RE: RE: Artifical Star

From: Rob Hawley (robhawley@No-Spam)
Date: Mon Jan 20 2003 - 19:27:08 MST


The concerns cited by Dennis were also echoed on the LX200GPS list. I am in
no way recommending that vendor. I paid by credit card and am prepared to
also stop payment if the device has not shipped. I am crossing my fingers
that will not be necessary. I should note that I contacted the BBB serving
Kansas and their report does not reflect the level of bad experiences I have
heard on the newsgroups.

The problem of creating a good star is harder then it seems. The light
source for a 10" SCT needs to appear no larger than .45 arcseconds or the
scope will resolve it as a non-point source. I leave to the reader to
compute the tradeoff of distance vs hole size to get that value. I was quite
surprised when I did the math. You need a very small round hole and a very
bright light source. The advantage of the Eztelescope unit was they claim to
have a very small hole.

If you don't want to take the hassle (risk) with eztelescope.com you can try
building it yourself. The light source you can get a radio shack (or
elsewhere). The small hole is more of a problem (see the discussion on
http://groups.yahoo.com/group/LX200GPS concerning the 25 micron orifices
available through smallparts.com). That is certainly my plan B.

Rob Hawley

_______________________________________________
sf-bay-tac mailing list
sf-bay-tac@No-Spam
http://seds.org/mailman/listinfo/sf-bay-tac



The Astronomy Connection -- Mailing List Archives