Halo around the full moon
Posted: Wed Mar 03, 2010 3:45 am
I am a complete amateur, but an avid skywatcher and APOD follower. Please excuse the following (perhaps) dumb question.
I have recently noticed a large halo around the moon, that had an apparent radius of the length of my hand at arm’s length.
Given that my hand measures 8 inches from wrist to finger tips, and my eye is 22 inches from my hand at arm’s length, how high are the clouds?
If I knew the angle of refraction, I could then estimate the cloud ceiling on a night such as tonight, where the halo is roughly one finger joint or one inch.
Probably a very simple task? (I’d probably do better using an actual ruler but the hand measurement is coarse but very convenient).
I would like to make a simple calculator that would give me this data easily on these clear winter nights.
Many thanks again to all of you who help us in our eternal quest for enlightenment,
Ian Seeley
I have recently noticed a large halo around the moon, that had an apparent radius of the length of my hand at arm’s length.
Given that my hand measures 8 inches from wrist to finger tips, and my eye is 22 inches from my hand at arm’s length, how high are the clouds?
If I knew the angle of refraction, I could then estimate the cloud ceiling on a night such as tonight, where the halo is roughly one finger joint or one inch.
Probably a very simple task? (I’d probably do better using an actual ruler but the hand measurement is coarse but very convenient).
I would like to make a simple calculator that would give me this data easily on these clear winter nights.
Many thanks again to all of you who help us in our eternal quest for enlightenment,
Ian Seeley