The following images were taken during the WGNSS Nature Photography Group’s trip to Garden of the Gods (GOTG) and other locations this past April. This group is currently being led by Miguel Acosta. If you are interested in joining us for one of the group’s monthly outings, please see details at http://www.WGNSS.org!
Many thanks to the photographers we met on the trail at Bell Smith Springs Wilderness who tipped us off to a spectacular mirror lake in the Shawnee. Miguel and I stopped at this location before heading back to St. Louis. The peak fall colors were obviously passed but this place screams potential and I hope to get there again next year. We had really nice conditions for this type of photography, with cloudy skies and winds which weren’t too bad. We could have found a few more compositions but the rains came and the winds got worse so we called it a day.
The waters here were not as calm as to be desired for our purposes, but using polarizer and neutral density filters allowed us to get long shutter speeds that helped to lessen the effects of any wind-blown ripples on the water’s surface. All images in this post from this location were taken with shutter speeds between 20 and 30 seconds.
In the photo above the wind was starting to move pretty quickly across the wider portion of the lake. Using a shutter speed of 30 seconds allows the ripples created to appear with a more painterly appearance.
During this weekend trip, some of us enjoyed the camping experience while others chickened out and stayed at hotels or cabins. Similarly, some of us stayed late at GOTG to do a little astrophotography. Well, I should say that I stayed late. 😉 After my friends nabbed a couple of quick Milky Way images, they headed back to their air conditioned rooms and I was left by myself to work on the photo seen above. This photo was made by combining 213 30-second images in the computer to build the star trails with the iconic “monkey face” and other rock formations that GOTG is known for in the foreground.
This was a great weekend of friends, photography, hiking and camping.
M42, B33 and friends The Orion molecular cloud complex is one of the most active regions of star formation and contains the brightest emission nebulas from our vantage point. The complex is between 1,000 and 1,400 light years from earth and is hundreds of light years across. This frame is just a small but significant portion of the whole complex and is one of four compositions I plan on making of this portion of the sky over the next couple of years.
Let’s discuss the objects. Even those with a small familiarity with the night sky should be able to determine where these objects are located once explained. Let’s start at the bright star in the upper left-hand corner of this image. This is Mintaka, the brightest (double) star in the asterism of Orion’s Belt within the Orion constellation. Going down and to the right, we reach the next star in Orion’s belt – Alnilam. The final star in Orion’s belt, Alnitak, is to the lower right of Alnilam. All three of these stars are tens of thousands to hundreds of thousands more luminous than our Sun. Alnitak is the primary reason we can see the reddish nebulosity known as the Horsehead nebula (IC434, B33). It’s strong ultraviolet radiation excites the hydrogen gas making up this nebula and releases hydrogen-alpha wavelengths that we can pick up on earth. Just a little to the lower left of the Horsehead is one of my favorite pieces in this composition. This is a very young star, still condensing and making its way out of the nebula.
To the left of the Horsehead is the Flame nebula (NGC 2024 and Sh2-277). This emission nebula is another birthplace of stars. It contains hundreds of young stars but specialized X-ray and infrared imaging is needed to resolve these.
To the right hand side of the image we first come to the comparatively smaller nebula known as Running Man (Sh2-279) and to the right of it lies The Great Orion Nebula (M42). M42 makes up a portion of the Orion’s Sword asterism and is the brightest nebula in the night sky. It is so bright it can be seen with binoculars or a low power telescope from dark skies. It is also the target of the first deep sky image ever taken – by Henry Draper in 1882. Within the star nursery that is M42 are approximately 700 young stars in various stages of formation. Throughout the image is a lot of darker nebulosity that is quite dim, requiring ample amounts of exposure time to resolve.
Collecting the data My original intent for this session was to image the usually paired group of Running Man and Orion. However, we were fighting to find a good night’s sky in December. The night we chose was forecast to be pretty clear but with 7-10 mph winds, gusting to 20mph. Because of the forecasted winds, I decided it wasn’t prudent to use the large and heavy 300mm lens that would be required to make these two the primary target. So, I decided to go with another composition that I had planned to do later. I used the much smaller and lighter 200mm lens that wouldn’t catch nearly as much of the wind and make getting accurate tracking of 30 second subexposures much easier. This image comprises a section of sky approximately 4 degrees by 6 degrees.
As I explained in last month’s image, M42 has a very wide dynamic range in intensity of its brightness. Due to this, I needed to take several sets of subexposures at different exposure lengths. Ultimately, I took seven different exposure length sets but only wound up using four of these in the final image.
Miguel and I imaged at our usual locale of Danville Conservation Area. On this night we ran into our first Conservation Officer who asked us what we could possibly be doing on such a cold and windy night. At first I was worried we would be shut down for the night as he mentioned that all conservation areas in the state were closed between 10:00pm and 4:00am. But, after some explaining and discussion he decided we were OK doing what we were doing and where we were doing it.
The sky forecasts were a little variable between the different apps we use. Some suggested that the skies would be mostly clear around sunset while others had clouds lingering until midnight. Thankfully, the skies cleared like magic a little after 9:00pm. We lost a couple hours of imaging time but in December you have to take advantage of what you can get. Temps were cold as you might expect ranging between -3 and -7 degrees C over the course of our session. I guess the temperature swing wasn’t as drastic as the last time I used the 200mm lens back in September because the focus of the lens wasn’t changing nearly as much as it had while imaging Andromeda.
Equipment For this image, I broke in a few new pieces of equipment. First, this was the maiden voyage of my astro-modified Canon 7D mkii. This camera has its IR-cut filter removed. This modification allows for much more of the Hydrogen-alpha light to hit the sensor that is mostly blocked from stock dSLR camera bodies. In order to get as much of that warm coloration seen in the Horsehead and Orion nebulas with a stock body would have required much more integration time. As mentioned above, I used the Canon 200mm f/2 lens. When used with this crop-body camera, this gives an equivalent focal length of 320mm.
Another new piece of gear allowed for less hassle over the course of the night. I purchased a “dummy” battery that allows me to power the camera over the course of the entire night with my “little” cart battery and an inverter that I typically use for attracting moths at night. I love finding new uses for stuff I already have! The $20 cost of the dummy battery was a most welcome addition to my kit.
I also picked up a really nice right-angle viewfinder that attaches to the end of the polar scope of the tracking mount. To make the rig as sturdy as possible, I like to set it up low to the ground. Doing this requires me to often crouch low or even lie on my belly while wrenching my neck to be able to see through the polar scope. This is not a comfortable position to be in while doing the fine tuning of the controls on the wedge mount to get precise polar alignment. This new piece of kit allows me to simply look down and much more comfortably make these fine adjustments with both hands.
Finally, I picked up a lens heater that will prevent the formation of dew and frost on the lens objective. This was also run from the main battery and inverter and seemed to do the job. Previously, I used chemical heat packs for hand warming that I attached to the end of the lens with a velcro strap. This new powered dew heater should be able to be used with all the potential lenses I use for astrophotography.
I guess I’m getting a little more tech involved but nearly as much as my astro imaging partner, Miguel. See discussion below.
Thanks a lot to my patient wife Sarah for the early Christmas gifts!
Other equipment: Skywatcher Star Adventurer tracker without guiding on a William Optics Vixen Wedge Mount. Gitzo CF tripod, Canon shutter release cable. Laser pointer to help find Polaris and sky targets. Lots of layers to protect me from the cold!
Imaging details Lights taken (ISO 3200): 30 seconds (389 taken, 284 used in integration); 15 seconds (108 taken, 90 used in integration); 8 seconds (209 taken, 194 used in integration) 1 second (195 taken and used in integration). Darks: 30 taken at each of the 4 exposure times listed above. Bias and Flats: Not taken. Removed most vignetting and some chromatic aberration while converting RAW images to TIF.
Processing I knew this one was going to be a challenge, due to using the new astro-modified camera and handling different exposure lengths to capture the dynamic range within M42 that I would need to show the details in the core of the nebula. I believe I have the data needed to do a better job on this part of the nebula but after nearly ten hours spent on the computer, I was happy enough with what I got.
What really came as a surprise was the amount of satellites that crossed this portion of sky. I estimate that 90% of my 30 second sub frames had at least one, if not several, satellite and/or plane trails. This technically isn’t a problem because in the stacking software I use (Deep Sky Stacker), you can handle the satellites by using Kappa-Sigma Clipping stacking within DSS. However, when using the high dynamic range (entropy weighted average) stacking mode, which will blend the different exposures automatically, you cannot use Kappa-Sigma-Clipping to remove the trails! Or at least not that I have been able to figure out. Therefore, I had to stack each of the sub-exposure sets separately and then blend using layers in Photoshop. This wasn’t too terrible but it did require a lot more time on the computer.
Problems and learnings I guess I didn’t learn my lesson the first time. Again, I walked away from the rig for 45 minutes without making sure the camera was taking pictures! I guess I was too interested in getting back to the car to read my book (Hail Mary by Andy Weir) and didn’t do my final check. It didn’t ruin the night but man was I pissed that I lost nearly an hour’s worth of potential integration when the targets were near their zenith. Never again!
I was also pleased to see that the output from DSS was relatively color balanced, requiring me to do very little to get accurate colors. Colors in these objects are subjective and free to change, but I strive to be as “accurate” as I can be. I was concerned by this because in the astro-modified cameras, naturally the red light is most abundant and many images taken with these cameras, when not color corrected, show way too much gaudy reds. I did not want my final product to look like that.
Probably my biggest regret is with the framing of this one. If I could do it again, I would have moved the frame more diagonally, allowing Orion and the Running Man to drift more towards the upper right-hand corner. This would have made a much better composition. But, I was primarily focused on keeping Mintaka in the upper left-hand corner as an anchor point for me to be able to see how much drift from the tracker was occurring. I’m going to try and think through the framing and composition better in the future.
Conclusion Overall, it was another fun night and I am pleased with the final outcome. Miguel and I enjoyed ourselves as usual and we keep finding new things to learn and experience with each outing. I’m looking forward to seeing Miguel’s image. He focused on Orion and Running Man – my original target for the night.
Aside I have mentioned numerous times previously that Miguel and I work together, typically imaging the same targets. However, we go about doing this in very different methods. Whereas I go about things in more of a manual, craft-like manner, Miguel is using state-of-the-art consumer level equipment. I realize that nobody cares (nor should they!) about what it took for the photographer to make their final image, but I thought it would be good to explain our differences in how we go about our image making processes.
Bill I use dSLR cameras much like the cameras anyone uses for daytime photography and typical fast (f/1.4 – f/2.8) camera lenses that allow me to capture as much light as I can. I use a standard consumer tracking mount that is considered portable. All it does is work by using gears and belts to point the rig at the same portion of the sky to match the change in position of the stars due to the rotation of the earth. I need to do the process of polar alignment manually, which is a PITA! I also must find and position my target by myself, using my eyes or a laser pointer to help me find that night’s target. I must also manually change the camera’s settings to what I need them to be and must acquire proper focus, which is not easy to do with a camera lens at these wide open apertures.
Miguel By comparison, Miguel lives on easy street! His imaging rig is composed of a temperature-controlled dedicated astronomy camera attached to a William Optics Redcat 51 apochromatic refractor AP scope. He uses a similar tracker but his is connected to a computer that is also connected to his camera and lens via a focus adjuster. This gives him three significant advantages. First, after pointing his polarscope towards the north, the computer polar aligns for him. He also has “go-to” capabilities. He simply tells the computer which object he wishes to target and the rig moves there! Even better, he can tell the computer the specifics on how he wants the target framed! Once on target in the framing he indicated, his rig now provides autoguiding. This means that the computer makes fine repositions during the imaging session, correcting for errors in the tracking that my rig suffers from. This means he can obtain much longer sub-exposure times. Where I am kept at 30-60 second exposures without significant star trailing, Miguel can get exposures in the 3-5 minute range. A distinct advantage indeed! To top it off, the computer in Miguel’s rig will obtain perfect focus for his scope and keep it there throughout the imaging session.
Miguel has spent a lot of money and time learning the components and how to control the different aspects of his computer software. I am not trying to sound the holier here, but I thought it would be interesting to describe the vast differences in our techniques and imaging rigs. I’m not hating, Miguel! 😉
I’m finally getting around to posting photos of some Leps that were taken during the WGNSS Nature Photography Group’s quite enjoyable visit to Prairie Garden Trust located in Calloway County, MO. I can’t express how much I appreciate this location and the people that manage it. Lorna and Henry Domke gave our group a personal walking tour around much of their fabulously managed naturescapes – in my opinion the perfect exemplar of how and why to manage natural areas. I thought I would have been back by now, but time has a way of moving too fast and there’s only so many weekends in the year.
Text from their website:
What the PGT will become
The PGT is a gem of a nature garden in central Missouri where people enjoy strolling by woods with large old trees, prairies filled with a mix of native wildflowers, and ponds and streams rich in native aquatic life. It is free of exotic, invasive plants and animals. Visitors are inspired there to learn about and take better care of nature.
What we do
The Mission of the PGT is to inspire people by letting them experience the beauty of nature found in a variety of enhanced native habitats on the PGT property.
What we believe
Native plants are good for healthy habitats, while invasive, non-native plants are detrimental and should be removed.
We believe that knowing what plants and animals exist here and how they change over time is valuable. We want to avoid harvesting natural resources on the property for income so mature habitats can develop here.
We support removing plants (using fire, herbicides and mechanical means) and animals (by trapping or hunting) as needed for the management of a beautiful habitat and to maintain the balance of nature, but not as a source of income or recreation.
We believe that quiet personal experiences in nature enhance well-being and that crowds detract from that.
We believe that unmanaged habitats tend to be messy, but they can be made more visually appealing by following an artistic landscape design. By having some areas of the PGT less tended and other areas along trails more tended, we offer a nature garden within a natural area.
We believe that knowing the natural, geologic and cultural history of the PGT property is of value. It’s where a coral reef developed 360 million years ago, where the Ozark hills meet the glaciated plains, where native Americans hunted 2000 years ago and where settlers built a thriving pottery almost 200 years ago.
As the wildflower bed in the front yard begins to mature, the pollinators have come in droves. I really enjoyed getting to know the members of the Hesperiidae (skipper butterflies) this year. Although suburbia seems to support only a few species, their numbers were great in my yard. Most of these are considered “grass skippers” due to their host plant needs. It makes sense that these species would do well in a suburban area with plenty of flowering natives. Most grass skippers will use zoysia and Bermuda grass as host plants. I hate to think how many larvae get destroyed in the neighborhood each season with the relentless lawn mowing.
These first three photos are the sachem (Atalopedes campestris). This is a very common species in the yard and they seem to have a very long flight season. I noticed they come in a variety of shades and patterns that can make identifying them a bit troublesome.
Next up is the overlooked beauty but common Peck’s skipper (Polites peckius). Along with the sachem, this guy was common for most of the flowering season.
The final skipper from the yard is a favorite among anyone who cares to notice skippers. The brilliant fiery skipper (Hylephila phyleus). Although I found a scattered few in May, June and July, they seem to have a little later season than the others. I found them in the tens in August and September.
If you want to have lots of skippers, I highly recommend planting asters in thegenus Symphyotrichum. This will attract skippers and many other insect pollinators who need these plants.
Finally, I found a very interesting solitary bee that was feeding on the Asclepias tuberosa that was blooming in the glade garden that installed around our mailbox this past May. This is a male carpenter-mimic leafcutter bee (Megachile xylocopoides).
The Pleiades Star Cluster (M45) The Pleiades, or as it is called in Japan – Subaru, has been near the top of my list of deep sky objects since I began to play in astrophotography. This star cluster is one of the most prominent objects in the night sky and can be easily seen with the naked eye, although it is a stunner through binoculars or a scope. Folks with very good vision under dark skies have been reported to be able to see seven stars, giving this cluster another of its names – the Seven Sisters. Whatever you want to call it, M45 is a relatively young cluster of approximately 1500 young stars (the cluster is thought to have formed around 100 million years ago). The majority of these stars are bright-burning blue stars and, as this cluster passes through a dust cloud in the Milky Way, the blue light from the brightest stars reflects off this foreground dust creating the blue nebulosity that surrounds them. M45 is potentially the closest star cluster to earth at about 444 light years away and is the nearest Messier object to earth.
Collecting the data Along with the Orion Nebula (M42), M45 is considered to be one of the hard easy targets for astrophotographers. It is relatively bright with a magnitude of 1.6, so that helps with not needing particularly long exposures that many dim DSO’s require. However, there is a lot of dynamic range in the light coming from the cluster, with bright stars, a nice nebula and much dimmer dust clouds that are not well lit by the stars. In my image presented here, you can see some of this dimly illuminated dust throughout the image. To really capture this dust well, a lot of integration and/or longer sub-exposures are required. I am happy to have pulled enough of the detail in these areas with heavy processing without too much injury to the photo quality.
To account for the high dynamic range presented with this target, I had planned on taking two sets of “lights/subs” so that I could capture the fainter dust and nebula without overexposing the bright primary stars of the cluster. Then, I could process these two sets in a way to blend the two exposures, hence capturing the total dynamic range presented. This is pretty easily said, but at my level of experience, it was harder to put this plan into place. I knew that I would have to experiment a little and make the decisions on my camera settings on the scene.
As usual, Miguel and I imaged M45 at the Bortle 4 sky location at Danville Conservation Area. Other than a few late hunters leaving with the sun, we had the place to ourselves except for the owls, coyotes, deer and armadillos. The forecasts were true and we had clear skies with mediocre seeing and transparency. It was a cold night! Temperatures ranged from the low 20s to about 14 degrees Fahrenheit over the course of the night. The heat packs on my lens and Miguel’s battery powered heat bands on his scope really did the trick with preventing dew and frost from forming on our optics.
Equipment For this target, I used the unmodified Canon 7D mkii and a 300 mm f/2.8 is lens. As usual, I reviewed my options at Telescopius and found that this was a good focal range (480 mm focal length equivalent). However, this choice would give me some problems.
I used the Skywatcher Star Adventurer without guiding mounted on the William Optics vixen style base. Although this is a great tracker and platform, I knew I would be pushing the boundaries of what this unguided setup could handle. At first, I could not get good tracking results with this heavy payload at 30 second sub-exposure lengths. With most photographers imaging this at 1-2 minutes, I knew I was really going to be pushing to get the signal to noise ratio where I needed it to be. But, the 30 sec subs where just unusable, so I took the first set at 20 seconds and ISO 1600. This would turn out to be a nice exposure for the brightest stars.
As I sat in the car thinking between outings to check battery life and focus, I knew I needed to find a way to increase my sub-exposure/signal if I wanted the image to be close to what I was envisioning. Around 11:00pm I decided to redo my polar alignment, rebalance and tighten down the rig to see if I could get to 30 second subs. I tried a few shots and although it wasn’t perfect, it looked like this could work. I checked the histogram on the back of my camera and it still wasn’t where I needed it to be. Although I was hesitant, I decided to increase the ISO to 3200. After doing this and checking the histogram, I knew I hit the sweet spot for the individual sub-exposures. Hopefully my calibration frames and the total integration time would keep the signal to noise ratio where I needed it to be. I shot another couple of hours at these settings to get the exposure I needed for the nebulosity and dust.
Imaging details Lights: 465 light images taken at 20 sec/ISO 1600 (manually removed obvious bad subs and used 408 subs for a total of 136 minutes of integration). 338 light images taken at 30 sec/ISO 3200 (manually removed obvious bad subs and used 216 subs for a total of 108 minutes of integration). Darks: 32 taken at each ISO Bias and Flats: Not taken. Removed most vignetting and chromatic aberration while converting RAW images to TIF
Processing I tried this two different ways. First, I created two different stacks in Deep Sky Stacker (DSS) from the two different sets of light data I had collected. I also stacked everything together in two different groups within DSS and used their “Entropy Weighted Average” (HDR) stacking mode. I then stretched and processed. For the first option, I used masking in Photoshop to blend the two “exposures” together to create the HDR effect. It was most likely due to the differences in how I processed following the stacking (this is not something I cannot do by recipe yet), but I found I like the image better when I started from the HDR stack by DSS, which is presented here.
Problems and learnings I already went into some detail about the struggle to get sub-exposure lengths where I needed them, pushing the boundaries on ISO and the need to redo PA and balancing to get to the sweet spot. There was also the time where I walked away for an hour without the shutter release button on the cable being engaged. Overall, I see the need to increase my efficiency. Not including the time it took to take the dark calibration frames and breakdown for the night, I estimate that we had about eight hours of good night skies to take our light frames. I was only able to capture about 5.5 hours of data in this time. Part of this is due to the time it takes to stop the process to check battery life and focus – this will always be the case. But I also lost time with the other things I mentioned. If things had gone perfectly, I could have had about two more hours of light frames. Ah well, I should get better with experience.
Conclusion This was a long and cold night but I think Miguel and I both think it was well worth the time and effort. I remember getting into bed a little after 6:00am, wondering if I had collected the data that I would need to make the image I had envisioned. It definitely isn’t perfect. I had to toss a lot of the 30 second sub-exposures due to pushing the boundaries of unguided tracking with that heavy payload and focal length. Even after that, a close look will reveal some ugly and mishappen stars due to imperfect tracking and shooting with the lens wide open. I’m not too concerned with the star quality, however. As long as the target looks good, I am happy. Maybe some day I’ll revisit M45 and use the 200mm lens. I should easily get 30-60 second subs with that lighter rig and hopefully have more of the prominent dust in a wider field of view.
Unfortunately, the story of the family in this nesting season has an unfortunate, and uncertain ending. At least, I do not know the final outcome of everyone. In early June, we had heard that the father was struck and killed by a vehicle on the River Road, within a few hours after Miguel and I left for the day. Our next opportunity to visit was a few days later. This was devastating news, obviously. In this species, both parents are critical in providing for the chicks and ensuring the best chances of successfully raising the entire brood. Still, with mom being a great provider and at least one, or potentially two, chicks capable of flight, we had good hopes that she could finish raising 1-3 of the chicks successfully. Once fledged, the parents still need to provide for the chicks for another 6-8 weeks until they are capable hunters. It would be a long hard struggle, but we had high hopes she would do her best.
Then more unfortunate news found its way to us. Another male had moved into the territory. At first this seemed like it might be good news, potentially someone to help mom complete the job of raising the brood. But as time went on, he seemed to be getting very aggressive with both mom and the chicks. He thwarted the mother’s attempts at bringing in food and harassed the chicks relentlessly every time they took to the air. Miguel and I visited for a number of hours over a few day period during this time and the number of successful feedings we observed were pitifully few – seemingly not enough for the chicks to complete their growth and perhaps move with mom to a different territory. We ended our observations around this time. I have heard through second hand accounts that mom was seen with two or three chicks flying away from the territory, so maybe there was a happy ending but I do not know.
I originally photographed M31 in August of 2020 as my first serious attempt in photographing a deep space object (DSO). I did not make many other attempts in DSO photography until the past couple of months where Miguel and I have had hard times thinking about anything else. There are multiple sides to this type of photography and so many ways to improve and learn. This is definitely the most technically challenging photography I have ever done. I’ll say this new attempt at M31 is a significant improvement over my first, mainly due to increased integration time and learning better processing techniques.
The Andromeda Galaxy (M31) You can learn a little about this section of sky by visiting my first post. In addition, here are a couple other factoids about this galaxy. One of the coolest things I’ve learned since getting into astronomy and DSO imaging is the size of a lot of these objects relative to other things that we all routinely see in the night sky. Sure, stars are small in our vision and there are a lot of very small objects that need very large focal lengths to see. But, many DSOs are actually very large. We don’t notice them due to their low magnitude of brightness. Many nebulas cover large parts of our sky, for example. For M31, it’s apparent size on the long axis is ~ 3.167 degrees. The size of the full moon is ~ 1/2 a degree, so M31 covers an area a little more than six full moons!
Andromeda was first formally described by Persian astronomer Abd al-Rahman al-Sufi in the year 964. Did you know that many of the first astronomers were living in the middle east? It’s true – many of the stars still carry their original Arabic names. Andromeda and other similar galaxies were originally thought to be groups of gas and stars within our Milky Way. The discovery and proof that Andromeda was its own “island universe,” like our own, did not occur until the 1920s. Over the last century, M31 has been extensively studied and is now thought to contain ~ one trillion stars.
Collecting the data The new moon period, which allows for the best low-light conditions for astrophotography, in October is troublesome. Miguel and I checked and double checked the forecast and found the best potential night was on October 22/23. We are finally getting some rain in eastern Missouri and most of this period is forecast for significant clouds. The night we chose was mostly cloudless but was not perfect. Winds were 10-13 mph with regular gusts up to 20 mph. In addition, seeing and transparency were on the poor side due to the winds and high humidity. This was not optimal, but it was still the best apparent night to try, so we did. To aid with the winds, we setup on the downwind side of a couple of hay bales and they did a pretty good job of acting as wind breaks. We imaged at my favorite site – Danville Glades C.A.
Equipment I had originally planned to shoot with my Canon R5 and the Canon ef 400 mm f/4 do ii lens. This framed M31 very nicely in Telescopius and I was eager to see how this lens performed in astrophotography purposes. However, with the winds forecasted, I decided to use a smaller lens that would be less likely to be affected. I wound up using the Canon 7D mk ii and the Canon 200 mm f/2.8 lens instead. This put M31 slightly smaller in the frame, but I thought it would still stand out well enough after a marginal crop.
I used the Skywatcher Star Adventurer without guiding and used my new William Optics vixen style base to mount the tracker on. This mount in combination of using a green laser pointer allowed for very good and easily obtained polar alignment. I’m happy to say that I need not dread getting PA any longer and I can make this step just part of the routine.
Imaging We had some clouds early on in the night. This wasn’t too much of a problem because they cleared out by about 9:30 pm and Andromeda was still in low latitude sky glow until about 10:00 pm. Imaging went pretty well. I did not have to throw out many lights due to wind or tracking errors. One problem that did become apparent was the quality of the stars. When wide open, this lens produces fat stars with pretty bad chromatic aberration. This was probably exasperated by the poor seeing and transparency. I knew this could potentially be an issue but wasn’t too concerned as I was mostly concerned about the galaxy. Anyway, next time I will stop this lens down by 2/3rds of a stop to try and improve this. The settings I used were f/2.8, 30 second exposures at ISO 1600.
Lights: 492 light images taken (manually removed obvious bad subs and used 447 subs for a total of 223.5 minutes of integration). Darks: 36 Bias: 50 Flats: Since flats are a pain to take and since I am using a camera lens that can be corrected for vignetting when processing the raw light files to tif format, I did not take or use flats for calibration. This was the first time I tried this and it seemed to work very well. This will be my new strategy going forward.
Processing Deep Sky Stacker worked! This was the first time I had good enough quality subs that DSS would register and process everything. After about one and a half hours of processing, DSO had processed my linear image. Processing was the biggest learning revelation I had from this project. Pieces finally came together. After stacking in DSS, I used various manual techniques in Photoshop along with StarNet for star removal, GraXpert for gradient removal and Astronomy Tools action set. I finally have a big picture of my step-wise work flow and this should get easier and better going forward.
Conclusions Including driving time, setup time, imaging time and processing time, I estimate it took about 20 hours of concentrated work to produce this one image seen here. When compared to my previous attempt of this object, I am quite satisfied by the results and the time spent was well worth it to me. The increase in integration time along with my improvements in post processing really paid dividends. Maybe I’ll try this target again in a couple of years if I have made improvements in equipment, techniques and processing.