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!
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.
The day finally arrived -- the solar eclipse over South America! After a year of planning, the day was finally upon us. I had packed my backpack and backpack camera case for my Sky-Watcher mount the night before, and I woke up at 5 AM to catch our 6:30 AM bus from a nearby hotel. We decided to book our eclipse day with Ecoturismo, with whom we had a daytime boat tour of the islands off the coast of Chile a few days prior for spotting the Humboldt penguin, among other creatures.
We made a few stops along the way to the village of La Higuera, about 50 km north of La Serena, including a gas station that was packed with people also travelling for the eclipse. But I successfully got my coffee, and everyone hit the bathroom and got some snacks, and we were on our way.
A large area had been set up just outside of the small village of La Higuera. Many people just pulled their cars off the dirt road and set up chairs and BBQs.
Ecoturismo had a couple of tents set up with a bunch of chairs and a large BBQ for feeding us all day.
A mobile cell tower had been erected as well, although bandwidth was limited because there were so many people there. Away from the area where most of us were was a series of white tents where several celebrities were said to be watching the eclipse.
I took my time getting my gear set up after we selected a spot so I could make sure I had everything right. It was only about 9:30 AM or something around there, and the partial eclipse didn't start until 3:22 PM. I attached my Nikon D5300 equipped with my Nikon 70-300mm lens at 300mm to my Sky-Watcher Star Adventurer DSLR tracker mount. To polar align it (roughly) in the daytime, I used my phone's compass and the tilt angle indicator of my phone using an app called GPS Status that I use all the time for astronomy. I weighted down my tripod with an open sack thing I found on Amazon that velcros to tripod legs, and I filled it with some rocks that were lying around. Then I plugged the mount into a cell phone battery and plugged my camera's USB into my tablet. I had logged into BackyardNikon the night before and left it open, and I tested the capture speed (sometimes it will trigger pictures every 3.5 seconds instead of 2.5 seconds, depending on whether it thinks it's a USB connection or serial cable). I put my Baader solar filter on the end of the camera lens -- it's a homemade one that was given to me with the Borg 76ED that I got from a fellow astronomy club member, and it was a little too big for my camera lens, so I lined it with bubble wrap before I left for Chile. I aimed the camera at the sun and focused it, and then taped down the focuser. Then I was all ready to go.
Then it was a long wait! I walked around and took pictures, browsed Facebook, sat back and enjoyed the sunshine, and chatted with numerous passers-by who were curious and amazed with my rig. Most of the other people in attendance didn't bring any cameras; they were just there to observe.
Showing our tour guide Felipe the partially-eclipse sun through out solar binoculars. It took some effort to convince people these were safe because of their special built-in filters, which means that they were well-educated on the risks!
Beside where my group was hanging out was a Chilean family, and a pre-teen boy was trying to figure out a way to capture the partial phases with his Canon DSLR after seeing the sun through our sun-oculars. He cut up a pair of solar glasses and taped it to the aperture, but it wasn't big enough to cover the whole thing. I helped him out (with my terrible Spanish), and we found some other cardboard pieces and tape to block the rest of the aperture. Then I helped him with the settings, and showed him how to chase the sun as it moved across the sky. He was very grateful and excited! I told him he could remove the filter during totality.
I checked my rig periodically and adjusted the camera as needed to keep the sun centered (my polar alignment wasn't perfect, obviously). I did accidentally kick the tripod at one point, but it wasn't too hard to get it back where it needed to be. Finally, we had first contact, and it was only a minute or so after that that we could see the moon just edging over the sun through our sun-oculars. It was a few more minutes before you could see it without magnification through the solar glasses.
I went over to my tablet about a minute or so before the partial phase started and hit "go" on my partial phase script. This took a few different settings of images every 5 minutes on repeat.
As the moon covered more and more of the sun, the quality of the light started to degrade, and I started looking for the pinhole effect, where light shining through a hole would have the crescent shape instead of a fully-lit circle. I was looking around for something with small-ish holes, since that's easier to see than criss-crossing your fingers, and I found it -- the chair on my traveling companion Chris' cane had holes in it that were perfect! So I tilted the chair toward the sun, and sure enough, you could see half-moon-shaped shadows of the holes on the ground. I looked up a couple words in Spanish to explain this to the people around me, and then went and showed a bunch of people the effect. My friends called me the science ambassador!
At long last, totality drew near, and I went over to my laptop to prepare the script for totality, which I would start at one minute till. I called out times in English and Spanish for the people around me, started the script, and took off the solar filter at 20 seconds. I didn't need to call out the last 10 seconds because I great shout went up, and nobody could hear me anyway. I watched the moon blot out the entire sun, and it was an utterly eerie and incredible sight. The sky darkened suddenly, and the corona slowly brightened into view. People were shouting and cheering, and I took a video on my other DSLR at the beginning of totality to capture the moment.
My traveling companion Manning shoved a pair of binoculars into my hands saying he could see prominences, but I didn't see them. I did admire the corona in the binoculars, something I missed during the 2017 solar eclipse in Wyoming. Then I took some wide images of the eclipse with my other DSLR, and I looked around to see the 360 degree sunset. It was mostly cut off for us by the mountains, but I could see it all along the west, where they were lower. I also looked around for stars and planets, and saw quite a few! Venus was shining very brightly below the sun, and I looked for Jupiter in the east, but I think it was too low behind the mountains. I thought I saw Mars and Mercury, but I wasn't 100% sure it was them. I saw several stars, including Sirius, possibly Rigel, Procyon, Canopus, Alpha Centauri, and Arcturus I think.
Nikon D3100, 18mm, f/3.5, 1/50s, ISO-400
Because the sun was lower in the sky, it looked larger (much more so than the above image indicates), but the corona didn't appear to be as large as the one in 2017. There were also no sunspots earlier, and there has been very little solar activity lately.
Seeing the sun as a black hole surrounded by a shimmering halo is totally eerie. Your brain doesn't quite know what to make of it. It was beautiful, natural and alien at the same time.
Then, just like that, my phone solar eclipse app ("Solar Eclipse Timer" on Android at least) was announcing "glasses on!", and I watched the sun re-emerge, which was spectacular. Then I put the filter back on my camera, and kind of stood there for a bit, unsure of what exactly to do. It went by so fast, it felt like less than 10 seconds! Finally I went to check on my images, and the last couple with the thin sliver through the solar filter looked a little out of focus. My heart sank. Were they all out of focus?? I scrolled through and checked -- they were, by just a hair. I had taped down the focuser, but the zoom had slid back at some point, which put it a little out of focus. However, I held out hope that they would still look good on a larger screen, as long as you didn't zoom in. I got some cool shots!
Just before second contact
Nikon D5300, 300mm, f/5.6, ISO-200, 1/2500s
Inner corona
Nikon D5300, 300mm, f/5.6, ISO-200, 1/400s
Outer corona
Nikon D5300, 300mm, f/5.6, ISO-200, 1/8s
Diamond ring at third contact
Nikon D5300, 300mm, f/5.6, ISO-200, 1/800s
I didn't have the diffraction spikes in the 2017 images because I used a circular telescope aperture instead of the straight lines of the iris inside of a camera lens, but I think it's a cool effect.
I re-started the partial eclipse phase script, and we hung around as the moon moved away from the sun's disk. We didn't get to see the sun completely re-emerge, however, since they sank behind the hills together, heading toward sunset.
Nikon D5300, 300mm, f/5.6, ISO-200, 1/2500s
Sunset was also a gorgeous moment to witness.
Finally, it was time to pack up and head back to La Serena. Well, us, and 250,000 other people as it turned out! It wound up taking us 4.5 hours to go the 50 km, and that was with our intrepid tour guide taking some American-style "shortcuts" around the other cars! We finally got back to the hotel at 10 PM, and I stayed up for a little while longer to post a few images (after installing Lightroom so I could apply the watermarks).
It was a very long but incredible day! It was an awesome experience sharing this solar eclipse with a few of my friends, strangers interested in astronomy, and many others who just wanted to witness this incredible spectacle.
Does viewing two total solar eclipses in a row make me an eclipse chaser? :D
[ Update: July 7, 2019 ]
While I was waiting for the moon to set to go out and do some observing from the Atacama Lodge the second half of my trip to Chile, I processed some of my corona images together into a single composite image. Cameras don't have as high of dynamic range as our eyes -- our eyes can see many levels of brightness at the same time, but the camera sees far fewer. As you can see in my images above, shorter exposure times make the dimmer outer corona dark, while longer exposure times make the brighter inner corona too bright to see any detail. There are many ways to process images to reveal multiple levels of brightness, such as people who make neat moon composites, the Milky Way behind brightly-lit foreground scenes (although this can sometimes also be done in a single shot with clever lighting), etc. The method I used here is the same as the one I used for the 2017 eclipse, known as the Pellett method, described here by astrophotographer Jerry Lodriguss, and in more detail in the blog post made it about here.
I won't put all the details here, since they are all in my blog post tutorial. But here's the rundown.
First, I selected several images with different exposure times, ranging from 1/4000s to 1s, which turned out to be 10 for me. Then, I radially blurred each one, and saved out those files as TIFFs.
Original (1/8s)
Blurred
Next, I subtracted the two images from each other with an offset of 128 to get a low-contrast difference image between the two that pretty much just contains the streamers themselves.
Difference image
Then, I added all of the difference images together.
Difference images added together
Here, you can see the streamers, some prominences, and the edges of the sun, since the input images weren't all taken at the same time, so the moon had translated across the sun's surface a bit. Next, I multiplied this image by the longest-exposure input frame.
Since the edges of the moon are messy and it didn't really stick around during the subtractions anyway, I copied the moon from one of the longer input images and enlarged it a bit to cover up the movement. Finally, I toyed with the exposure, contrast, saturation, and denoising settings, and covered up a few dust spots using clone stamp, and have this final product!
So awesome! You can see lots of detail in the corona, and even one of the little prominences. It's a little hazy because it was quite low in the sky, only 13 degrees above the horizon, which made it a bit hazy. One thing that is really interesting about the corona this time is how symmetric it is. This is likely due to the solar minimum we've been in for a while, which also means we haven't seen much in the way of sunspots for about the past year. So here's hoping that the 2024 eclipse across the US has even more excitement!
One last note I'll make here for anyone who's wondering - my images are rotated about 45 degrees from the sun's true orientation as observed visually from the same spot.
Science
Another really great thing about this eclipse in particular is that it crossed over so several professional observatories that exist in that area of Chile, including Cerro Tololo and La Silla, and a lot of research observations were taken at those locations. Much is still unknown about the sun's corona, which is essentially the sun's outer atmosphere that extends billions of miles into space, encompassing the whole solar system. It consists of charged particles of gas, and that gas has been superheated by some as-yet-unknown process to over one million degrees (that high, Kevlin, Fahrenheit, and Celcius are really all about the same), which is much hotter than the surface of the sun, which is about 5500 degrees C (10,000 F). Even though it is so much hotter, it's dimmer because it's very tenuous and spread out.
In addition to understanding the corona itself, the corona can tell us a lot about what happens on the sun's surface, as well as deeper inside, and can help us make future predictions for potentially electrical-grid-disrupting solar events. In 1859, a massive solar storm known as the Carrington event disrupted telegraph communications, caused lines to spark and short, and even activated telegraph equipment that was disconnected from power. Just imagine what something like that would do to today's electrical grids, computer systems, and satellites!
We have a few spacecraft that study the sun, including the corona, such as STEREO and SOHO. SOHO has an obscuration disk that can be put into place to observe the sun's corona, but only as far out as three times the sun's radius, meaning we can't observe the inner corona at all -- except during a total solar eclipse.
There are a variety of other interesting effects that are studied during total solar eclipses, such as the short-duration temperature changes, animal behavior, and how the temporary night-like conditions from a shadow that moves faster than the speed of sound across the surface of the Earth impact radio communications that bounce off the Earth's ionosphere at night. Many of these projects involve citizen scientists who collect data to be processed by researchers. There's a lot to do and see with eclipses!
Now that I've gotten fairly comfortable with astrophotography, it's been fun to experiment with different configurations, just to see what happens. It's a lot more fun to do when the weather is nice, and it was quite warm on Sunday night - in the upper-60s and lower-70s. Plus, since the forecast was dicey and the moon would be coming up after 1 AM, I didn't want to get too invested in trying to get a good image set.
Before the sun went down, I did have some time to pull out the astronomy club's solar scope again. The sun has been very boring lately, and it was boring again! It also appears that the transparency wasn't very good, although this wasn't terribly surprising given the presence of clouds.
As it got dark, I decided to try and run two setups out at the observatory. I've done this at star parties, but hadn't tried it yet at home. I just bought a new QHY5L-II to use as a guide camera, particularly with the off-axis guider I've been testing out, which now means that I have two good guide cameras. I also got my old laptop up and running for the Texas Star Party, and I just needed to install the Gemini ASCOM driver on it to use with the club's memorial scope. For the other experiments I had planned that night, I needed the ZWO camera, so I put my Nikon D5300 DSLR onto the memorial scope instead of the ZWO for the first time in quite a while. I had originally planned on doing that on Saturday night too, but forgot to bring along my T-adapter. The memorial scope is a Vixen 140mm neo-achromat refractor, and since it's an achromat, the blue channel is fairly fuzzy and blown out-looking on the ZWO camera, so it's better to image with the DSLR on it anyway, where the effect is less severe. I decided to image NGC 7380, the Wizard Nebula, after another astrophotographer in my club had recently posted a fantastic rendition of it. He did his in narrowband, but I figured I'd give it a shot anyway. It didn't come out great, but it's not bad either! It would be much better without all the light pollution...
Date: 2 September 2018
Object: NGC 7380 Wizard Nebula
Camera: Nikon D5300
Telescope: Vixen na140ssf
Accessories: Astronomik CLS filter
Mount: Losmandy Gemini II
Guide scope: Celestron 102mm
Guide camera: QHY5
Subframes: 47x300s (3h55m)
Gain/ISO: ISO-1600
Stacking program: DeepSkyStacker 3.3.2
Stacking method (lights): Auto-adaptive weighted average
Darks: 31 (70F)
Biases: 21 (62F, had to borrow from another set...closest I could find...)
Flats: 0
Temperature: 68-72F
I forgot that I haven't built up a library of bias frames to go with my dark frames, and my house is 76F right now while it's 90F outside, so I had to dig around my image library to find biases that were close. It's not usually that warm at night around here, so I couldn't find any. It was already going to be a pretty noisy image anyway just because of the ambient temperature, so oh well.
While that setup was going, I decided to try out an idea from one of my fellow club members, Derek: mount my 45x70mm Oberwerk binoculars that I won two years ago onto an equatorial mount and attach an imaging camera to one eyepiece, and a guide camera to the other! I figured that my ZWO's chip might be close enough to the front of the camera to achieve focus, so I decided to give it a shot.
I have created a monster!
Because the cloud situation was very uncertain this weekend, I didn't want to bring out a ton of my own gear, since it's a pain to move in and out of my second-story apartment. So instead, I grabbed the Celestron Advanced GT mount from the club's scope garage, took off the Celestron C8 that was on it, and put my ADM Vixen-style dovetail on it with the binoculars attached via a 1/4-20 bolt. The Oberwerk binoculars take standard 1.25" eyepieces, so I put 1.25" nosepieces on both my cameras and tightened them in like eyepieces. Since my USB hub was in use in the memorial scope dome because the USB cable for my guide camera wasn't long enough to not pull my laptop off the table when the scope slewed, I utilized the ZWO ASI1600MM Pro camera's internal USB hub (it has two USB 2.0 ports on the back) to plug in my guide camera and the mount.
Once it got darker, I turned on the camera and Polaris was in view as a bright, fat circle. I rotated the eyepiece holder to focus, but unfortunately was not able to bring it in far enough - the binocs just didn't have enough back focus. Darn!
It was suggested to me after I had already started tearing down that maybe a Barlow would bring it into focus. But I already had my next task in mind, so I decided to table that for another day.
Next, since the sky had cleared off nicely, I dragged out the club's Celestron CGEM mount and loaded the club's Meade 127mm f/9 apochromatic refractor onto it. I've suggested that we put the Meade into the memorial dome instead, since it's apo (meaning that all three wavelengths, red, green, and blue, are corrected, so the stars don't get those icky blue halos). The club is also planning on putting a brand-new Celestron CGX-L in there to replace the Gemini mount, since it's been having alignment issues, and the hand controller doesn't work very well anymore (I've been mostly controlling it with my computer). It's belt-driven, so periodic tracking error should be very minimal. Exciting! Can't wait to try it out. Anyway, once it was loaded on, I got it balanced, and then realized that we had the declination axis flipped around the wrong way! So I got some help to take it off and put it back on again. Then I went to go attach my guide scope and cameras to it, and I realized that I didn't have my 2"-to-1.25" adapter so that I could attach my 1.25" filter wheel to it. Luckily, the other club astrophotographer I mentioned earlier, John, was there, and I figured he might have the piece I needed. Sure enough, he did, and I was finally able to get going.
Once I got everything balanced and connected, I slewed over to Vega to focus, and I had to add a 21mm spacer to the camera in order to get it far enough back to focus. Luckily, adding length is easy, and I happened to have that spacer along because I've been needing to use it with the off-axis guider I've been testing. Once that was done using the Bahtinov mask from the memorial scope, I loaded up SharpCap to do polar alignment. Its polar alignment routine has worked really well for me since I started using it at the Texas Star Party, and it's super easy. However, this time, it kept saying I wasn't rotating the scope after I had done the rotation! I tried several times and went in both directions, but it still wasn't working. So I gave up and used Celestron's All-Star polar alignment routine instead, which meant I had to align first. The finderscope on this scope was kind of neat - it had a 90-degree-angled eyepiece on it that made it way easier to look in from all of the odd angles that equatorial mounts usually end up in. However, finderscopes can be harder to use than something like a Telrad or red-dot finder, especially when the transparency is good and all the stars look bright, and it also wasn't aligned very well to the scope. I had to fish around to figure out where the star needed to be in the finderscope in order to see it on my camera. But I finally got it aligned, and then polar aligned, and then aligned again. I took a frame on the Veil Nebula, but then it was already time to do a meridian flip. It flipped around...and the camera hit the tripod leg! That scope is sooooo long (1140mm focal length!). This meant that the mount kept trying to slew when it was blocked from doing so, which meant I lost alignment. After everything else that had already happened (including losing a spring in the grass from the dovetail tightener and searching around frantically in the grass for about five minutes), I threw up my hands and called it a night on that setup. Some clouds were rolling through anyway!
...Buuuuuuut I don't usually give up that easy. When the clouds cleared out, I really wanted to keep imaging, so I re-aligned (which was easier since I was already polar aligned, the camera was focused, and I knew the offset on the finderscope), and then slewed to the Andromeda Galaxy. I had the exposure time on 1/2s, and a screen stretch on the image, and I could see the galaxy's core! I love this camera so much. :D The funny part was that I could see it on the QHY5L-II's screen on PHD as well, which was really cool.
That fuzzy splotch on the upper left part of the image is M31, the Andromeda Galaxy!
I took a series of 60s frames, but I realized when I was processing them on Monday that I was an idiot and forgot to re-focus the camera after it hit the tripod, which surely knocked it back a little bit. It was just out of focus a little bit, so I didn't notice it when the images were going on my little tablet screen. I stacked it anyway just to see how my first images through that scope would look, aside from the focus.
See those bloated stars? Also don't mind the blown-out-looking core, this is a raw FITS image.
Despite the focus, it actually looks pretty all right...
Date: 2 September 2018
Object: M31 Andromeda Galaxy
Camera: ZWO ASI1600MM Pro
Telescope: Meade 127mm f/9 apo (club's)
Accessories: Astronomik L Type 2c 1.25" filter
Mount: Celestron CGEM
Guide scope: Orion 50mm mini-guider
Guide camera: QHY5L-II
Subframes: 22x60s (22m)
Gain/ISO: 139
Stacking program: DeepSkyStacker 3.3.2
Stacking method (lights): Auto-adaptive weighted average
Darks: 0
Biases: 0
Flats: 0
Temperature: -15C (chip), 68F ambient
Yeah that looks pretty cool! High magnification for a refractor, but that can also be useful. Can't wait to use it more.
After clouds covered up that part of the sky again, I was petering out, but still wanted to do more, since the Wizard Nebula was still unclouded, and I wanted to get as many DSLR images of that before the moon came up as I could. Mars was burning bright in the south, the seeing looked steady since the stars weren't really twinkling, and I wanted to try using an IR-pass filter as the luminance channel, so I pulled out the club's Celestron 8-inch Schmidt-Cassegrain and put it back on its Celestron Advanced GT mount that I'd borrowed earlier for the binoculars. I pointed it roughly north, and then had it slew to Mars. I couldn't see it in the camera, so I grabbed a 32mm eyepiece. The Telrad that was mounted on it was dead, so I grabbed the Telrad off of the club's 16-inch Dob, but since it was aligned to the Dob and not the C8, it could only get me close. I still had to fish around for a few minutes until it finally popped into the telescope's FOV. I got the camera focused, and then took a set of LRGB on it. Then I grabbed my IR-pass filter. This particular filter was given to me last year as part of a set of what I thought at the time were RGB filters, and I figured out that it was IR due to almost no light getting through it besides incandescent light bulbs in my house. When I popped it out of the filter wheel it had come to me in, it said "IR72" on the side, and a weird "S" symbol. I eventually asked in Cloudy Nights what they were, and someone told me they were actually part of a Schuler photometric UBVRI filter set (ultraviolet, blue, visible, red, infrared), which explained why the colors were coming out so weirdly when I tried to use them with the SBIG ST-8300M I was borrowing! So anyway, I have this IR-pass filter, and I've seen online that you can get better luminance frames for planetary imaging using an IR filter because IR light is less disturbed by atmospheric turbulence. Blue suffers a lot from turbulence, and a luminance filter also passes blue. I screwed it onto the nosepiece of the filter wheel, and then rotated the filter wheel so that the empty 5th hole was in view, and then re-focused the scope. Even though my camera has lower quantum efficiency in the IR part of the spectrum, it was still pretty bright.
Stacked image of Mars in the IR channel, 611/2023 frames at 10 ms exposure time, gain 50. It does look pretty sharp! It's rotated about 90 degrees because it was south and I was using an equatorial mount.
I stacked the color channels in RegiStax, and then combined first the regular luminance channel with the RGB channels in RegiStax. Sometimes it works, oftentimes it doesn't and I have to do it myself in Photoshop, but this time it worked. It turned out kind of dim though, so I had to bump up the brightness. Then I combined the RGB with the IR channel, which RegiStax didn't do right (even though I temporarily named it "L" since it needs that), so I had to align them myself in Photoshop. It came out great!
Using a luminance filter as the luminance channel
Using an IR-pass filter as the luminance channel
Details:
Date: 2 September 2018
Object: Mars
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8 (club's)
Accessories: Astronomik LRGB Type 2c filters, IR72 photometric IR-pass filter
Mount: Celestron Advanced GT (club's)
Frames: L: 882/2004
IR: 611/2023
R: 1014/2024
G: 649/2012
B: 799/2008
Exposure: L: 3 ms
IR: 10 ms
R: 5 ms
G: 7 ms
B: 25 ms
ISO/Gain: 50
Stacking program: RegiStax 6
An excellent experiment indeed! I'll be using this filter more often...
All in all, it was a fun night! I shut everything down around 2 AM because I was really tired, and I didn't want to sleep in too late, since I'm back at work on Tuesday. I spent all Monday afternoon processing. I used a bunch of different gear this weekend, most of it belonging to the astronomy club! Let's see, I used...5 different telescopes on 3 different mounts! It was nice not lugging around a bunch of gear for a change. I can't wait till I have my own backyard.
With the increasingly complex deep sky imaging rigs I have, and all of the gear that is necessary to make it work, it was nice on Thursday night just to throw my 8-inch Schmidt-Cassegrain, its simple alt-az mount, a battery, tablet, camera bag, table and chair into the car, like old times. Three trips got all the gear in the car instead of nine. It reminded me of when I first got started, and we get fit everything into the trunk of my then-boyfriend's Corvette. Now it usually takes the entire back of my compact SUV!
Before that, though, I helped mow the lawn at the observatory earlier in the evening, and I had brought along my camera bag in the hopes of having time to image the sun before it went below the trees. I got there late from work, so they were already mostly done. So I pulled out the club's Lunt solar scope, set it up on the club's Celestron NexStar SE mount (the exact same one I have), and first put an eyepiece on it to see how things looked.
The sun was so. Boring. Like, the most boring sun I've ever seen! No sunspots, no plages, not even any prominences. At first, I thought I saw a tiny sunspot, but it turned out to just be a dust mote on the eyepiece (it didn't stay with the sun when I tapped the telescope). As it turns out though, there was a sunspot there! It's about a third of the way up from the bottom, near the center.
After getting dinner with one of my friends, I went back to my house and loaded up my gear into the car. Since the moon is large and bright this time of the month, it was a planetary imaging night rather than a deep-sky night. Usually I do planets from my front yard, but the apartment building blocked where Jupiter and Venus were, so I drove to a nearby empty cul-de-sac on top of a hill. Venus was rapidly dipping toward the horizon, so I rushed to get everything setup, and was ready to go in about 10 minutes. Once I trained the camera on Venus, however, I could see right away that it wasn't going to work - the atmosphere was boiling like crazy that low, and Venus was a blobby, crescent-shaped mess. Oh well, next time.
This year is excellent for planet-lovers - literally everything is up right now if you stay out late enough (and Mercury rises before the sun in the morning - not by much though!). If you don't want to stay up late, you still get the best of show - Jupiter, Saturn, and Mars, plus Neptune if you so desire. I worked my way across the sky from west to east.
Jupiter was my first target, and after using my Bahtinov mask to focus on Arcturus, I centered Jupiter, and then cut the ZWO ASI1600MM Pro's frame size from its native 4656x3520 down to 640x480. The primary reason for this is faster frame rate. The atmosphere is always moving and swirling, and every once in a while, you get a clear column of air. A high frame rate will get you more frames in those moments of "good seeing." In addition, planets rotate, and Jupiter rotates fast - you need to collect your data within a 3-minute window to minimize the rotation. With a monochrome camera, that means collecting a few thousand frames on all four channels - luminance, red, green, and blue - in that time frame. I usually collect 2,000. When I run at a small cropped frame, and the planet is bright enough to have fast exposure times, I can get 100 fps or more. It only took about 20 seconds to get each color channel! However, I could see on the screen that Jupiter wasn't looking very good - it was pretty fuzzy, and I couldn't make out much detail. I could also see the edges undulating. This meant that the seeing was still pretty bad, even though Clear Sky promised 4/5 seeing conditions. It was only about an hour after sunset, though, so there was still ground heating and other sources of turbulence. If I came back later, then it might be better. But sometimes, the data can surprise you - and I was very surprised with this data set! The videos looked bad, but the RegiStax image quality ranking plot actually looked pretty promising, and then each color channel, once I stacked and applied wavelet deconvoution, looked great! It just goes to show, don't decide that your data is junk until you've given it a fair shake...
All my data that night also turned out weirdly dim, so I'm not sure what's up with that, but punching up the brightness in RegiStax helped.
Here's the final product!
Object: Jupiter
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: Astronomik LRGB Type 2c 1.25" filters
Mount: Celestron NexStar SE
Frames: L: 1141/2015
R: 1279/2030
G: 1024/2021
B: 1154/2010
FPS: 122
Exposure: L: 1 ms
R: 3 ms
G: 3 ms
B: 5 ms
ISO/Gain: 139
Stacking program: RegiStax 6
Not too bad! Not my best, but way better than I thought it would be based on the videos I took!
Next was Saturn! I decided to try something I haven't tried with this camera yet - adding a 2x Barlow. This is a lens that you can screw onto the nosepiece, and it doubles your magnification. It also doubles your effective focal ratio (so on my C8, from f/10 to f/20), which makes the image dimmer (this is a result of the light being more spread out among the pixels). So my frame rate was a tad slower due to the longer exposure time, but Saturn's rotation is much less obvious than Jupiter's anyway (and slower). The seeing was starting to settle by this point, but I still didn't get quite the sharpest image of Saturn.
Date: 23 August 2018
Object: Saturn
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: Astronomik LRGB Type 2c 1.25" filters, 2x Barlow
Mount: Celestron NexStar SE
Frames: L: (not used)
R: 577/2001
G: 602/2003
B: 393/2002
Exposure: L: 15 ms
R: 40 ms
G: 40 ms
B: 80 ms
ISO/Gain: 139
Stacking program: RegiStax 6
Next was Mars! Now that the dust storm as abated, there's a lot more surface detail to see. If the atmosphere cooperates, that is. I tried with the Barlow on, but they all came out too fuzzy from RegiStax - I didn't even bother combining the color channels. The un-Barlowed one looks better, although I did get some artifacts near the left edge.
Date: 23 August 2018
Object: Mars
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: Astronomik LRGB Type 2c 1.25" filters
Mount: Celestron NexStar SE
Frames: L: 778/2013 (not included in final)
R: 748/2021
G: 767/2011
B: 879/2025
Exposure: L: 0.3 ms
R: 0.6 ms
G: 1 ms
B: 2 ms
ISO/Gain: 139
Stacking program: RegiStax 6
Last week, the venerable lunar imager Robert Reeves gave me a tip on using the Shake Reduction filter in Photoshop to tease out a little additional sharpness. Sometimes it works, and sometimes it doesn't, but it did all right with this image.
Next was the moon, with the Barlow still on (I imaged the moon between the zoomed-in and zoomed-out sets on Mars). It's nearing full, but there were still some gorgeous shadows in the craters near the unlit edge. These take forever to register in RegiStax due to the large number of align points. I took the images with the red filter, since red light is scattered less in the atmosphere, and I find my images always come out sharper with that filter than with luminance, green, or blue.
Date: 23 August 2018
Object: Moon
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: Astronomik R Type 2c 1.25" filter, 2x Barlow
Mount: Celestron NexStar SE
Frames: 401/2000
Exposure: 4 ms
Gain: 139
Stacking program: RegiStax 6
I took a second set of images as well in a different area, but my mount is not the best at tracking, and the image shifts frame-to-frame ended up being too much, and it didn't come out well.
I swung back my Saturn after I re-did Mars without the Barlow, and got this much-better image.
Date: 23 August 2018
Object: Saturn
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: Astronomik LRGB Type 2c 1.25" filters, 2x Barlow
Mount: Celestron NexStar SE
Frames: L: 493/2021
R: 604/2018
G: 882/2021
B: 1005/2010
Exposure: L: 4 ms
R: 10 ms
G: 10 ms
B: 20 ms
ISO/Gain: 139
Stacking program: RegiStax 6
Also, it's not just the camera that was seeing less-colorful images than usual - I looked at Saturn, and it seemed almost de-saturated in color. Mars even naked-eye looked less red. I'm wondering if that is a result of the moonlight washing things out, or maybe some aerosol or smoke in the atmosphere, or something like that. My Jupiter image came out rather colorless indeed.
I only reluctantly packed up and went home at 11:15 PM - the atmosphere was getting more steady, and I wanted to try some different things. But I had to be at work the next morning, so off to bed! I really miss imaging DSOs - my last one was over a month ago - but planets are fun too. And you can actually see them in the telescope - sometimes better than the camera can!
To cap off a week of clear nights, we got one more, and it was very clear indeed! Not as dark as the Radio Quiet Zone of West Virginia from Sunday and Monday, but I got a lot done, as you will see here.
Day three of my cold brought, as predicted, sneezing and runny nose. I had taken a non-drowsy Sudaphed earlier, but after the four hours had elapsed, I still felt not too stuffy, so I didn't take another. I wish I had! Sitting outside at the observatory had my nose running like a water faucet. I quickly ran out of tissues from my car's tissue box, and I had to grab a roll of toilet paper from the observatory bathroom. I finished off two-thirds of the roll before the end of the night! I certainly sounded sick, even if I didn't feel very sick. By the end of the night though, it had started to move up into my head - my ears were ringing, meaning sinus pressure was building. Boo!
I got out to the observatory around 7 PM, and rushed to pull out the hydrogen alpha solar scope to grab a quick set on the sun before it dipped behind the trees. Still no sunspots, but a cool plage region to add some intrigue!
The "difference" mode when I placed the shorter-exposure granularity image on top of the longer-exposure prominence image to combine the two (difference helps to align the two images)
As it sank behind one of the taller trees, I caught it on video: Maple Eclipse of the Sun!
My minion Miqaela joined me again that evening for another night of imaging on her borrowed Explore Scientific ED80 refractor. After seeing how well I was able to image M51 Whirlpool Galaxy on a refractor, she wanted to try as well, with her Nikon D5300. Fellow club member Bob joined us as well, but without his scope, so he wheeled out the club's big juicy 16-inch Dobsonian. Fellow club member Perry joined us as well, bringing his 8-inch Meade Schmidt-Newtonian out for its first trip to the observatory. I was shocked that it was such a small group; a clear, moonless, and warm Friday night, and no one else wanted to come out?? Well they missed out!
While waiting for it to get dark, I get a head start on imaging by turning to something you don't need a lot of darkness to image: the planets. First was Venus, before it too went behind the trees. I tried to image it on the DSLR on the club's 5-inch Vixen refractor a while back, but it was tiny and basically just chromatic aberration all around. I didn't even talk about it in my log entry, apparently! This time, I used my 8-inch Schmidt-Cassegrain, which I had left set up from Thursday night on my Celestron Advanced VX mount, with my Borg 76mm apochromatic refractor riding on top for auto-guiding. I did leave my f/6.3 focal reducer on so that I would be focused and ready to go by the time it got dark enough to fine-tune my alignment model and then start imaging, but it came out quite nicely anyway!
Details:
Date: 13 July 2018
Object: Venus
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: f/6.3 focal reducer, Astronomik LRGB Type 2c 1.25" filters
Mount: Celestron AVX
Frames: L: 672/2004
R: 525/2011
G: 641/2012
B: 1060/2004
FPS:
Exposure: L: 0.1 ms
R: 0.5 ms
G: 0.5 ms
B: 0.5 ms
ISO/Gain: 139
Stacking program: RegiStax 6
Part of the reason I haven't imaged it very much is because my setup spot at my apartment is on the east side of the building, so it gets blocked by the building, and I didn't usually have my 8-inch out at the observatory, since I mainly go out there for imaging, and it's only recently I've been able to image once again with my 8-inch. When I was using my 11-inch, I have trouble pulling the planets into nice sharp focus on it - I might create an aperture mask for it at some point to sharpen the view.
After Venus, I slewed over to Jupiter, and grabbed a dataset on it too. I also went and looked at it through Perry's Schmidt-Newtonian. He had messed with the primary mirror a while back and now there's some chromatic aberration, but it was still a nice view. The "seeing" (measure of atmospheric stability) was excellent that night!
Date: 13 July 2018
Object: Jupiter
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: f/6.3 focal reducer, Astronomik LRGB Type 2c 1.25" filters
Mount: Celestron AVX
Frames: L: 668/2014
R: 468/1670
G: 490/1404
B: 970/2014
Exposure: L: 4 ms
R: 10 ms
G: 10 ms
B: 12 ms
ISO/Gain: 139
Stacking program: RegiStax 6
No Great Red Spot, and it's not my best image of it, but still got some nice cloud swirling detail. One of the things I love about my ZWO ASI1600MM Pro is that it's USB 3.0, which means when I crop down to a small frame size for imaging a planet, I can get 60+ fps, which lets me take a whole lot of frames very quickly. This is important for Jupiter, since it rotates quickly.
Later on, Perry called us over to his scope to watch Jupiter's moon Europa disappear behind the planet. It was neat to see it just hanging on to the edge for a few minutes!
It was getting darker now, but still not dark enough to start deep sky imaging, so I followed up on minor planet Vesta. I imaged it Thursday night as well, and the plan was to superimpose the two images together so you could see its motion. I did a Precise Goto, and recognized it in the 10s preview frames as having moved out of the trapezoid of stars it was in the day prior. I uploaded a jpeg screenshot to astrometry.net to confirm.
Since it didn't identify it as a star, it has to be Vesta. I double-checked it against the position of those labeled stars in SkySafari. A match! I took 10x60s subframes (and forgot to turn on guiding, so I only had one or two stable ones).
I picked a frame from Thursday night and a frame from Friday night and put them into DeepSkyStacker to register and align. I "stacked" them using the Average stacking mode, since all others looked terrible because I accidentally took jpegs the second night. Since Average mode averaged the light from Vesta over its two positions, I cropped out Vesta from one of the single frames and placed it on top of its two positions in the final image so that it wouldn't look weirdly dim for its oversatured size. In reality, it's only 0.5 arcsecs across, which with the resolution of my camera and telescope together being 0.6 arcsecs, is less than a pixel. But its light spills over across many pixels, indicating how bright it is - similar to how a bright star or planet looks bigger than the others to your eye.
Date: 12 & 13 July 2018
Object: Vesta
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: f/6.3 focal reducer, Astronomik L Type 2c 1.25" filter
Mount: Celestron AVX
Guide scope: Borg 76ED
Guide camera: QHY5
Subframes: 2x60s
Gain/ISO: 300
Stacking program: DeepSkyStacker 3.3.2
Stacking method (lights): Average
I measured the distance it had moved by measuring the number of pixels between the centers of each image of Vesta using the ruler tool in Photoshop, and then converting that to arcseconds and then arcminutes, knowing what the spatial resolution of my camera is.
Not only are Jupiter and Mars gorgeous right now, but Saturn pass through opposition just a month ago, and while it's not as bright in the sky as it was last year, it's phenomenal in the telescope! I looked at it in Perry's Schmidt-Newtonian, and WOW it was gorgeous tonight. Cloud bands, Cassini division, and brilliant color! So I ran over to my scope to image it too. I had the focal reducer on in prep for imaging deep sky objects later, so it's not quite as sharp (due to it being really small in the field-of-view), but still pretty!
Date: 13 July 2018
Object: Saturn
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: f/6.3 focal reducer, Astronomik LRGB Type 2c 1.25" filters
Mount: Celestron AVX
Frames: L: 721/2010
R: 865/2005
G: 565/2003
B: 1490/2010
Exposure: L: 25 ms
R: 50 ms
G: 50 ms
B: 100 ms
ISO/Gain: 139
Stacking program: RegiStax 6
After I finished grabbing Saturn images, there were enough stars out to firm up my polar alignment, if I cranked up the gain and exposure time. I went into SharpCap and ran its polar alignment routine again, and it came back with "fair," as opposed to Thursday night's "Excellent." I find that re-polar alignment is necessary from night to night on non-permanent rigs - they tend to shift around, either when taking gear on and off, covering and uncovering the thermal blanket, and maybe wind or settling into the grass. I made the adjustments and got it back to "excellent," and then re-aligned. My gotos still weren't very good for some reason, so I had to go a Precise Goto for every object. Those worked pretty well.
My deep sky task for the evening was to take advantage of the very clear skies and stable atmosphere and collect a bunch of luminance frames. My first goal was M20, the Trifid Nebula, which I had collected color frames on the night before. I tried to take 5-minute subframes, but that proved too long for the guiding error that was cropping up. It looks periodic in my 3-minute subframes, so I might try to train PEC (periodic error correction) my next night out. I haven't actually tried it yet.
Yucky, elongated stars on one of my 5-minute images. And several of my 3-minute frames.
After I got home and stacked it the next day, it came out rather nice!
Date: 12 July 2018 (RGB), 13 July 2018 (L)
Object: M20 Trifid Nebula
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: f/6.3 focal reducer, Astronomik LRGB Type 2c 1.25" filters
Mount: Celestron AVX
Guide scope: Borg 76ED
Guide camera: QHY5
Subframes: L: 17x180s (51m)
R: 6x180s (18m)
G: 8x180s (24m)
B: 9x180s (27m)
Total: 40x180s, 2h
Gain/ISO: 139
Stacking program: DeepSkyStacker 3.3.2
Stacking method (lights): Auto-Adaptive Weighted Average
Darks: 20
Biases: 20
Flats: 0
Temperature: -20C (chip)
Got some nice structural detail in the emission portion of the nebula, as well as the dark bands! The blue was hard to pull out, mainly thanks to light pollution, since it's a dimmer region than the red. If you look really close, you can almost see the two narrow antennae coming off of the big lobe that's in the top left edge of the red emission region.
I use a Microsoft Surface 3 tablet (not the Pro) to run all of my capture software. It's great because it's portable, has a long battery, and charges on a micro-USB port that can be plugged into a cell phone external battery, if needed. Since my cameras suck a lot of power, though, I have to make sure I run it on a 2.4A power supply, or else it will deplete faster than it's charging. One of the only downsides to it is the hard drive space - mine has 128 GB, 50 GB of which is the operating system. For deep sky object imaging, this is no big deal - a typical 2-4 hours of imaging is only a couple of gigs, since each frame is only 32 MB. Things get tricky though when I do planetary imaging, since I'm taking videos with 2000 frames per color channel. Even when saving out in the LuCam .SER format (which RegiStax loves and is suuuper quick with, by the way), which are much smaller than AVIs, that's still nearly 1 GB per video file, or 4 GB per target (since I need luminance, red, green, and blue). This adds up fast when you do multiple targets, and my hard drive filled up! I had to clear all of the movies off of my micro SD expansion card in order to copy over all of my planetary data from that night.
While those were going, we rotated around between looking at Saturn, Jupiter, and later Mars in the 16" Dob and Perry's Schmidt-Newtonian. I tried to find M51 Whirlpool Galaxy in the big Dob on my own, which I had never tried before. I got close, but it turned out to be very hard to see against the background light pollution. Way different than West Virginia!
When Mars was up later, we put a high-magnification eyepiece on it, and I observed it while playing Gustav Holst's "Mars, the Bringer of War" on my phone. It was a magical experience. 😍
Once I had about two hours of luminance data on M20, I decided to collect some luminance data on another target as well, since the sky was so good, and I didn't have to be anywhere in the morning. I wound up going with M16, the Eagle Nebula. Light pollution made it mostly a flat gray besides the pillars, but using some of Carboni's Photoshop tools - "Light pollution removal enhanced flatten" and "Enhance DSO reduce stars" - brought out a bit more contrast. I got some nice detail on the Pillars of Creation, despite my slightly stretched stars!
Date: 13 July 2018
Object: M20 Trifid Nebula
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: f/6.3 focal reducer, Astronomik LRGB Type 2c 1.25" filters
Mount: Celestron AVX
Guide scope: Borg 76ED
Guide camera: QHY5
Subframes: L: 16x180s (48m)
Gain/ISO: 139
Stacking program: DeepSkyStacker 3.3.2
Stacking method (lights): Auto-Adaptive Weighted Average
Darks: 20
Biases: 20
Flats: 0
Temperature: -20C (chip)
It was about 3:30 AM by the time I'd collected about 30 subframes on the Eagle Nebula, and I decided we'd probably better head out. Hopefully I'll get another chance soon to get the color images. Normally I don't stay out there past 2 AM unless I'm going to camp out, since after that point I'm usually too tired to drive home safely, but since I had woken up at 11:30 that morning, I had a little extra time on my hands. There was one more thing I wanted to image, however: Mars.
I couldn't see much of any surface detail on Mars in either one of the visual telescopes out that night, but I went ahead and imaged it anyway. Despite not being able to see much, the camera somehow did, and I got a decent image! It would have been better if I had taken off the focal reducer, but it was late and I didn't think about it, plus I still needed it for Vesta so that my images would match from the night before.
Date: 13 July 2018
Object: Mars
Camera: ZWO ASI1600MM Pro
Telescope: Celestron C8
Accessories: f/6.3 focal reducer, Astronomik LRGB Type 2c 1.25" filters
Mount: Celestron AVX
Frames: L: 701/2020
R: 655/2018
G: 450/2020
B: 578/2014
Exposure: L: 1.5 ms
R: 3 ms
G: 5 ms
B: 14 ms
ISO/Gain: 139
Stacking program: RegiStax 6
You can see the polar ice caps, dark terrain features, and its tenuous atmosphere on the edge! Mars is so awesome right now. Yes, it is the giant, bright orange thing hanging low in the southern sky after 11 PM, as many of my friends have asked me. And it's a real treat to look at in the telescope!
Finally, around 3:45 AM, it was time to pack up. Saturday night was not looking very good, and honestly I was pretty sure my body couldn't handle another night. I contemplated leaving my gear setup and coming back out to clean up the next day, but I knew I would probably regret it, since the sinus headache was already beginning to tug at the corners of my head. I convinced Miqaela it would be a good idea (she doesn't have her key yet, so she could only come back if I came back), and we packed up and headed home. I even hauled all of it inside when I got home - it takes 7 trips to get it all up the stairs and into my apartment! I hope my downstairs neighbor is a deep sleeper...
That's the mount, 8-inch Schmidt-Cassegrain, Borg 76ED in a Pelican case, tackle box full of tools, nuts, bolts, velcro, batteries, adapters, and anything else that comes in handy, accessory box with dew heaters, towel, power strip, extension cable, and other larger helpful items, counterweights box, ZWO camera bag, DSLR camera bag, telescope tripod, camera tripod, tablet, folding table, chair, and bag of warm clothes.
So the last week was a hardcore marathon of astrophotography! 17 data collects, four telescopes, 7 nights, and not enough sleep! It will take some time to recover, especially from this cold I'm still in the midst of as I finally get around to writing this on Sunday, but as always, it was totally totally worth it. Perry asked how I do it - "must be lots of coffee, and your enthusiasm helps, I'm sure!" he said. My response: "Coffee, enthusiasm, and sheer willpower!"
