Fw: RA/DEC Reference

From: Bjorn Gimle (b.gimle@chello.se)
Date: Wed Sep 05 2001 - 16:57:39 EDT


 50 years of a period of 26000 years makes about 0.65 degrees near the
 ecliptic , and 0.17 deg in declination near RA 0h and 12 h

 Hardly important for binoculars, but crucial for most telescopes, and
 absoluteley essential for determining TLEs.

 You may use any epoch, just as long as you know, and report, what you are
 using.

 TLEs are in 'Epoch  of current date', and most prediction programs,
 including SkyMap in az/alt mode, assume that, but SkyMap plots the tracks
 correctly relative to the stars in Polar and Rectangular mode also, even
 though the coordinate grids and cursor readout change.

> ----- Original Message -----
> ...
> >
> > Even so, isn't the difference between 1950 and 2000 generally negligle
> > for satellite tracking and data-collection?  Of course, it's best to use
> > the most recent coordinates, I know that....
> >
>
>

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