Confused GC5 GOTO

[AstralTraveller]

I have a Celestron GC5 GOTO mount that has become very confused.

The problem started on Saturday night. The pointing had been getting further and further off so I used the 'align' function to replace an alignment star with the DSO in Vela I was observing. I then asked it to go to another object in Vela and wound up in Lupus.

My first though was that the new alignment object was too far from the original alignment star (Pollux) and had confused the calibration program. So I powered off, moved the scope to its start position, powered on, checked that the controller knew the correct time and location and started a two star align. First target star was Acrux, which was near culminating - the scope pointed to low in the south-west. For Spica it pointed about 40 degrees below the horizon in the se. Several more cycles of off and on didn't change anything. So I spent the rest of the night doing it the old way. Tracking and direction arrows both work.

Tonight I set up the head in the lounge room and tried aligning again. Sirius was low in the se, Canopus near the SCP and Regulus below the horizon in the ne. I tried setting the home position (don't know what it does but it sounded hopeful), and then tried returning to the factory default settings and resetting time and location. No change.

The problem isn't a simple offset in RA and/or Dec. It was west of the target for Acrux but east for Sirius. The move from Sirius to Canopus was in the right direction but was too far.

So now I'm also confused. One thought I've just had - does it think it is controlling an alt-az mount? I've put it away now so I can't test that theory tonight.

Any of the famous IIS advice or will be much appreciated. :help::help::help:

[seeker372011]

Ok dont sweat it..I think I had exactly the same problem a year ago around the time of change over from dayight savings

check 1-is your power supply ok? not just your battery pack but also the physical connections-just make sure these are ok

check2-if power supply is ok-the cause of 90% of CG5 weird behaviour according to some accounts-then ther is only one thing left to do-do a complete factory reset. This will mean you will need to enter your lat and long etc but I'd be very surprised if your problem didnt go away when you do this

unfortunately till you do this reset the mount behaves really eccentrically


hope this helps

Narayan

[seeker372011]

I see you have done a reset-but power off wait 30 seconds at least and then do the reset

[sheeny]

Hmmm. On one or two occasions my CG5 has gone screwy. I think the problems came down to power supply and daylight savings time as Narayan mentioned, but it was a long time ago now and I haven't had the problem since I got the GPS unit.

Try a search on CG5 in IIS. No doubt lots of threads but I'm sure we've been through this problem before.

Al.

[sheeny]

AT,

Have a read of this and see if any of it helps...

http://www.iceinspace.com.au/forum/showthread.php?t=10917&highlight=CG5+problem

Al.

[asterisk]

Check the following:

1. On the top of the tripod there is a peg for adjusting your azimuth - it should be over one leg, not between two legs as often shipped - there is a spare hole to relocate the peg above one of the legs.

2. When you set up, make sure this peg is pointing to polar south, not magnetic - adjust for magnetic declination

3. Get a little round bubble level from Bunnings for example and put this on top of the tripod to level the tripod - the bubble on the mount is often placed incorrectly.

4. Have your correct latitude and longitude - use Google Earth if you don't have a GPS

5. The DEC alignment marks are often 180° out of place. The DEC port should be facing you as you look south over the telescope.

6. After the mount and telescope are in position, enter your lat and long (ensuring you enter south and east respectively), time non DST, date (month, day, year) and select a quick alignment.

7. Select Menu, Tracking and make sure you have south entered. Select Tracking Rate and make sure it is on sidereal until after you complete your alignment.

8. While at this stage, select a named star from the list (kepypad 8) near celestial south (eg, Rigil Kentaurus). Send the scope to this - use the azimuth and altitude knobs to do a rough polar alignment until the selected star is in the viewfinder cross-hairs - a mounted laser is excellent for this step

9. Turn off (use power supply to do this - the switch on the mount is not that strong and will break after repeated use). Speaking of power supply, the mount needs 12v (or slightly more) at 2 amps to work correctly - an emergency starting unit will suffice.

10. Turn back on, enter correct time again - lat and long will still be there from the first time. Select a 2 star alignment - follow this with at least 3 calibration stars - by the time you get to the third, the mount will be pretty well spot on.

After these steps, selected objects will be in the eyepiece when you send the mount to them.

For improved accuracy, drift alignment helps. Be wary of wild slews - an inbuilt problem with the CG5 mount - press any direction key to stop one of these and reselect a target - the mount will still know where it is and respond accordingly. If you turn the mount off, restart at step 10. If you move the mount, start at step 1.

Good luck

[OneOfOne]

My CG5 went nuts one night, I had aligned it with a star that was very close to the meridian, the next star was way out. The third one was also wacky. I "rebooted" (off and on again) and tried a star that wasn't quite so high...and it all worked.

[AstralTraveller]

Thanks everyone for the advice.

This afternoon I set the head up inside to start troubleshooting. Lo and behold, all the slews went to believable positions! So I set it up outside and tried a real alignment. It's as good as ever. That is to say just OK.

Even with 4 calibration stars it couldn't put Saturn in a 0.5 degree fov. The clouds have rolled in at the moment so I've left it running and I may find out later how well it is aligned. It certainly isn't too bad and I doubt better alignment will help much. Oh well, I knew it was at the bottom of gotos when I got it and I suppose you get what you pay for.

[OneOfOne]

Other than times when my mount went "wacky" or once when I forgot about daylight savings, my scope always put the target within the view of a 10mm eyepiece (100x). The first alignment was usually several degrees out, second one would be quite close, much less than a degree and the third one was generally "a formality".

[seeker372011]

it should land DSOs every time on small CCD chip and in the centre of your finder-the goTOs on teh CG5 are very good, it has other problems-backlash and PE but generally excellent GoTos

have you talked to your dealer?

I had once to swap my hand controller when the mount went wonky that could also be the problem