Re: [APML] Traveler as guider scope?

[KGKIRKLEY@aol.com]

In a message dated 3/7/02 7:42:55 AM, DPMESSIER@aol.com writes:

>Hello all,
>
>Has anyone used a Traveler as a guider scope?  I seem to be having flexure
>
>problems with my setup.  I have an AP155EDFS with a Losmandy dovetail plate
>
>on top, to which I attach a pair of Losmandy DR125 rings to hold the 
>Traveler.  Anyone else try this and have problems? If so, how did you correct
>
>them?  
>I am going to try to use the standard rings that come with the Traveler
>to 
>see if that helps, but of course then I can't align the scopes or center
>a 
>guide star. 
>
>Any suggestions?    
>
>David P. Messier

David:
I had the same experience you are having. 
I wanted to guide my 155EDFS with a Traveler and at other times, shoot with 
the Traveler and guide with a TV101. I experienced flexure in both cases.

I ran a series of tests, putting barlows and guiding eyepieces in both 
instruments.
I would place the same star on the crosshairs of both instrument's eyepieces.
I would pick a star at about 30-45 degress above the east horizon. Once 
aligned I would allow the mount to track for an hour or so. Then I figured 
out I could just slew the mount in RA instead of tracking in real time. I ran 
this test with various mounting set-ups.

The results:
1200GTO mount

1. Losmandy DSBS (side-by-side) Saddle, 155EDFS in AP rings on one side, 
Traveler in AP rings on other side. Flexure evident.

2. Losmandy DSBS (side-by-side) Saddle, 155EDFS in AP rings on one side, 
Traveler in Losmandy DR125 rings, less flexure but still evident.

3. 155EDFS in AP rings, Losmandy Plates top and bottom, Traveler in Losmandy 
DR125 on top, flexure still evident.

4. 155EDFS in AP rings, Losmandy Plates top and bottom, TV101 in Losmandy 
DR125 on top, flexure evident, although less.

At this point I, like you, posted a query on APML and APUG.
Roland responded that the Traveler and TV101 were really too heavy to be 
flexure free guidescopes. He suggested a lighter weight guidscope, like one 
of the 90mm f11's or his AP unit. I researched this and decided on the AP 
guidscope which has machined aluminum bands around the OTA. After mounting 
the AP guidescope atop the 155 with the DR125 rings and performing the same 
test, no movement was evident.

I still haven't figured out exactly what is moving when using the Traveler, 
either for imaging or guiding.

Kent Kirkley






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