Tag: astronomy

IC 1396
Approximately 2400 light years from earth, just outside the constellation Cepheus in a rich region of the milky way of our northern sky, lies a dense emission nebula catalogued as IC 1396. A birth place for stars, this huge and roughly spherical grouping of nebulosity is approximately 3° wide. The interior of this sphere houses a cluster of stars formed from the internal condensing gases. With most of these gases used up in the production of these bright young stars, the interior now contains minimal nebulosity. These new stars now provide the energy that excites the remaining hydrogen gas in the nebulosity shell, and is responsible for the magenta-red appearance.

This region contains numerous catalogued points of interest, including quite a few dark nebulae that thread their way around the shell’s perimeter. These dark nebulae lie between us and the radiating stars of the shell’s interior.

The most famous feature of this deep sky object is IC 1396A, commonly known as the Elephant’s Trunk Nebula. In my image, it appears at approximately 9:00. This nodule of nebulosity is also a site of star formation. Recent infrared images have shown stars less than 100,000 years old within this pinnacle of dust and gas. The bright orange supergiant star known as Herschel’s Garnet Star lies to the north at 6:00. You can find an annotated version of my image by clicking here.

Collecting the data
It had been about 10 months since I had an astrophotography outing. This was mostly due to life interfering during periods when the new moon met up with conducive weather. I guess I also wasn’t too excited about trying during warmer months with my astrocamera that has been plagued with the dreaded Canon sensor banding. For an October session, we would find unseasonably warm conditions that had me worried about this issues as well. Thankfully, this turned out to be a non-factor.

For the most part, weather and other conditions were near-perfect. Winds were a little higher than we would like to see them but were not a significant problem. Miguel and I travelled to our usual site at Whetstone Conservation Area. I was a bit surprised to see that the secret of this location was out – as several astronomers (seemingly all visual on this night) joined us. This was a hearty crowd but respectful and did not interfere with our activities.

Date and location
Imaged on the night of 05/06 October 2024 at Whetstone Creek Conservation Area in Callaway County, Missouri (Bortle 3).
Dark period: 20:09 – 05:37
Target period: 15:31 – 03:58

Conditions
You gotta love a forecast for such a clear sky night so close to the new moon. Skies were forecast to be completely clear and they were. Temperature bottomed out in the mid sixties and winds were high, with some gusts peaking to 10 mph or more. This is not ideal, but I only threw out one sub that was blurred due to either wind or me bumping something during the exposure.

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.

Imaging Details
Lights taken (ISO 3200, f/4, 120 second exposure): 165
Lights after cull due to tracker error, wind, bumps, clouds, etc.: 164
Used best 90% of remaining frames for stack for a total of 147 subs used for integration (4h 54m)
Calibration frames: none

Processing
RAW files stacked in Astro Pixel Processor, GraXpert for gradient removal, Affinity Photo 2 with JR Astrophotography Macros v18 for stretching and other cosmetic adjustments.

Problems and learnings

Acquiring data
Considering I took nearly a year off from astrophotography, I have to say that I was pleased with how well this night and the subsequent image turned out. Polar alignment was quick and easy and I had no problems getting the two-minute individual subs with my tracking. As the star scores suggest from APP, my initial focusing was off a bit, but I corrected for this approximately halfway through the night.

As usual, I struggled a bit more than I should have with finding and framing the target. I have a need to learn something here that I feel I would greatly benefit from. Typically, I don’t have much of an issue finding my target, using tools like star hopping and the oh-so-nice astronomy apps available on our phones. My issue lies in not knowing the exact orientation of the object when, in cases like these, the object is relatively dim and I cannot make it our very well in an individual sub. In this case, I found the Garnet Star, and could make out enough of the nebula to know that it was in my frame. However, I just wasn’t familiar enough with or confident I knew in which direction the object lied in relation to this indicator star to be able to set my composition. Ultimately, I did my best and crossed my fingers that I wasn’t going to be cutting off anything important in my composition.

To a well-seasoned observer of the night sky, this problem may sound ridiculous, but because of the earth’s rotation, the relationship in direction of the object to the indicator star can change over the course of the night. I don’t know. Maybe this is much easier than I make it out to be. However, this single problem typically costs me 1-2 hours of imaging time each session and I would love to get more efficient at this. Please let me know if you have any tips or tricks.

Keeping the ISO high and exposing a little more to the right seemed to keep the dreaded Canon banding away again. I suppose I can say this is a fruitful strategy and I will keep this up in the future.

Processing
During my hiatus in AP, I have ditched all Adobe products and switched to Affinity Photo for my processing needs. I knew this was going to tax my already lacking AP processing abilities and it probably did. Someone who was skilled in the arts could probably do a much better job than I did. In this case, I manually performed the stretch and then finished it off with a few actions I found in a nice little bundle of AP macros made available by James Ritson.

One very surprising outcome for me was the fact that I somehow found a method for stretching that preserved the star colors. Even though I used methods that were supposed to do this in the past, this was never really the case and I was forced to exchange star color for bringing out the details in the DSO. What was the difference here? Beats me. Maybe I didn’t stretch this one as much as I typically would? Or, maybe there is something inherently different between doing these things in Affinity Photo compared to Photoshop?

Conclusion
It was nice to be back in the AP saddle again. Longer nights on the cold side of the equinoxes make this a little more fun for me, although there are still a lot of summer objects I hope to get someday. I definitely need to improve my post processing, but so far, I like what I am able to do in Affinity Photo.

This is an area I hope to get back to next year by either attempting a tighter focal length of the elephant’s trunk or by going after other objects that are plentiful in the Cepheus region. As always, if you made it this far, thank you. I appreciate your attention.