Author: Ceibatree

The Cygnus Veil Complex @ 260mm

astrophotography

The Cygnus Veil Complex
The Cygnus Veil, also known as the Cygnus Loop, is a large (~ 3° in diameter) emission nebula created by a supernova explosion that occurred ~ 20,000 years ago. It lies an estimated 2400 light years from our solar system within the Cygnus (Swan) constellation.

Due to the large size of this gaseous complex, most astrophotographers choose to separately photograph distinct portions of the loop, or those portions of the loop that can be seen in visible light. The nebula on the left-hand side of this image is known as the Eastern Veil (Sh2-103, NGC6992, NGC6995), and on the far right lies the Western Veil, or the Witch’s Broom (NGC6960). In between these two lies Pickering’s Triangle (NGC6979), which was first discovered by the Scottish-born photographer, Williamina Fleming in 1904.

Somewhere inside this loop is the compact stellar remnant – the remains of the star that went supernova. Depending on the size of the star, this will either be a neutron star or a black hole. Both of these options are very difficult to identify as they do not emit much in the way of detectable radiation. Despite attempts by astronomers, the identity and position of the compact stellar remnant have not yet been discovered.

Collecting the data
Due to the interference of clouds and life requirements, I missed the previous two new moon phases and it had been close to three months without an AP session. I was eager to get out there under clear skies in lovely September temperatures. Miguel found us a new imaging location – Whetstone Creek Conservation Area. This location has slightly darker skies (Bortle 3 vs. Bortle 4) and is only about a ten minute longer drive from my front door. To top it off, it is also seems less popular (at least during my first visit). I definitely have a new home for my astrophotography pursuits!

Date and location
Imaged on the night of 14/15 September 2023 at Whetstone Creek Conservation Area in Callaway County, Missouri (Bortle 3).
Dark period: 20:46 – 05:15
Target period: 15:30 – 05:10

Conditions
The forecast was great for the night we chose for this session, but it turned out not to be perfect. We lost two hours of potential imaging time due to clouds that would not clear out until about 22:00 and clouds remained in the lower west that screwed up another hour or so on the late end. Temperatures were great, but seemed quite cold, with lows in the upper 40s F. Winds speeds were perfect with nothing above 4 mph across the night.

Equipment
Astro-modified Canon 7D mkii camera, Askar ACL200 200mm f/4 lens (260mm focal length equivalent), Fornax LighTrack II tracking mount without guiding on a William Optics Vixen Wedge Mount. QHYCCD Polemaster. Gitzo CF tripod, Canon shutter release cable, laser pointer to help find Polaris and sky targets, lens warmer to prevent dew and frost on lens, dummy battery to power camera, lithium battery generator to provide power to camera, dew heater and laptop computer.

This was “first-light” for my new Askar 200mm lens – a lens specifically designed for astrophotography purposes. It is excellently built and provides a distortion-free field of view which was a hindrance of my Canon 200mm f/2.8 lens. When perfectly focused (read more of this below), it will definitely shine in comparison to my old 200mm focal length option.

Imaging Details
Lights taken (ISO 3200, f/4, 120 second exposure): 178
Lights after cull due to tracker error, wind, bumps, clouds, etc.: 146
Used best 95% of remaining frames for stack for a total of 138 subs used for integration (4h 36m)
Calibration frames: none

Processing
RAW files converted to TIF in Canon DPP, stacked in Astro Pixel Processor, GraXpert for gradient removal, Starnet++ for separating nebulas from stars, Photoshop CS6 for stretching and other cosmetic adjustments.

Problems and learnings

Canon banding
After months of diving into the forums and other online sources of information, I came away with only one strategy to hopefully avoid the terrible “Canon banding” problem I faced in a couple of previous sessions during warmer temperatures. In order to get my target above the sources of noise, I elevated the ISO used. In addition, I increased the sub exposure time. Increasing the sub times was partly in necessity of using a lens with an f/4 widest available aperture. I also moved the peak of the histogram for these exposure further to the right than I typically have. Thankfully, with my new tracker and polar alignment process, two-minute subs were easily accomplished without any issues. I could definitely go longer, but keeping the ISO at or above 3200 would not allow for this in order to keep the histogram where it needed to be.

After reading from a number of trusted sources, suggesting dark frames offer little-to-no benefit using my particular camera, I eliminated taking dark frames and any other calibration frames. This was an experiment. In practice, with enough total integration time to remove noise in the stack, I do conclude that dark frames/calibration are not necessary in my AP process. Additionally, there is some thought that using dark frame calibration can increase the potential for Canon banding and other issues that can show up during the stretch. This is a welcome finding indeed! With taking longer sub-exposures now, taking the required number of dark frames could add well over an hour to my night sessions.

The downside of using such an elevated ISO setting is the reduction in dynamic range. This probably does mean I am losing some tonal gradients and perception of sharpness in the final image. However, this is better than dealing with the banding problem that almost kills the project. I will keep this strategy moving forward.

Focusing
The new lens offers great focusing aid. It has two focusing rings – one for coarse and one for fine focus, and each of these has a lock so that you will not inadvertently change these over the course of the evening. But, the tool is only as good as those who yield it. I had a little trouble with the fine adjustment and realized that the majority of my frames were not optimally focused. Overall, the image doesn’t suffer too badly from this oversight. With the focus problem and the never-optimal seeing conditions in Missouri, my FWHM (Full Width at Half Maximum) were in the 6-8 range. An FWHM of two or less is considered optimum for the uber astrophotographers out there. Always learning!

Processing
I would really like to improve my processing skills for this work. Although I love the amount of hydrogen-alpha (the reds and magentas) that my sensor collects, the blues and star colors seem to get lost in the stretch. From my knowledge, I am using the correct curves adjustments that are supposed to avoid this, but there should be a lot more of the blues that are emitted from oxygen emission in this target. In addition, the blues are coming out more teal-colored, which I do not find all that attractive.

Conclusion
With all the challenges I discussed above, I suppose I am relatively pleased with this one. I think I left some detail on the table, but there is enough there to make it interesting. The image handled the stretch well with no real signs of the dreaded Canon banding. This is an impressive and interesting target. I may try again using the 300mm lens. At that focal length, it is a tight fit. I hesitated to use it this time because of the potential of losing some of the target during cropping to eliminate stacking artifacts around the frame edges.

What do you think? Is this worth the time and effort? After looking at these images for so long, I find myself unable to really give them the critical eye needed to make this judgement. Feel free to leave a comment with your opinion.

Indigo Bunting – Nonbreeding Male

birds, Nesting Birds of Missouri, wildlife, wildlife photography

This Indigo Bunting was found in mid-August of this year at Little Creve Coeur Ecological Area in St. Louis County, MO. This is either an immature male or an adult male that quickly molted into nonbreeding colors.

Saddleback Caterpillar – 2023

insects, Lepidoptera, macro, WGNSS Field Trips, wildlife, wildlife photography

We had a great time this past Saturday when the WGNSS Entomology and Nature Photo Groups got together for our great caterpillar hunt at Pickle Springs C.A. in Ste. Genevieve County, MO. Of course I was primarily looking for the Limacodidae – the slug moth caterpillars. We’ve had better results with the slugs, but we did find five species over the course of the day, including a spun-glass slug (Isochaetes beutenmuelleri) and this saddleback (Acharia stimulea). Unfortunately, I was the only one to see this one as I spent some time by myself in the late afternoon looking through hundreds of young oak trees at Hawn State Park.

As always, we did find a few other species of interest, unexpected things and, as of now, unidentified creatures. I will be posting more from this trip in the near future.

I decided to go for stacking this nice saddleback. With so many details and intersecting lines, I knew this might be a risky attempt. I think they turned out pretty nice.

As much as I like the convenience and price of my wireless Godox flash system, it does come with some aggravations. One thing that frustrates me is the ease in which the controls can be inadvertently changed when carrying the system around on a strap. Then, the flash doesn’t work and I have to take the time to figure out what happened and make the necessary adjustments. Or, after powering the transmitter and flash down, the settings in one or the other change for some reason.

Another thing that drew my attention when putting these stacks together is the variable light output when taking a stack of images like these. Despite everything in the camera and flash units being on full-manual control, the illumination provided by the flash varied noticeably from one image to the next. This is something I never noticed when using my Canon branded speedlights. Thankfully, the differences between exposures, in the slivers that are used to make up these final images, is not noticeable at all. So, maybe I’m complaining about nothing.

Here is the first stack, also featured at the top of the post. The head of the caterpillar is facing you but is not visible as it is covered in the protective hood. Additional protection is also afforded by the obvious sharp tubercles that can break off into any would-be predator, injecting toxins that burn and irritate, an experience that I think is very similar to that of brushing up against nettles.

Saddleback caterpillar (Acharia stimulea). This image was taken with a 180mm macro lens on a full-sized sensor camera, composed of a 37 image focus stack at f/11, 1/125 sec and ISO-250.

The next stacked image is an overhead view. I am putting this one in as a full-sized jpeg file. So, be sure to click on the image to see the details up close! The remnants of the mucous-like silk they secrete as the glide about the leaf surface can be seen towards the bottom of the image.

Saddleback caterpillar (Acharia stimulea). This image was taken with a 180mm macro lens on a full-sized sensor camera, composed of a 26 image focus stack at f/11, 1/60 sec and ISO-250.

Virginia Snakeroot (Endodeca serpentaria)

macro, native plants

Virginia snakeroot (Endodeca serpentaria) is an easily overlooked cousin of the much more familiar Dutchman’s pipevine (Aristolochia macrophylla). Belonging to the Aristolochiaceae (birthwort) family, both species host the pipevine swallowtail butterfly. The Aristolochiaceae family is composed primarily of tropical woody vining species. Virginia snakeroot is an exception in the family, being neither tropical, woody nor a vine. This species is a low and slow growing herbaceous perennial native to Missouri and is a really nice find.

The hastate leaves and growing habit of Virginia snakeroot (Endodeca serpentaria). Note the ground-level flower.
Flower of Virginia snakeroot.

Osmia taurus – Taurus Mason Bee

Hymenoptera, insects, macro, wildlife, wildlife photography

Casey and I found these mason bees in mid April this year at Hughes Mountain N.A. I had no clue what these were but was intrigued to “discover” a new-for-me bee so early in the season. Unfortunately, I was to find out it is yet another introduced species. Apparently these were first found in Maryland in the 1970’s and have spread west since then.

Eastern Bluebird Nesting Season – 2023

Backyard Gardens, birds, Nesting Birds of Missouri, wildlife, wildlife photography

The Bluebirds had another great year. I was much to busy to do the typical monitoring I normally like to do, but they did have three clutches this year with a total of 12 fledged birds (3, 5 and 4 eggs in 1st, 2nd and 3rd nests). Immediately after putting up the nest box in early March, a pair took control and made their first nest. After completing this, I cleaned the box and began a daily routine of removing nesting material from the non stop Eurasian Tree Sparrows. I removed nests 1-2 times per day, often removing up to eight inches of nest and sometimes with an egg or two. They were relentless. This went on for at least six weeks. I was wondering why the Bluebirds didn’t come in and take over so I could have a break when I finally decided to have a look in the Wren box, which they did use in a previous year. Yep, inside I found five young chicks (nest 2). I took advantage of this and was able to take a few photographs that I am sharing here. They then went back to the Bluebird box for their third nest. These chicks fledged a couple weeks ago.

I knew the ETS would be back to this box in a heartbeat like they do every late summer and fall, so I removed the Bluebird box for the season. I think three clutches for the season is great, although it wouldn’t have surprised me to see that the Bluebird pair might try for a forth. But, I think it might be better not to push the female too far and let her build some fat for the winter.