[AZ-Observing] Re: Polaris Transit

  • From: Stan Gorodenski <stan_gorodenski@xxxxxxxxxxxxx>
  • To: az-observing@xxxxxxxxxxxxx
  • Date: Fri, 02 Mar 2007 14:20:43 -0700

Tom,

tpolakis@xxxxxxx wrote:

>Stan,
>
>How accurately do you want the azimuth of your polar axis to be
>

Getting Polaris in the center of the eyepiece within, say within 15 
seconds of time, is easily doable. I just did the azimuth adjustment 
last night and it was no problem. The error comes in with 
non-orthogonality of the axis, the center of the eyepiece not being in 
line with the optical axis of the telescope, and the accuracy of the 
transit time of Polaris. The first two are difficult to take into 
account and so I am proceeding assuming the best, for now. The transit 
time of Polaris appears to be difficult to accurately know. I was not 
too concerned about how accurate Guide's value was for the transit time 
when I did the azimuth adjustment last night because I knew I was going 
to have to go back and tweak it some more after I get the altitude 
adjustment done. In the meantime I could check out Guide's value, as I 
have just done through these messages and doing the calculation myself. 
It appears Guide's value is good.


>anybody pitched in yet with a transit time from Guide software=3F  The aut=
>hor
>Bill Gray seems to be the most interested in high accuracy, and I think
>it's still the charting software of choice for astrometry types=2E
>  
>

 From my calculations, which could be wrong, it appears Bill Gray's 
value is the most accurate which supports your statement that he seems 
to be the most interested in high accuracy. His 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). This is from a program, version 8, that I 
received 5 years ago! I think this is a good program.
Stan

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