Re: ATM Global Positioning System

[jerry@cts4.europe.dg.com (j.royston)]

You mention that the GPS receiver will become useless next September.
If it's a modern one it will have no problem, an an old one will be
able to find its position by starting from scratch. Look at 
www.garmin.com for information on the weeknumber rollover problem
next September.

Best wishes, Jerry
> 
> >Perhaps Meade should incorporate an  Oncore board in its LX series of
> Go-To
> >scope.
> >Then when turned on, the scope would know the precise time and exactly
> where it
> >was located. I'm surprised that neither Mel nor Chuck have incorporated
> this
> >feature in their computer-controlled scopes :-).
> >
> 
> I have taken a close look at this for the MacDobs system, and have plans
> for a GPS module. In fact I have had quite a bit of discussion with several
> amateur astronomers, both in this forum and those in the San Jose area.
> 
> Let's see if I can reconstruct the gist of these discussions. Bear with me,
> this is a bit fuzzy. Hopefully those more knowledgable than I can explain
> it better.
> 
> Three entities are needed to establish absolute position and time for any
> given site. These are the geographical location (lat, long) on the earth,
> the current sidereal time, and the location of at least two guide stars.
> Since there are actually four or five points of reference given in the
> above set, and we only need three points, an absolute position can be
> established quite nicely. A GPS can give you two of the three references,
> with star alignment giving the third. Or, using star alignment and the
> current longitude or time, the remainder can be calculated. Three star
> sightings define an absolute position in space. You then need an additional
> quantity to establish the position on the earth. Since we don't need to be
> all that precise in our calculations (especially with the wide tolerances
> we use in our scopes and measuring apparatus), we can just about guess the
> thrid quantity and correct for it with our measurements. So, "watch" time,
> or the general latitude and longitude are "good enough" to get us to where
> we need to be. After that, we get closer and closer to precision with every
> additional star alignment we make.
> 
> So, having GPS then becomes an "it might be nice for those needing more
> toys" or a holiday gift or something like that. Now, because I happen to
> have a GPS receiver, I will probably create a GPS module for the MacDobs
> system to do this. That is, assuming I can get working on the module before
> my GPS receiver becomes useless next September. The more important piece of
> this puzzle is to have the ability to accurately align a scope to stars,
> and the ability to use that information in the star calculations.
> 
> So, Mel (and others) how was my explanation?
> 
> -JackB
> ===================================================================
> "My name is bud lightbeer. I come in pieces!"
> 
> 
> 
> 
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