Accurate Polar Scope Alignment

[ndastgir]

Hi All,

I am trying to do an accurate polar scope alignment. Now, I have ready most of the manuals and guides available on the web, but couldn't find an answer to one question:

Does the telescope need to be at HOME position when performing polar scope alignment? or the telescope (RA) position is irrelevant??

Much appreciate any advise/suggestions by the pro's, and highly experienced members of the forum.

Naeim,

[JamesF]

The telescope position is irrelevant. The point of aligning using the polar scope is to align the mount, not the telescope. If you're really after accuracy, you'll be wanting to read up on drift alignment I imagine.

James

[JamesF]

Perhaps I should be more specific. The point of aligning using the polar scope is to align the mount in alt and az, not in RA or DEC.

James

[ndastgir]

Many thanks James,

Alt/az alignment, that explains it. I'll look into drift alignment now.

Naeim,

[K3ny0n]

Leave you scope in the house, and just do a polar alignment with your mount.

Rob

[Black Knight]

I'd just echo what the others have said. I would only say in addition that doing PA alignment and adjusting the mount with with the scope attached can have serious consequences for the bendy Alt/az bolts (alt in particular), supplied with Skywatcher mounts. Best to leave the scope off while you align PA

[JamesF]

I do my alignment with the scope off the mount and then have a final tweak after mounting up the scope in case I've disturbed things when doing so.

James

[Freddie]

Same here. Get it lined up then add scope for final drift alignment to get it spot on.

Naeim, just one thing to check. Were you talking about aligning your polar scope in the mount or using the polar scope to do a polar alignment of your mount?

[ndastgir]

Same here. Get it lined up then add scope for final drift alignment to get it spot on.

Naeim, just one thing to check. Were you talking about aligning your polar scope in the mount or using the polar scope to do a polar alignment of your mount?

I am talking about alignmnet of the polar scope itself. i.e. select a date when polaris is in transit, then rotate the date disc, then loosen the thee screws holding the polarscope.

what I was wondering was if the position of the telescope is not important, why would one need to loosen those screws to align the polaris with the date/time? why wouldn't we just rotate the mount in RA??

another point, should the date disc be fixed to the polarscope? or should be loose?

[geoffers1]

Hi. Sorry for sounding a bit thick (total noob) how do you PA without a scope attached? I'm trying to PA my scope that I just bought (one clear night since I got it) and couldn't manage it. So I asked on here and was given some very good instructions on how to achieve it (sorry can't remember who at the moment). However the instructions relied on a scope being attached and looking through the eyepiece etc.

Totally confused.com now

[Black Knight]

Does your mount have a polar scope fitted? You would use that.

[JamesF]

Ahh. I bet the 130EQ doesn't come with a polar scope. If it doesn't then you can roughly align the scope north and set the latitude scale correctly (assuming it has one), but after that you can probably only improve things by plate-solving images or drift alignment. Unless of course the 130EQ comes with some method of guaranteeing that the OTA is perfectly aligned with the RA axis?

For what purpose are you wanting to polar align the mount? Just visual use, planetary imaging., something else?

James

[x6gas]

I am talking about alignmnet of the polar scope itself. i.e. select a date when polaris is in transit, then rotate the date disc, then loosen the thee screws holding the polarscope.

what I was wondering was if the position of the telescope is not important, why would one need to loosen those screws to align the polaris with the date/time? why wouldn't we just rotate the mount in RA??

another point, should the date disc be fixed to the polarscope? or should be loose?

Doing the polar alignment using setting circles is really hard work and, IMHO, not worth the effort.

You need to ensure that the polar scope is aligned along the centreline of the Alt and Az axes of the mount. You do this by centering the crosshairs of the polar scope on something and looking to see if the centre of the crosshairs move as you rotate the RA; I won't go into full details as it is covered in depth elsewhere on here (e.g. http://stargazerslounge.com/topic/154378-polar-scope/page__st__20__hl__+polar%20+finder#entry1559482).

Then use polar finder - free software here: http://myastroimages.com/Polar_FinderScope_by_Jason_Dale/ to show you where polaris should be in the finder scope for your location / date / time.

[JamesF]

Once the polar scope is properly aligned with the RA axis then I turn the RA axis to where the time and date rings are at midnight on November 1st. At that time and date the Polaris indicator on the reticle should be in its lowest possible position. On my polar scope there's a line running across the diameter of the reticle to the Polaris indicator, so with Polaris at the bottom of that I rotate the polar scope until the line is parallel with something vertical. Job done.

James

[ndastgir]

Doing the polar alignment using setting circles is really hard work and, IMHO, not worth the effort.

You need to ensure that the polar scope is aligned along the centreline of the Alt and Az axes of the mount. You do this by centering the crosshairs of the polar scope on something and looking to see if the centre of the crosshairs move as you rotate the RA; I won't go into full details as it is covered in depth elsewhere on here (e.g. http://stargazerslou...er#entry1559482).

Then use polar finder - free software here: http://myastroimages..._by_Jason_Dale/ to show you where polaris should be in the finder scope for your location / date / time.

Does this mean that I don't need to put the mount in 'home' position and adjust the polarscope with the three screws at all?

[JamesF]

There's a really good guide to aligning your polar scope on Astro_Baby's website. I'll find a link in a moment. It's for a HEQ5 I think, but it works for others. The only bit I do differently is the alignment of the reticle, as per my previous posting.

James

[JamesF]

Here you go:

http://astro-baby.com/HEQ5/HEQ5-1.htm

You don't need your scope on the mount for any of this. In fact it's easier if you remove the scope and weights. Once the polar scope is aligned then when I want to use the mount I set it up using Polaris without the scope in place, doing a final check after mounting up the scope.

James

[JamesF]

Does this mean that I don't need to put the mount in 'home' position and adjust the polarscope with the three screws at all?

Where the mount is doesn't matter and in fact you'll move it around during the alignment process. The point is to align the polar scope with the RA axis by adjusting the screws.

You must do this for the polar scope to be useful. If you drift align only then you don't need to do it, but if you want to use the polar scope at all, it is pretty much useless unless it is properly aligned.

James

[kirkster501]

Don't adjust your polar scope reticule at night - do it in the day with the TV arial method.

Steve

[Davey-T]

If you really want to use setting circles there's a good article in July Sky at Night mag on how to do it.

Dave

[ndastgir]

Many thanks to everyone. the links where very useful, particularly Astro Baby's website. I managed to align the polascope. now waiting for a clear sky!

Naeim

[JamesF]

Good news. I'm about to redo mine as I want to replace the knurled screws used for adjusting mine with grub screws.

James