Polaris ?

[Moon monkey]

Hi I have an EQ5 mount, and I have no problem polar aligning it

My problem is this .... I canot actualy view polaris through my scope ..it is always to low does this mean my polar scope is out of line ??

Cheers MM

[NGC 1502]

Hi MM, do you mean you cannot see Polaris through the main scope, or through the pole finder within the polar axis ? German equatorial mounts (GEMs) like you have are a bit hard to point the main tube in the area near the pole, this is normal, and no cause for alarm.

If used for visual observing, a very accurate polar alignment is not needed, near enough is fine. For imaging, accurate alignment is a requirement.

Regards, Ed.

[Stargazer51N]

Hi moon monkey,

I'm not familiar with the EQ5 but there should be a latitude scale on the side of the mount and an adjustment to raise and lower the polar axis of your mount. Setting this scale to match your latitude should put you in the right ball park. Also on my mount you have to turn the tube 90 degrees to align a hole through the mount with the polar scope.

Hope this helps.

[Moon monkey]

Hi Ed ... yes I cant see polaris through my main scope

I am trying to image with my scope ... but the stars seem to drift ?? just wonderd if this was part of the problem ??

Cheers MM

[Stargazer51N]

Hi MM,

This may seem a silly question, but do you have a drive motor fitted to your EQ5?

[Capricorn]

So what is there between you and polaris to prevent you seeing it?

And yes the drift is because of the inability to polar align. For imaging it must be aligned and with fair accuracy.

[Moon monkey]

ok ... not sure people fully understant what i am trying to say

Yes the mount is fully goto..

I can get polaris in the polar scope not a problem...

But i cant see polaris through my main scope... it seems to be too low ??

Cheers MM

[faulksy]

you need to align your polarscope to your mount

[ollypenrice]

As above, perhaps. What you do is set the mount head up so that the polarscope is pointing at some daytime object a reasonable distance away. The you turn the mount round and round in RA while looking through the polarscope. The centre mark on reticle should stay in the same spot, not describe a circle. You adjust the three tension screws till this is so.

It is often out on SW mounts.

Olly

[Stargazer51N]

Hi MM,

I don't think it's possible to view Polaris with the main scope on a GE mount. This is because the main tube rotates around the centre line of the mount (which is pointing at Polaris) and the tube is fixed on a parallel several inches away from this centre line. This will mean that there is a small circle of the sky around the point that the mount is aligned to that the main tube cannot physically be pointed at.

With regards to the stars drifting have you ...

1) calibrated your polar scope reticule to your mount?

2) calibrated your setting circles?

3) rotated your mount to the correct position ( using the date / time scales on the polar axis) before aligning to Polaris?

Check out these videos on YouTube that talk about polar aligning a mount.

[steelfixer]

I would suggest you read Olly's and Stargazer's reply again.

It sounds very much like your polar scope is out of alignment.

Unless what you are looking at through the polarscope is very close to you, you should always be able to see the same object through the main scope with a low power ep even if its off center.

[Moon monkey]

Thanks for your help .... but i seem to be getting conflicting advice

Thanks for the links Stargazer51N I will take a look

[hemihaggis]

mm why do you need to see polaris anyway ? once you do your polar align , then you do two star align on the handset you are all done ready to observe ?? simples squeek

[brantuk]

Ok I think I know what you're saying MM. You can see polaris in the polar scope but not in the main scope. So first thing to do is try a lower power eyepiece like 25-30mm. It may appear in the center of that which suggests at higher powers the polar scope isn't aligned to the mount.

If you still can't see it in the low power ep however - that would suggest the scope isn't aligned to the mount properly. Check the tube rings and dovetail where the ota is attached to the mount. There could be some misalignment in there - ensure the dovetail is sitting flush against the base of the clamp.

Make sure the rings tighten up evenly and pull the tube into alignment with the mount - I usually have the underside bolts snicked up hand tight so the rings can grab the tube and align naturally before tightening the underside bolts.

Let me know if it's still out - there may be a further unanticipated problem

[UnderTheRain]

I've yet to buy my first scope I'm going to my local astro club for the first time on Thursday but I've been reading an aweful lot of stuff aswell and I think I'm going to save up and get a 250pds on a neq6 mount but with xmas in the middle it will probably be in the first week in jan. I just wanted to say thank you to Stargazer51N for those youtube links on alignment they very helpful especially to someone like me whos completely new.

Thanks :-)

[ollypenrice]

Good point arising there regarding what's called Cone Error. I hadn't thought of that. Cone error is the name given to misalignment between the telescope and the RA and Dec axes of the mount. Briefly, the mount is pointing at Polaris but the telescope isn't. Your tube rings are off kilter or something like that.

I think Stargazer 51N is mistaken in one small respect, if I'm reading the point correctly. The answer implies that the offset of a few centimetres between polar axis and scope axis would be discernible. Not so. The offset of almost 200 million miles between the Earth's orbital position in Spring and its orbital position in Autumn took about 200 years of positional astronomy to discover!

But I will continue to bet on the polarscope being misaligned.

Olly

[Stargazer51N]

I think Stargazer 51N is mistaken in one small respect, if I'm reading the point correctly. The answer implies that the offset of a few centimetres between polar axis and scope axis would be discernible. Not so. The offset of almost 200 million miles between the Earth's orbital position in Spring and its orbital position in Autumn took about 200 years of positional astronomy to discover!

Hi Olly,

Oops, I stand corrected. I must admit I've never tried pointing the main scope at Polaris so I was making what I thought was an 'educated guess'.

[Moon monkey]

I am now very confused !!! Dont know if should be able to see polaris through my main scope or not ??

I am very pleased people want to help .... but im not sure guessing will help

[brantuk]

If your mount is polar aligned correctly then you should be able to see it in the center of the finder and the main scope. Without actually being there it's sometimes hard for folks not to do "intelligent guessing" depending on how they interpret the question. Mistakes can arise even with the best of intentions. Did you check alignment of the polar scope yet?

[Moon monkey]

Cheers I will check the polar scope in as few mins

[Moon monkey]

Polar scope is spot on

[brantuk]

Ok when you polar align the mount (without the ota on it) are you ensuring polaris is in the little circle on the circumference of the bigger circle. If you get it in the small circle then turn the RA - the pole star should follow the circumference of the big circle through 360 degrees - you can check this against a dot on a wall but will need to lower the latitude to do it.

[ollypenrice]

In that case you should cetainly see Polaris. There is no doubt about this. It is perfectly visible with all mounts bar an unusual design called the English mount which doesn't concern us here.

Let's go from stage one.

Your mount is leveled and the polarscope points at Polaris, ideally with the correct offset as per the instructions but since it's less than a degree we don't need to panic about it.

You set the RA axis with counterweights north of the mount and as low as they will go.

You set the Dec axis with the tube aligned parallel to the polar axis and the objective as high as it will go. If you do that it is pointing to within less than a degree at Polaris, full stop. It cannot be otherwise. Your cone error would have to be gargantuan for it to make Polaris lie outside the field. The dovetail bar is properly seated in the saddle plate?

Like the rest of us, you will be capable of leaving the lens cover on so do check that!!

Polaris is a visual double with one much brighter component.

The only thing I can think of is that you might have been assuming that you didn't need to declutch and align the scope towards Polaris once you had aligned the mount. You do need to do this. Forgive me but I'm just trying to cover all bases.

Olly

[JKB]

OK I had the same problem. PS aligned perfectly but when looking through scope Polaris does not sit in centre of eyepiece. This is with the scope sat on top of the mount and 'looking' towards Polaris i.e. as would be set up to home position.

To view polaris you have to actually move the mount a fair way, like almost upside down. Think of the position RA 02h 31m 49.09s and DEC +89° 15′ 50.8″

I don't think this post helps actually but what Im trying to say is you can see it but its not as easy as first seems!

Cheers

Jamie

[Moon monkey]

Thanks I will try all of the above once I get a chance...

Yes I set polaris in the small circle and when i rotate it stays exactly on the line

Olly.. i will try to manualy aim my scope at polaris when i get a chance I know the other night when i used goto it wouldnt quite goto it ... ps... im sure the lens cap wasnt on

Cheers MM