Jerry wrote:

Would you mind sending me a copy of your alignment spreadsheet?

Jerry, The spreadsheet, which just digitizes the spreadsheet in the 1991 S&T Sinnott-Baldwin article, can be downloaded from: http://members.csolutions.net/fisherka/astronote/astromath/Polarmisalignment... I will send you an article copy offline. Some qualifiers: 1) I consider it a dated technique.  The spreadsheet seeks to progressively minimize polar alignment errors from the 1 deg range to a 3 arcmin error range by looking at the difference between measured and ephemeris star positions.  This technique has been supplanted by polar drift alignment and polar drift alignment optimization tools built into, I understand, Maxim DL, and into K3CCDTools.  Nonetheless, not finding a comparable spreadsheet anywhere on the web, IMHO the Baldwin spreadsheet was information worth preserving for future use by digitizing it, so I ported the article's spreadsheet formulas to Excel. 2) The Baldwin article has two principal residual applications, IMHO. a) The article and spreadsheet was a good learning exercise for studying the trignometry behind the fundamental astronomical spherical right triangle.  I found standard texts on spherical trignometry to be a bit thick and uninteresting without some practical exercises.  It's important to understand where all the gee-whiz computerized features in our modern telescopes come from, in order to properly understand the limitations of their use. I was reminded of this last Saturday when I update synched an alignment star in my hand controller that was a wee-bit too close in RA to only other alignment star in a two star alignment.  I assume the sin or cos function failed as a result and on the next slew, the alt-az mounted scope started doing comical loop-d-loops before I could rip the power cord out. b) It is useful for high-precision alignment of GEM mounted scopes where the northern sky and Polaris is obscured from view, e.g. - the south facing backdoor of my apartment or both the SLAS Grimm and Ealing scopes which are blocked to a north Polaris view.  Using Baldwin's spreadsheet, you can systemactically reduce the error in GEM polar alignment down to a range where the more modern technique of video or CCD camera assisted polar drift alignment can be done.  But I do not use Baldwin's spreadsheet regularly for this purpose, only on those rare occassions if I am forced to by circumstances. (I'm just lazy. It is easier in north blocked locations to just set up an alt-az computerized goto, whose internal computer doesn't care if you can't see Polaris or not. -:)) Clear Skies - Kurt