4-Vesta location.

[Ryanlaw2]

Got a DS2114 for Christmas.  First decent scope after years of clunkers and kluges.  My wife likes it too because it's keeping me out of the online poker sites.

First project was tracking 4-Vesta as it approaches opposition.  Though it's a bright 7 Mag., I'm in the belly of Orange County, CA, with naked eye visibility limited to 1st mag stars and Jupiter, so locating it was a test of patience.  Once I found it and tracked it for 3-4 nights, I realized that the Autostar planetarium placed the asteroid some 20' away from its actual location to the ESE.  The GOTO on the scope seemed to be off by a similar amount but the celestial coordinates from each are significantly different.  This wasn't a problem after I'd located 4-Vesta, but was certainly confusing for several nights.

Can someone with more experience confirm and/or explain the error?  Was the ephemeris wrong when the software was generated, or has Vesta changed its orbit?

Thanks.  The scope really is a gas.

- Tom Ryan

[Ryanlaw2]

Clouds the last few days.  For lack of something better to do I checked out concurrance between AutoStar Suite and GOTO in the scope memory.  Lack of concurrance on the position of all planets.  Differences of 3' (Pluto) to 17' (Mercury), average was 9.375' observed, 9.51' calculated.  Largest component of error is in RA. 

Checked position concurrance on a few stars, delta was less than 1'.

Because the GOTO function is so erratic (should be called GONEAR) it's hard to tell if it is more accurate than the AS Suite.

Hope the weather clears soon so I can knock off the doodling and go back to observing.

- Tom Ryan.