Help with calibration in PHD please

[michaelmorris]

I’ve only just started trying to use PHD for guiding. Last night was my first night trying to use it in anger. I attached my canon 1000D to the back of my 80ED which is piggy-backed on my F10 8” LX200. I attached my Meade DSI to use as a guide camera. I slewed around a little to get a decently bright guide star on the DSI chip. The ASCOM telescope driver and camera driver loaded up okay in PHD. I checked that the stars I had in the view were actually stars and not just hot pixels. After focussing I pressed stop then pressed the ‘target’ symbol and selected my guide star. After 61 attempts to calibrate in DEC an error message came up saying that there we not enough telescope movement to allow the software to calibrate. Can anyone help me solve this?

Thanks

[Sparrow]

Hi Michael - I'm not exactly an expert with PHD as I've only just started using it myself - your problem is familiar to me though - I had exactly the same problem - in the end I realsied that I'd set the DEC guide mode to "North" instead of "Auto" - Also, I increase the calibration steps up to 2000 to start with - I've since gradually decreased this figure to about 800 which seems to work for me

BTW - Don't forget you can take a dark with PHD which will then illiminate hot pixels from the view making sure you're not accidentally aligning with a hot pixel.

This may not be the answer but it's a start.

Regards

John

[RobH]

Hello Michael.

When calibrating in DEC, the first command that PHD issues is a North command. Before you start calibration, make sure you've talen up any backlash in your DEC axis by nudging the mount slightly north with the hand controller.

If there's too much backlash, the DEC calibration will fail.

Make sure you have a good longish calibration step, especially near the pole.

Don't pick too bright a star to calibrate on, and make your exposure time 3 seconds or so.

Cheers

Rob

[adamsp123]

This could be the answer to the problem as posted by me in equipment help. I was trying for the Iris neb NGC7023 which is near the pole, and the DEC calibration failed in the same manner.

[michaelmorris]

On further investigastion it looks to me as though it might be a problem with ASCOM. I've very recently upgraded to ASCOM 5 and the drivers don't work on Cartes Du Ceil either. I'll have to investigate this further. Has anyone else had a problem running an LX200 Classic on the new ASCOM 5 drivers?

[Ant]

I doubt it's ASCOM 5 as I use that fine with PHD.

Click on the "Brain" button, up near the top is the calibration step length - increase it.

That I think will be the issue - I get that message from time to time.

I agree with Rob, make sure that the exposure length is (I use 2 seconds as the DMK cannot exposre for 3) 2 or 3 seconds...

Cheers

Ant

[beamish]

(I use 2 seconds as the DMK cannot expose for 3)

Cheers

Ant

I thought the dmk would exp upto 1hr

I agree about increasing the calibration, experiment. I had similar messages when I first tried PHD, but that all stopped with just a small increase in calibration step.

Karlo

[Ant]

Yeah It will go up to an hour - maybe even more.

But it will not do 3 seconds. The scale is something like-

2sec

2.3sec

2.8sec

3.4sec

don't ask me why... Not normally an issue, but I like round seconds

Ant

[michaelmorris]

All fixed. I installed the latest ASCOM drivers for my LX200 Classic and it all started working. Looks like either the previous version had a glich or my original installation of the ASCOM drivers went wrong.

Thanks for the help. I've learned a bit about PHD on the way.