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Help with testing HEQ5 pro mount please?

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#1 Michael Morris

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Posted 02 August 2010 - 01:29 PM

I find myself in the rather enviable position of having two second hand Skywatcher HEQ5 Pro mounts! I bought one then the another was offered to me at a knock down price and just couldn’t say no! The plan is to keep both for a short while, work out which is the better of the two mounts, and sell the other one. (The old bank balance can only stand this situation for a few weeks.) Both look to be nice mounts and appear to have been well looked after.

As far as I can see there are a number of things I need to test.

Mount 1 is a recently upgraded (black) HEQ5 has the latest electronic board (with the dimmable polarscope illuminator) and a synscan controller.
Mount 2 is a newer HEQ5 Pro (in white), but is not so recent as to have the circuit board that allows for a dimmable polarscope illuminator. The previous owner fitted a resistor to dim the illuminator and this seems to allow me to find polaris without any problems.

Both power up and have pretty solid axis with no play when clamped. The Synscan controllers both work okay and have the latest firmware. All the relevant bits are present and seem to work okay.

As far as I can tell the two most important things I should test are GOTO accuracy and tracking.

Testing GOTO accuracy should be easy - do 3-star alignments on both using the same stars and see if one is consistently better at putting the target in the centre of the field of view.

Tracking is where I have a problem. How do I test tracking accuracy?
One obvious way is to put a star in the centre of the field of view and see if it drifts. However, my fear is that all this will tell me is how good my alignment was on each mount, not how good the tracking is. Is there another, more objective (but relatively quick) test I can do?

Is there anything I’ve missed?


#2 Michael Morris

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Posted 03 August 2010 - 01:50 AM


#3 Tapio



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Posted 03 August 2010 - 02:00 AM

You could use a webcam and K3CCDtools software to produce a periodic error curve.
If you want you can later make a graph (with PEAS software) based on K3CCDTools produced log file.

#4 mega256


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Posted 03 August 2010 - 03:59 AM

If you have a web cam ,ccd,,,use PHD to test each one..You can use your main scope if you want..Just look at the GRAPH
in phd and compare the 2 mount...works great ,look at the avg's,the smaller the better..

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