Beginner Autoguiding Problems

[boardriderz (Jimmy)]

So after a few days at the QLD Astrofest earlier this month I received an amazing amount of help from may of my fellow Astronomers there and I think I got my set up working. I am for the first time going to try guiding my Orion Atlas, through my AT65Q with my not very sensitive web cam planetary imaging camera.

The part of connecting the hardware and getting it all to communicate with each other has been done and I am driving it all with EQMOD, CdC, Alignmaster and PHD (to start with). Just to let you know, at this stage I am not imaging, but just trying to get PHD to track correctly.

The mount has good alignment through using the Webcam and Alignmaster (within 2" of SCP). However after locating a bright star and starting guiding with PHD the Star almost immediately starts slipping out of the box and after a min or two I hear the dreaded beeping of star lost. I loose the star steadily in the same direction each time?

The problem is that I dot know where to start looking for the problem. I am pretty sure the mount is physically good, solid (no flexing), balanced and well aligned. Do I need to increase the sensitivity to the guiding corrections or is there a standard speed correction needed for my mount.... it almost seems as though it is not tracking at the correct speed?

Any thought would be greatly appreciated.

[jjjnettie (Jeanette)]

In the Brain Box, Make sure the Disable Guide Output box isn't checked.
Because it sounds like the mount isn't guiding at all.

Apologies if you've already checked that out.

[boardriderz (Jimmy)]

Nope, that is all good, was actually attempting to giude as I could see the corrections in Dec and RA, they were however maxing out at 1000ms pulse length in RA to the East and 150ms in Dec to the South. If this helps at all.

[Garbz (Chris)]

The only time I have seen something similar I had the telescope accidentally set to the wrong side of magnetic declination, I compensated 12 deg the wrong way putting my 24 deg from south.

Enabling PHD instantly caused the guider to clip to one direction and drove the star straight out of the frame.

Problem was solved after re-alignment.


Does the star appear to dramatically move when you're not guiding?

[boardriderz (Jimmy)]

I used Alignmaster software to do my Polar Alignment and it puts me within a minute or two of the South Celestial Pole so I have to think that this isnt the problem. It might not be PHD but be something to do with EQMOD?

[Grimmeister (Anthony)]

Hi Jimmy,

Have you had a look at the pulse guide settings in EQMod, it sounds like the autoguider port rate setting may be too low or the ASCOM PulseGuide Setting may be too low.


Have a look at this guide http://eq-mod.sourceforge.net/docs/EQASCOM_Guiding.pdf

It explains it all.

PM me if you need more help or if these don't fix the issue.

Cheers

Anthony

[Geoff45 (Geoff)]

Originally Posted by boardriderz

I used Alignmaster software to do my Polar Alignment and it puts me within a minute or two of the South Celestial Pole so I have to think that this isnt the problem. It might not be PHD but be something to do with EQMOD?

Just because a piece of software tells you that you are polar aligned doesn't necessarily mean it's true. Try just letting the mount track without guiding. If the star stays in the field of view (maybe moving around a little because of PE) then your polar alignment is OK. If it drifts out rapidly, then your polar alignment is off or your tracking rate is wrong. If it drifts out EW, then it's probably tracking rate. If it drifts out NS its almost certainly polar misalignment.
Geoff