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QHY PoleMaster

johnrt

By johnrt
in Discussions - Cameras

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PeterCPC

PeterCPC

Posted
Posted

The AVX only starts tracking once you have completed an alignment - any alignment. QHY say that it is better if the mount is tracking before you do the Polemaster routine.

So the only way I can have it tracking is to do an alignment but once done I can't do it again without powering off.

Peter

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gnomus

gnomus

Posted
Posted
5 minutes ago, Zakalwe said:

Why would you do a star alignment before polar alignment?? Does your mount not start tracking as soon as it's powered up? If not, just start it tracking, then polar align then do a star alignment.

Sorry Stephen, I must have missed something earlier in the thread.  Does the mount need to be tracking for the Polemaster routine to work properly?  If so, why?

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Zakalwe

Zakalwe

Posted
Posted
48 minutes ago, gnomus said:

Sorry Stephen, I must have missed something earlier in the thread.  Does the mount need to be tracking for the Polemaster routine to work properly?  If so, why?

Hi Steve,

I think that the tracking needs to be running during alignment. I can't see it making that much difference TBH unless you are taking ages to align the mount.

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PeterCPC

PeterCPC

Posted
Posted

QHY state that it's best if the mount is tracking - contrary to what they said originally.

Peter

53 minutes ago, gnomus said:

Sorry Stephen, I must have missed something earlier in the thread.  Does the mount need to be tracking for the Polemaster routine to work properly?  If so, why?

 

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RayD

RayD

Posted
Posted
6 minutes ago, Zakalwe said:

Hi Steve,

I think that the tracking needs to be running during alignment. I can't see it making that much difference TBH unless you are taking ages to align the mount.

I'd agree with this.  It takes me such a short time to align and adjust, I can't see that tracking would play a significant role.  However, if you are slow or have to move between an obsy and warm room it may make a difference, but I wouldn't have thought on the final alignment as that is then only centering on Polaris.

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Zakalwe

Zakalwe

Posted
Posted
1 hour ago, PeterCPC said:

The AVX only starts tracking once you have completed an alignment - any alignment. QHY say that it is better if the mount is tracking before you do the Polemaster routine.

So the only way I can have it tracking is to do an alignment but once done I can't do it again without powering off.

Peter

Ahh, OK. So you have to do the alignment to get the mount tracking. I presume that you then do the polar alignment and then switch the mount off and back on to clear the bad initial star alignment?

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RayD

RayD

Posted
Posted

I'd say it's just the time between aligning the circles in the first stage, to then selecting a star, rotating the mount twice, then back to park, and then align the circles again, in that time I guess they will have moved, and with how accurate the PoleMaster is, I suspect it sees that movement.

Once the initial Alignment is done and you are then fine tuning Polaris, I wouldn't have thought it matters, but if you're slow completing the above, I guess the stars will have moved a fair bit in the eyes of the device?

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RayD

RayD

Posted
Posted
14 minutes ago, RichLD said:

I must say, in the 2-3 minutes it takes me to PA with the PoleMaster I haven't noticed a difference with tracking on or off. Mind you, I only tend to image at widefield scales these days.

Me too, but I suspect in the manual they have to account for people using for the first time, or just taking their time doing it.  I have used it for quite a while now, and have done it before and after alignment, and personally haven't noticed any difference, but then like you I'm doing it pretty quickly now.

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James

James

Posted
Posted
1 hour ago, RichLD said:

I must say, in the 2-3 minutes it takes me to PA with the PoleMaster I haven't noticed a difference with tracking on or off. Mind you, I only tend to image at widefield scales these days.

Yep, me too...

1 hour ago, RayD said:

Me too, but I suspect in the manual they have to account for people using for the first time, or just taking their time doing it.  I have used it for quite a while now, and have done it before and after alignment, and personally haven't noticed any difference, but then like you I'm doing it pretty quickly now.

... my first time took about 10 mins so it may have made a difference! I tend to forget to turn the tracking on but like you haven't noticed a difference not putting tracking on.

James

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StevieDvd

StevieDvd

Posted
Posted

The polemaster may not be fitted centrally in the polarscope slot for all mounts, and don't need to be, but the further out from the axis the faster any inaccuracies can occur.

I think a fair amount of PA adjustment routines are not helped by the users not realising that tweaking the Alt/Az bolts has changed their park point and the process should be re-iterated after a clean restart from the parked position.

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PeterCPC

PeterCPC

Posted
Posted
16 hours ago, Zakalwe said:

Ahh, OK. So you have to do the alignment to get the mount tracking. I presume that you then do the polar alignment and then switch the mount off and back on to clear the bad initial star alignment?

Exactly so. I think that I will try two iterations of the Polemaster next time and then align.

Peter

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StevieDvd

StevieDvd

Posted
Posted

Just a quick thought, is the polemaster setup secured OK?  If you have yours fitted in the polarscope hole this tracking on/off should not be such a big deal.

I don't know how sensitive or accurate the alignment bolts on the AVX are but these are usually the weak point in the process, getting that last small difference out - bit like missing the hole in golf if your putt is to hard or to weak :-)

It has been said by others that the last tweak gets changed when you lock the alignment bolts in place even to the point where it was suggested to leave a small error to allow for the locking movement.

Let's hope we can help you sort this out

 

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PeterCPC

PeterCPC

Posted
Posted

Yep all secured ok.

Yes you have to watch the last tweek as it can move the alignment. To be honest, even a PA error of as much as 2-3 minutes does not seem to adversely affect the guiding so I think that I'll just accept it as is. When you use PHDLab the PA error gradually improves as time goes on.

Peter

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iapa

iapa

Posted
Posted
On 15/02/2017 at 07:45, PeterCPC said:

Exactly so. I think that I will try two iterations of the Polemaster next time and then align.

Peter

Once your mount is tracking ( I assume by just doing a Quick Align) before you start PA with Polemaster, you do the step in PA where you rotate around RA axis by 30degrees,twice, then back 60 to starting position. Some people will need to do this every time is they tear down after each session.

  • rotate 30deg,
  • rotate 30 deg
  • rotate back 60 deg

I think this is potentially shifting the position of Polaris in the image view as it will have moved but you have shifted the camera centre by that rotation - you will never get back to precisely the same point even if you set home position, and return to home 3rd step. 

Is that not negating the benefit of tracking - which is apparently ensuring that the movement of Polaris is minimised in the image whilst doing PA (particularly for people who are slow like me).

I expect that in practice, the more often you do it the less time it takes, and the less Polaris has moved so you don't need to worry about this.

And the optimum solution is a pier in a shed that exposes the mounts on demand where you only need to do this once :)

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StevieDvd

StevieDvd

Posted
Posted
28 minutes ago, iapa said:

Once your mount is tracking ( I assume by just doing a Quick Align) before you start PA with Polemaster, you do the step in PA where you rotate around RA axis by 30degrees,twice, then back 60 to starting position. Some people will need to do this every time is they tear down after each session.

  • rotate 30deg,
  • rotate 30 deg
  • rotate back 60 deg

I think this is potentially shifting the position of Polaris in the image view as it will have moved but you have shifted the camera centre by that rotation - you will never get back to precisely the same point even if you set home position, and return to home 3rd step. 

Is that not negating the benefit of tracking - which is apparently ensuring that the movement of Polaris is minimised in the image whilst doing PA (particularly for people who are slow like me).

I expect that in practice, the more often you do it the less time it takes, and the less Polaris has moved so you don't need to worry about this.

And the optimum solution is a pier in a shed that exposes the mounts on demand where you only need to do this once :)

It is not an exact rotation and you are using the pivot point of the mount which won't change. As it's a video feed you align a mask with some stars around the ncp so again the movement is controlled visually and not by an excat number of degrees rotation. Though as soon as you adjust the alt/az bolts the pivot point will change, hopefully for the better, and therefore a second session should improve it further.

 

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barkis

barkis

Posted
Posted
On 31/01/2016 at 20:32, sloz1664 said:

I've used mine twice now. A doodle to setup and a fantastic alignment of 0.3 arc secs.

No wet knees trying to squint through a polar scope. :hello2:

Steve

 

Doh, senior moment. What my fingers should have typed is....................... 0.3 arc mins.  :iamwithstupid:

 

Steve

So, 18 arc seconds then. Still mighty close. Considering that Polaris is  2,520 arc sec. 
from the NCP.
 

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