Re: M27 and filters: It's the colors, Dumbbell!


Adams and the F64 Club. Each phograph must be in complete focus throughout its depth of field, each photo must use the full range of light available to the photographer and that full range must be seen in the final image. After Man Ray came along everything went to H and few learned basic fine or technical photography. Not that I don't like the occasional photo with the subject swinging a flashlight around to record the tracings but to me it's not reality. Perhaps I am a purest and new to astrophotography, this has been a lingering question since I began. My thanks to all who have responded. I've learned a lot from all of you. -Best, Robert

On 08/04/2022 9:57 PM Brian Kaine <briankaine@...> wrote:

The use of color in astronomical imaging, and especially regarding DSOs, is a very complicated subject.
Even in terms of simple RGB imaging where we are trying to render objects as they “naturally” occur, there
are countless variables involved. Let’s consider the following:

The optics of our telescopes obviously affect the colors we record. Reflector vs. refractor? Different types
of glasses used in lens manufacture? Coatings? Surely we have all heard of different brands of refractors
yielding images that are warmer or cooler to the eye.

Much the same can be said for RGB filters. Which brand do you care to use? Astrodon? Astronomik?
Baader? Chroma? ZWO? They all differ to some degree in the wavelengths they pass for each channel.

What about the atmospheric conditions when we record our images? Urban or country location? Manmade
light pollution? Particulate matter in the atmosphere? Are there fires raging out west?

How about the software we use to process our images? MaxIm DL? PixInsight? Photoshop? StarTools?
Like it or not, they all influence how we do things and how they turn out.

As Pete has mentioned previously, what about our own individual eyesight? No two people perceive
color exactly the same. Even considering my own vision, I perceive colors as slightly cooler with my left
eye. Granted, it’s a subtle difference, but it’s there!

And regardless of how hard we try, we will never know if we are getting things right. Robert has it absolutely
correct; we don’t know how DSOs truly look up close in space, and getting there anytime soon to check
on it isn’t very likely. The best we can do is to make our images aesthetically pleasing, but unfortunately
"pleasing" isn't necessarily the truth.

Personally, I sometimes wonder if all of the effort I put into RGB imaging is really worth it to me. The
most inspiring astronomical images I ever saw were backlit transparencies of Messier objects at a long
gone gallery in Chicago’s Adler Planetarium. They were monochrome, each and every one.

Perhaps one day I’ll switch to working in luminance alone; just taking nice deep images. Maybe Ansel
Adams had it right after all.


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