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[furledd]

Correction - Dumbhead here read RPM and its RPH - so its a lot slower than i expected!

 

Plus newbie mistake #2 - i assumed the ascension scale would stay put and i would watch the fork mount zero move against it, but it aslo moves WITH the fork mount so it never "moved" against the scale that i could see. Weird way of making a scale but once I marked the housing with TAPE against the scale, i saw movement.

 

Sorry guys..

 

Just got a used scope last week. The scope would not track and i noted no movement so i pulled out the Synchron motor and even though the motor is running, the tiny output gear is not turning. The motor is 110V 60 CY 3W 0.75 RPM  and i should be able to see the gear turn about like a second hand at 0.75 RPM.

 

Anyone know how to pull one apart? Is this problem fixable?

 

Or, does anyone have a spare motor, or know where i can find one?

I emailed Hansen Corp who still makes some but never heard back. Astroptx doesnt show any in inventory.

 

Anyone have an old Criterion 4000 in pieces willing to sell your Synchron .75 RPM gearmotor ?

 

Dwight

Edited by furledd, 10 July 2015 - 06:57 PM.

[DAVIDG]

 The reason why the RA scale doesn't move is that once you calibrate it by first polar aligning your scope and then pointing it at an object that you know the Right ascension (RA) and Declination you can rotate the RA  scale to read that value and that value won't change unless you move the scope to another object.  Now as long as the drive it turned on you can then look up the RA and DEC of any object you wish to observe and move the scope to  reads those values. What you have is called a driven RA circle. On many telescopes the RA circle is not driven so after a few minutes of viewing an object, the RA reading will no longer be correct so to find the next object you have to readjust the RA circle to read the  correct RA value  or note how much time has passed since you first calibrate the circle and add that value to RA reading of the next object you wish to observe. So having a driven RA circle removes those additional steps.

 

                     - Dave