Tag: Bill Duncan

NGC 281 – Pacman Nebula

astrophotography

The Pacman Nebula (NGC 281)
The Pacman Nebula is a large emission nebula that is approximately 48 light years across and nearly 9500 light years from earth. It was named for its resemblance to the popular Pac-Man character in video games, although you’ll probably have to use your imagination to see this in my image (Pac-Man is facing towards the top of the image). Unlike the the popular Namco mascot, this Pac-Man does not gobble up dots, it is actually creating them; NGC 281 is a star forming region that lies near the constellation Cassiopeia.

Collecting the data
Miguel, who is now getting serious into deep sky object (DSO) photography, and I met at what is now my favorite location for this work – Danville Conservation Area in Montgomery County, MO. This is classified as a Bortle 4 sky location and we were working under near perfect conditions of a new moon, no clouds, low winds and cool temps (mid to low 40s). Selecting a great night was one of the successes of this project. Miguel was just beginning to work on his new rig, attempting polar alignment for the first time and trying out his more sophisticated system of go-to and guiding. I use a simple unguided star tracker and the camera gear I use for normal daytime photography and had my target in mind and planned a night of imaging.

The photographer’s kit used in this project.

Gear used
Canon 7d mkii, 300mm f/2.8 lens is mki, Sky-Watcher Star Adventurer tracking mount with extra counterweight balance, Bahtinov focus mask, red-light scope, heat packs used for prevention of dew formation on lens, all setup on a sturdy Gitzo carbon fiber tripod and anchored to a concrete block.

Imaging details
Lights: Approximately six hours with 30 second subs (manually removed obvious bad subs and used 512 subs for integration.
Darks: 32 darks captured in field after imaging
Flats: 40 flats taken the next day from home
Bias: 67 bias images

Processing
Image shown here was stacked using Sequator. Stacked file was processed in PhotoShop CS6, manually following processes described in various YouTube videos. See below for details learned from this processing session.

Problems and learnings
This was a good night but definitely not perfect. Again, I struggled with getting proper polar alignment. My main issue was not identifying Polaris, necessarily, as we were easily able to find it with our naked eyes. The problem came from being able to correctly identify the star while looking through the reticle. Ultimately, I picked the most likely candidate and went with that. I didn’t have much star trailing in my 30 second subs, so I think I did an OK job. I did notice that the tracking was off and I had to recenter the target about once an hour, but that is due to using an unguided tracker and the weight of my rig. This is something I’ll just have to remember to do with future objects.

William Optics vixen style base mount. A must have!

I have picked up a couple pieces of gear that will dramatically help with achieving proper PA on future projects. First, I purchased a green laser pointer that I can shoot directly through the reticle and line up perfectly with Polaris. More importantly, I finally picked up a new wedge/base mount to support the tracker. This is the piece that is critical in getting proper PA. The mount that comes with the Sky-Watch Star Adventurer is severely lacking in many ways and is frankly a POS. The William Optics model I now have (see photo) is all metal, allows for more precise control in declination and is much easier to control right accession with. The differences are like night and day! I didn’t have these two things for imaging NGC 281, but I have them now and tried them in the yard one night and achieved perfect polar alignment in less than 15 minutes! I feel much less anxiety about this step now and wish I hadn’t waited so long to pick up this base mount.

The biggest mistake of the night was something I was aware of but simply forgot to handle. I left the settings for auto orientation on in the camera. This means, as the mount tracked the object over the course of the night, about half of my images were in the horizontal orientation and half of them were in the vertical orientation. This is a much bigger problem than it seems. In most software, you can change the orientation of an image with a simple mouse click. However, the orientation is actually embedded in the exif data of your RAW files. I came to find out that most stacking programs will not orient all of the files for you and, therefore, I was losing half of my light subs in the stacking process. It is possible to change the exif data to make them all the same, but this requires computer skills that I simply do not have. Thankfully, Sequator did accept all of my subs, but it is not the best software for stacking DSOs. I would love to fix this in the data I have collected for NGC 281 and be able to stack in Deep Sky Stacker or ASTAP one day, but I will definitely remember to turn this function off in camera in the future.

Processing after stacking was the usual barrel of fun. I found it a little easier than I did for M31, but I think I have a long way to go. I was hoping to get much more detail in NGC 281. I think I had ample integration time and feel there may be some detail I can pull out with better processing. Maybe the fault lies in my images themselves and I could do better with PA and tracking. It might also have to do with the focal length. With the 480mm focal length equivalent used for this object, I don’t have much more opportunity to improve here, but I could have used a 1.4x teleconverter and get 672mm focal length equivalent. I think there was room to do this with this object, but I would have had to recenter more often and lost some light gathering in the process. Maybe next year!

The author setting up for a night of imaging. Photo by Miguel Acosta.

Conclusions
Despite the final outcome, which I am satisfied with, this was a lot of fun. I’m finding that I can have fun doing almost anything as long as I am outside. This is getting truer all the time. Although this process has its frustrations and anxieties, I guess you can call that a “good stress.” I’ll always remember the pair of Barred Owls squawking away at each other and the coyotes howling and barking on at least three sides from where Miguel and I worked. In addition, while I was breaking down at about 3:00 am, two armadillos noisily burst through the grasslands, coming up to within ten feet of me to see what I was doing.

My hope is to continue this and image one object a month. I think I can sacrifice one good night’s sleep a month for such experience, learning and memories.

Clear skies!
-OZB

Catalpa Sphinx (Ceratomia catalpae)

macro, wildlife, wildlife photography

Miguel and I found an aggregation of the catalpa sphinx moth caterpillars on a caterpillar hunt in early September. I have been looking for this species for a while so this was a nice find. Of the ten or so we found, one was infested with the parasitoid braconid wasp cocoons. See photos below.

Lesser Scaup Hen – May 2022

birds, Photography from the boat, wildlife, wildlife photography

Photos taken of a Lesser Scaup hen taken from my canoe in Ellis Bay at Riverlands Migratory Bird Sanctuary in May, 2022. Due to the large area of white on the face and the lack of white wing bars in the primary flight feathers, I feel reasonably confident in calling this bird a Lesser Scaup, but please let me know if you have evidence to suggest otherwise.

Female Lesser Scaup
The white wing bars stopping at the primaries suggests this is a Lesser Scaup hen.

2022 – Year of the Limpkin!

birds, wildlife, wildlife photography
A visitor from the south, this Limpkin was found in early September, 2022, at the lake of the Japanese Gardens at the Missouri Botanical Garden in St. Louis, MO.

Prior to 2022, the Limpkin, a bird with a normal range from Florida to the north to northern Argentina to the south, had never before been recorded in the state of Missouri. This year there have been at least 10 birds recorded in the state so far, the latest finally coming from the good part of the state! 😉 The bird featured here was found in early September by Cathy Spahn at the Japanese Garden of the Missouri Botanical Garden in downtown St. Louis City. This was extraordinary timing as the annual Japanese festival at MOBOT was going on at the time. This meant large crowds of people. Several of us arrived early on the morning of the 5th and found the bird quickly, giving us great looks and not seeming to mind the presence of people at all.

Here the Limpkin can be seen in the context of the Japanese Garden, with visitors on the zig-zag bridge, or Yatsuhashi, across the water.

The Limpkin looks like a heron in appearance, but is actually the only extant member of its own family, the Aramidae, and is actually considered most closely related to the rails. It is also unique in feeding primarily on apple snails but will feed on other types of snails, freshwater mussels and clams and small aquatic arthropods like crayfish as it forages through its preferred habitat of brushy swamps and marshes.

The crooked overlap at the tip of its bill is not an abnormality. This aids the Limpkin in removing snails, their preferred food, from their shells.

This influx of Limpkins into the Show Me State wasn’t exactly a surprise. Limpkin reports outside of Florida began around 2015, with records being found in Georgia, and other southeastern states over the following years. Birders have been waiting for them to show up in Missouri for a few years and now they finally have. The reasons for their northward spread are uncertain but are likely due to the spread of an exotic island apple snail originally from tropical and subtropical South America.

The Limpkin foraging among the lotus at the lake of the Japanese Garden.

I had thought about chasing Limpkins previously seen in the state in 2022 but couldn’t get myself talked into the roughly 600 mile round trip drive this would have taken. I’m so glad I saved the gas! This was quite the experience and I’ll be interested in seeing how long this bird stays in St. Louis. Here are a few more photos of this fantastic bird.