EQASCOM sync headache - what am I missing?

[brancusi]

My question is probably best expressed as - how on earth do I sync the telescope (AZ-EQ6 via EQMOD) through Stellarium on a star near the pole?

I'm trying to establish a workflow where I use plate solving via AstroTortilla to sync the scope setup to the sky before an imaging session, as such the scope is accurately polar aligned, but otherwise UN-ALIGNED when I start.

I thought I would be able to do this;

1) Point telescope randomly at the sky

2) Take a 10 sec exposure

3) Plate solve to find central RA/DEC

4) Sync the scope to this position

It seems that steps 1 through 3 are fine - I did this last night and could plate solve every image I took - but NONE of them would sync. I was getting error messages about the sync being ignored because the delta in position was too large (apologies I didn't write down the exact message) and so I could never get the ASCOM Ra/Dec to match the solved image :-(

In desperation I put the scope roughly in weights down pointing north and then tried to use Stellarium Scope to sync on Polaris to at least narrow the error so that subsequent plate solves would work - but every time I used sync, the command was simply ignored unless I tried to sync on a star that was a long way from the pole - it felt that the software was blocking me without telling me what was going wrong. 

Is my plan to do this without an initial one star alignment flawed? Is there really no way to force EQASCOM to think the scope is at a specific Ra/Dec? It could be I was just too cold last night to think clearly but it felt that I was so near and yet so far from getting it all to work ...

Help appreciated!

Thanks,

Roger

[Merlin66]

Roger,

I can't talk about the AZ-EQ mount...

BUT I have been using EQMOD and CdC for the past few years (an NEQ6pro mount) and never found a problem syncing a selected star (in CdC).

I then use an off-set to GOTO my target - usually a faint spectroscopic object.

Don't know if this helps.....

[Zakalwe]

If the synch position is too far from where EQMOD *thinks* the scope is pointing, then it won't accept the synch. Look into the message centre (by clicking the + key) to see if this is the case.

This is why an obsy scope is "Parked" each night...it gives the system a known starting point. if you are setting up each night, then you'd use a rough Park position...for example I used to use counterweights down, OTA horizontal.

Edited March 2, 2015 by Zakalwe

[Zakalwe]

To fix the problem (as your mount has encoders), set a park position in EQMOD (CW down, OTA vertical or horizontal).  manually move the scope to that point. Expand EQMOD and hit ReSynch encoders. That will align EQMOD to the encoders in the mount.

[chrisshillito]

Power up the mount in the home position. i.e. Scope pointing at th pole, counterweights straight down. Or use the hanset to do a auto home.

When EQMOD connects to an unparked mount it expects it to be in the home position. Some small error from home is tollerated (and is usual) and can be corrected for by the alignment process - but if the error is large eqmod will assume user error (i.e. Synching on the wrong object) and deliberately ignores the synch request.

Chris.

[brancusi]

Fantastic help - thanks all, and the clouds have even parted for long enough for me to test it all now works. Getting the home position roughly right was indeed the key to it.

[Tim Long]

I'm having a similar but different problem. I'm using EQASCOM with an EQDrive drive system, on a mount with no clutches. So I can't simply unlock the clutches and move to the home position. I can only move the mount by means of the motors. Since my initial misalignment is > 15 degrees (more like 150), I can't seem to get the initial sync needed to even do a 1-star align. Anyone have any suggestions as to how I might resolve this?

--Tim