Bolton Astronomical Society

Success with primitive GoTo
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Author:  rwilkinson [ Sat Feb 25, 2012 9:01 am ]
Post subject:  Success with primitive GoTo

I've just been experimenting with a Tasco GuideStar alt-az mount: a 10-year-old GoTo system. This is a re-badged version of an early Celestron NexStar (the non-upgradable GT model, with a number of well-known bugs!).
This model was obviously sold in the US market (the pre-loaded city database and time-zones are all in the USA), but I managed to work out how to enter my lat/long co-ordinates and time-zone.

Last night I fitted my little 80mm f/5 refractor onto it to give it a try. The only alignment option on this model is "Auto" (2-star) and after a couple of false-starts. it got quite close to its first star: Sirius.
Then it chose Rigel as its second alignment star, and was then able to GoTo M42 OK. But with two alignment stars so close, I anticipated that its calibration wouldn't be much good for the whole sky; and indeed it missed Jupiter by a few degrees. :(
So then I repeated the Auto-Align, but after lining up on Sirius as the first star, I kept skipping though its choices of second star until it got to Mirfak (in Perseus). And I made sure that my final centring of the alignment stars was done with the Down and Right buttons, to remove the effects of backlash in the gears. Using this calibration I was most impressed with its performance: it went straight onto M42, M31, Jupiter, M45 and even M1. Finally I called up Mars (which was behind the trees at the time) and left it tracking - sure enough, 20 minutes later I had another look and saw Mars emerging from behind a branch, centred in the eyepiece! :D

So the moral of this story is - make sensible choices for alignment stars - particularly if you only use two!

Author:  rwilkinson [ Sun Oct 06, 2013 7:17 am ]
Post subject:  Re: Success with primitive GoTo

I've just got this old mount back from Sharples, and have adapted it to run my Go-To Binoculars:

I tried it out last night, and having Aligned on Vega and Mirfak it was able to GoTo M31, the Double Cluster, M13 and M92. I tried it on M27 but it was too hazy (and I'd forgotten to fit the dew-caps so my objectives were misting over by then).

Author:  bbones [ Sun Oct 06, 2013 9:03 pm ]
Post subject:  Re: Success with primitive GoTo

Nice piece of work Ross, the lawn looks good as well.

how did you get the head to fit on the tripod?

Author:  rwilkinson [ Mon Oct 07, 2013 7:48 am ]
Post subject:  Re: Success with primitive GoTo

bbones wrote:
how did you get the head to fit on the tripod?

I've posted the answer in the original thread:

Author:  rwilkinson [ Fri Oct 11, 2013 9:23 am ]
Post subject:  Re: Success with primitive GoTo

rwilkinson wrote:
I tried it on M27 but it was too hazy

It was much clearer on Wednesday night, so with my 15x70 binoculars on this mount I was quickly able to find the Dumb-bell and M81 & 82.

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