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HEQ5 Polar alignment...help please!!!


Ben Cole
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Probably the first of many questions.

First up...when preparing the mount to do a polar alignment I am confused by the following.

I tighten the setscrew on the RA setting circle to lock it at zero as instructed.

The instructions then go on to say:

"Now rotate the telescope around RA axis so that the RA Circle indicates 1h 0m on the bottom set of numbers "

And shows this diagram:

fig5.jpg

Problem is, after I've locked the setting circle the setting circle scale doesn't move at all except when the screw is unlocked but in this state the circle just slips about. I can't see how it could ever move when locked becuase it locks it to the body of the mount which never moves in RA. Do I have a problem or a faulty mount?

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In order to do a possible sidestep here maybe the following question can be answered.

My polar scope reticule doesn't match the one the instructions says it should have. It has diagrams of the big dipper and Cassiopeia.

If I line these constellations up and get polaris in the little circle then I am polar aligned correct? I don't need to mess with the setting circles etc? (provided the polar scope is correctly aligned to the mount axis and the reticule is centred)

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Thanks Blinky. After thinking about it and realising I had a more detailed reticule than I expected I came to the conclusion that the reticule with the different stars on it negates the need for any calculations with/calibration of the setting circles and reticule.

I gather the calculations the manual describe are to account for the varying position at any given time of the year of the NCP relative to Polaris.

At least if I am correct here I can align.....then improve my knowledge later to allow navigation by setting circles.

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In order to do a possible sidestep here maybe the following question can be answered.

My polar scope reticule doesn't match the one the instructions says it should have. It has diagrams of the big dipper and Cassiopeia.

If I line these constellations up and get polaris in the little circle then I am polar aligned correct? I don't need to mess with the setting circles etc? (provided the polar scope is correctly aligned to the mount axis and the reticule is centred)

Yes mate, that's all you need to do to polar align.

Captain Chaos

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For visual observing, when Polaris is in the circle you will be fine.

When you say "for visual observing" are you implying that it's not very accurate?

I was under the impression that if the polar scope was aligned to the mount correctly and the reticule is properly mounted, if I then line up the stars to their correct markers it was as accurate as I was going to get.

What other steps are there to align more accurately?

Or do you just mean get polaris in the "big" circle not the small polaris marker circle?

I believe if you download the manuel for the EQ6 there you will find the images for use with the polar finder you have.

The manual for the EQ6 and the HEQ5 is the same so I have the images.

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Alinging Polaris in this way will be fine for visual oberving, the image may drift but it will be very very slow and give enought time for you to have a good look without having to move the 'scope. For imaging I think a good alingment on Polaris would be OK for short exposures of around a minute or so, this is the setup I have, althought maybe that explains why my piccies are not very good! :D

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Chaps

Visual observing is nowhere near as critical, because you can simply adjust the RA and bring the object back into view. For imaging, you want to keep the object slap-bang in the middle.

For more accurate polar alignment, google on the Drift Method of aligning, or just polar alignment and how many ways there are of doing it!!

More accurate = more time!

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With my HEQ5, I can do 2 minutes easily by only putting Polaris in the centre of the little circle. With visual, you would need very high power and a reticle eyepiece to detect any drift at all in five minutes. If you intend to peer at something for an hour, you should maybe drift align, or just nudge the target back into view every twenty minutes. I can't think why you would want to do that, but it would work.

I've lined my HEQ5 up using the polar 'scope and I can shut the shed up when clouds arrive, then open it an hour later. The target is still in the FOV of the webcam, but might need recentering very slightly, because I left the mount tracking. So far drift aligning hasn't been necessary as the subs I use are governed more by the PEC than alignment error.

HTH

Captain Chaos

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Thanks Captain. That method of alignment should be fine for me then. IT'll be a while before I have a requirement for drift alignment that's for sure :shock:

Probably looking to do a max of 1-2mins exposures I would have thought.

With the weather being so awful I thought I'd get the polar scope properly aligned during the daylight today so I'm good to go............now just need some clear skies!!!!! :x

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