Bogdan Borz:Alex Nicholas:
How many hubble SHO images don't have green in them? and why would we want to attenuate the hydrogen out of the image?
I guess it really depends on what you're trying to achieve with your image. If you're going for 'pretty picture' then, do what you like... If you're trying to specifically highlight the different gasses that make up a nebula, then why would you cut out the green?
I would always leave the green in an image, would I scale the green to be less extreme in some cases - of course, but I would never drop it out to be significantly less than SII or OIII, unless the target I was imaging was composed that way....
Hi Alex,
Well, a lot of iconic Hubble images do not have green in them. Here are some examples:
- compare the Pillars of Creation from 1995 vs 2005, the green and the magenta stars are gone. https://scitechdaily.com/hubble-revisits-pillars-creation/
- Ring Nebula https://esahubble.org/images/heic1310a/ - no green
- Lagoon Nebula https://esahubble.org/images/heic1517a/ - no green
- Mystic Mountain in Carina https://esahubble.org/images/heic1007a/ - no green
- Helix Nebula https://esahubble.org/images/opo0432d/ - no green
I don't believe that the Hubble team is cutting signal out by reducing or "zapping" the green, or that they don't know what they're doing. This is pretty much contrary to the idea that if the Hubble palette uses 3 filters, you have to leave green in the image, if not it becomes a bicolor image etc.
Of course there is an aesthetic criterion involved. Some astrophotographers on astrobin are really good at keeping the green in the image with nice results, some images look best without it imo. Everyone is free to keep it or clear it as they like, but there is no obligation for it to be present in the Hubble palette.
CS,
Bogdan
There is absolutely some green in a few of the examples you shared above.
Pillars of creation (new version): Look around the brighter parts of the pillars, between the yellows and blues.
Ring nebula: Above and below the blue center are bands of green.
The Carina shot has a touch of green.. similar to the Pillars shot. A small touch of green between the yellows and blues.
The two shots that lack green, Lagoon and Helix are the least interesting to look at IMO.
The amount of green seen in some of these images is usually the balance I try to strike with my SHO images. I do admit, some of mine are over the top green but most of them have little hints.
