[time-nuts] Sidereal time
jfor at quik.com
Fri Jan 15 20:49:30 UTC 2010
> J. Forster wrote:
>> That's the point I was making earlier.
>> Most telescopes have a FOV of at least 15 arc-minutes. You only need to
>> get the guide stars into the field and go from there.
>> Also, a telescope's pointing can be off in BOTH RA and Dec. Dec has
>> nothing to do with siderial time.
> If the axes arent exactly orthogonal or the polar axis (assuming an
> equatorial mount) then the declination as measured by the telescope
> encoder is dependent on time.
That effect is second order at most. Do the trig.
> If the mount is alt-alt altazimuth etc then both axis coorrdinates are
> time dependent.
> An automated telescope doesn't always have an observer available to do
> the fine pointing corrections.
Serious telescopes have auto-trackers. You put the cursor on the guide
star and put it into track mode.
> Since there has been no statement about the telescope aperture or field
> of view the assumption that the FOV is 15 arc minutes or more may be
See other email for examples.
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