The Tarantula Nebula

[Robby]

"Correct" colour is very assumptious. Just becaus it is film, doesnt' mean the colours are correct... Every film has a different colour balance, and in many respects are even more variable than digital..
Eddie T had some good comments re. colour in a thread about a year ago.
He reckons he can calibrate for "correct" colour based on some reference stars. http://www.iceinspace.com.au/forum/s...ad.php?p=27413 Post #31.
I'm sure you have all seem his award winning 2070 pic http://astroshed.com/ which is colour calibrated...
IMHO there is no such thinkg as "absolutely correct" colour in Astrophotography. Pretty pics are the go here as far as I'm concerened... So as long as we enjoy what we image and get a couple of "wow's" from friends and family I'm happy!
Cheers

[Itchy]

Hi Robby,

I absolutely agree with you about colour. Indeed, I have heard it said that colour film shots are biased to the red. We are so used to seeing red film shots that we tend to expect the same from digital. Of course, an modded camera certainly picks up the Ha a lot better. NGC2070 is a very interesting object for colour. Here are two shots that i have done with an unmodded 300D. The first one is straight prime focus. No matter what I did I could not get any red in the nebula. 12 months latter, I shot 2070 again, same scope and camera, but with a Baader UHC-S Filter (and a lot of careful processing).

Cheers

[PhotonCollector (Paul)]

Hi Robby and Itchy,

yeah I didn't want to say previously..... but since you have said it for me.

I certainly do and always have believed we have been "conditioned" over the past several decades (the film era) to expect to see nebula as red (or a hue thereof).

I don't really agree that all emission nebulae are just glowing in H-alpha (red) I think some glow in H-beta as well. H-beta is in the green part of the spectrum ! Don't get me wrong I'm sure lots of nebulae are just emitting Ha.

After Robbys posts on this thread I rechecked my images of the Tarantula to see if I could make it all red - but that would have meant removing all the photons collected in the green channel - which didnt make sense to me. I mean to say - if the camera collected strong photons in the green region of the spectrum then according to the data this nebula (2070) is glowing in green as well as red.

I guess this could be checked by seeing if the Tarantula is known to glow in Hb as well as Ha.

On this issue - you may note the amount of green I managed to get in a previous image of the Helix nebula at this location http://www.skylab.com.au/pmsa/Helix%20Nebula.html

I can say with certainty that the same camera on my 8-inch f/6 reflector basically did not reveal any green in the Helix (I'm using the 12-inch f/5 now) even with longer exposures.

Great talking to you guys

Paul Mayo