Re: AP-1200 pointing and guiding data

John Menke <domepage@...>

I have a 1200 mount with a 6in. f12 and ST7.

With moderate attention to orthogonality and scope alignment, I get
about 3-4 a-min pointing accuracy (this is the max error) at all parts
of the sky. If I worked at it, my impression is that this could be
knocked down to 2-3 a-min. without too much trouble. Of course, it is
also easy to goto a local target, resynch, then move to the object of
interest. If T-p[oint or something similar is used, one should be able
to do better than that. My uncorrected tracking is 3 a-sec peak to

Using the ST7 guide chip, I regularly track with a precision of well
under 0.5 pixel (roughly 1 a-s at f12). Combining images is easy--all
you do as add them (no alignment issues). I have done many 2-4 hours
of ten minute exposures at either f12 or f22 with all round stars.

John menke
Technical Innovations

twocat@... wrote:

I'm new to your group and considering the purchase of an AP-1200
Mount. I have been unable to find any data on the pointing accuracy
or guiding accuracy when using common CCD cameras such as the SBIG ST-
7,8,9 etc. Does anyone have any first hand data they would share on
pointing accuracy with or without the use of pointing programs such
as T-Point and data on guiding using a CCD camera? Any data and
comments are appreciated.

Gary Vander Haagen
Gray Dunes Observatory, Michigan

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