clear sky chart

Job 9:9

Job 9:9-10
9 He is the Maker of the Bear and Orion,
the Pleiades and the constellations of the south.
10 He performs wonders that cannot be fathomed,
miracles that cannot be counted.

Wednesday, March 30, 2011

Analysis of Recent Photos

Ever since I built the clock drive (and the 127mm refractor), I have noticed a lack of quality in my images.  I had assumed I would get better resolution while using the clock drive, being able to eliminate the slight motion blur as the object moved across the field.  I found the images worse than before I began using it.  I therefore have to conclude that the problem is in the clock drive.  Because the camera magnifies the images so much greater than a regular eyepiece, I have to conclude that any minute amount of vibration and/or stepper motor resolution is causing a problem.

The way I see it, after looking at the last 2 Saturn images in my last post, I have concluded that the problem is caused by stepper motor vibration as well as the resolution.  Therefore, this is what I plan to do to resolve the problem.  First, I'm going to mount the motor itself on rubber shock mounting grommets, as well as possibly adding some mass to the base of the mount.  These two things should reduce the vibration substantially.

The second modification I want to consider is gearing down my stepper motor even further.  I have several stepper motors in my collection.  I will take a look first to see if they all have 7.5 degree step rotation.  If so, I am going to gear down what I have at least 10:1 more than I already have.  I figure that will clean things up substantially.  This will require me to make a whole new motor mount for the clock drive.  The next time I image, I will not use the clock drive, unless I do some low magnification lunar stuff.  This problem seems to manifest itself worse when using high magnifications.  Because Saturn is so difficult anyway, I feel I would get better images if I let it crawl across the field and manually reset.

Therefore, I will first mount the motor on the grommets and see what effect that has.  Then if necessary, which probably will be, I will redesign the motor drive to gear it down at least 10:1 slower than it currently is now.  Stay tuned, I will, of course report on my progress.


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