Re: Basic guidelines for narrowband imaging +/- Full Moon

david w pearson

My experience with some full moon limited testing with increasing moon separation distance using a 7nm Ha filter has shown.... that
the background noise will become asymptomatic at about 60 deg distance from the moon.  I saw a 57 % reduction in background noise in going from 18 deg to 42 deg moon separation, and then another 17% reduction from 42 to 63 deg moon separation.   very flat beyond 60 deg.
Background median value is 5x lower at 63 than 18 deg.   
In previous testing from full moon down to quarter moon has shown that the asymptote is about the same at 60 deg.   Of course the background and noise get worse from quarter moon to full moon.    Nothing you can do about that , except either accept the increase in noise or don't shoot near full moon.
SII results were the same.    However ,Oiii doesn't like any moon illumination, so unfortunately Oiii must compete with LRGB for imaging time.

Sorry i don't have any 3nm Ha results to provide....i would guess they would be similar.
dave based on 5 min exposures at -20degC with SBIG CCD camera at 7200 feet.

On Monday, January 17, 2022, 11:16:08 AM PST, Ted Mickle via <tedmickle@...> wrote:

I’d like to do some 3nm H-alpha imaging about 30 degrees away from the Moon tonight at 1,000mm focal length.

Does anyone have rough guidance on narrowband imaging when dealing with a Full Moon?  In other words, how bandpass, focal length and angular separation can be quantified for each of the narrowband filters?

Any guidance is appreciated.


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