Polar scope problems

[Gino Arcari]

hi, i bought a polar scope for my cg-4 and i don't really understand how to install it, why does it have two setting circles? it won't even fit in. Any help would be great, thanks 

[The universal]

Hi gino,

Remove the existing unit with setting circle that is already installed. Unscrew it and it comes out. Then put the full polar scope in

[Gino Arcari]

How do I actually do that? I'm really confused

[The universal]

Just going from memory, but do you see where you have your fingers on the polar scope on the very bottom pic, well put your fingers on the same part that is already attached to the mount. Turn the whole thing anti clockwise to unscrew the whole part until it comes out of the mount.

Then screw the polarscope into position

You should see threads behind the setting circle on the polarscope. The part that is already attached to the mount also had these threads. You simply unscrew the existing setting circle part out of the mount and swap it for the polarscope.

Hope I explained that ok

[Gino Arcari]

Okay thank you very much, ill give it a go tomorrow and let you know how i got on because I've gone to bed now:)

[Gino Arcari]

I tried and I still can't work it out:( what should i do?

[jambouk]

Are you part of a local astronomy club? Can they send an email out to see who lives near you who could come and help?

If it were my mount, i'd wrap my dominant hand around the black collar next to the setting circle on the mount, and turn anti clockwise, it may be screwed in hard. You need to check there are new screws or bolts somewhere which may be preventing it turning.

Search for this mount in the search function, find out on here who else owns one, and private message them.

Good luck.

Jd

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[Gino Arcari]

Ahhhhaaa! I've finally got it off and I've screwed in the polar scope..Im really confused though because what where the original parts for? I thought that 3 screws on the black part would insure the polar scope is pointing straight..like a finder scscope on a telescope? Do you understand what I mean? If not ill post pics

[jambouk]

Yes, the three small screws on the polar scope are to align the polar scope with the RA of the mount. Fix the cross hairs of the polar scope on something in the distance (a chimney say), then rotate the RA axis by 180 degrees, and ideally the cross hairs should remain in the same place; if they don't then you need to keep altering the screws (very small amounts, and don't do them too tight) to keep the cross hairs always in the same place when you rotate the RA. It takes ages to do and do it sitting down as it will kill your back and you'll get utterly annoyed with it make sure the polar scope unit is screwed i to the mount nice and tight first.

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[Martin Meredith]

Yes, the three small screws on the polar scope are to align the polar scope with the RA of the mount. Fix the cross hairs of the polar scope on something in the distance (a chimney say), then rotate the RA axis by 180 degrees, and ideally the cross hairs should remain in the same place; if they don't then you need to keep altering the screws (very small amounts, and don't do them too tight) to keep the cross hairs always in the same place when you rotate the RA. It takes ages to do and do it sitting down as it will kill your back and you'll get utterly annoyed with it make sure the polar scope unit is screwed i to the mount nice and tight first.

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Having spend a good hour doing this on Sunday for the first time I can only agree!

And I'm not convinced I got it right... The object I focused on may have been too close because it would shift if I moved my eye the slightest amount, making checking if it was central almost impossible anyway. Time for another go with a more distant object later...

Martin

[Lonestar70]

Hi Gino,

Pleased to see you have managed to get the old unit out and the new one fitted

The three chrome screws on the original unit were for centering the first generation of polar scopes... now no longer made.

These have now been replaced with the current version that you have got... centering the new version is now done using the small grubscrews around the edge of the first black ring... it requires a 1.5mm Alan key to be used.

All you need now is some sort of polar scope illuminator (red LED) to allow you to see the graticule in the dark.

You should find several posts on this subject on the forum (try the search facility)... it will be the same illuminator as used for SW  EQ mounts.

Keep happy.

Best regards.

Sandy.

[jambouk]

There should be a warning on the polar scope box: "attempting to align this to the mount may pose significant harm to your mental and physical wellbeing..."

For most mounts, i suspect getting this "roughly" aligned is accurate enough, as it's hit and miss how you position the polaris circle when you come to polar align anyway! I suspect if there is just a bit of movement of the cross hairs when you do a 180, that will be good enough. Ideally none, but i've never achieved "none" and i can do reasonably good polar alignments with it.

Aligning the polar scope is definitely a day time job; doing it at night on polaris must be hideous! Cold and frustrating.

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[JamesF]

Aligning the polar scope is definitely a day time job

Absolutely.  I do the alignment during the day using a distant target, then set the setting circles to midnight on 1st November and rotate the polar scope reticle to place the Polaris indicator at the bottom by lining it up with some convenient vertical such as a door or window frame.  That gave me good enough alignment for planetary imaging.  If I wanted any better then I used the polar scope to get roughly right and drift alignment afterwards.

James

[Davey-T]

There should be a warning on the polar scope box: "attempting to align this to the mount may pose significant harm to your mental and physical wellbeing..."

Aligning the polar scope is definitely a day time job; doing it at night on polaris must be hideous! Cold and frustrating.

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Not having one of those usefull distant objects championed by Astronomy Shed et al I actually found it easier and more acurate to use Polaris.

Dave

[Gino Arcari]

thanks everyone, I've fitted it and aligned the 3 little screws and they seem perfect as i move the r.a 180 degrees, now i really confused about the setting circles and what the transit of polaris is...do i have align it every time i go out? I've looked at astro babys heq5 for idiots but it makes no sense..

[jambouk]

Not having one of those usefull distant objects championed by Astronomy Shed et al I actually found it easier and more acurate to use Polaris.

Dave

That is hard core!

Jd

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[Davey-T]

You need to centre the ubiquitios distant object in the Polar scope center and rotate the scope in RA from side to side and adjust the three little screws to keep it centered when it rotates, don't undo them all at once, the Astronomy Shed video is worth a look.

Dave

[jambouk]

I'll let someone else explain all that.

Good luck with it all.

I'll just say, if you don't have motors, or if you do have motors and are planning to only image things in the solar system, i'd only bother to do a very rough polar alignment; anything else at this stage will be overkill.

Jd

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[JamesF]

You only need align the polar scope axis with the RA axis once (generally).  That's with the three grub screws.

You only need set the rotational position of the reticle once.  That's done using an index ring held in place by one or two grub screws next to the setting circles.  AstroBaby's site goes into this, but using the current time and date and position of Polaris.  As any correct time, date and position will work I always use midnight on 1st November because at that time the circle on the reticle for Polaris should appear vertically below the centre spot of the reticle.

Then when you go out, you release the RA clutch, rotate the RA axis so the index mark is correctly aligned and the time and date are correct for when you're observing (in GMT, always), re-lock the clutch and then use the alt and az adjusters on the mount to put Polaris in the indicator circle.  Then you're done.

As has already been said, if you're just working visually then you don't need really good accuracy.  Good accuracy helps for planetary imaging, very good accuracy is required for long-exposure imaging.

James

[Davey-T]

Have a look at this, may help or may just confuse you more

You may have to join Astronomy Shed to view tutorials, no bad thing though.

Dave

http://www.astronomyshed.co.uk/forum/viewtopic.php?f=19&t=4006

[JamesF]

I always use midnight on 1st November because at that time the circle on the reticle for Polaris should appear vertically below the centre spot of the reticle.

Note that at this point Polaris is actually "higher" than the NCP, but the polar scope inverts the image, so you're seeing the reticle and the position of Polaris upside down, hence the Polaris marker being at the bottom rather than the top when you do the alignment this way.

James

[Gino Arcari]

thank you all for your attempts to help me out, i just still can't make any sense of the setting circles...ill post pictures so you can all see where I'm at, position that the right ascension axis looks very awkward but thats the position its needs to be in to make polaris directly beneath ncp.

[jambouk]

What camera and lens did you take those pictures with? The last picture is lovely!!!

It doesn't matter where the RA is, as long as you have the small polaris circle in the correct place; once the small circle is correct, more rhe azimuth and elevation bolts to put polaris in that circle, which then polar aligns the mount... then return your RA to a normal (home) position and the mount stays polar aligned. Then move the RA and dec as much as you like and it stays polar aligned. Simples

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[JamesF]

Ok, the position of the mount is fine even though it looks odd.  Don't worry about that.  There are two more things you need to do.  Turn the month/day setting circle (it will spin freely) so that the mark for 1st November lines up with the large 0 on the time circle.

Now the ring next to it with the single white line index mark needs to be loosened.  There's one, perhaps two, grub screws to do that.  Once it is loose, turn it so that the index mark lines up with the 0 on the inner scale of the date ring (the one closest to it), making sure that the time and date rings remain aligned at 0 and 1st Nov.  Then re-tighten the grub screws on the index ring and you're done.

The process for alignment with Polaris is then to align the index mark with the 0 again, release the RA clutch and turn the RA axis to set the current date and GMT time on the setting circles and lock the clutch again.  Then use the polar scope to find Polaris and using the alt and az adjusters on the mount move the mount so the little Polaris circle on the polar scope reticle coincides with Polaris.  Then you're done.  Release the RA clutch to allow the RA axis to return to its normal position and mount up the scope.

James