Sequence start - what to expect from PHD2 at startup?

Hi Folks. I normally start up and calibrate PHD2 independently before starting a SGP sequence. I read somewhere that SGP can instruct PHD2 to calibrate and guide.
I’m not finding that to be the case and I get the error message that the autoguider is not guiding and do I want to continue without dither? etc. Assuming PHD2 is running, what is the intended logic between SGP and PHD2 at the beginning of a sequence?

  1. Connect PHD2 equipment if not already connected?
  2. Cycling exposure, if not guiding?
  3. Force star selection if not guiding?
  4. Force calibration if no calibration is in force?
  5. Force guiding, if calibrated, but not guiding?

It would be useful to know what is meant to happen and then I can verify that the beta2 on my system is working as intended.


Its been cloudy here for so long I can hardly remember my last time:( However, I believe I started all the programs including PHD2. I connected everything - including the camera and telescope in PHD2. I had the sequence set to start in a couple of hours. I hit start sequence and left. The sequence started a couple hours later as planned when I was gone. PHD2 then found a guide star, calibrated and started guiding - all ok.

So, it seems if PHD2 is turned on and connected ok, SGP will take care of the rest.

I think that PHD2 has to be taking images. SGP seems to prompt it to calibrate and start guiding, but IIRC PHD2 needs to be looping before the sequence starts.

Actually, PHD2 only needs to be connected to equipment. SGP will start looping and guiding, including selecting a guide star and calibrating if necessary.

Personally, I like to make sure I am calibrated already before starting the sequence in SGP. That way I can choose the calibration location (near declination zero). I usually just use the auto-restore calibration option to reuse my previous calibration.


I agree with Andy. My experience is PHD2 does NOT need to be looping before the sequence starts - just connected.

I do that as well and typically will get the object into position with SGP so I can select a guide star and watch PhD guide for a dozen or so corrections before I do anything with the SGP sequence. That allows me to tweak the PhD settings if need be for the seeing and such before starting the sequence. At that point one can either allow it to keep guiding or stop it and let SGP restart it, either seems to work fine.

Thanks folks. Tim - have you verified that is still the case with 2.4 Beta (2)? The weather is awful right now and I have no way to go back and test at the moment.
When I quickly tried it, SGP would not instigate the guiding but was highlighting that guiding was not working and did I want to abandon dither etc.

buzz, I think you probably encountered the situation where upgrading from 2.3 to 2.4 beta requires you to select the auto-guider. If you do not explicitly make the selection, it defaults to “No auto guider” and you will get the warnings about no dither etc.


Hi Andy - unfortunately that was not it. SGP 2.4 beta(2) has been working fine with the autoguider and dither and PHD2 were selected and the server was active. It just expected PHD to be already guiding when the sequence started. It may be because this was the second night of a sequence. I will try to nail it down to a set of circumstances.

No, buzz, I didn’t verify this information with the 2.4 beta. I probably should have mentioned this with my comment. The weather here has been so bad that I am unable to do hardly anything since the beta came out. Sorry for any confusion.

Thanks Tim. I’m having similarly atrocious weather. I will try some controlled variations when I get the opportunity.

I get this message - I have no idea why.

Hi Swag72, that’s the one - are you using 2.3 or 2.4beta(2)?

I got it using 2.3, so upgraded to beta expecting it to go … nope, still the same.

A friend used a simulator and couldn’t replicate this issue. I wonder if it’s a bug that needs fixing?

I also recall seeing that message once in a while with 2.3.X but do not recall under what circumstances or how I resolved it. I know that is not much help but the weather has mostly sucked here for quite some time.

I hope that someone from the SGP team can shed some light on this, what causes it and how to deal with it.

All, I had an unexpected clear night tonight. The good news is that the problem does not always occur:

PHD 2.4.1b, SGP Beta 2, Win 7 64 bit

My system works if auto slew/center are enabled at the start of the sequence. The exposure cycling in PHD2 is initiated, calibration occurs and it starts guiding. I restarted both programs and disabled auto slew/center at start of sequence ie it goes straight into imaging - the system fails with the message in swag’s post. Without changing anything else, I cancelled the dialog, enabled auto slew/center on start of sequence and hit run sequence… it worked fine. I went back and did some dabbling, it is the auto-center that seems to pave the way for it to work. I repeated the experiment a few times and the failure mode was consistent with the auto center setting. I’ll write it up as a bug report.

PHD2 will now auto-start (and calibrate if required) on sequence start.

Do I need to update my beta version for this to happen Ken?