HEQ5 polar alignment

[Dinu Adrian]

Hi! I've had the HEQ5 mount for a while now and I feel like I can do a lot more provided that a I can make a better polar alignment. I've been following the procedure presented in the user's manual and found out that getting a perfect alignment is almost impossible. I use the mount with an 200mm f/5 newtonian and a Canon 100D to do some DSO imaging and the longest exposure I've been able to shoot are 40 seconds long. The average is around 20 seconds. What I find surprising is that when I got the 40 second exposures the reticule of the polar scope was not perfectly aligned with the axis of the mount, I guess this error canceled the other errors that I had while setting everything up. The errors must have come from the inaccuracies of my mount. I am thinking of trying to adjust the polar alignment after everything is up an running by pointing at a star and moving it to the center of the image by using the azimuth and altitude knobs. I may only move it half way through and then do the same thing on another star, probably on the other side of the sky. All this time I would be doing test exposures to see if anything improves. I would be delighted if you can share a method of polar alignment which could help me, I'm a bit confused. It would be great practice those methods, so any help would be great. Thanks!

Adrian

[kendg]

I use the polar alignment routine in the handset. Works a charm.

Make sure the tripod is level.

2 star alignment. Polar alignment. Rinse lather repeat a couple of times and finish with a 3 (or 2) star alignment. 

I have never used the polar scope on my az-eq6. Now I just use astrotorilla to get things centered.

[jambouk]

Yes, the handset routine is very good. I wrote a guide on what I do about it somewhere on here.

James

[Dinu Adrian]

Thanks, I'll try to reduce my errors while setting everything up, I guess that's the problem.

[Philip Benson]

I have an EQ6 Pro but I believe this method is just as applicable to you.   The first thing to check is that your polar scope is centred or aligned properly within the polar axis of the mount.  You can check this during the day by setting up the mount so that you can see the top of a nearby telegraph pole or TV aerial in the centre of the cross hair in the polar scope.  Then without any load attached to the mount rotate it through 180 degrees and watch for any drift of your chosen target from the centre of the crosshair.  If you need to adjust anything follow the procedure on page 12 of the manual.

 Once you are happy with that you can then download a free utility called Polar204 which will show you the correct HA for Polaris for the time you are setting up your scope.   Simply make sure that the position of Polaris in the polar scope matches that shown in Polar204 and that should be good enough to allow 5 - 10 minute exposures.   You will still need to autoguide since in my experience the HEQ5 drive system is not precise enough to allow for unguided exposures of more than 2 or 3 minutes.

 

Once I had mastered this method of polar alignment my system tracked very nicely.

[dph1nm]

On 07/05/2016 at 15:05, Dinu Adrian said:

I use the mount with an 200mm f/5 newtonian and a Canon 100D to do some DSO imaging and the longest exposure I've been able to shoot are 40 seconds long. The average is around 20 seconds. 

Which is about what I manage with an unguided HEQ5 at similar pixel scale. The periodic error in these mounts is usually too large to do much better (without autoguiding).

NigelM

[Dinu Adrian]

On 5/11/2016 at 12:22, Philip Benson said:

I have an EQ6 Pro but I believe this method is just as applicable to you.   The first thing to check is that your polar scope is centred or aligned properly within the polar axis of the mount.  You can check this during the day by setting up the mount so that you can see the top of a nearby telegraph pole or TV aerial in the centre of the cross hair in the polar scope.  Then without any load attached to the mount rotate it through 180 degrees and watch for any drift of your chosen target from the centre of the crosshair.  If you need to adjust anything follow the procedure on page 12 of the manual.

 Once you are happy with that you can then download a free utility called Polar204 which will show you the correct HA for Polaris for the time you are setting up your scope.   Simply make sure that the position of Polaris in the polar scope matches that shown in Polar204 and that should be good enough to allow 5 - 10 minute exposures.   You will still need to autoguide since in my experience the HEQ5 drive system is not precise enough to allow for unguided exposures of more than 2 or 3 minutes.

 

Once I had mastered this method of polar alignment my system tracked very nicely.

I've aligned the polar scope with the polar axis of the mount and still got 20 seconds... Weirdly enough, the 40 seconds exposures were done with the polar scope slightly misaligned with the polar axis of the mount. I feel this means that the short exposure times I have are not due to the polar alignment itself but to the inaccuracies I have while setting up the mount and tripod. The tripod of the HEQ5 doesn't have a built-in level so I have to use one that I usually have laying around to do the job. It may not be perfect since the tripod slope may change slightly while I set the rest of the telescope up. As for the software, I have not tried it, so I'm going to, the next time I observe. Thanks!

[Jannis]

On 5/12/2016 at 15:06, dph1nm said:

Which is about what I manage with an unguided HEQ5 at similar pixel scale. The periodic error in these mounts is usually too large to do much better (without autoguiding).

NigelM

+2 on this... If i was lucky i could get 60 sec subs where i only had to throw 1 out of 3 frames... now i can do 600sec subs and throw less then 1 out of 5.