Help please people!
So up until the other night when i set my gear up and do an alignment I was able to leave the scope for a while without the star drifting off too much.
Last night I was out after a long cloudy period to get busy testing the new computer. Much to my dismay, the stars seem to drift waaaay to fast?
With sidereal tracking chugging away the star will drift (movement every second) from centre towards the rhs of finder. I need to up and right button to recenter.
Turn tracking off and they rapidly start heading toward bottom left of finder.
Now this was never anywhere near as pronounced on any previous night.
Can’t even get a 2 second shot now??
Any ideas? This is driving me mad.
. Check you have entered a - degree setting , Also try taking your OTA ( Tube ) off and turning it 180 degrees then turning the mount and tube
so they are are pointing up again . , this will turn the RA of the mount 180 degrees , hope this makes sense .
I know this could be a silly question , but the mount is pointing south ? not north , sillier things have been done by us all .
Brian.
Quote:
Originally Posted by Pepper
That’s interesting Brian. What would cause that?
I’m pretty sure I set the location to south?
Yeah def pointing south...........ish
Did a little testing yestiddy while cooking tea, I let it run and monitored the axis movements. Dec didn’t budge, ra was tracking at 1 degree/4 min and seemed to be rotating the correct way.
I did notice however my altitude setting screws were a few deg out. So polar alignment was probably bad.
Would my symptoms describe bad polar alignment?
Yeah def pointing south...........ish
Did a little testing yestiddy while cooking tea, I let it run and monitored the axis movements. Dec didn’t budge, ra was tracking at 1 degree/4 min and seemed to be rotating the correct way. I did notice however my altitude setting screws were a few deg out. So polar alignment was probably bad.
Would my symptoms describe bad polar alignment?
Yes,especially as you say you ...
Quote:
Originally Posted by Pepper
need to up and right button to recenter.
That's not to say that there may not be other issues, but certainly a large error in polar alignment would have similar symptoms to what you reported. As to the apparent speed of the motion across your display, that would depend on your focal length and the angular distance the object is away from the South Celestial Pole.
To understand the abberant motion you mentioned think of two circles that need to be concentric around the South Celestial Pole: one describing the true star motion and the other the rotational axis of your mount. Now set these two circle centres askew vertically to try to recreate your altitude error and you can possibly see how this could lead to the abberant motion you observed. I think it's a good thought experiment.
Make sure you enter the correct time into the handcontroller
Remember it’s US. Month / Day / year
A few degrees out in PA is going to make your stars drift quickly depending on your altitude and azimuth
I attached an old school way but good way to align your tripod and mount toward true celestial south called the solar noon meridian method better than a compass with magnetic declination setting
Also attached the Synscan Polar alignment routine which works for me every time , gets to sub arc minute alignment
Make sure you balance your mount in both axis and set your home position correctly
Good luck
Cheers
Missed one important item, make sure your tripod is perfectly level , forget the in built bubble level on the mount head use a good Stanley boat level 300mm long not a cheap plastic one and level across 3 axis on top of the tripod base with the mount removed, then install your mount head
Cheers
NB: the tripod must be on a solid surface like pavers, concrete, stone, rock etc... not grass or gravel / soil
I've had this type of thing before (possessed goto behaviour) caused by embarrassing errors like getting the E/W, N/S in the GPS coordinates wrong, using deg/minutes coordinates instead of decimal (and vice versa), having tracking switched off/the track rate incorrect, the RA/DEC motor drive cables plugged in around the wrong way (older GOTO design than the eq5) etc etc.
I think the synscan the N/S in the GPS coordinates is entered as +/-, we are minus in Australia.
Suggestion - when you point it roughly at the SCP, does a goto command (say rigel Kent) get remotely near the target? If it goes off somewhere random, it's likely a gps location issue. If it goes to where it was/will be (somewhere in the arc around the SCP), more likely be a time/date issue. If it gets it pretty close, but won't track, I'd look at the tracking rates/basic setup.
Here's the Idiots Guide aka "SYNSCAN for beginners":
1. Forgetting to level the tripod (D'uh).
2. Forgetting to set the mount with the RA axis aimed roughly at the pole (using a compass).
3. Forgetting to align the mount to +/- 0.5 degree with the pole (using dec circle or drift method).
4. Forgetting to put the scope in the PARK position before power-up the handset (and you wonder why it slews 90 degrees off, or into the ground...)
5. Forgetting to clamp the axes before commencing the SYNSCAN alignment routine.
6. "Fat finger" or ID=10T errors when configuring the SYNSCAN handset - eg setting the latitude to N when it should be S, timezone to being - 10h instead of +10h, daylight saving on/off.
All of the above play havoc. Only solution is to redo all the steps.
Symptoms:
A. If all works more-or-less but GOTO are consistently off by a degree or so in some direction, redo steps 1, 2, 3, and check the clutches are firm. If the clutches are locked and you're sure the rest was OK, use the PAE function to force a correction in particular areas of the sky, or redo from scratch.
B. if the result is an objects consistently drift in dec, and GOTOs are off be a few degrees, you missed steps 2 or 3.
B. During the SYNSCAN alignment, if the first slew to a target is way off target (ie >10 degrees, possibly 90 degrees or more) you have probably missed steps 4 or 5 or you have committed sin #6.. = power off and redo from scratch.
C. Failing to clamp the axes is fatal. This results in wacky results - some GOTO's will be close, some will be waaaay off. Power off and redo from scratch.
D. Slipping RA clutch - when clamped, push the scope in RA and it slips. As alluded to recently, if you are using an AZEQ6 the RA clutch can slip - no matter how tight the handle is pushed - when the clutch material has compressed with use. A temporary fix is to balance your scope so it doesn't slip when clamped. But a more permanent fix may require maintenance - ie disassembly - to fix the clutch.
I think this is good advice regardless of the mount. I am having goto issues with my CGX which I hope to rectify using these tips and others in the post I raised.
. Check you have entered a - degree setting , Also try taking your OTA ( Tube ) off and turning it 180 degrees then turning the mount and tube 
