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EQ6 PE at 10. and 5.1 Seconds

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#1 Jeffrey Sugden

Jeffrey Sugden

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Posted 04 April 2009 - 12:38 PM

I ran an autoguider test the other night and ran a log as well. Running the log through PECPrep, I find the following:

Period Mag Phase PE
454.1 37 -50
272.4 26 -141
154.2 30 -140
118.4 26 69
93.9 24 3
67.5 24 -129
43.5 24 -137
40.1 21 -48
21.3 20 100
20.1 22 -38
17.0 22 60
11.1 22 -84
10.3 34 -136
10.2 100 128
5.2 21 93
5.1 21 -36
5.1 40 139
5.0 23 22
5.0 23 -51

I am guessing the 10 second and 5 second is caused by the transfer geartrain teeth. How do I accomplish that?

Thanks,

#2 Mert

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Posted 05 April 2009 - 10:48 AM

Hi Jeffrey,

The 10 second ( 10.1 ) is the tooth to tooth contact
period caused by the stepper rotation ( 122 seconds ).
On the 5 second, I don't know, but likely these are
harmonics of the stepping frequency.

I see there are still components of the worm-period
and it's spurgear present as well as the stepper.
Did you use PEC during guiding?

#3 Jeffrey Sugden

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Posted 05 April 2009 - 08:17 PM

No. I just used PHD and an Orion autoguider. The tooth to tooth noise is on the order of 5 times bigger than most of the other noise. I think if I can get rid of that I will be in real good shape.

Do you have any ideas about how to reduce or eliminate that part of the noise?

#4 ccs_hello

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Posted 06 April 2009 - 06:35 AM

Jeff,

10.2 is caused by 12 tooth stepper output gear (122 second stepper full rotation cycle) touching the transfer idler gear. Belt drive is suggested (hpcgears.com in UK has the 47-tooth pulley).

Clear Skies!

ccs_hello

#5 Mert

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Posted 06 April 2009 - 11:55 AM

You might try another solution which requires some
machining but IMHO seems to work fine.
The amplitude of the 10.2 second in guided log
dropped to aprox. 0.3".
I use 47 teeth transfer gear and a new machined
RA-assy plate as well as transfer gear running on
a bearing. ( on the left the 36 tooth gear and on
the right the 47 tooth transfer gear )
Regards,

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