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:
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 ;)):
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.
Total Integration Time: 3hr 30m
Number of Subs: 84
Flat Frames: 30x
Bias Frames: 200x
Exposure per Sub: 150s ISO 400 f/4
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.