Hi Paul
Thanks for the input. I also emailed Andras about the problem and he told me that he knew about it. He also said that I could edit the PEC table in Pulsar Commander either directly or with an Excel file. I may try that.
The reason for doing this is because I am having real trouble getting this mount to guide, and I thought that if I could eliminate some of the PE error it would help. PEMPro is reporting a peak to peak PE error of about 6.5 arc seconds before correction. I don't think the PE error is that bad without correction and thought I could guide out most of it anyway, but that doesn't seem to be the case. I can get by with short focal length refractors (just about) but I want to use a longer focal length SCT, and that's the main reason for buying the G42 mount.
I am using an 8" f10 Meade LX200 ACF. I did most of my original testing at f10 with a Starlight SXV-H9 and that is how I generated the PE curve. I did some unguided exposures at f10 of 200, 400 and 600 seconds, i.e. 1, 2 and 3 worm cycles repectivley. What I saw in the results was trailing in RA which approximated the PE.
Last night I used an AP 0.67 focal reducer and my QSI 583 wsg. I used a Lodestar binned 2x2 as the guide camera in the QSI off axis guider port. I tried guiding with both MaxIm V4 and V5.
The trouble is, as I have never used a long focal length scope for imaging before, I am not sure what I should be expecting regards tracking accuracy. What I am seeing is, at best, +/- 1 pixel and often +/- 1.5 or 2 pixels in RA and less in DEC. I am seeing jumps between exposures of 1 pixel in RA, and sometimes either axis may drift off by up to a pixel or so for several exposures before heading back to where it should be. Since the Lodestar pixel scale is about 2.8 arc seconds per pixel, each pixel shift relates to about a 3 pixel shift in the QSI.
I know the seeing can be a problem at this sort of level, but given good seeing I thought I should be able to do better than this. I have tried just about everything I can think of to improve matters but without success. I would have thought that I should get a few good exposures, but all of them show trailing of varying degrees in the stars.
I am not sure if that's what I should expect, if there is a problem with the guider or the mount, or if I am just plain dumn..! I know the guider is doing something because I can make it worse!
I have had a few problems with this mount; first the USB driver chip failed in the Pulsar2 and had to go back for repair, then I bought a 3A 24v power supply as recommended in the manual which promptly tripped out due to surge. Then I found out that 24v wasn't good for the Pulsar2 anyway, so bought a 13.8v supply recommended by Peter at Eliptica. This was rated at 5A with a trip out at 6A. This tripped out the first time I used it, so I am now using a Maplin's 13.8v supply with a 9A surge rating.
Add to this the fact that I can't download a PE curve from PEMPro and that I can't get good tracking, I am getting more than a little frustrated. I live on the edge of a lake, and at 3am this morning I came very close to chucking the mount in it.....!
Now, I am sure that this is a good mount and either I am doing something wrong or there is a problem somewhere that needs solving, so if anybody can give me some advice or help regarding this it would be very much appreciated.
If anybody would prefer to email me direct then please do so at:
peterchance(at)btinternet(dot)com
Sorry for the long post and best regards
Peter
