Nature Photography
Bird, wildlife, and landscape photography by Jon Rista
The Pleiades – Eight Months Later
For those of you who have followed my blog for a while, you’ll know that I started doing deep sky astrophotography at the beginning of this year (2014). I think my first night out imaging was February 12, 2014. On that night, I battled patchy clouds, wind, a poorly calibrated mount and bad guiding, and a severe ack of knowledge to produce my first astro image of The Pleiades. The Pleiades, the Seven Sisters, is an icon of winter night skies. Often called “The Micro Dipper”, as to the naked eye it sort of has that appearance, I’ve wanted to see the Pleiades close up since I was a little kid. Back in February, my first attempt did not do this subject justice:
My first attempt at imaging the Pleiades. Imaged with the EF 600mm f/4 L II, 7D, Orion Atlas EQ-G, Orion SSAG guider, BackyardEOS, DeepSkyStacker, and Photoshop.
If you’ve ever seen the Pleiades yourself, the image above doesn’t look like much more than what you might see with your own eyes, or maybe a pair of binoculars. Unsatisfied with this result, I tried again about a month later. This time, I managed to pick up more of the detail around the seven+two stars (the seven sisters, and mom and pop ;)):
The Pleiades Reflection Nebulas
Slightly more detail on the reflection nebula, non-emissive dust and gas that reflects the light of the nearby stars, in this case the pleiades themselves. Overall, though, still not much more than you can see with your naked eyes. Starting in September this year, I started gathering light frames on the Pleiades again. This time with the Canon 5D III instead of the 7D, for a much wider field of view. I knew there was much more to the Pleiades than could be seen with the naked eye, or what I’d been able to gather before. Based on some of the work I’d seen produced by other (vastly more skilled) astrophotographers than myself, I knew that there was a lot more to the entire region, beyond simply the primary reflection nebula around the Pleiades themselves.
Throughout most of my time imaging since I started in February, I’ve been using filters to allow me to gather more detail on faint emission nebula. Starting with the Pleiades, I decided to try targets that don’t work well with filters. Removing the filter means I would be limited to much shorter exposures, making it a lot more difficult to get any amount of exposure on the faintest bits of nebula. It was to my surprise, then, when I finally started merging my individual light frames together that I saw the faint reflection nebula in the extended space around the Pleiades itself. I had hoped to get a little more nebulosity within the primary object, I hadn’t hoped for much beyond that. As I kept processing, I realized that there was a LOT of additional nebula there. Far more than I had expected, more than just about any image I’d ever seen of this particular object had ever shown (with the exception of one, from one of my favorite astrophotographers, Rogelio Bernal Andreo…PHENOMENAL wide field imager with a talent for pulling out faint structure in brilliant detail and color that I believe is exceptionally rare. He’s one of the greats of our era.)
The faint reflection nebula that surrounds the Pleiades extends throughout the entire region of sky. It reaches farther east into the heart of Taurus, it reaches farther north into Perseus, around the brilliant red California Nebula. It continues on up through various regions around the north pole, through the Big Dipper and right up to Polaris. This faint nebulosity is part extended dust regions of our galaxy, and was given the name “Integrated Flux Nebula” or IFN by astrophotographer Steve Mandel as part of his Unexplored Nebula Project. The light reflecting off of this faint nebula is an aggregation of all the light from the relatively nearby stars, even the collective of stars in the Milky Way itself, and a small amount of Hydrogen Alpha emission. The IFN around Pleiades was known, however that the dust extended up through the northernmost peripheries of our galaxy was not well known until Steve gave it a name in 2005, and started naming individual regions of IFN nebula.
Now that I know I can pick up some of this nebulosity with my current equipment, once galaxy season rolls around again next year, I think I’ll give a shot at imaging the IFN around M81 and M82, two galaxies I previously imaged.
Technical Details
Total Integration Time: 3hr 30m
Number of Subs: 84
Flat Frames: 30x
Bias Frames: 200x
Exposure per Sub: 150s ISO 400 f/4
Processing Details
Integrated with DeepSkyStacker
Initial processing with PixInsight (calibration, stretching, initial NR)
Intermediate processing with Photoshop w/ Carboni’s Astronomy Actions
Final processing with PixInsight (additional NR) and Photoshop (Diffraction spikes)
Imaged under Bortle Scale Orange Zone, suburban city light pollution (grayish-orange skies), from my back yard outside of the Denver Metro area.
2 Comments
Comments are closed.
Nature Photography 
Jon, Beautiful. I emailed you through CR a while back. I have been out in my back yard a few times since then to orient myself with tracking, etc… That was a hurdle to overcome in -10 degrees! I don’t live in a dark site (10 minutes from Burlington, VT) so I have been using a LPS filter. My first images of Pleiades look just like your first attempts! Would you mind sharing how you made such a leap? If I am to interpret your post correctly, you took many more shorter exposures without the filter and as you added exposures the details emerged? Are you using photoshop or Images Plus (or similar)? Also, how did you get the diffraction spikes?? Are you using a telescope or a camera lens? Thanks in advance for sharing whatever you are willing to. You can email me if you don’t want to post publicly. Your blog on astro posts is a real inspiration to me. Thank you, -Chris
Hi Chris! Sorry for the late reply…I seem to not be getting email notifications of comments on my blog at the moment. I did not intend to ignore you. The cold can definitely be a challenge. I’ve imaged out well east of the Denver metro area during the end of December, temps 0F but more like -15F with wind chill. Brutal!
Regarding imaging the Pleiades more deeply. The biggest thing I can offer is: Stick with your target. Most beginners try to image quickly, getting only a couple of hours on a target at a time. Astrophotography, especially from any light polluted area, is all about the integration time. The total exposure time across all your individual light frames (subs). My last Pleiades image was hours of integration…in the end, I think it was around five or six hours. The critical point though, is it took me many nights to get that much data. I think I imaged that one target for several nights over a period of over a month. Just gotta stick with it. Even despite that much integration time…the image noise was quite heavy, and required some rather extensive noise reduction which softened a lot of detail. The only way I’ll do better is to drive out to where the skies are really dark, and get much longer exposures.
I also imaged unfiltered for this target. Light pollution filters block out certain amounts of light, and result in strange color casts. For your normal emission nebula, LP filters are fine, they pass the colors of the nebula. But for reflection nebula that just bounce back the light of nearby stars, which is what Pleiades is, LP filters tend to block out a lot of light, which results in strange colors for the stars. So, I did not use a filter for the Pleiades image. Because of the light pollution, I had to use short exposures, and because the exposures were short, I needed hundreds of them. (And, hence the reason it took multiple nights.)
As for the software I use, I use Photoshop and PixInsight. More and more, I use PixInsight for things. It’s the best software out there, by far, for astrophotography processing. It’s somewhat expensive, ~$250 depending on exchange rate. I believe it is well worth the cost if you are serious about astrophotography, though.
I use my Canon EF 600mm f/4 L II camera lens, and my 5D III, for imaging currently. You can actually do quite a lot with your basic camera gear if you can find a way to mount it to an equatorial tracking mount. You could use any prime telephoto and a DSLR, and get some pretty amazing results. I highly recommend starting that way, especially if you already have the camera equipment. All you need then is the mount. You can expand your kit as you go, once you learn the ropes, get into guiding, figure out all the nuances of tracking efficiently, learn how to process, etc. I’m finally to the point where I need a CCD to take my work farther…and I’m also contemplating some real telescopes so I can do more advanced things with my guiding, etc. It’s a long journey…there is a ton to learn. Just start with what you have, get an equatorial tracking mount, and start learning. 🙂