RA motor simple question

[cal1985]

hi all. i have polar aligned my scope. however whenever i swap to a new target i have to adjust the RA motor speed. is this normal or have i done something wrong ?

[barkis]

A lot depends on your mount and controller.

Some controllers have the means to select various speed rates, and they are usually marked on the handset.

To track an object in the sky other than the moon, select sidereal rate. Whether or not you have a lunar rate will also be marked.

Other speeds are slew speeds which allow the scope to be moved fairly quickly to another object.

Sometimes it's quicker to slacken off the clutch, and manually move the scope to another target. If you do that, the gears of your drive may have some backlash that might introduce a delay before the drive takes up, and the object may have moved out o the field of view, in such a case, you need to use a slightly faster rate to catch it up, and once you do, switch back to sidereal rate to keep it tracking.

All I've said depends on the type of system you have.

Ron.

[cal1985]

the mount is a eq2 and the motor is a skywatcher RA motor it has a north and south switch and a knob that adjusts the speed

[star_chaser]

i have the celestron 130eq with ra motor drive and i have the same trouble as yourself.im not sure of the quality of your drive but i was asking the same question and it seems my drive is not very good but i wasnt loosening the clutches when moving scope and think this was putting pressure on motor (was doing a moon mosaic) so was gonna try this next time because it seems to be ok if i dont move the scope

not sure how handy you are at making things but some on here have made there own motors and see a great improvement. i think there is a thread in the diy section but it seemed a little tricky for me

and to anyone should the clutches be loosened before moving scope with motor running or at anytime ?. as when i re tighten them the scope moves a bit not ideal when doing a mosaic of can i just switch of motor them move

hth and sorry for the slight highjack star

[edit] i should have realized my motor was not very good as i have to set it to southern hemi but live in the northern hemi

[barkis]

The north south switch, as you know is for selecting the hemisphere, so in our case, that is north.

The speed knobs job is to let you select a rate which will keep a star in the field of view of your eyepiece. I would leave it at that rate, as it is the one you will use the most. Any large moving of the telescope should be done by releasing the RA clutch, and rotating the scope manually to the new target, the re locking the clutch.

Any drift will probably be due to slack in the gearing, and it will need to catch up. A way to counteract that, is to place the telescope in advance of a new target, and that will allow any backlash to catch up, and the drive take up again.

This is not a sophisticated system, and drive accuracy may fluctuate due to voltage variations, temperature changes etc.

It is designed to allow fairly long periods of viewing an object, but it may not cope too well under high magnifications.

Ron.

[Adrian]

The north-south switch will also depend on which side of the mount you put it on. Mine is set to northern hemisphere and is attached to the 'west' side of the mount, but if I reattached it on the 'east' side then I would need it to spin the other way in order to track and so it would be set for southern hemisphere.

To adjust for the backlash you can also run the motor at a higher speed in order to catch up to the position you require.

[cal1985]

thank you all for your comments this has helped alot

[star_chaser]

The north-south switch will also depend on which side of the mount you put it on. Mine is set to northern hemisphere and is attached to the 'west' side of the mount, but if I reattached it on the 'east' side then I would need it to spin the other way in order to track and so it would be set for southern hemisphere.

To adjust for the backlash you can also run the motor at a higher speed in order to catch up to the position you require.

i can only attach my mount to one side