Thanks, Jeff!
I was fortunate enough to get a set of USNO A.1 on CD ROMs. Are there any plans to make the USNO B.1 available on CD ROM or DVD?
Currently I do my supernova searching with a 5" refractor and an ST-8E camera (on loan from a friend). 90-second exposures get me 17th magnitude, sometimes 18th. One day I hope to get a larger telescope. I was thinking that might give me shorter exposures, as there was really no point in "going deeper" when it would take me past the limit of the catalogue. If I ever get my hands on a USNO B data set, I'll have to rethink that!
By the way, on the night of 6-7 January while I was imaging NGC 253 in Sculptor I managed to photograph LEDA 198196, which Guide8 tells me is 900 million light years away. And on the night of 4-5 January while imaging NGC 779 I got LEDA 138489 at a distance of 1.1 billion light years. Not bad for a 5" scope!
And many thanks are due to Bill for all of the capabilities he has built into Guide8. Without the additional information provided by Guide, these objects would have been uninteresting smudges on my pictures. With Guide's help, I am filled with awe at what I am observing! I am reminded of a quote by Carl Sagan: "After 4 billion years of evolution, the most intelligent being on our planet was algae." That is the era I was "looking back" to. Thanks for a great program, Bill!
Clear skies to all,
Pat Madden
-----Original Message-----
From: Jeff Medkeff [mailto:
jeff@...]
Sent: Thursday, January 09, 2003 4:28 PM
To:
guide-user@yahoogroups.com
Subject: Re: [guide-user] USNO B.1
At 02:27 PM 1/9/2003 -0600, you wrote:
>Recently someone referred to the USNO B.1. I assume
>this is an improvement on the USNO A.2. Is there a
>website where I can learn more about this?
The main difference IMO is source density (one billion objects down to
V=21) and the inclusion of proper motions. Like A2, magnitudes are not to
be trusted.
The gory details can be found at:
http://xxx.lanl.gov/abs/astro-ph/0210694
--
Jeff Medkeff
Sierra Vista, Arizona
http://www.roboticobservatory.com/jeff/
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