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Eq3-2 polar alignment scope


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I got one of these as most people seem to think its a good idea and i guess for those who understand it i will be, i however seem to be getting a little lost....

First off when i screw the Polar alignment scope in its not sitting right i dont think, the cross in the centre does not hold a centre position it spins and circles slightly as i screw it in is this normal ????

Next questiuon am i suppose to screw it all the way up into the mount and leave it there or not ???? i was guessing maybe i had to set it to the current time by spinning it round so altering the position of the big dipper to teh left of the right of polaris or maybe i am supposed to match the night sky as i see it forgetting the actual current time i dont know.

Once this is settled i then i presume i put polaris into the small circle that is sitting on the edge of the circle in the centre of the eyepiece, with the cross and NCP, polaris should then i presume travel around the circle as the night progresses around NCP....????

I just cant find a decent web site to help me out showing me exactly what to do with the view i have through the polar aligment scope....can anyone advise pleas please please...

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Hi Malc

Its not easy but here you go:

1. Screw in Polarscope fully.

2. Point towards a point and move mount in RA 180 degrees and adjust so cross stays on same point. (you will have to do this several times. Use the tiny grub screws to adjust)

3. When aligned find the time of Polaris transit for your location HERE

4. Turn your RA till the small circle for polaris is at 6oclock through the polarscope

5. Unlock the time setting ring (small screw on PS) and set the time/date to match the time of Polaris transit. Lock screws.

6. all set!

7. Now when observing, turn RA to match the current time/date and using your adjustment screws (Lat bolts and Longitude screws) to place polaris in the small circle. [These are the bolts on the mount not RA/DEC movement!]

HTH

Cheers

Edited by JKB
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I've been tinkering with this over the last week or so. My initial conclusion is that the polar scope adjustment on the EQ3-2 is a bit rubbish (this is for the older style EQ3-2, not the new one). Basically I found it nigh on impossible to accurately align the scope with the mount using AB's "centre scope, flip 180 degrees, adjust by 50% of the error, flip back 180 degrees and repeat" method because there was just too much slack in the polar scope housing once the adjustment screws were released. The reason yours doesn't remain focussed on the same point is probably because it isn't propertly aligned with the mount and you need to go through that same alignment process. Screw it in all the way and see how you get on.

Because of the slop in the mounting I eventually removed the polar scope from its housing and found an O ring that would fit over the inner end and held the scope about a third of the way along inside the housing, pretty much like a finderscope. That made adjustment far easier, though I seem to recall that it reverses the sense of AB's adjustment instructions. I did the adjustment indoors because it was dark and it was easier to do, but it's probably ideally done during the day using a distant landmark to focus on (and without a scope

on the mount). You should end up with the cross-hairs of the scope rotating about a fixed point as you rotate the mount about the RA axis.

In a thread which I have currently lost, someone explained that all the rigmarole with polaris transit times is not required. Fortunately I made a note of the method, which is:

All you do (as a once-off procedure) is to loosen the Index Ring (that's the black ring with a single white line on it), look through the Polar Scope at its markings on the reticule and rotate the scope around such that the Polaris target mark in the reticule is now located at the exact bottom* of the view. Then reposition the Date Ring so that November 1st** is at the top, and then rotate and align the Index Ring so that its white line aligns with meridian offset zero against the Date Ring. Then lock the Index Ring's set-screw - it should never need adjusting again***. The Date Ring is left free to rotate.

In everyday use then, with the mount set-up, just start by locking the RA Ring so 0:00 (midnight) is at the top, then twist the Date Ring so that your location's longitude meridian offset aligns with the white mark on the Index Ring on the Polar Scope, and then rotate the entire Polar Scope (normally by rotating the telescope's entire RA Axis) such that today's date (on the Date Ring) aligns with today's current time (on the RA Ring - but not including Daylight Saving Time). Lock off the RA axis, peer through the Polar Scope, and adjust azimuth and altitude to get Polaris into the marked place on the reticule.

That certainly all worked for me when I tried it a few days ago. Thanks to whoever wrote it. I wish I could credit it to the right person.

James

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Hi Malc

Its not easy but here you go:

1. Screw in Polarscope fully.

2. Point towards a point and move mount in RA 180 degrees and adjust so cross stays on same point. (you will have to do this several times. Use the tiny grub screws to adjust)

3. When aligned find the time of Polaris transit for your location HERE

4. Turn your RA till the small circle for polaris is at 6oclock through the polarscope

5. Unlock the time setting ring (small screw on PS) and set the time/date to match the time of Polaris transit. Lock screws.

6. all set!

7. Now when observing, turn RA to match the current time/date and using your adjustment screws (Lat bolts and Longitude screws) to place polaris in the small circle. [These are the bolts on the mount not RA/DEC movement!]

HTH

Cheers

Why do i get the feeling i dont have anything small enough to adjust the polar scope which i believe need doing from what i have tried so far :D

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A very small screwdriver is almost certainly required.

James

UPdate ran down to B&Q got ripped off for a set of allen keys and managed to aligh the polar scope so when i flip the cross stays more or les son target give or take a little drift

Edited by jasperuk
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On mine, the index ring on the polar scope is held in place by a slotted grub screw. I didn't need any allen keys to adjust it. The alignment adjustment is done with knurled screws turned by hand. It's possible that yours may be different if it's the newer model.

James

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  • 1 year later...

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