HEQ5 Pro - Problem or Normal ??

[Eddie Jones]

Hi All,

When my scope is (properly) polar aligned and in the park position, Polaris isn't dead center in the main scope.

Checked polarscope alignment and whist its not perfect - error is very tiny (about the width of the tramlines rings where polaris sits when aligned)

Attached is a video

Mount  / Polarscope ia trained on the bottom of a distant wind turbine

phone camera> reticule eyepiece (on the main scope) rotated

Could there be a problem with the top of the mount (can they be adjusted ?)
Would welcome any comments or suggestions

Thanks !

 

Edited June 25, 2020 by Eddie Jones
Made Video file smaller

[carastro]

You won't see Polaris in the Main scope as Polaris is 1 degree away from the Pole.  Your main scope will have bigger magnification, so the distance from the pole will be greater and in some cases you wont; see it at all in the main scope.

Unless I have misunderstood your problem. 

I presume your mount is in that very strange Latitude position in order to point at a street lamp. 

Looking at your video, your polarscope appears to be non orthogonal as you should start with the head of the street lamp on the cross hairs and then rotate the RA.  If the head of the street lamp moves from the centre you need to adjust the polarscope with very small grub screws on the polarscope itself.   

If it's not orthogonal you won't be able to polar align properly using the polarscope.  

Carole  

Edited June 25, 2020 by carastro

[Eddie Jones]

Thanks Carole - I did wonder if that might have something to do with it, but great to have someone more knowlegable to confirm
BTW mount positioned almost horizontal to get most distant object I can see (windturbine) for polarscope callibration

 

[SimM]

The video is from the main imaging scope? What you see are called "cone errors". They are where any scope is not completely at right angles (perpendicular) to the declination axis - you might think of this as "around" the RA axis.

For the main image, you might try rotating the dovetail in the mount 180 degrees - it might seat better?

Or swapping the rings front to back. Or putting shims under one/both/most corners of the rings (where the y bolt to the dovetail).

However, in the HEQ5 HC there is an alignment to remove the effects of cone error - all scopes will have this to some extent?

With a 3 star alignment the extent of cone error is known and compensated for.

What you see is independent of where Polaris is in the main scope. To do PA with the polar scope, you don't even need the main scope to be attached?

Separately, if the image in the polar scope is also moving, then half the error (which isn't cone error) can be taken away by referring to the manual and carefully centred with three small grub screws.

If the clock display isn't at 12 o clock this can also be corrected - but isn't necessary as you already know where 12 o clock is on a clock without numbers?

This stuff is in the manual. There is a newer graticule display that's not mentioned in the manual - is on an addendum sheet.

Simon

Edited June 25, 2020 by SimM

[carastro]

Quote

In the HEQ5 HC there is an alignment to remove the effects of cone error

I hadn't realised the video was from the main scope, so my comments on orthogonality fo the poalrscope can be ignored.

However: 

Quote

In the HEQ5 HC there is an alignment to remove the effects of cone error

 I have an HEQ5 handset and cone error, but never knew there was anything in the handset, where would I find it and it is only in the latest firmware and I never updated mine?

Carole 

[SimM]

46 minutes ago, carastro said:

I hadn't realised the video was from the main scope, so my comments on orthogonality fo the poalrscope can be ignored.

However: 

 I have an HEQ5 handset and cone error, but never knew there was anything in the handset, where would I find it and it is only in the latest firmware and I never updated mine?

Carole 

I have probably spent more time reading the manual than using the mount to collect images!

NB the 2 star alignment requires minimal cone error but that's not a precondition for 3 star. A little cryptic, perhaps? Cone error is later in the manual. (two snippets from the manual).

Simon

[carastro]

Many thanks for that.

Carole 

[Eddie Jones]

Thanks SimM for your great information!
I've downloaded the manual
I'll have a look at correcting the cone error (when its cool enought to concentrate)

In the meantime, I'll continue with 3 star alignment and let the HEQ5 fix it 'automagically' 👍