QHY PoleMaster

[PeterCPC]

I have a query re the latest version of Polemaster.

When you do the very last stage of adjusting the axis to pole you are presented with a small representation on the left of the screen showing the square and circle. Now I presume that you carry out the adjustment using this small image. What I have found, however, is that, if you hover your mouse over polaris the image does not match the image shown on the left. Invariably I find that the larger image that you get by hovering the mouse does not look like you need as much adjustment as is indicated on the small image. Has anyone else found this and which do you use for the adjustment?

Peter

[Dr_Ju_ju]

Hi Peter,

I do all adjustments using the magnification window, apart from when you have to rotate the guide stars.

For the last part, you don't hover over Polaris, you hover over the red\green circles.

 

[PeterCPC]

Thanks. Yes, that's what I meant. So do you notice the discrepancy between the two?

Peter

[Dr_Ju_ju]

The last part is fine-tuning the mount and usually requires little adjustment of the bolts. I find I usually do tiny adjustments to cater for tightening of the bolts etc..

[PeterCPC]

Well I have noticed that, at the last stage, when I hover the mouse over the axis/pole (red and green) that they are more in line than the magnified view shows on the left pane.

I might raise this on the QHY forum.

Peter

[PeterCPC]

The answer on the QHYCCD Forum is that you should use the image on the left pane for final adjustment rather than the view obtained by hovering the mouse over the axis/pole.

Peter

[Demonperformer]

Truth to tell, the alignment produced in the first part of the exercise is so good that I usually find the corrections needed during the final stage are so small that the adjustment screws on my mount (NEQ6) are too coarse for the job, and if I try to make changes I usually end up making the alignment worse, not better.

[Gina]

I found the adjustment on the NEQ6 too coarse too - that was even without PoleMaster.  The EQ8 is a lot better but also more expensive, of course, but the EQ8 is better in so many ways.

[Grierson]

On ‎15‎/‎11‎/‎2016 at 06:52, Demonperformer said:

Truth to tell, the alignment produced in the first part of the exercise is so good that I usually find the corrections needed during the final stage are so small that the adjustment screws on my mount (NEQ6) are too coarse for the job, and if I try to make changes I usually end up making the alignment worse, not better.

Agreed, probably more so on my more humble EQ5. First attempt last night, trying to double click outside with cold hands is also a pain but the result was well worth it. - John 

[solarboy]

I have one I cannot fault it very simple to use I can polar align in 5 mins and its bang on  just follow the on screen instructions you can't go wrong 

Pete

[dyfiastro]

Good evening everyone.
After getting the mount back from tuning and repair I have had a better chance to try the polemaster out.
Over the last few nights my guiding has been ok but I could see there was still room for improvement. After trying a few things I decided to see just how good my alignment was and decided to compare it to sharpcap.

After going through the process with the polemaster as normal I went over to sharpcap and it with that, Sharpcap is reporting my alignment off by over a few arc minutes. I then went and corrected it and run the routine again using the polemaster software and that reported it was now off again. adjusted according to sharpcap and my guiding has improved compared to the last two nights and the conditions are a lot worse tonight.

The fine tuning is spot on according to polemaster when I ran that and I have the cable on the east side etc... as per the manual.
The only thing that I can see may be wrong is that the template has never really lined up correctly and my stars are never central.

Any advise would be great

regards

Mark

[StuartJPP]

I did a comparison between Sharpcap and PoleMaster. Note that my PoleMaster is not a genuine PoleMaster but a QHY5L-II-M with a 25mm CCTV camera.

 

[dyfiastro]

1 hour ago, StuartJPP said:

I did a comparison between Sharpcap and PoleMaster. Note that my PoleMaster is not a genuine PoleMaster but a QHY5L-II-M with a 25mm CCTV camera.

 

Thanks I have replied to your post to try and keep things uniform.

[mbalkham]

Interesting post on the comparison. Last night I got a good result with polemaster and good pointing accuracy but my phd2 guiding results weren't as good as I'd expected/hoped. I undertook a PHD2 drift alignment and improved my PA (but worsened my pointing accuracy even with a new 3 star alignment). I'm thinking of adopting a 2 stage PA routine using first polemaster for a (very good) 'roughing in' and then a find tune using PHD2 drift. Then doing my 3+ star alignment for sorting my goto.

Anyone else playing with a multi stage approach to PA? Or am I doing something wrong to need to do this?!!

[PeterCPC]

Even after you get your PA with Polemaster you still have to do the normal 2 star align (whatever) to callibrate the GOTO. Perhaps the issue is with PHD not Polemaster. PHD should be able to cope with an imperfect PA. Maybe the Polemaster is not so accurate in the Southern hemisphere - have you raised this on the QHYCCD Forum?

Peter

[rodmichael]

Does anyone have information or a sense of whether QHY will or can develop a PoleMaster adapter that works with the Celestron CGX mount?

[rodmichael]

In the CGX thread on CloudyNights, this conversation took place about 10 days ago:

 

FROM DERIK FROM CELESTRON:

"Re: handle on the front of the [CGX] Dec axis.  Yes, you can remove that.  4 screws.  But the PoleMaster does not need to be perfectly aligned columnated with the RA axis to work properly. So you can mount it to the handle or you can put it on the (optional) polar finder bracket.

Re: Polar alignment and astrophotography.   What applies to all equatorial mounts, not just CGX.   I am not astrophotographer, but ASPA will usually converge to within 10 arcminutes of the pole.  (it might take 2 iterations).    You can find a calculator to compute the dec drift for you, but empirically I find that corresponds to a drift rate of about 1 arc second per minute near the celestial equator.   This is comparable to the drift in RA due to mount/tube flexure.    And both are much smaller than the drift rates caused by Periodic Error.   Moreover, a small amount of easily correctable Dec drift can be desirable since it sets up the option of unidirectional autoguiding.     Nevertheless, PoleMaster is a fine product.  It is probably more accurate than ASPA and has other advantages as well.   I hope it does extremely well.     Again, I don't do astrophotography so take this last paragraph with a grain of salt."

 

I have some questions for anyone out there more familiar than I am with the QHY PoleMaster camera:

    1.  Has anyone tried one of the PoleMaster mounting alternatives that Derik from Celestron suggests, i.e., mounting the PoleMaster to the front handle of the CGX or mounting one on an "optional polar finder bracket?"
    2.  Is QHY planning a PoleMaster adapter for the CGX?
    3.  Is a CGX adapter possible?
    4.  If I chose to mount a PoleMaster on the optional [Celestron] polar finder bracket or on the front handle of the CGX, does the PoleMaster software need to know the position of the camera relative to the RA axis?  I had presumed that each adapter QHY fields had to be correlated with the software to define the position of the camera for proper calculations in the program.
    5.  Does anyone know where to find an optional Celestron "Polar Finder Bracket" for the CGX?

[PeterCPC]

I have been finding that, if I do the final adjustments, the PA error is higher than not doing them. I have raised this on the QHY Forum but no responses yet.

Peter

[Demonperformer]

I've always had that impression, Peter. I put it down to the fact that the first part is so accurate and the controls on the (NEQ6) mount are so coarse. Trying to make such small adjustments on the final part, I always seem to 'over-shoot'. It will be interesting to see what comes back from the forum.

Thanks.

[PeterCPC]

Well the topic has been viewed many times on the QHYCCD Forum but no replies - make of that what you will.

Peter

[PeterCPC]

I saw recently that in the Q and A section of the QHYCCD Polemaster site that they say it's best done with the mount tracking. Originally they said to carry out the Polemaster adjustments and then do a 1 star align so that would infer that the scope was not tracking (mine is AVX).

I raised this on their Forum and they said that either method was ok. How are folks on here doing it generally? Do you do a rough align to get the scope tracking before you do the Polemaster adjustments or after with more precise align. I certainly find that doing the Polemaster first and then doing a 2 star align with my AVX means that I cannot get it as accurate as they suggest is possible. I use PHD Lab to check. I am considering doing a second PA after the 2 star align but then that would/could mean another 2 star align.

Any thoughts - particularly if using an AVX?

Peter

[StevieDvd]

If you consider how the system works then having the mount tracking can be a little more accurate depending on how long you take to run the process through.

It calculates the centre of rotation from several stars around polaris and compares that with the actual centre (ncp).  Over time those stars rotate around the ncp so if you have the mount running that rotation is negated/reduced.

 

 

 

 

[PeterCPC]

Yes thanks but I really want to know how other AVX users are doing it.

Peter

[Droogie 2001]

I have an AVX and I align with the Polemaster with mount on but no alignment set. Once done I perform a 'quick' alignment and the use plate solving for accurate alignment. I too have wondered if I would get better alignment if I run an alignment routine. However as I only need to run quick align I haven't given it much attention. 

[StevieDvd]

Polemaster is recommending the mount is running at sidereal rate and this is active whether you have accurately star aligned or not. Reading the manual for your mount I would suggest the 'quick' alignement as Droogie 2001 has mentioned, it probably just starts the mount at sidereal rate. Once you PA is adjusted you would do a proper star alignment (and again for each subsequent time you adjust the PA).

Unfortunately Polemaster does not help with star alignment as such. If you had 100% accurate PA and switched the amount off your star alignment is only as accurate as your starting position versus your first star alignment (unless your mount can set the home position correctly each time).  So even Polemaster is being a little over zealous saying that a single star alignment is all that's needed.