Quote:
Originally Posted by jase
Rob,
To save you a bit of time, I just got off the phone to a friend who has an identical filter/camera combination (Astronomik type IIc and KAI-11000 chip). He's performed G2V star tests close to zenith and determine the R:G:B ratios to be close to 1.15:1.0:1.10 respectively. So if R=1 - 1:.85:.95. You can shoot all the same i.e 1:1:1, then colour weight them during the RGB combine.
This of course should only be used as a guide. Some objects will require different colour weights. For example if your framing M45, you'd probably increase the B weighting. Also, optical coatings can affect wavelength transmission resulting in colour weight variations. Finally, leave your B data aquisition until the object is high (70+ degrees) in the sky. The B wavelength (around the 475nm) is seriously affected by atmospheric dispersion far more than R and G wavelengths.
Would still recommend doing your own G2V star tests, but hopefully this will get you up and running quicker.
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Hi again Jase,
Yep, I always apply atmospheric extinction factors to my weights... as you know, the further we are imaging down from 90degs, the greater the multiplying factor has to be added to the blue wave length as it becomes muted by refraction... so I always check my altitude when taking my RGB's for an image and simply apply the multiplier factor..... well I do it to all my channels as the chart I have depicts for that altitude.
I think we'll let Rob get his head around his weights first, then he can do some reading and down load a chart with these factors....
I reckon your friends weights look pretty close to what would be pretty close to what robs setup will be from what I have judged.
Rich
