Re: [APML]: Guiding Guidance

[Brad Wallis <wallis@pepe.jpl.nasa.gov>]

> 1. What are the pros and cons of using an off axis guider vs. using a
> guide scope--say an ETX with a barlow.

depends on your system .. with most SCT systems a guidescope is not
even feasible due to mirror motions on a long exposure ...  but
basically IMHO ... the off axis guider solution is the fastest and
easiest way to get up and running for a beginner ....  

I personally prefer the guidescope solution but it requires a lot
of work to eliminate bugs and flexure from the system ...

when it comes to shooting a comet .. you had better be able to use
a guidescope ... an off-axis guider will not work ....

when it comes to starting up to try and use a guidescope I would
recommend using a refractor for the guidescope ... less flexure
problems to debug this way ...  but if you need a large guidescope
then you will need to build a very sturdy reflector for the guidescope.

Brad Wallis
http://voltaire.csun.edu/wallis_provin.html