Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3032
Loc: Smoggy Bottom, Baytown,Texas
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Anybody ever tried this? I'm thinking web cam and clear plastic dome cover....
Hubert
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www.smoggybottom.org
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Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2423
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Has anybody tried what????
Nothing there relating to what you are talking about!
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Wes
Atlantic Beach, FL
Some bino’s from Miyauchi 5x32 Binon's up through Garrett 20x110 Signature's,
Some telescopes from a Stellarvue 80mm NHNG up through a couple of 8” reflectors…
And a wonderful 4.25" Delmarva Shiefspiegler!
Some good friends, made here on C/N.
Oh- several cats and a wonderful wife!
Anyone want a cat???? :-O
"When your work speaks for itself- Don't Interrupt" -Gamble Rogers
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39506
Loc: Phx, AZ
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Wes - see the topic line! 
Hubert; what do you have in mind? Looking for clouds?
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
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DAVIDG
Pooh-Bah
Reged: 12/02/04
Posts: 1429
Loc: Hockessin, De
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There was article is Sky and Telescope about 2 years ago about doing this for studying meteors. Also SBIG has/had a commerical version.
- Dave
Quote:
Anybody ever tried this? I'm thinking web cam and clear plastic dome cover....
Hubert
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Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schief. 60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4.5" f/16 Schupmann Medial refractor, 14 Stellafane awards 7 in optics
Engineering = Taking what you have and making what you need.
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3032
Loc: Smoggy Bottom, Baytown,Texas
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Yes, basically clouds to start with, I'd like to do meteor watch, but I'm not sure a webcam would be sensitive enough.
Went to the local hobby shop, and I've got an experiment cooking.
Hubert
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3032
Loc: Smoggy Bottom, Baytown,Texas
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Thanks, Dave, I'll see if maybe it's online.
Hubert
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www.smoggybottom.org
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Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2423
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Uhhhhhhhh...
What am I missing here???  I see nothing related to a homebuilt sky camera on the website! That's what I was looking for when I went to the link!
DOH! O.K., I went to the link (website) looking for something related to the question!  The question stands alone- nothing to do with the website!
Sheesh... I need a good night's sleep....
Wes
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3032
Loc: Smoggy Bottom, Baytown,Texas
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I suppose I might have been clearer, Wes.
1)Has anybody built such a camera?
2)Will a webcam work?
3)Does the plastic dome distort the view?
4)If so, is there a special type of dome material?
Etc, etc.
Has nothing to do with my website (yet).
Hubert
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www.smoggybottom.org
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Wes James
Carpal Tunnel
Reged: 04/12/06
Posts: 2423
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Yeah~ *sheepishly* I figgered' that out... finally!
Not your fault- mine!
Wes
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eqcradle
member
Reged: 04/26/07
Posts: 36
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Do you mean an all sky camera?:
http://www.iceinspace.com.au/forum/showthread.php?t=34281
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Sky Captain
Scope Builder
Reged: 11/07/04
Posts: 5731
Loc: Seattle Washington
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Quote:
Anybody ever tried this? I'm thinking web cam and clear plastic dome cover....
Hubert
Hi Hubert, I have been toying with the idea myself and have found a website that I'll get the dome from. You can find it here.
The web cam for live views won't be sensitive enough, you'll need atleast a 2 second intergrating camera and a fast lens in the F1 to F2 range. Obviously the larger the front aperture on the lens will help too.
Due to circumstances, I missed the Perseid shower last night\this morning and was set to view\record the event.
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Equipment Overload!
Kerry.
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3032
Loc: Smoggy Bottom, Baytown,Texas
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Yes, that's what I meant. Thanks for the link.
Hubert
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www.smoggybottom.org
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DAVIDG
Pooh-Bah
Reged: 12/02/04
Posts: 1429
Loc: Hockessin, De
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Surplus Shed also has them, http://www.surplusshed.com/pages/item/m1588.html
You might consider an 'All Sky' camera made by use a convex mirror and the camera position over the top of the mirror looking downward to make an inexpensive fish eye lens. Back in the good old days people would use "baby Moon" chromed hup caps for the mirror. There any article in Sky and Telescope somewhere in the 80's about doing this.
Another neat thing to do would be use a plastic transmission grating over the lens to record the spectra of bright meteors and a motor with a chopper to determine their velocity.
- Dave
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Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schief. 60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4.5" f/16 Schupmann Medial refractor, 14 Stellafane awards 7 in optics
Engineering = Taking what you have and making what you need.
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JAT Observatory
Space Freak
Reged: 02/20/05
Posts: 5608
Loc: Eastern PA
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The key here is make sure the dome section of the cover does not distort the image. There is also the issue of dew in the more humid areas unless the dome is heated some how.
If you are planning to use the system to capture meteors you will need the exposure to be long enough to capture the streak. I have my set to 10 second exposures. This allows for a clear display of the meteor's path across the sky.
The other thing is you need to find a way (software) to auto detect and capture the meteor (or satellite) or software that will auto analyze captured AVIs or stills. Not doing so means you will end up looking through a whole nights worth of images in real time. Not something you want to do.
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-Marcus
The problem with free speech is even the stupid have a voice.
http://jatobservatory.org
12" LX200R on a Paramount ME
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JAT Observatory
Space Freak
Reged: 02/20/05
Posts: 5608
Loc: Eastern PA
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Before I purchased an allsky/meteor camera I played with making one myself. I used a DSI and 180 camera lens with a glass dome. It worked but it had some issues. The glass dome caused distortions. Heat build up was also an issue which cause excessive noise in the images. (I still have some noise issues in the summer with the SBIG unit as the camera is not cooled but the metal box helps dissipate the heat.
The pros with using a dome is it reduces reflections and water runs off easily. The pros with flat glass is it can be made of a filter to attenuate moonlight or help filter out skyglow.
As far as software I can't remember the name exactly but It was called something like "UFO capture" It had a lot of features but I ended up not buying it and I used it on a webcam. It could detect things moving in the sky by analyzing the video.
Below are images of my DSI allsky test camera. It actually worked petty well with no cover. The problem with it was mounting it and I could not find analysis software for it. I guess now since CCDSoft and MaxImDL work with the DSI you could write an blink compare script to detect meteors or satellites. You can see I had a fan attached to the camera's back to help with cooling and the assist in moving the air inside the dome.
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-Marcus
The problem with free speech is even the stupid have a voice.
http://jatobservatory.org
12" LX200R on a Paramount ME
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39506
Loc: Phx, AZ
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Marcus; that is a pretty nifty setup. Is that a bell jar from a vacuum system?
Would the distortion be less if you moved the camera up so it did not "see" through any of the vertical walls?
Not exactly a trivial problem is it? 
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
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Mike I. Jones
Pooh-Bah
Reged: 07/02/06
Posts: 1093
Loc: Fort Worth TX
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Yes, the camera needs to be moved up, such that the center of curvature of the dome coincides with the average entrance pupil position of the fisheye lens. The entrance pupil of a fisheye is not stationary over the FOV, but instead moves toward the front of the lens with increasing field angle. If you positioned the entrance pupil within 1/4" or so of the dome COC, the imagery should improve noticeably. If possible, the fisheye needs to be centered on the dome COC as well. In the picture it looks a little off-center.
That won't eliminate distortions due to casting ripples in the dome section, but it does minimize them, as the lens is looking perpendicularly (or very nearly so) through the dome at any point in the FOV.
Mike
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56 mirrors, lenses, 16" f/6 Newt, 6" f/10 refractor, TOA-130S, Tinsley 5" f/15 Mak, 6" f/4 RFT, Coronado PST. Still to build: 24" f/10 Modified Dall-Kirkham, 10" f/26 Mak, 8" f/12 apo, spectrohelioscope, Herrig, Schupmann, and a new design you'll like.
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3032
Loc: Smoggy Bottom, Baytown,Texas
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Here is a shot of the test rig. The dome is a true hemisphere, 4" or so in diameter. From the hobby shop.
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www.smoggybottom.org
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Pedestal
Post Laureate
Reged: 03/11/06
Posts: 3032
Loc: Smoggy Bottom, Baytown,Texas
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And here is a test pic. The dome does not appear to have much distortion, but the field of view is not large.
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www.smoggybottom.org
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JAT Observatory
Space Freak
Reged: 02/20/05
Posts: 5608
Loc: Eastern PA
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Moving the camera up would have helped but I had other issues:
1. Mounting was issue, since I was limited as to what I could do with the dome*. Also because of the DSI's USB cable location and CCD chip offset I wasn't able to place the lens in the center of the dome. It was even more offset during the test setup than what the above pictures show.
2. The dome’s the top suffered from optical problems. The issue really showed when a satellite streak crossed through the center of the dome.
But I have to say while the image produced wasn't a full 180 degrees it was still better than the 90 x 140 degree image produced by my purchased camera. I may have to revisit this again if I can find an enclosure since the camera now works with other software.
* The dome was borrowed (without my wife's permission or knowledge I might add) from her anniversary clock.
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-Marcus
The problem with free speech is even the stupid have a voice.
http://jatobservatory.org
12" LX200R on a Paramount ME
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