[AZ-Observing] Re: Polaris Transit

  • From: Brian Skiff <bas@xxxxxxxxxx>
  • To: az-observing@xxxxxxxxxxxxx
  • Date: Fri, 2 Mar 2007 14:28:19 -0700 (MST)

>>  [Guide's] ...apparent RA for the Sun
>>  was off by only tens of seconds of time compared to the values given in
>>  the 2007  Observer's Handbook, page 158 (of course, this assumes the
>>  Handbook values are correct).

     For the apparent coords of the Sun, you'd really want to take
into account one's topocentric position, rather than a straight
geocentric position (if real precision actually matters), and it could
be that the RASC Handbook positions are geocentric, or maybe for
some 'center of Canada' location.  I'd be willing to bet that Bill Gray
does indeed at least allow for this, but perhaps tweaking of input
parameters would be involved.  This would account for the tens of
time-seconds difference Stan quotes, and which ought to be calculable
to an arc-second or so for any instant (tens of time-sec is a huge 
error by comparison, so something is amiss).

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