--- Joe Bauman <bau@desnews.com> wrote:

Very nice, Curt -- what type of lens were you using? Was it super-wide? Thanks, Joe

Joe, I used a recently purchased low-end Zenitar 16mm/2.8 fisheye lens. I principally purchased this lens for making NELM sky study photos. I wanted to keep the cost down - it's $125 instead the of $375 for a mid-low end Pentax lens or $500-1000 for professional lenses. Although made in Russia, the lens seems to have good sharp definition. A drawback to it, as compared to mid-to-high-end lenses, is that the Zenitar makes a "true" spherical image. High end lenses "correct" the spherical image such that straight lines traversing near the center of the image (great circle lines on a normal hemisphere) appear straight. See review and photos at: http://www.jimtardio.com/zenitar.html Apparently Photoshop can be used to "correct" the fisheye effect of great circle lines. http://www.photoslave.com/misc/zenitar/zenitar.html For my purposes, the mathematically more "correct" rendering of the Zenitar is more useful. The width side of the 35mm frame has about a 160°-170° FOV. The height of the 35mm frame is smaller - I haven't measured it but it's probably around 120deg. The TFOV is blocked off by aperature masks on the outside of the lens: http://cgi.ebay.com/NEW-FISHEYE-ZENITAR-K-2-8-16-LENS-PENTAX-RICOH_W0QQitemZ... As for making photos of ISS overpasses, although I'm still working on an acceptable picture, I've concluded the best shots can be made under two conditions: 1) A morning sunrise pass where the ISS travels from darkness and into the Sun and the sky has an EV value between 4 and 6. The ISS will reach a -2.0 mag brightness and is visible even during morning civil twilight. This gives a good uniform field of blue sky light. These pictures can be taken from an urban area. It probably isn't practical to use a wide FOV lens for the morning shots because even at f/22, the exposure time is too short to make a meaningful streak. 2) An evening ISS pass just at or after astronomical twilight were the ISS is +1.0 mags taken from a rural area without light pollution and an EV value of -1 to 1. Although the ISS leaves a fainter track, the image can be exposed to bring out an interesting stellar background field. The best picture I've seen in that category was Dan Bush's photo on the August 30, 2005 www.spaceweather.com page. http://www.spaceweather.com/swpod2005/30aug05/bush.jpg - Canopus56(Kurt) __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com