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497 Firmware problem

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#1 CraigNZ



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Posted 08 March 2014 - 12:18 PM

I use SkyX to remotely control my LXD75 mount with the 497 Autostar hand controller.  NOTE: I am located in Southern Hemisphere.


Each night, before beginning my observation plan, I use SkyX to slew to a known star in the vicinity of my targets, center the reference star in the eyepiece and then use SkyX Synchronize command to correct the Telescope position (RA, DEC) to match the sky catalog.  I can now accurately move in the area to each of the targets.  The Synchronize command sends the RA and DEC of the reference star followed by the #CM: to the telescope.  The telescope now sends corrected RA and DEC positions to the software.  So this is all working.

What I have noticed though is each night the amount of correction required to synchronize has been getting larger, to the point where lately I couldn't even find the reference star in the finder.

Thinking that maybe this is some sort of cumulative error I did a hard reset on the mount (Meade LXD75) and reinitialized everything.  I then started SkyX and had the telescope slew to the Moon (which was conveniently located in the day sky).  I then centered it in the eyepiece and noted both the Moon's position and the Telescope position.  Then synchronized, parked the scope turned everything off, rebooted then repeated the exercise.  I repeated this several times.  Here are the results:

Measurement 1 (first synchronize after a hard reboot of mount):

TEL: 03 55 44, 18 18 59
Moon: 03 56 21, 18 19 50
Diff: 37 s in RA


Measurement 2:
TEL 03 55 22, 18 17 06
Moon: 03 56 38, 18 20 58

Diff: 76 s in RA


Measurement 3:
TEL: 03 54 21, 18 18 58

Moon: 03 56 47, 18 21 33

Diff: 146 s in RA

Measurement 4:

TEL: 03 52 11, 18 20 57
Moon: 03 56 55, 18 19 46
Diff: 284 s in RA

Measurement 5:

TEL: 03 47 33, 18 20 15
Moon: 03 57 04, 18 22 38
Diff: 571 s in RA

Measurement 6:
TEL: 03 38 09, 18 20 55
Moon: 03 57 12, 18 23 10
Diff: 1143 s in RA

Measurement 7 (did not synchronize this time):

TEL: 03 38 27, 18 19 47
Moon: 03 57 24, 18 23 55
Diff: 1137 s in RA


Note how the error in RA is doubling each time the telescope mount is powered up and the moon recentered in the eyepiece.  The only time the error did not change was when I did not synchronize (send CM command to the mount)

So I think what is happening is the sign of the correction (note that the problem is in RA only) should be reversed for the southern hemisphere.  If the mount does not change the sign of the correction then it will add the wrong correction to the already incorrect offset resulting in a doubling of the error in RA.  I am pretty sure the firmware (43Eg) is not taking the hemisphere into account when making the offset correction when starting up.



a) has this been fixed in the 497EP hand controller firmware and if so, can I simply replace my 497 hand controller with the EP version, or

B) is there someone out there who can check the firmware to confirm this and provide a patch




#2 MistrBadgr


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Posted 08 March 2014 - 06:13 PM



I don't have a clue about an answer, but I am watching your question for an answer.  Hopefully, someone will know.


Bill Steen

Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#3 Mark Sibole

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Posted 10 March 2014 - 04:15 AM

Have you checked this on a star?I know there has been issues on lunar and planets in the past ..

Mark Sibole
MTSO Observatory
Fife Lake, Mi.


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