Re: PHD2 & older non gemini G11 & Lodestar x2 setup help needed.

[Andy Galasso]

Hi Richard,

It sounds to me like PHD2's guide signals are not being received by your mount. It's probably best to ask on the Losmandy forum about how to connect an ST-4 guide cable to your particular mount, or if the mount is compatible with ASCOM pulse guiding. An ASCOM connection is the preferred method for PHD2 assuming your mount supports it; if not, you'll need to connect with an ST4 cable running between the Lodestar and the mount. Once you have an ST-4 connection to the mount, or if you have an ASCOM connection to the mount (preferred), then the next step would be to use the Manual Guide tool (menu Tools => Manual Guide) to confirm that PHD2 can get the mount to move.

Andy

[Richard44W]

Hi Andy,

Thanks for the tip. I found out I had setting under "mount" wrong, needed to be camera only. I was also told I might need a GPUSB. I changed the setting, and now the mount is receiving commands. It calibrates quickly now, and my settings don't switch to defaults. Graph looked real ugly when using 2 second exposures on guide camera, would look ok for a minute than go crazy in dec, When that happened Ra would start over-correcting. I need to take mount apart and clean/lube it. Never been done, 15 years old.

If I do 1/2" exposure on guide camera I get much better results, was able to take a 315" exposure using 450d at 1500mm fl and the stars were just starting to get elongated.On that image I got:

RMS Error
Ra 0.16 (0.68)
Dec 0.14 (0.57)
Tot 0.21 (0.89)
RA Osc 0.35

Other settings: Ra Agr = 60
Hys = 15.00
Min mo = 0.10 (ra & dec)
Mx Ra = 300
Mx DEC = 1523

[Andy Galasso]

Hi Richard,

0.89" combined RMS is not a bad result at all for a 15 y.o. un-tuned mount.  I think you will see an improvement if you tune it up.  The conventional wisdom for a G11 is to keep the balance biased slightly to the East to keep the worm gear contacting on one side.  I also have a G11 and found that this really does help RA guiding performance.  The folks on the Losmandy group will have lots of good information for how to clean up and tune the mount.

If you have further guiding questions, please be sure to share your guide log (instructions here.)

Andy

[Richard44W]

Hi Andy,

Thanks for your help. Attached is a log file with several runs. Towards the bottom is the longest one, over 5 minutes. I have no clue what it all means, perhaps someone here can decipher it?

Thanks,

Richard

[Andy Galasso]

Hi Richard,

You can view the log in PHD2 Log Viewer.  Here's the plot of that last 4m+ guide session.  You had decent guiding (0.93 arc-sec combined RMS) until around 4:15:30, then things fell apart with wild excursions in RA and Dec.  That's exactly the kind of thing you would expect to see for a mount >10 years overdue for a clean/re-lube. I think you should proceed with your plan to service the mount and I'm guessing that should take care of (or greatly reduce) the problem.

Andy

[bw_msgboard]

Also, Richard, if you upgrade to the 2.5 release, there is a Guiding Assistant tool to help you understand what your mount is doing.  Between that and using the LogViewer tool, you’ll be able to learn more about your guiding performance and thus ask more specific questions.  Specific questions are more likely to get responses on the forum…

 

Good luck.

Bruce

 

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[Duncan Munro]

The mount behaviour below is typical of an autoguider that tries to guide in both axis simultaneously with a Losmandy/CI-700 digital drive. My Meade 208 XT AG does exactly the same thing. The mount guides calibrates and guides well for a while and then tries to issue a simultaneous guide command and things rapidly go downhill as the mount either stops running in RA or moves very rapidly as the guider tries to compensate.

Duncan