[rogerg (Roger)]

Originally Posted by Omaroo

1) has a built-in clock which is reasonably accurate

Correct. I find I need to update the clock once every few months, usually correcting it by about 30 seconds.

Originally Posted by Omaroo

2) that you want the scope, once parked and turned off to keep on tracking time with that clock

That's right, the clock keeps ticking. It doesn't keep "calculating tracking" or anything, it just keeps the time 'accurate'.

Originally Posted by Omaroo

3) want the scope to power up, know the time and that it's at 0,0 home position, and then slew to an object without doing any further alignment that session?

Yeap. I'm expecting to do a plate solve upon startup (to allow for some innacuracy in pointing) but at the moment it's too far out (up to a couple of degrees I think) for the plate solve to be successful.

Originally Posted by Omaroo

I gather that it has SmartDrive - so how do you intend to get past the SmartDrive calibration test on startup? Wouldn't that affect the post-startup position?

Yeap, that does move it a little. I don't think that is a large contributing factor - the movement is relatively small, the kind of movement I'd expect a plate solve to be able to handle. If not, I have considered writing a little application to, after the test, counter-act the movement done by the test, but that might be a bit hit and miss on the accuracy.

Originally Posted by Omaroo

I'm sorry if I sound daft, but having a GPS version I'm not sure how the older models did this.

If you sound daft then I sound daft . I have some reasonable understanding of the situation but it's still a bit like the blind leading the blind

Originally Posted by Omaroo

I assume that Meade the GPS version so that people could do what you are trying to do.

To tell you the truth, I have never understood the use of the GPS in LX200GPS. I haven't delved in to it deeply to work out what the advantage is.

I first assumed it was implemented so you didn't have to align - it'd start up and know exactly what angle of north it's pointing at. Then I found out they hadn't done that and star alignments were still needed. Time - yeah, sure, they'd probably get the time from the GPS, but the LX200 classic's quartz clock isn't that inaccurate to desperately require GPS. It's kind of off topic to this discussion, but I don't understand what the GPS gives the LX200 that the classic doesn't have, other than gimmic.