--- Kim Hyatt <kimharch@cut.net> wrote: <snip>
Rob described the Hartmann mask for me, "cardboard disc same size as OTA w/ 3 evenly spaced holes, placed over the front . . .
My camera Hartmann mask looks like this - it's not very precise - http://www.astropix.com/HTML/I_ASTROP/I08/I0817/I0817.HTM See also Reeves trick of using a bright wide-double to focus using the Hartmann mask and a star trail exposure. http://www.astrofoto.org/tips/focus/ You can also use a magnifier. Nikon makes (made) a proprietary magnifier. I use a hand-loupe per Lodriguss - http://www.astropix.com/HTML/I_ASTROP/TOC_AP.HTM More difficult is the star trail test - I haven't done this one - http://www.astropix.com/HTML/I_ASTROP/I08/I0818/I0818.HTM See Jerry Lodriguss's focusing pages - http://www.astropix.com/HTML/I_ASTROP/I08/I0812/I0812.HTM Enjoy - Canopus56 (Kurt) ____________________________________________________ Yahoo! Sports Rekindle the Rivalries. Sign up for Fantasy Football http://football.fantasysports.yahoo.com