Chuck, I enjoy viewing (and cracking wise), but you make me aware that I am certainly not an astronomer! What a beautiful job. 73, lh On 9/16/2011 12:59 PM, Chuck Hards wrote:
Here are photos of the test housing I made from scrap plywood. Once I have finalized spacing, I'll remake it in either aluminum or fiberglass. But this is sufficient for testing. I may add a cookie-can dewcap for some test images, hopefully I'll get out for those in coming weeks. If not this new moon, next. I stuck an old Pentax SLR camera body on it for scale and to demonstrate how the camera attaches, but when I'm at full speed, I'll have a digital camera attached.
There is also a test photo I made with a 2mp digital camera, just to see what the FOV is going to be like. No attempt at collimation or fine focus was attempted, it's just a hand-held shot against the fence so I can extrapolate what the full field of view will be. I'll dig out the protractor this afternoon and report back, but my initial estimate is at least ten degrees on the sky!
Anything could happen with this. Once I get it all squared-on, I may end up stopping it down a bit to tame field curvature. Because it started life as a camera lens though, I'm hoping that it's reasonably flat across most or all of a digital camera chip.
The desire here is to achieve large-aperture resolution in wide-field sky shots, something a much smaller commercial wide-angle lens can't match. We'll see if this surplus camera lens is up to the challenge.
Comments appreciated, criticisms accepted graciously. Unless I've been drinking. ;-)
Link to album:
http://s260.photobucket.com/albums/ii24/JethroTull1958/ATM/6-inch%20astro%20...
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php