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Old 19-09-2014, 04:15 PM
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codemonkey (Lee)
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codemonkey is offline
 
Join Date: Jul 2013
Location: Kilcoy, QLD
Posts: 1,522
Quote:
Originally Posted by Octane View Post
It's all a mystery!

You need to buy a Paramount ME II.

H
haha. That's it! I'll let the wife know what to get me for christmas ;-)

Quote:
Originally Posted by DJT View Post
Graph 2 is interesting. You have an FWHM of over 6 on your guide star but your guide exposures are just 1 second. Chasing seeing? Your other graphs have fwhm between 3 and 4. The intent is to make as few adjustments as possible so take longer guide exposures? Also gives all your other settings less to deal with.
I suspect this is actually it. I still see stars bouncing all around the place even when guiding is disabled so this suggests to me either:

1) Seeing
2) Mount problems
3) Physical instability somewhere

I saw a thread saying that my area has had terrible seeing lately, so maybe that's all it is. I've done exposures up to 5 seconds long to try and offset seeing, but I was still seeing the star bouncing around from exposure to exposure.

Quote:
Originally Posted by Shiraz View Post
you need to recalibrate phd when you change the guide rate - otherwise it will not compensate by the right amount and you will see wild swings.
Yeah, while that's obvious I'm not actually sure if I did that or not lol. I'll try it again.

Quote:
Originally Posted by Amaranthus View Post
Yep, as Ray notes, you MUST recalibrate PHD after making a change in the sidereal rate - otherwise the corrections will be 5 times too large compared to its training movement! I'm still convinced this is the problem.

Task:
-- Set guide rate at 0.5x sidereal in ASCOM (leave other settings as is).
-- Set exposure to 3 sec.
-- Set noise compensation to 2x2 mean.
-- Set RA aggr to 80 and Hyst to 15.
-- Set DEC to resist switch.
-- Set min movement of both to 0.25 pixels.
-- Set max RA and DEC movements to 1000 ms.
-- Point at DEC 0 and maybe 5 degrees east of the meridian.
--(Re)Calibrate PHD. Make sure that calibration used at least 8 steps (if not, adjust the pulse duration in the Brain settings).

Do all this, and report back
Thanks mate! I'll try that tonight if the weather holds

Quote:
Originally Posted by mithrandir View Post
Lee, you can't change it in EqMod. You have to edit the log before PHDLab can cope.
Ah ok, that explains why I haven't seen a setting for it. Thanks :-)
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