Seven Sisters

Pleiades star cluster imaged at Prineville reservoir Oct. 1.
Pleiades is actually the logo for Subaru automobiles if it looks familiar (rotated)

Specific Feedback Requested

Technical Details

Is this a composite: No
Modified Nikon D610
300 w 1.4 @ 420mm
EQM-35 mount
2 hours image time.
PP in Astropixel, Capture one, Affinity photo


Dan, this is such a cool image. I like everything about it. 2 hours image time is a lot…maybe not for astrophotography though. Thanks for posting this.

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I don’t know anything about deep sky mages but this looks great. Everything is so sharp and the contrast looks great.

Dan, I still have questions (rhetorical) about your processing. Saturation of the blues feels overdone and the center of each star has been dimmed down to gray, which looks very strange. The added diffraction spikes just feel overdone, but might look better without the gray star centers. (The spikes occur in reflecting telescopes from the vanes supporting the central reflecting mirror and wouldn’t occur with a camera lens.)

The red nebulosity around the cluster is an interesting touch that I haven’t seen before.

The lens and sensor are doing a very good job but the small stars are elongated, which may be due to polar alignment being off.

Two hours of light collection is minimal. The more photons that can be collected, the better an object’s fine details can be brought out. Longer acquisition times and/or different processing should let you bring out more detail in the nebulosity and colors in the BG stars.

If I may, here are two views of the Pleidaes for comparison:

Thanks Diane, I appreciate it… my processing is just what I think is fun to do, especially given that Astro is all subjective mostly anyway and colors are totally subjective since they are just colors assigned to different gas types…
My star spikes are done with guitar string and duct tape to the lens hood. It works pretty well for a totally non tech approach. They were not added in post, they are on the image.
The center of the stars I did lower too much , they were blown.
Of course 2 hours is minimal but in Bortle 1/2 sky it is difficult to not blow highlights even at that time length.
The red nebula I have also not seen on others but it is in the Raw files. My camera is modified with an HA filter so the reds are pretty intense.
My processing is evolving, I do not use Pixinsight yet, just Atropixel for stacking and stretching and Capture and Affinity for star removal and finish processing.
I also try to shoot several targets in a couple nights to get the most out of my time in Bortle 1 so I limit each target to 2 hours just so I can have more subjects to work on and learn from.
I am not guiding yet, so do get some star elongation with my $750 EQM mount at times, I was shooting unguided 3 min subs at 420mm.

Colors are only subjective in narrowband imaging, where colors are assigned to various spectral emission lines, and even then there are standards such as the Hubble palette. A color sensor such as a modified camera will capture actual colors with the same sorts of leeway we have in terrestrial imaging, and they can be manipulated realistically or otherwise. Daylight WB renders the colors accurately. I’ll admit I have a bit of a pet peeve about colors and tonalities being pushed unrealistically and viewers not having a basis for knowing they have been pushed. It’s not that different from super-saturating a sunset or autumn foliage.

Clever about the guitar strings. I would worry less about stars being blown than being gray. It sounds counter-intuitive but the advantage of many hours of photon collection is that stars can be given an exposure that will show their true color (which depends on their temperature, from blue to yellow, orange and red) and the right software can stretch the dark end of the histogram to what seems an impossible degree, to pull out the dim details of nebulosity without blowing out stars.

I wonder if 1-minute subs would be better, both for star colors and streaks. I know how hard it is to get out in good conditions, but it would be worth one try for the longest session you can get on a single object.