RE: Major Mark IV Problem

[mgutzwiller@lanvision.com]

I too see the double peak but the dip is close to the noise level (I get 125
ADU's sigma noise.)

What bothers me is that the separation of the peaks is about 5 pixels which,
if I remember right, is about 20 steps of the RA motor.  Can the vibration
be this large and not affect the repeatability or stability of the motor?
Or is the mount flexible enough to allow this kind of vibration away from
the motor?

Mike G.


		-----Original Message-----
		From:	Chris Albertson
[mailto:chris@topdog.pas1.logicon.com]
		Sent:	Tuesday, March 16, 1999 4:40 PM
		To:	mgutzwiller@lanvision.com
		Cc:	tass@wwa.com
		Subject:	Re: Major Mark IV Problem

		mgutzwiller@lanvision.com wrote:
		> 
		> Is it possible that the problem is not vibration but a
miscalibrated drive
		> rate?  It would be easy to tell the difference.  If the
star streaks get
		> longer with longer exposure it's a drive rate problem.  If
they are constant
		> for differing exposure lengths then its most likely a
vibration problem.
		>

		Mike,

		Look at Tom's sample star image.  I see a double peak.  It
could be
		caused by sinusoidal oscillation where the dwell times would
be longer
		at the ends then at the center.  My "good" software is at
home so I'll
		look in more detail later but by eye I see two peaks that
each look
		like streaks them selves.  The streaks are diagonal so maybe
there is
		some error in the tracking rate and some polar misalignment
so they
		_would_ get longer over time but if the double peak is real
I think
		it proves there is vibration also.

		 
		--Chris Albertson

		  chris@topdog.logicon.com                Voice:
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