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Old 09-08-2011, 07:59 PM
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[1ponders] (Paul)
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An interesting read on autoguiding

I've often felt that many imagers are trying to use too long a focal length guidescope when trying to autoguide. I've never had anything to prove this except in practical evidence. I have far less guiding problems using a 200mm finderscope than I ever had using a 420mm guidescope. And this is imaging at 1800 - 2000 mm imaging scope FL across a variety of mounts.

This article though seems to go along way to convince me I'm right. Again I can't prove what he is saying, but it makes sense to me and the evidence I've seen with my own gear tends to support his ideas.

http://www.wilmslowastro.com/tips/autoguiding.htm
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Old 09-08-2011, 08:56 PM
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h0ughy (David)
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i agree it is an interesting read - almost makes you get a finder guider scope for the 127mm ed
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Old 09-08-2011, 09:00 PM
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[1ponders] (Paul)
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well I've been using a 50mm Stellarview with my VC200 and its worked a treat. Even putting in the figures for the Ex-view autoguider at 16 micron pixels I still only need a 100mm guidescope even at 0.1 centroid accuracy
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Old 09-08-2011, 09:05 PM
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h0ughy (David)
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well the 127 is only 952mm FL and i was toying about getting one before for a travel setup (LOL)
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Old 10-08-2011, 05:14 PM
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thanks Paul - very interesting read. I've found 200mm greaet for my Newt, but good to hear short FL has worked well for your 2m FL too.
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Old 10-08-2011, 06:41 PM
gbeal
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I use a converted 50 finder and Lodestar, works a treat. Plate solves at about 176mm focal length if I recall correctly.
Mine's hard mounted to the dovetail saddle.
Gary
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Old 10-08-2011, 08:25 PM
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Tandum (Robin)
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All well and good without flex. One micron movement in a 170mm guider equals about 2 degrees of movement at 2 meters. I'm using guide scopes when imaging under a meter and an oag over a meter and that's working for me.
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Old 11-08-2011, 09:26 PM
Ross G
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Hi Paul,

Thanks, an interesting article.

I have been using a Vixen 7x50 finder scope as a guide scope for my widefield DSLR lens set up and it has been working a treat.
I have tried the finder/guider on an 8" F4 Reflector and it worked well.
I am about to replace the guide scope on my refractor with the finder guider. This should save weight and help the portability of my setup.


Ross.
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