jeffr
New Member
Posts: 15 
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Post by jeffr on Mar 28, 2016 5:00:02 GMT
Im just looking for general ideas, rules of thumb, experience when it comes to cloud cover and video astronomy.
I think there are some obvious examples of too much cloud cover. But Im not sure about the rest.
I thought about approaching "how to judge the clouds" from the star magnitude POV.. for example, If i can just barely see a star with the magnitude of 3.3 through the clouds, what are my chances of imaging something of a 6.6 mag? Id wager it might include other factors such as general light pollution of the area, but from the stand point of "just the clouds man"?
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Post by Ken James on Mar 28, 2016 12:15:58 GMT
G'day Jeff. You have an interesting plan, but each location will have differing results with the same amount of cloud cover. Light pollution will make clouds glow and change the whole Video Astronomy experience as far as the camera seeing through them. I live in a totally dark town with zero light pollution. Even with low cloud there is nothing to illuminate those clouds, so any faint light peering through from space is picked up by the camera. I have often (yes, often) wondered why my focus looks a slight bit off only to walk outside and find my sky completely clouded out from horizon to horizon, yet I still have a great view of a Nebula or galaxy still on the screen 'Live'. It just has slightly fuzzy stars. This often happens when I am broadcasting on NSN. Either me or a viewer will comment on how the focus looks a tad off. That's when I discover I am clouded out  Someone with a small amount of light pollution would experience a similar effect, but could lose view of some of the fainter parts of an object but still see the brighter parts. Someone with heavy light pollution could lose view of everything even with light mist in the sky. Now, forget about the amount of light pollution, then you have the thickness of cloud to think about. Or the density  It would be a hard phenomenon to categorize. |
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mrwizard
New Member
Someday the sky in Tacoma will clear, I'll have a working mount and camera (all at the same time)
Posts: 40
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Post by mrwizard on Mar 28, 2016 14:46:55 GMT
With our light pollution in Tacoma, WA (a full press white zone) even a slight haze shuts me down for anything but the moon.
Craig in Tacoma
aka MrWizard
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Post by aussiehowie on Mar 29, 2016 2:11:00 GMT
Love your "JeffR lives / doesn't want to live in Alabama" tag! Jeff, why do you want to gauge cloud cover? If I see cloud out, and the 'live' satelite image sequences on the web show cloud rolling my way I don't bother setting up (I dont have an observatory). If I had an observatory, then I'd probably be out there observing even if I saw some cloud and just keep going until the image just plain disappeared off the screen  So yeah ... why do you want to categorise it? Interested to know. And in case it helps I did find a link on the web about calibrating a DSLR on certain settings for your area's specific light conditions to find the LP reading/rating. If that might help you let me know and I will hunt for the link (EG find your normal LP reading using the std settings DSLR shot to zenith or whatever, and so on any particular night from then on a different reading MAY be the result of cloud cover?). cheers Howie |
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jeffr
New Member
Posts: 15
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Post by jeffr on Mar 29, 2016 5:03:10 GMT
Love your "JeffR lives / doesn't want to live in Alabama" tag! Jeff, why do you want to gauge cloud cover? If I see cloud out, and the 'live' satelite image sequences on the web show cloud rolling my way I don't bother setting up (I dont have an observatory). If I had an observatory, then I'd probably be out there observing even if I saw some cloud and just keep going until the image just plain disappeared off the screen So yeah ... why do you want to categorise it? Interested to know. And in case it helps I did find a link on the web about calibrating a DSLR on certain settings for your area's specific light conditions to find the LP reading/rating. If that might help you let me know and I will hunt for the link (EG find your normal LP reading using the std settings DSLR shot to zenith or whatever, and so on any particular night from then on a different reading MAY be the result of cloud cover?). cheers Howie The reason I want to categorize it is because there are varying degrees of cloud cover. I can really only take my telescope out on Friday evenings because of the particular schedule. so when things interfere with that- mostly rain and heavy cloud cover- it gets frustrating knowing ill have to wait at-least another week. So Id like to be able to go out at night, gauge the cloud cover numerically- reference to the visible magnitude in the OP. I have the light pollution maps www.lightpollutionmap.info/ and I understand how light side of things may impact imaging options.. . The dslr zenith shot sounds interesting also, but I actually a ccd camera (revolution imager) so I do I simply base it off of "partly cloudy = yes, mostly cloudy= no" even if during the mostly cloudy I can see fainter stars with my naked eye peeping through? |
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Post by Ken James on Mar 29, 2016 11:48:58 GMT
Jeff, this site might help you. It is an Australian site for Astronomers called 'Skippy Sky' and is usually fairly accurate. It also covers North America. -Just select North America from the map, then when it opens select which part of North America you want to check in the top row of selections. For you it would be 'South Central'. -Then select what you want to check in the second row (low cloud, high cloud, all cloud, seeing, jetstream, etc) -Then select how many hours into the day you want to check (today or tomorrow) (+6, +9, etc right up to +120 hours) HERE: www.skippysky.com.au/ |
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Post by aussiehowie on Mar 29, 2016 12:29:46 GMT
Sounds like you need an all-sky camera setup Jeff. Maybe you can advertise for a 2nd hand one?
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jeffr
New Member
Posts: 15
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Post by jeffr on Mar 30, 2016 6:28:54 GMT
Jeff, this site might help you. It is an Australian site for Astronomers called 'Skippy Sky' and is usually fairly accurate. It also covers North America. -Just select North America from the map, then when it opens select which part of North America you want to check in the top row of selections. For you it would be 'South Central'. -Then select what you want to check in the second row (low cloud, high cloud, all cloud, seeing, jetstream, etc) -Then select how many hours into the day you want to check (today or tomorrow) (+6, +9, etc right up to +120 hours) HERE: www.skippysky.com.au/What an intriguing site, thanks! |
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Post by Rick in NWArk on Apr 19, 2016 20:00:53 GMT
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