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Subject: PICTOR 201 WORKS
From: Glenn Strachan
Reply To: mapug@shore.net
Date: Tue Sep 26 08:36:59 1995
>
> How is your Pictor 201 autoguider working out? What magnitude stars can you use?
>
> Thanks in advance.
>
> --
> Stephen Edmondson
>
Hello,
Well I'm here in COLORfull COLORADO waiting for the stars to show from behind the clouds that Howard is sending from Arizona... i.e. monsoon.
I have been able to lock and guild on Mag 7.0. But, then discoverd that the Celestron off-axis guilder did NOT have enough back focus; so I have NOT yet taken a picture. What the heck... Go for a Lumicon Giant Easy Guilder... It's ONLY another $400.00.!#$%!! Must be 10" or greater for the Giant Easy...It REALLY is a GIANT!!!
I was able to perform various focus and search tests (using the standard star diagonal, while I was waiting for the Giant Easy to land on my door-step). The 201 guild is great!!! It got lost in a cloud, went into 'S'earch mode, and back to 't'racking all auto-magically. During 'S'earch mode it allows the LX200 to track by itself.
The Mag 7.0 track was in my VERY light polluted backyard (~4.5-5.5). The temperature was about 50F (10C). Focus value was 44 for this Mag 7.0 star, seeing at about 35x/inch. I have NO doubts that with better seeing, >45x/inch, and cool temps the 201 should be able to live up to the 8.0 or better specs.
The NUMBER ONE problem I was having is the BACKLASH setting of the LX200. The 201 (understandably) wants the scope to move N/S when told to due so... I had set the backlash at a value of 10. This is NOT enough for my scope. I now have backlash set to a value of 45. In effect, the lower value made the scope un-responsive to the 201's requests for N/S movement, the 201 gave up and 'Er'rored out.
The NEXT big issue is to get FOCUS right. This has proven to be an iterative process. 1. Using the star diagonal, seat the 201 in ALL the way. 2. Get some star to work (Mag 3-4). Search routine at 5,5. 3. Go to the Focus routine, allow the 201 to AE as many times as it needs to. At a focus value greater than 75 it will close down exposure time (AE). I believe this is important to the 201, so that a bright star is not blinding it. 4. Using the SCOPE'S FOCUS get the HIGHEST value possible. At this point the 201 should be focused. 5. NOW, remove the 201 and make a para-focal eyepiece (two is better than one). I have the 6mm illuminated and the 26mm standard eyepieces BOTH para-focal to the 201. The 26mm is great as a wide view and getting close to a guild star. The (BAD-WORD) Celestron 6mm is great as a guilding/measuring device. 6. I have found that the CCD is NOT in the center of the 1.25". At F/10 I have measured 'UP' 45 arcsecs from center. I set the guild star at this position, remove the eyepiece, insert the 201; and there you go: S == 5,5...
After using a bright star, continue to go down in magnitude. Each iteration will achieve a better focus comparison to test the eyepieces with.
Then all you need to do is: WAIT FOR CLEAR SKYS!!!!!!! It's easy, RIGHT???
--Glenn Strachan Storage Technology Corp. 2270 S. 88th St. Louisville, Co. 80028-0217 MS0268 VOICE: (303) 673-2242 FAX: (303) 673-8196 Glenn_Strachan@stortek.com