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Mildly confused here.

I have a skywatcher EQ3-2 mount. And when I look at the declination axis it doesn't seem to point straight when it is set to 90.

Not sure if Iam explaining this correctly but bascially at 90 it seems to pointing to one side and not exactly straight?

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It should be pointing at the Pole star (Polaris) when set at +90  :smiley:

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At +90 it should aim at the pole star named Polaris, If you own a compass, aim it 90 north, and see if it lines up with your scope, if not, your setting circle (DEC) may be out of line

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Hi.

I realise this thread is not new, but have just noticed exactly the same thing as the OP. When you have the top rotating section set dead straight with the scope off, the dial looks adrift. But note that the slot for the dovetail doesnt run straight through the top section - no idea why. So although the dial looks skewiff, it is probably OK.

I spent quite some time deliberatley realigning the dial before realising my mistake late last night. So now I hae to re-align it again Grrr.

Equally puzzling is that if you look at the pointer on the opposite side, its about 10 degrees adrift from the other. Cant see why at all.

Cheers

Tom

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Well for start it is the RA axis (Polar axis) that points at Polaris, the DEC axis points at 90deg to it. Whatever, the DEC axis is also the one that carries the balance weights. The setting circles should be adjustable such that they can bet set to read correctly when the mount's axes are in nominal position.

ChrisH

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I hope I can clear this up! I think the point the OP was making is that the Dec dial appears off centre when viewed from the front - and I agree.

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Aaarggh. Sorry, previous post of mine incomplete.

View from front does make dial appear offset:

EQ3 2 020

And also the dovetail slot is somewhat angled in the mount:

EQ3 2 003rot

However, I checked that with the Dec pointer showing 90 deg.....

EQ3 2 017

..... the scope was at maximum elevation using a inclinometer:

EQ3 2 009

The reason I am keen to ensure that this is accurate, is because the easiest way for me to get polar alignment (without polarscope (yes, I know I should get one))  is to set Dec to 90, and then get pole star visible in scope. Provided the Dec is accurate, and the tripod is level, this works OK.
The other point, no pun intended, is that when the indicator shows 90, the pointer on the other side appears way off. It shows about 80deg:

EQ3 2 018

I really hope this makes sense, and might even be of some help to someone!

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You maybe mixing the two systems you find in mounts, the Alt-Azimuth and the equatorial. The equatorial is designed so that you can track an object easily based on your location/latitude. Maybe these pictures of the two grids will help differentiate between them.  

95o1mx.png

This is the normal vertical horizontal axis system from the normal perspective 

2vv3u3s.png

This is the system you have in your eq mount.

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You maybe mixing the two systems you find in mounts, the Alt-Azimuth and the equatorial. The equatorial is designed so that you can track an object easily based on your location/latitude. Maybe these pictures of the two grids will help differentiate between them.  

Thanks for this. Am only a novice, but I think I do understand the 2 systems as you describe them.

The OP said:

Mildly confused here.

I have a skywatcher EQ3-2 mount. And when I look at the declination axis it doesn't seem to point straight when it is set to 90.

Not sure if Iam explaining this correctly but bascially at 90 it seems to pointing to one side and not exactly straight?

and I think he meant the Dec dial doesnt appear straight. I agree and posted a photo (#1) of this, which hopefully does show that it looks offset. The point I was trying to make is that even though it looks offset, when the Dec is set to 90 using the indicator, the scope is at maximum elevation (for the given alt setting) ie the Dec indicator is correct, even though the dial appears offset.

Of course I may have misunderstood the OP.

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Your mount looks just like my mount, the Astroview mount from Orion.  Mine is black; they must be made by the same company.  Anyway a while back I had the same concern when I looked at the mount straight on and it did not seem straight when I had the DEC set at 90°. Upon further investigation I noticed that the azimuth was not centered.  After centering the azimuth everything looked fine.

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Thanks for this. Am only a novice, but I think I do understand the 2 systems as you describe them.

my bad I just realized the date of the topic, I answered to the problem in the first post. 

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Nice one Tommohawk, downloading that inclinometer app now. 

I noticed that RA offset at the weekend and also the offset on the dec dial.  Its been on my mind since.

Bought a spirit level to help get the scope perfectly level and also stuck some aligning labels on the RA axis so i could tell when the weight bar is parallel to the ground. Now just need a 30 or 40mm ep so i can actually see the stars rotating round the ncp when i flip the RA axis by 180 degrees.... 25mm EP was a little constricted for that.

Even so, was the best polar alignment i've had yet (no polar scope either). But at least it seems like the offsets are just compensating for something in the design of the mount.

Cheers

Mark

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The reason I am keen to ensure that this is accurate, is because the easiest way for me to get polar alignment (without polarscope (yes, I know I should get one))  is to set Dec to 90, and then get pole star visible in scope. Provided the Dec is accurate, and the tripod is level, this works OK.

The scales on those mounts are not reliable and you don't need them. If you want to polar align the way you are suggesting then set your scope to a declination of roughly 90° which you can do by eye, look through the scope while you rotate it through RA. If you are at 90° you will see the image spin in the view. If you are not the image will move left, right, up, down etc. Tweak until the image in the scope spins and you know you are the scope is align to the mount's polar axis 90°. Lock the RA and Dec and then adjust azimuth and altitude using the scope to polar align on polaris (or that bit just near polaris where the pole really is). Now lock alt and az, unlock RA and Dec and you're set up. No need for scales, not even a need to make sure the tripod is level.

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 If you are at 90° you will see the image spin in the view. If you are not the image will move left, right, up, down etc.

Yep agreed 100%. I just use my method to get to this point a bit more quickly.

But at least it seems like the offsets are just compensating for something in the design of the mount.

Cheers

Mark

Maybe the dial is straight and everything else is wonky. Relativity and all that!

Cheers

Tom

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I use this guide for setting up EQ mounts - it's specifically for NEQ6 Pro but the same principles apply to any EQ mount. It describes how to level the tripod and then line up the RA axis perpendicular to the ground, and then level up the Dec axis and turn it through 90degs so it's in line with the RA axis in the home position. It's very accurate and makes polar alignment a breeze. Hth :)

http://stevebb.com/polar_alignment.html

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Thats a nice method. The mount looks nice too - makes mine look a bit flimsy! One problem I have is that of multiple obstacles around the house, mostly trees, so I have to keep re-locating.

Unfortunately the scope came with a finderscope, a few EPs and a Barlow.... but no chainsaw.

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Posted (edited)
On 29/01/2014 at 23:12, Tommohawk said:

Aaarggh. Sorry, previous post of mine incomplete.

View from front does make dial appear offset:

EQ3 2 020

And also the dovetail slot is somewhat angled in the mount:

EQ3 2 003rot

However, I checked that with the Dec pointer showing 90 deg.....

EQ3 2 017

..... the scope was at maximum elevation using a inclinometer:

EQ3 2 009

The reason I am keen to ensure that this is accurate, is because the easiest way for me to get polar alignment (without polarscope (yes, I know I should get one))  is to set Dec to 90, and then get pole star visible in scope. Provided the Dec is accurate, and the tripod is level, this works OK.
The other point, no pun intended, is that when the indicator shows 90, the pointer on the other side appears way off. It shows about 80deg:

EQ3 2 018

I really hope this makes sense, and might even be of some help to someone!

I know that it is not the newest post, but I have the same issue.

I have new EQ3-2 and I was hell of a wondering why I see nothing on my second session (firs time I was looking for Tycho nebula, which is visible only in X-rays). I ve put water-based inclinometer on it and realized that the one pointer with black triangle is correct, the other white one is exactly 10° off. Actually the correct one is quite hidden with Dec motor and if you are watching starting with west Dec move, you better off using the bad one pointer and just subtract 10°.

I see no reason why it is off and my guess is that it is construction mistake?

Edited by Aliam Sigsaly

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On 29/01/2014 at 13:21, Tommohawk said:

Hi.

I realise this thread is not new, but have just noticed exactly the same thing as the OP. When you have the top rotating section set dead straight with the scope off, the dial looks adrift. But note that the slot for the dovetail doesnt run straight through the top section - no idea why. So although the dial looks skewiff, it is probably OK.

I spent quite some time deliberatley realigning the dial before realising my mistake late last night. So now I hae to re-align it again Grrr.

Equally puzzling is that if you look at the pointer on the opposite side, its about 10 degrees adrift from the other. Cant see why at all.

Cheers

Tom

Yep, still the same after 5 years. Left-one is correct.

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