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Newbie to guiding. PHD2 woes.


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Hi all, hoping for some help here.

I have a ZWO ASI 120mm and Astro Essentials 50mm guidescope from FLO and I'm using an HEQ5-Pro mount. Both StellariumScope and APT are able to talk to the mount and I've been using plate solving for a few months. 

I set up PHD2 using the connection wizard. It connects fine to the guide camera and happily finds a guide star. it also seems to connect fine to the mount but when I try to guide, it spends ages on the first calibration step and then claims the star has not moved enough. I tried using the manual control option in PHD2 and discovered that the mount is not responding to PHD2 at all. I am not using the ST4 cable so PHD2 should be talking directly to the mount.

Any ideas what to do next? I am thinking of ditching the connection profile and re-creating it from scratch.

Edited by Penguin
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How is the mount connect to your laptop/PC, is it via a cable into the bottom of the handset or have you replaced the handset with an EQDIR cable?

If it's via the handset, have you put the handset into PC Direct mode (in the Utilities menu on the handset)?

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 Also have you enabled server mode in phd2 >tools you need to do that to enable Apt to communicate to phd2 via ascom  , have you created a Darks map in phd2 just incase a hot pixel is being chosen , also in Eqmod check pulse guide settings are not default 0.1 change both Dec and Ra to about 0.6 I had issue when I started guiding and this setting was the issue .

Edited by bottletopburly
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Not sure why you are using stellariumscope - doesn't the latest version of Stellarium now have scope control built in ?

Remove the ST4 cable and connect the camera via USB.  

You've already mentioned that the planetarium software can see and connect to the scope, so the presumption is that you are either using an EQDIR cable to connect the mount direct to the PC, or using a serial cable via the handset in PC-Direct mode.  If that is the case then there is no need to use ST4, and use the USB connection for the camera.

I don't use SterlariumScope, so can't advise on how to set up pulse guiding within it, but in EQMOD there are two sliders than need to be adjusted to x0.9 for the pulse rate in order to make these mounts move enough for PHD2 to detect the star movement.  You also need to ensure the ASCOM platform is installed and up to date.

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Thanks for the replies.

  • I am not using the ST4 cable. I am also not using the hand controller. I have a USB cable from the laptop to a USB hub on the pier. From the USB hub I have a USB cable to the guide camera and an EQDIR cable to the mount (and another USB cable to the imaging camera).
  • I was using StellariumScope and Stellarium as a test to verify what programs could talk to the mount and which could not. It sounds like I may need to update Stellarium but that's a side-task.
  • I have not knowingly enabled Server mode in PHD2, I'll check that out. but even when the only software running on the laptop was PHD2, the mount still ignored it.
  • I have created a Darks map in PHD2 and the star is definitely not a hot-pixel: none of the stars in the looped images were moving when PHD2 was trying to calibrate. They also didn't move when I tried the manual control in PHD2.
  • There was a setting that was set to 0.1 in PHD2 that I tried to adjust. I think it was "Guide Speed, n.nn x sidereal". It didn't seem to make any difference and was always back at 0.1 when I went back into the settings. This is the only setting I have fiddled with in PHD2. I have not looked at the pulse guide settings in EQMod. It might have been those that the various videos I watched were referring to. I'll look into it.
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Excellent feedback - makes things clear

I use EQMOD and Cartes du Ciel  with PHD2 and it all works for me - I'm not sure about the relationship between Stelarium Stelarimumscope and EQMOD, so can't really advise on how that works, but having two ASCOM interfaces between the scope and the other software may be adding to the issues 

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53 minutes ago, Penguin said:

 

  • There was a setting that was set to 0.1 in PHD2 that I tried to adjust. I think it was "Guide Speed, n.nn x sidereal". It didn't seem to make any difference and was always back at 0.1 when I went back into the settings. This is the only setting I have fiddled with in PHD2. I have not looked at the pulse guide settings in EQMod. It might have been those that the various videos I watched were referring to. I'll look into it.

The Guide Speed in PHD2 and Pulse Guide Settings in EQMOD are the same setting. If you change the RA & DEC setting in EQMOD to something between 0.6 & 0.9, then open PHD2 it should be the same in there. 

When you connect to the mount in PHD2, is it telling you it's connected and what setting are you using for the mount? It should be "EQMOD ASCOM HEQ5/6" and not "On Camera".

This PHD2 Best Practice may also help if you haven't had a look through it. ;)

Edited by Budgie1
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Ok, had a few goes again this evening and, after fiddling with a few things and finally creating a new profile from scratch, it calibrated and started guiding. Yay!

However...

The guiding accuracy seemed to be several arcseconds. Maybe there are settings I can fiddle with to improve this. Maybe my focus was out or something else like that. Maybe the mount could have been better balanced. Maybe there's just too much backlash (there is quite a lot in both axis but I get binding if I tighten it up any more) 

Bad guiding numbers wouldn't bother me if the images were good but the stars are very much not round in the 4-minute subs I took to test, so I definitely need to do something.

I cannot get PHD2 and APT to work at the same time. It all seems as though the two should work together: I want to use APT to go to a target using plate solving and start guiding through PHD2 but I don't know how to do that. Only one of these programs seems to be able to talk to the mount at any one time. I do have PHD2 in server mode.

I'm attaching tonight's PHD2 logs, in case anyone fancies having a look.

PHD2.zip

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Guiding accuracy will come, try running the PHD2 Guide Assistant to see what it says and then update your settings with what it recommends. I normally run it for 5 + minutes to give it a good amount of data to work with.

Also make sure your PA is good and I take it you've eliminated as much backlash as you can. When I got my HEQ5 new, I found quite a lot of play in the gears between the drive motors and the worm drive gears, adjusting out this play made things better but now I've done a Rowan belt conversion. ;)

The way I normally work with the software is as follows:

  • After PA & focusing, I slew to my target using Cartes Du Ceil (this also connects to the mount via ASCOM).
  • Take an image with APT and plate solve to make sure I'm on target.
  • Start PHD2, calibrate if required, and start guiding.
  • When the guiding has settled, start the imaging session in APT and allow APT to tell PHD2 when to dither.

Like you say, only piece of software can send commands to the mount at one time. so I get APT to do what it needs too before PHD2 starts guiding. You can send a slew command to the mount from APT, Stellarium or CDC but PHD2 will stop guiding when the slew starts. 

Keep at it, you'll get there. :D  

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11 hours ago, Budgie1 said:

Guiding accuracy will come, try running the PHD2 Guide Assistant to see what it says and then update your settings with what it recommends. I normally run it for 5 + minutes to give it a good amount of data to work with.

Also make sure your PA is good and I take it you've eliminated as much backlash as you can. When I got my HEQ5 new, I found quite a lot of play in the gears between the drive motors and the worm drive gears, adjusting out this play made things better but now I've done a Rowan belt conversion. ;)

The way I normally work with the software is as follows:

  • After PA & focusing, I slew to my target using Cartes Du Ceil (this also connects to the mount via ASCOM).
  • Take an image with APT and plate solve to make sure I'm on target.
  • Start PHD2, calibrate if required, and start guiding.
  • When the guiding has settled, start the imaging session in APT and allow APT to tell PHD2 when to dither.

Like you say, only piece of software can send commands to the mount at one time. so I get APT to do what it needs too before PHD2 starts guiding. You can send a slew command to the mount from APT, Stellarium or CDC but PHD2 will stop guiding when the slew starts. 

Keep at it, you'll get there. :D  

My routine is more or less the same.

  • Being permanently set up, there is no need for me to PA each session.  This was done using Sharpcap's excellent PA tool.
  • Open Cartes Du Ceil, connect to the mount via EQASCOM, unpark, and slew to ta bright star near the intended target
  • Place a Bahtinov mask over the OTA and open up APT and take an un image for focusing - adjust if required.
  • Remove mask and slew to target via Cartes Du Ceil
  • Take an unguided image to check framing
  • If' the framing is OK, launch PHD2 and connect to the mount and guide camera
  • Let PHD2 autoselect the start and let it run a calibration session
  • Once its started guiding, let it settle for a minute or two before running a plan in APT

I don't use APT for target selection or any other integration.  It's simply used to control the DSLR and run the plan which is typically 30 subs of 5 minutes at 800 ISO.  Any longer exposures and I start to get bright background due to being in a town location.  I'm old school, I run a planetarium application to control the scope, a guiding application to handle the guiding and an imaging application to control the primary camera... These days  IMO there are too many applications that try and merge the boundaries between those tasks, and I think this is where the problems lie.

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Thanks @Budgie1 and @malc-c, that's useful.

I'll definitely run the guiding assistant to see if that improves guiding. I'll concentrate on that until I can get round stars in a 3 to 4 minute image. I normally use around 3 minute subs, partly because of star trailing but also due to light pollution. I'd really just like to get proper round stars in a 3-minute sub!

Then I think I will try consciously moving to Malcom's workflow, substituting Stellarium for Cartes du Ceil. I had just got used to using plate solving in APT though so I may insert that for the Slew to target step. I can see the logic in keeping all these applications separate but plate-solving does justify combining imaging camera and mount control I feel.

 

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With most things there are always multiple ways of doing things.  I'm not saying my way is the way it should be done, just one that I found works for me... I've never done plate solving, other than the routine used by Sharpcap to get polar alignment.  But I also have the luxury of having an observatory so once set up there should be less need to repeat that step.

Good luck, and let us know how you get on

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15 hours ago, Penguin said:

Ok, had a few goes again this evening and, after fiddling with a few things and finally creating a new profile from scratch, it calibrated and started guiding. Yay!

However...

The guiding accuracy seemed to be several arcseconds. Maybe there are settings I can fiddle with to improve this. Maybe my focus was out or something else like that. Maybe the mount could have been better balanced. Maybe there's just too much backlash (there is quite a lot in both axis but I get binding if I tighten it up any more) 

Bad guiding numbers wouldn't bother me if the images were good but the stars are very much not round in the 4-minute subs I took to test, so I definitely need to do something.

I cannot get PHD2 and APT to work at the same time. It all seems as though the two should work together: I want to use APT to go to a target using plate solving and start guiding through PHD2 but I don't know how to do that. Only one of these programs seems to be able to talk to the mount at any one time. I do have PHD2 in server mode.

I'm attaching tonight's PHD2 logs, in case anyone fancies having a look.

PHD2.zip 22 B · 2 downloads

One thing that will help is to make sure your polar alignment is as good as you can get it to be, test the polar scope itself for alignment (youtube should help with that) as it has several grub screws on it to alter it. Using the scope I would have been anywhere from 3 to 9 arc minutes out, PHD2 Guiding assistant will tell you the error in alignment, IIRC if its under 5 mins then guiding should be decent, over 5 mins and it may give more error resulting in the assistant wanting you to alter the pulsing. There is quite a few ways to dial in your alignment for better tracking, drift alignment in PHD (free), Sharp cap software (subsciption) or polemaster separate camera/software combo (pricey). Great vid here with detail in depth about PHD and where to have your scope pointed when you do a calibration. Might be worthwhile to take a look at some of the mount tuning vids for your mount in RE to something like the rowan belts etc, I would try to identify the problem first though without throwing money at it first.

 

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I agree, PA helps a lot, but another factor that can affect guiding is cone error, and flexure, both of which have been documented here on the forum and no doubt on Youtube

This is an old video, but one of the best 

Then perform a Polar alignment

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I have an almost identical setup. HEQ5, CDC, APT and PHD2 with EQMOD. It works ok although guiding is not brilliant. My scope is a SW200PDS Newtonian. The scope is too big for the mount and catches the wind but it works well enough for my needs.

It took a long time to get it to work as well as it does.  I get 1.25 arcsec RMS total. DEC is a lot better than RA. In RA I get random spikes which I think are caused by wind catching the scope. I made an adapter so that I could mount the guidescope directly in the saddle. Then I could test everything without the oversize scope causing problems.

Adding the belt mod to the mount improved things no end. Then I changed all the bearings in the mount and serviced it and that made a big difference.

I don't think backlash in RA causes problems because the mount is always driving in RA but backlash in DEC is a problem so you have to minimize that. Once I got it working reasonably well I was able to record a PE profile which I processed in PECPREP and I run PEC in EQMOD and that improved things too.

I've tried playing around with PHD2 settings but usually made things worse. In the end I created a new profile in PHD2 and used all the default settings and parameters and that's what I run with now.  The only one I've changed is that I select "use backlash compensation". You have to be careful how much compensation you use. If you use too much it tends to oscillate either side of the zero position.

Selecting multiple star guiding was an improvement.

I've used guide assistant but frankly when I use the recommendations the guiding is usually worse.

I've found the PHD forum excellent for advice but you will have to upload a PHD2 log to get answers. This is the URL

https://groups.google.com/g/open-phd-guiding

Cheers

Steve

 

 

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Something I forgot. I was getting odd dropouts in the communications between the mount and my laptop. I was getting error messages in PHD2 which made the problem look like a software compatibility issue but it eventually turned out to be a power supply problem. I have a mains powered power supply which gives 12.5V but someone on this forum told me that the HEQ5 needs 13.7V for the comms to work reliably. In the end I bought a 13.5v power supply and that cured the comms drop out problem.

 

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