Monday, May 20, 2019

#187 - Friday, May 3, 2019 - Baggin' Targets: Texas Star Party Night #6

Thursday night was cloudy, so I'll talk about Thursday in Friday's entry.

I slept in till 12:15 PM on Thursday, and was glad that the forecast for Thursday night called for clouds.  I needed a break!  Luckily, Friday's forecast was strong.  I slept so hard that I didn't wake up at all for all the sound of my aunt and uncle packing up and leaving.  I missed lunch and just had some oatmeal instead (I brought an electric kettle down with me), and then I set up some timelapses around the ranch during the day so I could build another Texas Star Party timelapse video.

A curious onlooker.

I used my Vixen Polarie laid on its side to do some panning.  I got a lot of questions about it as I roved around the ranch moving from spot to spot!

That afternoon, we took a trip to Alpine to see what was there.  We found a bookshop and wandered around for a while, and it was attached to a coffee shop, where I got myself a much-needed chai latte.  

My parents perusing the books

They had some beautiful sketchbooks, and I was trying to think of someone to buy one for.  One of my friends, Stephanie, was getting married soon, so I thought it would make a great gift!  One of the employees even wrapped it for me and tied a big beautiful bow.

After stopping at another coffee shop because my dad decided later that he wanted coffee, we drove back to the ranch in time for dinner.  After dinner Thursday night was a talk by Amanda Bayless of the Southwest Research Institute called "Black Holes Don't Suck" about the recent image of the black hole in M87 and gravitation waves.  It was a great talk, and well-attended, with a great number of questions.  Amateur astronomers fall into the category of having just enough science knowledge to be dangerous at a scientific Q&A, haha.  After dinner, we sat outside under the clouds for a while enjoying the ambiance, and there were quite a few holes in the clouds, which were not very thick.  We checked off the last item on my family's "Rising Star" observing pin list, which was Mars.  It was on its way to the horizon, and we first found it naked eye, and then I pointed my 8-inch SCT that direction.  We're quite far from it ortbitally-speaking at the moment, so it was very small in the eyepiece.

On Friday, we stopped by the pin-giver of the Texas Star Party, John Waggoner, to receive our observing pins.  I got my Smoke & Mirrors pin, and my parents got their Rising Star pins, their first!

That night after dinner, we attended the talk by Babak Tafreshi, "The World at Night."  He does nightscape photography all over the world, and he made me want to buy a fast lens and try and get better at it!  His images were breahtaking.  Following his talk was the Great Texas Giveaway #1, but my name was not pulled.  My mom's was though, and she won the first two volumes of "The Night Sky Observer's Guide" by George Kepple and Glenn Sanner, an exhaustive work covering the northern sky year-round and all sorts of deep sky objects, where to find them, what they are, and how to observe them in different-sized telescopes.  My mom handed them off to me, and I'm planning on going through them to find not-oft-imaged targets!

Later in the evening, I received a very nice note from a follower of my Facebook page:

"Hi, my six year-old daugher, Mackenna, and I love looking at your pictures.  She thinks it's neat that you're a girl and you get to do pretty awesome things (this is how we justified letting a six year-old watch the PG-13 rated Captain Marvel!).  As a father, thank you for being an example to my young daughters that math and science are cool."

I had a big ol' cheesy grin on my face as I read it!  I try to get out in the community as often as I can to be an example of a female scientist for everybody out there.  There's a phrase, "You cannot be what you cannot see," and it's so true -- it's hard to imagine ourselves doing something if we haven't seen someone else "like us" do it before.  The idea that you can do something can be planted in your head by seeing someone who is "like you" doing it, especially at a young age, but even when we're older.  Both for the boys and the girls -- young girls can see that they could be a scientist too, and boys can see that it's not weird.  So hello Mackenna in McKinney, TX!  Science is exciting and awesome, and there are so many different ways to get involved in it, like astrophotography!  For me, I do science both professionally as a physicist, and for fun as an astrophotographer.

With another clear night ahead, I dashed down to the observing field after the talk and drawing and after changing into some warm clothes quickly in the bunkhouse.  Within 15 minutes of arrival on the lower field, the Takahashi FSQ-106N with my uncle's SBIG STF-8300M on my Celestron AVX was up and running, and I was imaging by 10 PM.  I slewed to and centered on M81 and M82 using Sequence Generator Pro.  The first hydrogen alpha image I took looked out-of-focus though, so I slewed to Capella to re-focus, only it wasn't in the field of view!  So I slewed home, and the index markings on the mount weren't quite lined up.  So I shut down the mount and re-aligned.  It worked just fine after that.  I focused the H-alpha filter, and then slewed to a southish star to re-calibrate PHD2's autoguiding (calibration works better far from the pole).  However, on its way around, the power cable for the SBIG camera got caught and pulled.  The cable I had in that bundle was the one for fellow astronomy club member Phil's SBIG camera that I was originally going to use, so I grabbed the power cable for my Uncle Chris' SBIG that I was actually using and plugged that one in.  It wasn't part of my bundle, so I had to take care with it as I slewed around.  It worked, but I had to re-align again because of the pulling on the mount.  Finally, I started imaging on M81 and M82, but it was already 11:30 PM somehow!!  

I set up the sequence to take L and H-alpha frames, with the H-alpha ones first.  I checked the subframes, but didn't see any of the red jets.

Since my uncle wasn't sure what order the narrowband filters were in inside the SBIG camera's integrated filter wheel, and since the OIII filter on the M16 data from Wednesday night was so bright, I tried the OIII filter, but didn't see much more -- at least, not in AvisFV, the simple FITS viewer I use.  Looking at it later though, I did indeed see the jets a little bit in PixInsight...

Well crap!  I took a bunch of what I thought were H-alpha frames, but they were either actually OIII or SII.  Later on, I actually looked at the filters, and figured out that the order they're in is OIII, Ha, and SII in the filter wheel, as opposed to Ha, OIII, SII like I thought.

Over on the Borg, I tried swapping out the short 2-inch connector with a longer one I have hoping to get a better connection with the Hotech field flattener so that it would stay flat with the focal plane, but unfortunately, it's too long and I couldn't reach focus.  So I put the shorter one back on.  It was cold enough that I didn't have too much trouble removing the nosepiece of the field flattener from the connectors.  My dad came over to help, and we rigged up a way to hold it up.

I took the picture the next day, but basically we took one of my short bungee cables and looped it behind my filter wheel (it's held down by two thumbscrews on the back) and then connected the hooks to the bolt on the top clamp.  It did a good job of holding it up, although it turned out to still not quite be flat, I don't think.  My stars at least didn't have little seagulls, but they were definitely more skewed on one side of the image than the other.

Since it was after midnight, I decided to go ahead and grab some images on Centaurus A, which I didn't get to image last year.  It's an irregular galaxy far enough south that I can't see it from my home location.  It comes up just 15 degrees or so in that part of Texas, so the guiding was all over the place due to thick atmosphere.  But there it was in my 3-minute subframes!

Centaurus A, ZWO ASI1600MM Pro, Borg 76ED, Luminance channel, 180s, gain 139

Once these were all rolling, I decided to take some long-exposure selfies with the fast lens, as well as pictures of my parents.  My dad, with his new knowledge of how to use my 8-inch SCT on its Celestron NexStar SE mount, was off to the races on completing the "Smoke and Mirrors" Texas Star Party 2019 observing list.  He would find the object (I need to make some adjustments to the mount since the backlash has gotten really bad; he did have to hunt around a bit), and then my mom and aunt would come check, and they would check it off.  They finished the required 26 objects of 45 that very night!  It took me a bit to find focus in the fast 35mm lens I was using, but I eventually did and got some cool shots.

My parents doing some visual observing.

Me with the Takahashi on my Celestron AVX mount, and Jupiter and the Milky Way behind

My minion Miqaela with her Celestron AVX and a borrowed Stellarvue

Me and my two TSP imaging rigs.  The fuzzy orangish blob up and to the right of me is indeed the massive globular cluster Omega Centauri.

Once Centaurus A got too low, I switched the Borg over to M8, the Lagoon Nebula, but the guiding looked terrible and the stars weren't quite round.

Single 3-minute subframe of M8; Borg 76ED apo refractor with ZWO ASI1600MM Pro and Hotech field flattener

Zoomed in

I couldn't think of much else to do for it, so I just let it run.  If you zoom out, it's not so bad...

Over on the Takahashi, I moved it to the Elephant Trunk Nebula to give that another try, but the guiding was going crazy, making huge swoops up and down.  

So I stopped everything and decided to check the balance on the mount.  It was a little off in declination, but I need a longer dovetail bar.  I hung a dec balance weight in the front, but it wasn't quite enough -- I moved it forward a bit and moved the counterweight down on it (at least as far as it wouldn't hit the mount), and got close at least.  Then I re-aligned, polar aligned with Celestron's All-Star Polar Alignment (super easy with a red dot finder), re-aligned, focused, and calibrated guiding.  Plate solving didn't seem to want to work in Sequence Generator Pro this time around though, so I just compared the brighter stars in the image to the map on SkySafari and hopefully got it lined up by hand.  The guiding looked much better now, only 1.5 arcsecs RMS of error.  It was pretty noisy though.

I took a test frame with the OIII filter (which I thought was Ha at the time), and I couldn't quite see it in AvisFV, but the stars looked right, so I uploaded it to to plate solve.  It had a nicer-looking stretch than AvisFV's, and sure enough, I could just see it!  

By the power of stacking, it will be revealed!  Hopefully.

It's a lot easier to see in the actual Ha channel.

Oooooooh, aaaaaahhhhh

Since I only had a few hours left in the night and this would be the last night I could image on it, I decided to rotate through each filter instead of taking all of the shots for one, then rotating to the next.  Easy with an electronic filter wheel and SGP!  Then I could have at least some of each of the three narrowband filters, whatever I could get out of the rest of the night.  I wound up with 6 OIII's, 5 Ha's, and 6 SII's, 10 minutes each.  Not a bad haul!

I also set up a timelapse the second half of the night to get another round of the Milky Way rising since I needed more nighttime scenes for my TSP 2019 timelapse.

It was another all-nighter!  I got to bed at 6:45 AM!  And slept till 11:15 AM!  Only a couple of hours, but I also needed to eat.  A pretty good final night!

[ Update June 9, 2019 ] 

Centaurus A (but no B)

I went to process the Centaurus A image on May 26th, but alas, all of my blue filter images had a tree in them :/ I may be able to extract the blue from the luminance channel by subtracting the red and the green in some way, but a rough attempt didn't really work.  I will investigate it.  In the meantime, here's the luminance channel.

Date: 3 May 2019
Location: Texas Star Party, Fort Davis, TX
Object: Centaurus A (NGC 5128)
Attempt: 1
Camera: ZWO ASI1600MM Pro
Telescope: Borg 76ED
Accessories: Hotech field flattener, Starlight Xpress 5-position 2-inch filter wheel, 
Astronomik Type 2c LRGB 2-inch filters
Mount: Celestron AVX (borrowed)
Guide scope: Orion 50mm mini guide scope
Guide camera: QHY5L-II
Subframes: L: 17x180s
   Total: 1h37m
Gain/ISO: 139
Stacking program: PixInsight 1.8.6
Post-Processing program: PixInsight 1.8.6
Darks: 20
Biases: 20
Flats: 0
Temperature: -20C (chip)

It came out relatively sharp for being so low in the sky -- from the Texas Star Party, it only gets as high as about 14 degrees, which is well inside the thick part of the atmosphere.

Centaurus A is a rather unusual galaxy.  At only somewhere between 10-16 million lightyears (we're not sure which), it's the nearest strong radio-emitting active galactic nucleus to us.  Active galactic nuclei (AGN for short) are dense regions in the center of some galaxies that are far brighter than normal over some part of the electromagnetic spectrum.  They are particularly interesting because the characteristics of that light indicate that it's not actually from stars, but may instead be from the accretion disk of a supermassive black hole.  The most powerful AGNs are known as quasars, and we can see their light from sometimes billions of lightyears away.

M81 & M82

It came out great!  I wrote it up in the May 1, 2019 post here.

Elephant Trunk Nebula

This was another experiment in narrowband on the Takahashi, and though a little dim, came out quite nicely.

Date: 3 May 2019
Location: Texas Star Party, Fort Davis, TX
Object: IC 1396 Elephant Trunk Nebula
Attempt: 3
Camera: SBIG STF-8300M (Uncle Chris')
Telescope: Takahashi FSQ-106N
Accessories: SBIG filter wheel, Baader 8nm narrowband 36mm filters
Mount: Celestron AVX
Guide scope: Orion 50mm mini-guide scope
Guide camera: QHY5
Subframes: Ha: 5x600s
   OIII: 5x600s
   SII: 6x600s
   Total: 2h40m
Gain/ISO: N/A
Stacking program: 
Post-Processing program: 
Darks: 20
Biases: 20
Flats: 0
Temperature: -20C (chip)

When I combined the channels for this one, it looked a little off -- and then I realized that the trunk was blue and the background orange, unlike the rest of the Hubble palette images I saw on AstroBin.  So I still had two of the filters mixed up!  It turns out they're in order of SII, Ha, and OIII (which, conveniently for remembering, is the red-green-blue order of the Hubble palette).  So I swapped the SII and OIII filters, and then it looked right!

Elephant Trunk nebula in the middle of processing when I realized I had two channels swapped.

Here's my process.
- Master dark & bias previously generated
- Calibrated lights with master dark and superbias
- Applied weights with SubframeSelector
- Scale: 2.02 arcsec/px
- Gain: 0.37 e/ADU, 16-bit
- Noted highest-scoring frame
- Registered frames with StarAlignment, with highest-scoring frame as reference
- Stacked frames with ImageIntegration, Wisorized sigma clipping for rejection method
- Cropped with DynamicCrop
- Skipped DynamicBackgroundExtraction because it's like all nebula
- Denoised with MultiscaleLinearTransform, with extracted luminance mask
- Stretched with MaskedStretch
- Ha: 0.075 target background, rest default
- OIII: 0.15 target background, rest default
- SII: 0.2 target background, rest default
- Adjusted curves on each channel to improve contrast with CurvesTransformation
- Combined with ChannelCombination in Hubble palette SHO
- Did SCNR to kill green
- Adjusted color with curves
- Realized I had two filters switched (SII and OIII) in right order!
- Applied HDRMultiscaleTransform, with range mask
- Adjusted curves with CurvesTransformation
- Saturation
- Reduced red background (tried using range selection inverted for this)
- Denoised with MultiscaleLinearTransform, with extracted luminance mask
- Reduced magenta stars tone
- Created mask with ColorMask script
- Dilated stars with MorphologicalTransform (MorphologicalSelection, 0.90, 5x5)
- Desaturated magenta with ColorSaturation
- Ran DarkStructureEnhance script
- Rotated 90 degrees couterclockwise with Rotation process

I'll likely mess with some more color schemes for this one too!  Pretty pleased with the result.

No comments:

Post a Comment