> 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. >> -John >> >> >> >> > 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 > invalid. See other email for examples. -John =============== > > > Bruce > > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
