Quote:
Originally Posted by Prickly
Hi Bert,
That a very nice shot. You have brought out the detail very nicely. The tarantula is a great object for this type of image. Would like to see lagoon too when it is back up.
Can you clarify - for O3 blue and O3 green have you used the same O3 image for both the blue and green channels or did you do something slightly different?
Also did you refocus between the O3 and the Ha imaging? Im presuming so because of the achromat.
Results are extremely sharp and the fridge seems to have worked a treat.
Well done,
David
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David O3 is detected by the green and blue pixels almost equally. That is why O3 is a cyan colour. Cyan is the absence of red light in a colour additive system (see first image of additive colour diagram). Below is an image of the spectral sensitivity of a Canon and Nikon due to their Bayer filters and UV/IR filter or that is unmodded.
From here
http://www.astrosurf.com/buil/d70v10d/eval.htm
You can see how O3 affects both the blue and green pixels equally.
Ha only really affects the red pixels.
By assigning HA to red and O3 green to green, O3 blue to blue you get a far more 'natural' colour of nebulae. Stars also end up white. It is then easy to add full colour data to get the star colours.
Bert