An interesting read on autoguiding

[1ponders] (Paul) · #1 09-08-2011, 08:59 PM

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

h0ughy (David) · #2 09-08-2011, 09:56 PM

i agree it is an interesting read - almost makes you get a finder guider scope for the 127mm ed

[1ponders] (Paul) · #3 09-08-2011, 10:00 PM

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

h0ughy (David) · #4 09-08-2011, 10:05 PM

well the 127 is only 952mm FL and i was toying about getting one before for a travel setup (LOL)

RobF (Rob) · #5 10-08-2011, 06:14 PM

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.

gbeal · #6 10-08-2011, 07:41 PM

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

Tandum (Robin) · #7 10-08-2011, 09:25 PM

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.

Ross G · #8 11-08-2011, 10:26 PM

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.