittering stars, the Orion constellation nice and high in the southwest, and a half-moon floating near the meridian.  Before I covered the scope, I decided to grab a video of the moon.  The camera was still warming since the run had completed not long before I got up.  Between that and Orion's morning position, it means winter is coming!!

Date: 21 October 2019 (morning)
UTC: 21 October 2019 13:45
Location: East Bay area, CA
Object: Moon
Attempt: 32
Camera: ZWO ASI1600MM Pro
Telescope: Takahashi FSQ-106N
Accessories: Astornomik H-alpha 2-inch T2 filter
Mount: Celestron AVX
Frames: 1076/2003
FPS: 23 fps
Exposure:12 ms
ISO/Gain: 139
Stacking program: RegiStax 6
Processing program: PixInsight 1.8.7

Sunday, October 20, 2019

#234 - Saturday, October 19, 2019

I spent the day giving one last go with my Celestron CGE Pro.  Quick recap: I got that mount back in May 2017 and brought it to the Texas Star Party, where it performed beautifully.  It also did a great job at Green Bank Star Quest in July 2017, delivering 8-minute guided frames at least with my C11 mounted on top.  But then at the Hidden Hollow star party in October of that year, it had some really bad guiding.  I put an eyepiece on it and saw that the stars were jumping back and forth as I slewed in declination.  RA looked buttery smooth.  I didn't get to pull it out again until the following summer, and over the course of the next year I tried out various fixes in the couple times a year I actually set it up.  I meshed the worm drive gear and worm gear closer together, which did help fix some wobbling I felt in the dec axis (I could physically rock the axis back and forth a bit), but didn't help the star jumping.  Finally, I took the dec axis motor box totally apart, discovered two things.  One, with a multimeter, I saw that the voltage was oscillating around 11.5-12V, while the RA axis held a steady 12.5 or 13 or so.  Second, with the motor completely detached from the mount except for electrical cabling, I could feel the motor pulsing rapidly in my hand, like something was sticking or rubbing on the inside.  The same happened when I plugged it into the RA electronics, which ruled out a control board or supply voltage issue.

A couple months ago, I got a tip from one of my Astro Imaging Channel buddies to try a voltage step-up converter to supply the mount a little more voltage, like 13.5 or 14V.  But while I was preparing that setup today, I realized that my AC power connector, the one I usually use, was already delivering 13.5V.  So that wasn't the problem.  Something is definitely wrong with the motor.  I could get one of the few leftover at Celestron's warehouse, but it'll cost me $500.  And if you've followed the saga of my Celestron CGE-series mounts, you'll know I've already spent far too much money trying to get a functioning one!   So I'm going to try and sell that mount and my CGE to get some money to help fund an Astro-Physics mount.  I'm done messing around, I want a mount that works!!

Evening rolled around, and it was still partly cloudy out, but the forecast promised it would clear.  I re-did alignment and polar alignment in the meantime, and a star I had it slew to was quite close.  However, when I went to center a target in Sequence Generator Pro, it still wasn't getting closer to the target -- it was just staying the same distance away.  I had turned off the "sync" option the previous night in hopes that that was the cause of the mount not tracking well after a meridian flip or some target changes, since you have to un-do sync in the hand controller to sync on another target for Celestron.  There were two other options besides "none:" "scope offset," and "target offset." I tried scope offset, but it did the same thing.  Then I tried target offset, and it finally centered!  Woot!  I had a solution.

While I was busy making that change, the clouds suddenly evaporated, and the sky was totally clear.  Woo hoo!  Transparency wasn't great, however.  I just had to hope it would improve.  I started the sequence, and went back inside.

I checked back in on it around midnight before I went to sleep, which happened to be right when it was centering M31 Andromeda Galaxy, which I've been having trouble with.  The centering worked this time, woo hoo!  The first frame came in, and it looked fine, but during the second frame, I watched the PHD guide graph start to go off the rails in declination.  Even after I picked a new guidestar, which can sometimes fix that kind of drift, it was still running away.  So I went back into SGP and nudged the scope a little bit in dec, It was set at 0.5 degrees per second though, so it ended up being a bit of a jump.  But that fixed the runaway, woot!  SGP had some trouble re-starting the sequence, however, so I closed and re-opened the sequence, and it got off and rolling again.  I went to sleep.

Unfortunately, I had un-checked the "center target" boxes for several of the targets when it was having issues centering them, so my targets the rest of the night were not centered.  Rawr!  The Heart Nebula and M31 happened to center properly, but I deleted my data for NGC 2174 and the Rosette Nebula.

Both M42 and M31 had tracking issues after the meridian flip, and I saw log messages for SGP saying stuff about losing the guide star or being unable to settle the autoguider.  I did manage to get a couple of good frames on M31, but none of the M42 ones came out.

Hydrogen-alpha image of M31 -- the core glows bright at all wavelengths I guess!
If I zoom in, I can see some knots of star-forming regions toward the edges, which will hopefully come up in processing.

Saturday, October 19, 2019

#233 - Friday, October 18, 2019 - Refinements

Since the Heart Nebula went behind my plum tree sooner than I thought it would last night, I adjusted the sequence to end the Heart a little earlier, and then I have it jumping back to the Pacman Nebula until NGC 2174, the Monkey Head Nebula, is high enough to image.  Sometime soon I'll figure out how best to map my backyard's horizon, and then at someday I'll look into some scheduling software...with so many clear nights, I'm constantly adjusting the times in my sequence to keep up with the ever-sliding timing of targets!  Oh well, that's what seminars are good for, getting things done on my computer... :D

I noticed while watching the sequence last night from inside on my desktop that the initial gotos before centering were quite a ways off, so I re-added a few alignment and calibration stars.  I also un-ticked the "Sync" box in the Plate Solve tab of Sequence Generator Pro, since I wondered whether that was causing the issues with M42 and M31 not tracking after the meridian flip.  The mount only likes to be synced on one thing at a time, and I'm not sure if SGP handles that right for Celestron mounts.

I watched the Pacman Nebula center in SGP, and the RA offset was stuck at around 200 pixels and wouldn't improve!  So I re-added another alignment star, which helped get it closer, but it still wouldn't get lower than 65 pixels.  So finally I just turned off centering and let the sequence run.

On the second round of the Pacman Nebula, after the Heart went behind the tree but Pacman had emerged in the north, I saw in the SGP log the next morning that it failed to meridian flip, but I don't know why!  I decided I would re-align the scope from scratch (rather than re-adding alignment stars) the next night.

I still got some tree in the first Pacman Nebula sequence -- I really need a way to map out my yard!  It would make setting up the sequence much more precise rather than guessing.  Anyone know a good phone app or something?

The sequence ultimately aborted upon failing to meridian flip on the second Pacman sequence, so I didn't get any of the rest of my targets for the night -- NGC 2174, M31 Andromeda Galaxy, Rosette Nebula, or M42 Orion Nebula.

Sooner or later I will get this right!!

Friday, October 18, 2019

#232 - Thursday, October 17, 2019

Now that winter is creeping toward us (although it will be the mildest winter I've ever experienced now that I live in California!), the sky is getting darker earlier and earlier.  This is usually a cause for joy for astronomers, since it means we don't have to stay up as late and can get an earlier start, but since I have an evening class on Tuesdays and Thursdays, it means I get home well after dark on those days :(  And the second semester of that course is at the same time next semester!  Who wants to teach that late??

I got set up and then checked the alignment because the plate solves for the last few nights have been pretty far off in their first attempts.  The star I told it to slew to wasn't too far off from center, so I added it to the model (replacing another star) to firm it up a bit.

Another issue has been hitting the self-imposed slew limit while trying to image M31 and M42, which cross the meridian during their imaging windows.  The Celestron AVX mount is capable of tracking to 20 degrees past the meridian, but because my dec axis has a gap in it after I removed the plastic ring inside because it was partially the cause of that axis being extremely difficult to turn, now it has a tendency to slip down a bit, which caused the worm gear to separate from the axis gear and caused a lot of problems for me (including a pile of fine gear-grind dust!).  So I went to the Meridian setting in the hand controller and set it to Disabled so that it wouldn't try to stay on one side of the meridian or the other, but would just go to whatever side of the meridian the object was on.  The mount and SkySafari seem to slightly disagree on when exactly transits occur, even though they both use the J2000 epoch for their catalogs, which makes things a little complicated.

So hopefully that little fix will work to let the images of M42 and M31 happen.  We'll see!

Morning update: That still didn't help. :(

Wednesday, October 16, 2019

#231 - Tuesday, October 15, 2019 - Just Another Night

After a couple of cloudy nights (gasp!), I was back at the ol' routine of plugging in the tablet, pulling off the cover, waking up the mount, opening PHD and Sequence Generator Pro, and hitting Go...just another night of my camera collecting photons while I collected z's!

I copied the data over in the morning over breakfast as I always do, but saw that there were some problems still.  When it started on M31 Andromeda Galaxy, it needed to go over from east of the meridian to west (the issue I was having with the mount "jumping" around before on the western half of the sky has been fixed -- it would appear that my cable bundle was potentially pulling on the dec cable a little bit on that side, causing it to slightly unseat.  I adjusted the cable position, and when I remember, I'm going to tape down the dec cable).  However, it was clear that it was hitting my self-imposed slew limit of 5 degrees, since every image was just a long star streak.  I wondered if it wasn't actually flipping, but was trying to reach it from the east side?  I don't have a way to tell.  SGP doesn't store side-of-pier in the FITS header.

In addition, Takahashi refractors, for all of their glory and image perfection, are pretty unstable in holding focus with temperature changes, so I hear.  Well now I know -- my focus is always slightly out by the morning (and back to perfection the following evening).  Sometimes it doesn't go out too much, and sometimes it is too out-of-focus for me to keep the images.  Thus was the case for the Rosette Nebula images in the morning.  Oh well.  I also had some thin clouds roll through -- it's easy to tell using PixInsight's Blink process, since the images will appear a lot brighter than the rest (it sets the stretch settings based on the first image).

Keep on keepin' on!

Sunday, October 13, 2019

#230 - Friday, October 11, 2019

It was cloudy on Thursday night, but I'm back out on this lovely Friday night!  There is some smoke in the air from the fires that started during a particularly dry and windy couple of days that prompted PG&E to shut off power to hundreds of thousands of customers throughout the region.  Luckily, my house was not one of them (although I have everything I need to run my telescope off battery power!), but classes were cancelled at UC Berkeley (where I'm working on my PhD) on Wednesday, Thursday, and Friday due to having the power shut off.  The light pollution likely dropped a fair bit (although the majority of the downtown area of San Francisco was not shut off), but I couldn't tell because the moon was high and bright.  I've got my monochrome ZWO ASI1600MM Pro attached with a hydrogen alpha filter, and while the moon does reflect the sun's hydrogen-alpha-wavelength light, the filter is narrow enough that you can largely continue to image with narrowband filters during the bright moon phases.

I spent Friday afternoon working on quantum mechanics homework at a cafe near campus, and then late afternoon/early evening on a "hike" (really a steep road climb...but fun nonetheless!) with some of my classmates.  After the hike was a trip to the bar, of course.  I didn't get started imaging until about 10 PM.

I set everything up and let it roll (after adjusting the sequence earlier in the day), and I checked back in from my desktop using TeamViewer before I went to bed, and things were looking great!  The atmosphere and my mount were both cooperating to give me 1-arcsecond-RMS guiding, which was really exciting.

And it showed!

Zoom-in view of the heart of the Heart Nebula, 5-minute exposure, H-alpha filter

That is going to look awesome after I stack it.

Also before I went to bed, I drank some absolutely delicious loose-leaf Earl Gray tea steeped in a Mercury module-shaped infuser that my astro-buddy John M very kindly sent me.  I started processing all the images of M77 I've gotten over the last month as well.

After going to bed and reading for a bit, I checked in on the mount since I heard it slewing to the Andromeda Galaxy.  The plate solve process in Sequence Generator Pro was showing offsets of something like 8,000 pixels, so I figured that the mount was trying to go past the slew limit.  But why?  I had the slew limit set to 5 degrees past meridian, and M31 wasn't super close to crossing yet, and I had the meridian option on the hand controller set to "favor east."  Not wanting to get up and go outside, I just set the start time to 12:45 AM instead, after it had transitted, and slewed the mount to a star that it could sit on for a while until M31 was ready.  I did the re-slewing (and checking where the scope thought it was) using Cartes du Ciel, from my cell phone, using the TeamViewer remote desktop app.  So cool!!  All from the warmth of my bed :D

I had a dream that night that it rained, and the dec axis did the crazy-slew thing, and it defocused, and I couldn't get outside fast enough to protect it from the rain, and I forgot to put the Takahashi back on and still had the C8 on there from imaging the ISS so all of my larger targets were going to be too zoomed-in-on, all kinds of stuff!  But when I looked outside in the morning, everything was fine, of course.  It bumped into the slew limit again while imaging M42, which I also don't understand because it doesn't transit until 5:22 AM and I start imaging it at 5 AM.  I need to dig a little deeper into SGP settings to see if I can do something about which side of the meridian it chooses.  It seems to override the "favor east" setting on my mount.

Friday, October 11, 2019

#229 - Wednesday, October 9, 2019 - Luck of the ISS-ish

I was looking at the forecast in the Astropheric app on Monday, and saw a nice high ISS pass was coming up on Wednesday.  Imaging the International Space Station has been on my "astrophotography bucket list" ever since I saw it was possible with an 8-inch reflector.  I decided I'd give it a shot -- an experimental run this time, and a better one the next.

I opened up my trusty SkySafari app and got to work planning.  The ISS zips through space at 17,000 mph relative to the surface of the Earth, crossing the whole sky in just a few minutes.  Timing, and correct positioning of my scope, would be essential.  It would be a far easier task in something wide-field like my Takahashi, but since the ISS is quite small sitting up there 250 miles above the surface, I needed a scope with magnification and resolution.  My 8-inch Schmidt-Cassegrain was up to the challenge.  All 2 meters of its compacted focal length!  I turned on the FOV indicator in SkySafari for my ZWO ASI294MC Pro and the C8, and set about finding a good spot from which to image it.  The highest point of its pass would be the closest, which for this pass was 71 degrees altitude.  However, that would happen in the northeast, where there was a reasonable chance it would be behind my plum tree.  So I picked a more easterly position, which put it farther away, but had a better chance of success.  I decided on a star that it would pass near, and picked that position as where I'd have Sequence Generator Pro center.  Then, I would switch to SharpCap for the actual capture, since it captures way faster than SGP (and does video).

Mid-afternoon, when I needed a break from doing homework, I went outside to take off the Tak and attach the C8.  Thanks to the handy cable bundle I've made for it, all I had to do was detach the bundle in one place from the mount, and take off the whole thing.  I just left everything plugged in (although I did unplug my other ZWO camera from the USB hub so that my programs wouldn't get confused).

I got started with dinner late, and thus didn't get outside until 7:05 PM, when the pass was at 7:20.  I wanted to get out there at 6:50 to make sure the alignment offset between the two was not too bad, and get it focused.  I slewed to a star to see what the alignment looked like, but the camera USB cable I had routed through the cable hook on my mount didn't slide like it was supposed to and tugged on the dec axis instead, so it didn't make it to the star, and threw off the alignment.  I didn't realize that's what had happened at first though, so I just re-added stars to the alignment model, but then model was still not really working.  

Time was running short, so I decided just to have SGP plate-solve its way there.  However, when the PlateSolve2 module opened up, it had 0's in for the FOV, even though I had input the FOV earlier!  This turned out to be a result of not having put the parameters also into SGP's Control Panel for that sequence, I think.  So I quickly pulled up the note on my phone that had them, and had it try again.  It didn't crash this time, but it spiraled around for a while trying to find a match for the frame.  When the clock hit 7:20, I had to give up -- I only had 45 seconds left until it came into my rough FOV.  Time for plan B -- chase it!  

So I hurriedly disconnected, SGP, opened SharpCap, set the settings (I had decided on 1 ms exposure time and 139 gain after looking up a few examples in similar scopes), set the video time limit to 3 minutes, and hit Start Capture.  I turned on my red dot finder, and saw that the bright dot of the iSS was actually going to pass through about where my scope was actually pointed.  I watched it go through the red dot, and saw a flash on my computer screen -- I got it!!  Then I had a thought.  Why not keep chasing it?  So I grabbed the hand controller and, watching how it moved, anticipated where it would be next.  I put the red dot there, watched a few frames flash on the screen, and then moved on to the next spot.  I got it 5 or 6 times!!  

I opened up the AVI to see how it looked (I forgot to switch to SER format!).  I had a super-screen-stretch on the video feed in SharpCap so that I could see it easier, so I wasn't sure whether 1 ms would be actually bright enough.  But I decided to err on dimmer than brighter, since you can pull dimmer pixels up, but you can't push saturated pixels back down.  I jogged through the video slowly, and mostly it was all black.  But then I caught a brief flash -- there it was!!

I was so excited to see how it came out that I unplugged my USB hub just to copy the data off onto my hard drive (I couldn't find my larger flash drive, and the hub is unpowered and couldn't support both the hard drive and the power-hungry cameras at the same time).

While I had the C8 on, I decided to grab some moon and Saturn images as well.  Unfortunately, there was a lot of heat coming up off the cement pad that my scope is on, which showed up in the video as large, undulating shimmers instead of the small-scale shimmer more indicative of bad atmosphere.  The concrete pad is nice for physical stability, but bad for temperature and localized air distortion.

After that, I took the C8 off and put the Takahashi back on with my ZWO ASI1600MM Pro and hydrogen alpha filter.  I went ahead and just re-aligned the mount.  Since it was still well before 8 PM, I decided it was probably time to re-polar-align, since undoubtedly the tripod has shifted around from me moving around the scope, taking the cover on and off, and a small earthquake we had last week.  After I adjusted the polar alignment using Celestron's All-Star routine, I went to re-add the alignment stars to fix their positions, but the mount was way further off than it should have been.  So I rebooted it, but it was still largely under-slewing in RA.  I rebooted it a few more times, but it kept behaving the same way.  It also had some erroneous alignment star data -- it said Altair was still in the eastern sky, even though it was well past the meridian by this point.  I double-checked my location data, time, and date to make sure nothing got scrambled -- everything looked fine.  Finally, I tried just aligning anyway, and that seemed to work -- by the time I got through the five stars, it was doing a good job of landing them near the center.  Weird.

I paused to admire the stars, and noticed that Cassiopeia was high enough to clear my neighbor's garage already, and further to the right of my plum tree than I had thought.  Maybe I could catch M31, the Andromeda Galaxy?  I opened up SkySafari, and it looked like yes, it would be high enough as it neared the meridian to clear my plum tree after all!  So I added that to my target list (and took off M33, since I had over 130 hydrogen alpha frames, which would be plenty!).  I needed another target before M31 was high enough, however.  Since Cassiopeia was more visible than I thought in my partially cut-off sky, I wondered where the Heart Nebula was, which I have been dying to get a good image of.  (My last attempt came out pretty bad, and we had cloudy winters in the midwest).   Much to my delight, it was far enough east of my tree that I figured I could get it for a little while!  So I added that too.  But I still needed a target to fill a gap in the morning hours before the Rosette Nebula was high enough, so I went a-hunting for something good in H-alpha.  I checked my H-alpha observing list in SkySafari, and saw a nebula I had forgotten about -- NGC 2174, the Monkey Head Nebula.  It's way far up in Orion, practically in Gemini, and so would be high enough to image before the Rosette cleared my neighbor's garage.  It was magnitude 10, and rather large, but I figured I'd give it a shot, despite the large, bright moon.

The next morning, I looked at my new targets -- and was very excited!

5-minute H-alpha frame on the Heart Nebula

5-minute H-alpha frame on the Monkey Head Nebula (NGC 2174)

Cannot wait to stack these!!

ISS Images

I started the sequence and went inside to process my ISS images.  First, I brought the AVI video into VirtualDub and broke it up into single frames that would be a lot easier to scroll through and find all the frames that had captured it.  I found 69 frames total!  I put them into RegiStax, but it didn't like how dim the ISS was, and wouldn't let me pick alignment points.  They were quite dim, so I opened one of them up in PixInsight, stretched it, and then applied that process to all of them using ImageContainer.  Of course, these were all JPGs, but the histogram peak was sufficiently narrow that they sort of acted like raw files.  I saved them back out, and tried again with RegiStax.  It worked, but the image at the end was all black.  Probably it had a hard time detecting this small thing and didn't align the frames properly.  So I brought the frames back into PixInsight, and used its FFTRegistration script to give it a go.  It did a good job; however, I realized as I used the Blink tool to scroll through them that stacking them wasn't going to be an option because the ISS had a different size and rotation in every frame since my frame rate was kind of low.  So I took the first frame, where it was the largest and relatively sharp, and processed that by itself in PixInsight, reducing noise, adjusting the curves, and applying some sharpening via the MultiscaleLinearTransform process.  It came out pretty great!

Because I broke up the video in VirtualDub, all of the color information was lost, since it doesn't debayer.  So I looked for an app online that would debayer my videos (which may also solve my problems with processing raw color camera videos in RegiStax in general).  I found one that I came across once before but hadn't explored yet: PIPP (Planetary Image Pre-Processor).  It has a whole host of tools that are going to be very useful!  I passed the video through it and got debayered TIFF images out the other end, with timestamped filenames and everything.  

While I was going through the images, I saw that a different frame had a sharper, if slightly smaller, image of the ISS, so I went ahead and processed that one instead.  Stretch, curves, and then denoising and sharpening with MultiscaleLinearTransform (yes it is a versatile tool!).  Super exciting result!

Date: 9 October 2019
Location: East Bay area, CA
Object: ISS
Attempt: 1
Camera: ZWO ASI294MC Pro
Telescope: Celestron C8
Accessories: Astronomik L Type 2c 2" filter
Mount: Celestron AVX
Guide scope: N/A
Guide camera: N/A
Exposure time: 1 ms
Gain/ISO: 139
Acquisition method: SharpCap
Stacking program: N/A
Post-Processing program: Planetary Image Pre-Processor, PixInsight

I am extremely thrilled to have gotten such nice detail on my very first attempt!  I did not believe that it would go this well!  I'm excited for more.  I've got some satellite tracking software setup in the works, and I'll also eventually add a 2x Barlow for increased magnification.  I'm also going to try not Barlow-ing, and cropping the frame instead so that I can up the frame rate and get multiple frames with the ISS at about the same size and angle so that I can do some stacking.  I'll also try with my monochrome camera -- no color, but the resolution is a lot higher, due to the smaller pixel size and the fact that it's monochrome.

[ Update: October 22, 2019 ] 

I processed the Cocoon Nebula image last weekend, but haven't had a chance to write it up yet.  October 9th was the last night I took data on it, which is when I have decided to write up the processing for these multi-night extravaganzas.  

The Cocoon Nebula (IC 5146) is a combination reflection, emission, and dark nebula, all in one gorgeous package. It's located up high in the constellation Cygnus, the swan. Lying about 4,000 lightyears away, it spans 15 lightyears (or 12 arcminutes, for you observers out there - a little less than half the width of a full Moon for everyone else!). Besides the gorgeous color and detail, there is an enormous dark nebula that forms a thick line with the Cocoon Nebula, blotting out background stars. I didn't pick it up as much as I would have liked in this image, but that is hard to do from such light-polluted skies!

The emission part of the nebula is the pink/red area, which is caused by a characteristic red glow emitted from hydrogen gas energized by the young, hot stars in the nebula. The dim blue halo around it is the reflection nebula part, where gas is reflecting the blue starlight. The dark portions are molecular gas that absorbs light.

This image is a combination of RGB (color) images and monochrome hydrogen-alpha images taken with my monochrome camera and a special narrowband filter that cuts out all other wavelengths of light except for a narrow slice right around the deep red color of H-alpha emission (656.3 nm). The H-alpha helps to accentuate the red (which is the bulk of the nebula), as well as refine detail in the nebula, since the deep red light is less disturbed by the atmosphere than the wide-band color.

After five weeks of photon collection, both color and's the result!

Date: RGB: 1, 7, 8, 9, 19, 20, 22, 23, 24, 25, 28 September
  Ha: 30 September, 1, 2, 3, 9 October 2019
Location: East Bay area, CA
Object: IC 5146 Cocoon Nebula
Attempt: 3
Camera: RGB: ZWO ASI294MC Pro
    Ha: ZWO ASI1600MM Pro
Telescope: Takahashi FSQ-106N
Accessories: Starlight Xpress filter wheel, Astronomik CLS 2-inch filter (RGB), Astronomik H-alpha T-thread 12nm T2 filter (Ha)
Mount: Celestron AVX
Guide scope: Orion 50mm mini-guider
Guide camera: QHY5
Subframes: RGB:  141x180s (7h3m)
   Ha; 22x300s (1h50m)
   Total: 8h53m
Gain/ISO: RGB: 120
  Ha: 139
Acquisition method: SequenceGenerator Pro
Stacking program: PixInsight 1.8.7 
Post-Processing program: PixInsight 1.8.7
Darks: RGB: 40
   Ha: 20
Biases: RGB: 100
    Ha: 20
Flats: 0
Temperature: -15C (chip)

Whew!  My data files get longer and longer!  

So this image consists of nearly 9 hours total of color and H-alpha data, as you can see in the description.  It's so exciting to be able to get that much data on one target.  Now that I don't have to drive out somewhere, set up, stay up late, pack back up, drive back, and then haul all my crap up to my second-story apartment, I am more free to collect a lot of data since it requires little effort on my part (on a nightly basis, at least!  It's taken a lot of legwork to get to this point!)  

So processing this image was really interesting.  I haven't done a whole lot with adding H-alpha to color datasets before, so it was exciting to see what it would do.  To compare how big of a difference the H-alpha channel makes, I also processed a RGB-only image.  Here's that result:

So you can see a bit more of the blue reflection nebula halo around this one, but the contrast, detail, and saturation in the main part of the nebula is far less than the H-alpha version.  Fascinating!  What a difference.

Here's the whole process:
- Calibrated lights with master dark and bias
- Unticked "optimize" for darks (in RGB data) to prevent amp glow from showing up
- Added weights and rejected frames in SubframeSelector
- Debayered RGB frames
- Registered with StarAlignment
- Cropped with DynamicCrop
- Stacked with ImageIntegration
- AutomaticBackgroundExtraction
- Denoised with MultiscaleLinearTransform, with lum mask
- Corrected color with PhotometricColorCalibration (RGB)
- Attempted Deconvolution, but it didn't do much (most of the stars have very little eccentricity!)
- Combined Ha and RGB channels with Light Vortex Astronomy method
- Stretched with HistogtamTransformation (liked the result better than MaskedStretch)
- Increased contrast with HDRMultiscaleTransform, 9 iterations
- Reduced stars with Light Vortex method
- Tweaked a bit more with CurvesTransformation
- DarkStructureEnhance script
- Cropped with DynamicCrop

I've been largely using DynamicBackgroundExtraction after giving AutomaticBackgroundExtraction a try once and not liking it, but Warren Keller's book Inside PixInsight gives some suggestions on the settings, and after some tweaking, I found that the result was at least as good as DBE, but with waaaay less work on my part.  So I've added that process icon to my workspace for quick access.  It's getting pretty crowded!

Side note -- is anybody else having issues with PixInsight after the 1.8.7 update?  Mine sometimes crashes processes randomly, or they'll just disappear, or a few times the entire program has crashed.  Was very stable before that update.  A patch update just came out the other day -- hopefully that fixes the bugs.

Thursday, October 10, 2019

#228 - Monday, October 7, 2019 - Focus Pocus

Who needs city light pollution when you have the moon??  Pesky thing is slowing my astrophotography efforts!  It wasn't going to set until 1:15 AM, so I took my time getting outside and set up.

Well, since it was up, I went ahead and imaged it...

Date: 7 October 2019
UTC: 8 October 2019, 05:44
Location: East Bay area, CA
Object: Moon
Attempt: 28
Camera: ZWO ASI1600MM Pro
Telescope: Takahashi FSQ-106N
Accessories: Astronomik H-alpha T2 filter
Mount: Celestron AVX
Frames: 1430/2010
FPS: 5 fps
Exposure:10 ms
ISO/Gain: 139
Stacking program: RegiStax 6

All right, I suppose it is kind of pretty...

I updated the imaging sequence to not start until 12:30 AM.  As I was getting gear connected, I noticed that the guide camera could see some stars from the home position.  I wondered if it might be enough to do a "real" polar alignment with SharpCap instead of Celestron's All-Star Polar Alignment, which I'm not completely sold on.  (I put "real" in quotes because I'm still not 100% sure about SharpCap's either).  I rotated the RA axis 90 degrees, which I would need to do for part of the procedure, and I saw fewer, but still a couple of stars (different angle through my plum tree, looking at the same patch of sky).  I popped over to SharpCap to see what the main imaging camera could see.  Unfortunately, it wasn't enough stars so do polar alignment, at least not through the H-alpha filter (which I didn't feel like taking off and re-focusing).  Darn!  Maybe in the winter when the leaves are gone.  If the leaves fall here.  Do they fall here??

Once everything was ready to roll, I headed off to bed.  In the morning, I pulled down the frames, and to my dismay, the focus drifted enough with temperature that they were all bad!  Into the recycle bin they go.  I've emailed Technical Innovations about the Robofocus not working, but they haven't gotten back to me yet.  Hopefully they will soon...I'd love to fix one rather than have to buy one!

#227 - Sunday, October 6, 2019 - Outreach Again!

Between my trip to Chile and my move to California, I haven't had a lot of time for outreach.  I finally go to do a little at Sunday night's Members-Only Viewing Night of the Eastbay Astronomical Society.  The EAS is based out of the Chabot Science Center, and they have some pretty incredible telescopes on a really nice deck above the main building.  One of them is a 20" Warner & Swasey refractor, through which I got to enjoy some gorgeous views that evening.

In a dome to the left of the 20-inch, named "Rachel," is "Leah," an historic 8-inch Clark refractor made in 1883.  

In a roll-off shed to the right of Rachel is "Nellie," a glorious 36" Schmidt-Cassegrain (I think) reflector that is used for NEO (near-Earth object) research.  

With a good ol' Telrad on top. :D

I brought along my humble 8-inch Schmidt-Cassegrain scope on its Celestron NexStar SE mount and got it set up on the patio.  There were a few families present for telescope viewing that night, and I showed off the moon and Saturn to them, which is always a delight, for both the kids and the adults!  Seeing those craters up close is a totally different experience.  And actually seeing Saturn's rings is a surprise to many people!  Despite lots of thin passing clouds, the atmospheric seeing conditions were astounding that night.  Like rock-solid steady.  It was amazing!  I did bring my ZWO color camera and grabbed some video in between the clouds, but I haven't processed it yet (RegiStax has been having trouble with my color videos anyway -- may need to give AutoStakkert a try).  

Through the 20-inch refractor, I had the pleasure of enjoying a few targets that evening.  First was M57, the Ring Nebula, which despite the moon, had great contrast against the background!  I couldn't resolve the central star, but it was gorgeous to look at nonetheless.  Next, I got to see dazzling globular cluster M15, which through a 20" aperture boasted hundreds of individually-resolvable stars that glittered in the sky.  Finally, we went over to a type of star that I have not really observed much of before: a carbon star, in particular, T Lyrae.  Carbon stars are interesting because they're in the asymptotic giant branch (near the end of red giant stars' lives), and they've largely run out of hydrogen to fuse and are instead fusing helium through the triple-alpha process, which produces carbon.  Oftentimes, these stars have hydrogen-burning shells, but every 10,000-100,000 years or so, they will develop a helium-burning shell instead, which causes hydrogen fusion to stop for a period of time.  This causes material from the core to rise up (including lots of carbon), and the star's luminosity increases.  The rising-up of carbon makes the star expand, which makes it cool enough that helium can no longer fuse, and hydrogen fusion restarts.  These are known as helium flashes.  After many of these, enough mass has been lost that the former red giant becomes a white dwarf inside a planetary nebula.  The carbon that rises up to the upper part of the star gives these stars a strikingly red appearance.  It was really neat to see in the eyepiece!

The EAS & Chabot volunteers closed up the domes around 9:45 as the clouds grew thicker.  It was a fun evening, and I was sad to go!  Of course, I did need to get to bed for my 9 AM class on Monday morning.