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Lunar Landscape No. 2 (38)
scobert
![Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 1636 W: 16 N: 1867]](http://i1.trekearth.com/misc/g-s-g.gif) (5327) | This will be the last photograph of the moon that I will post for at least a few weeks. I don't want to bore you too much with my moon shots, but the weather has been bad for astronomy in Colorado this winter and I have had to take astrophotos for brief interludes between all of the stormy weather that we have had for the past four months. I am new at astrophotography and I find it to be fascinating and challenging. I am a good amateur astronomer and an experienced photographer and I am wondering what took me so long to start this process. I am learning as I am experimenting, and I hope that my experiences can be useful for Trek Earth members who would like to try this type of photography for themselves.
I took this uncropped photo tonight using eypiece projection through my 66mm F/6 refractor and my Televue 5mm Nagler eyepiece using my Nikon CoolPix P5000 digicam. This technique is referred to as "afocal" photography. Astronomers refer to the atmospheric conditions as "seeing". Good "seeing" occurs with clear and stable skies with a minimum of turbulance. Tonight I had bad "seeing" (but not awful) with plenty of atmospheric turbulance created from the clearing snowstorm. Denver, Colorado is at the base of the Rocky Mountains and the tumultuous air currents make very good "seeing" conditions more of the exception than the rule. Some of the best skies for astronomy, in terms of clear and stable skies, is on the island of Hawaii, of all places. The semi-arid skies of the American West have air turbulance and the skies East of the Mississippi River are usually stable but visibility (transparency/clarity) is more limited due to the humidity. Light pollution (in urban areas) is an issue with faint deep sky objects, but is not much of an issue with bright objects like the moon and the planets.
The focal length of my small refractor is 400mm (F/6). I used a 5mm eyepiece and the magnification of looking through an eyepiece is determined by dividing the focal length of the telescope by the focal length of the eyepiece. 400 (F.L of telescope) divided by 5 (F.L. of the eyepiece) equals 80 power. With the increased magnification of zooming into the eyepiece with my digicam, I estimate that the magnification was around 120x (133x is the maximum effective magnification limit for this aperture...66mm). The image would have been much sharper with good seeing, but good seeing has been scarce in these parts lately. Hopefully the skies will be clearer and calmer later this spring. I also used a small polarizer in the eyepiece to reduce some of the glare on the moon's surface. The greater the magnification the more atmospheric currents affect the image. I am surprised, due to the poor seeing conditions, that this shot came out as good as it did.
*Please see the two WS photos for a visual demonstration of how this setup works.* |
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| Altered Image #2
scobert
(5327)
Nikon D300 with 60mm Macro
Edited by:scobert
(5327) |
| I also included a closeup of my Nikon Coolpix P5000 digicam, and the Televue 28mm eyepiece adaptor coupled with the Nikon UR-E20 adaptor and my Televue 5mm Nagler eyepiece. This setup is lightweight and simple to use and much easier than trying to couple a much larger and heavier DSLR. The digicams have another advantage; they have leaf shutters and are not prone to "mirror slap" like SLRs are. |
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| Altered Image #1
scobert
(5327)
Nikon D300 with 60mm Macro
Edited by:scobert
(5327) |
| This is my complete setup, excluding my telescope mount. Included are my small telescope, CoolPix P5000 digicam, the Nikon UR-E20 (28mm threads) adaptor, the Televue 28mm eyepiece adaptor, 5mm Televue Nagler eyepiece and the 90 degree mirror diagonal (optional). |
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