[APML] G-11; Results of gear lapping and overhaul

["Glenn Ray" <glennlray@mail.ev1.net>]

For Y'all's Info:

Well, after some reassuring advice from Dan Norman, Stu Travelbee, 
and Richard Crisp (THANKS, Guys!), I decided to lap the RA gear 
myself (gulp).  I used 1 micron Luster-Lap (from McMaster-Carr); 
ran the drive at 16x for 4 revolutions.  Also re-lubed all needle 
& thrust bearings.

My previous PE was +/- 8", with strong swings >4 arcsec/sec.  This 
made it difficult to guide at anything less than 2x, or very short 
exposures.

Last night I ran a preliminary tracking test (ST-4, guiding at 
2032mm and tracking stars near meridian/equator).  I used CCDTRACK 
to record the tracking data (it outputs to a log file) and plugged 
the results into Excel.

Summary:  
1) Total PE has been reduced to +/- 4 arcseconds.  
2) Each revolution of the worm (4 mins) has three cycles of error 
with peak-to-peak of about 4-5 arcseconds each.  
3) There is a total RA drift about 75 arcseconds per hour (too 
fast). 

While I'm happy about cutting the overall PE in half, I'm 
perplexed about the other two findings.  I can't imagine a 
physical scenario that would cause the quick cycles.  Because I 
only did a rough drift alignment (N-S okay, but E-W a little off), 
I wonder if RA showed a component of that alignment error.

I really suspect both are related to electronics, but can't 
confirm that until I do another run.  I noted several people on 
the Internet who noted similar RA drift, but no answers.  

After performing a second run, I plan to post an article with 
procedures and results on my website.  I also will investigate 
using PEC to try and smooth it further.  I will welcome any 
suggestions or additional information.

Thanks,

Glenn Ray
Cypress, TX
http://users3.ev1.net/~glennlray/Astro



>> >----- Original Message ----- 
>> >From: "glennlray" <glennlray@mail.ev1.net>
>> >To: <astro-photo@seds.org>
>> >Sent: Wednesday, January 07, 2004 2:28 AM
>> >Subject: [APML] Semi-OT: Precision Machine Shops in Houston 
area?
>> >
>> >
>> >> I am considering having the RA gear on my G-11 lapped and am 
looking
>for a
>> >good precision machine shop in the Houston, Texas area.  I may 
consider
>> >companies outside of Houston if none can be found here.  I 
don't think I
>can
>> >lap the gear myself, unless someone here convinces me I can.
>> >>
>> >> Please reply off-list.
>> >>
>> >> Thanks,
>> >>
>> >> Glenn Ray
>> >> http://users3.ev1.net/~glennlray/Astro
>> >>
>> >>
>> >>
>> >>
>> >> _______________________________________________
>> >> Astro-Photo mailing list
>> >> Astro-Photo@seds.org
>> >> http://seds.org/mailman/listinfo/astro-photo
>> >>
>> >
>> >
>>
>
>
 

________________________________________________________________
Sent via the EV1 webmail system at mail.ev1.net


 
                   
_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo