Autoguding with ZWO camera, AVX mount and PHD2 settings

[CSM]

I have managed to autoguide with this setup, but have problems with PHD2 since polar aligning - it did need it. And am now getting rather confused over the actual profile settings choices.

ZWO are still saying to select ZWO ASI camera, then On Mount, but there are other options ZWO related and suggestions elsewhere that with the AVX mount you should connect the PC to the hand controller, or was it the hand controller to the mount, I forget!

[Thalestris24]

Hi

Yes, PC to hand controller, hc to mount. Guide cam to PC via usb (best not to use st4). Ascom platform installed on PC and ascom zwo driver in PHD2.

Louise

[newbie alert]

I connected the  laptop to the handcontroller and the camera to the laptop with my AVX 

[CSM]

Thanks Louise.  So Camera is ZWO ASI  and Mount is ZWO USBST4 (ASCOM)?

[Thalestris24]

4 minutes ago, CSM said:

Thanks Louise.  So Camera is ZWO ASI  and Mount is ZWO USBST4 (ASCOM)?

Mount should be Celestron Telescope Driver (Ascom). No need for any st4 if you have laptop to hand controller connection and Ascom platform + Celestron driver.

Louise

[CSM]

Hi Louise - Have the laptop to hand controller connection but there is no Celestron Telescope Driver (Ascom).  There is the one I mentioned and Generic Hub (ascom) and ASI ST4 Telescope Driver (Ascom)

[Thalestris24]

15 minutes ago, CSM said:

Hi Louise - Have the laptop to hand controller connection but there is no Celestron Telescope Driver (Ascom).  There is the one I mentioned and Generic Hub (ascom) and ASI ST4 Telescope Driver (Ascom)

Do you have Ascom platform and the Celestron driver installed? Do you have the latest version PHD2?

[CSM]

Many thanks Louise.  Just downloaded the Celestron driver (interesting read) - have latest versions of rest.  One day programmers will realise that user instructions for idiots are very important and really do help the user - I speak as a programmer/systems analyst of nearly 60 years!

If it remains clear tonight maybe I will get some actual guiding done.

[CSM]

One unfortunate consequence is that I lose the use of the mouse as I only have 3 usb ports and one of them is normally taken up with the wireless mouse.  Have to use the touchpad which I do not like. Ah well.

[Thalestris24]

You can use a simple hub for a couple of low bandwidth devices without causing any problems

Louise

[CSM]

Thanks again Louise.  Will look into using a hub.  Unfortunately last night was a failure after a few hiccups caused star and object on either side of the meridian, and getting used to the touchpad.  Then all I got when trying to use PHD2 on looping was a very white screen.  Slightly baffled at the moment.  Any thoughts?

[Thalestris24]

Hi

Well, first, avoid the meridian to start! Not sure about the white screen, though focus is quite critical and you need to get the guide cam exposure time right. Usually around 2s is good. Make sure the 'screen gamma' slider is position towards the left. Also it needs to be dark (or nearly so) - guide cams are very sensitive. I'm not personally familiar with zwo cameras so don't know what settings they have. Maybe try focussing at twilight but with a very short exposure - PHD2 lets you go down to 0.01s. Sharpcap is useful (and free) since it lets you do much shorter exposures so can help with focussing when it's not dark enough for imaging - you might even be able to get a guide cam image on a cloudy day if you can point towards a distant terrestrial object and set the exposure to the low milliseconds. Just have a play with it :) Or maybe you can currently see the Moon in the West just as it gets dark or Jupiter in the south east? Once you find focus with your guide cam, just leave it/lock it. You shouldn't need to change it again. I'm not sure what guide scope you have?

Good luck

Louise

 

[CSM]

Hi Louise - I wasn't able to change the screen brightness since I had never had to use the touchpad before and it doesn't operate the way other laptops had.  Now sorted with that.  Yes - have read around and see that the exposure probably needs to be much less than I had set.  I am using a Celestron Off-Axis guider and the ZWO ASI120MM camera.  Have previously set up the focus so I know  where it should be.  Also need to familiarise myself with the Celestron Telescope Driver and make sure it is set up with the Ascom platform properly.

Thanks again.

[Thalestris24]

Hi

Ok - an oag can complicate focussing a bit but if you've had the zwo in focus before, that's good. If the focus hasn't moved - even better! Is that a carbon fibre sct? An aluminium one will likely be on the heavy side for imaging on the avx but you might get away with it. Which planetarium program are you using? I use Stellarium with StellariumScope - works for me . The Celestron driver should just work but you may have to do some setup in Ascom. I can't remember now - you may have to run the Ascom diagnostic utility.

Louise

 

[CSM]

Hi Louise

Don't think the weight of the tube is a problem. PEC also good though not using it with PHD.  Backlash when I did use the PHD guide assistant was allegedly not worth worrying about and is disabled on the mount. Went into the Ascom diagnostic and selected the Celestron Telescope driver though not sure whether that makes any difference as there didn't seem to be any save option.  I shall find out when I next go out 

 

Cheers

Colin

[Thalestris24]

34 minutes ago, CSM said:

Hi Louise

Don't think the weight of the tube is a problem. PEC also good though not using it with PHD.  Backlash when I did use the PHD guide assistant was allegedly not worth worrying about and is disabled on the mount. Went into the Ascom diagnostic and selected the Celestron Telescope driver though not sure whether that makes any difference as there didn't seem to be any save option.  I shall find out when I next go out 

 

Cheers

Colin

You can check the basic setup indoors during the day to make sure you're ready to go, That's what I'd do. The avx does have a reputation for having a lot of DEC backlash (my own avx is no exception!). It can show up during the PHD2 calibration sequence. You may be able to ameliorate it by guiding in one direction. I think Ascom autosaves its settings.

Louise

[CSM]

4 hours ago, Thalestris24 said:

You can check the basic setup indoors during the day to make sure you're ready to go, That's what I'd do. The avx does have a reputation for having a lot of DEC backlash (my own avx is no exception!). It can show up during the PHD2 calibration sequence. You may be able to ameliorate it by guiding in one direction. I think Ascom autosaves its settings.

Louise

I have had two apparently different results.  First, when using the guiding assistant and with what seemed a reasonable though not perfect calibration said that no correction was needed for backlash.  The second was when I tried to redo a calibration after redoing the polar alignment when it seemed to get 'stuck' on clearing backlash. I had actually done backlash adjustments in the mount prior to all of this which didn't seem to make much difference to the performance - backlash was cleared to use PHD.  The scope is permanently setup in an observatory, so not quite sure how I would check backlash with PHD.

[Thalestris24]

As I recall you have to run the guiding assistant for about five minutes and I think there is a checkbox to check backlash? (Though maybe it does it by default when you tell the guiding assistant to halt). If your setup is fixed, you shouldn't need to redo the polar alignment unless you change something. It's a bit catch 22 in that you need a good PA in order to do a calibration. But you have to do a calibration first so it's an iterative procedure. But with everything permanently setup you shouldn't have to do a calibration and PA each time.

Still, as I said, the avx does have DEC backlash and there isn't much you can do about it.

Louise

[CSM]

11 minutes ago, Thalestris24 said:

As I recall you have to run the guiding assistant for about five minutes and I think there is a checkbox to check backlash? (Though maybe it does it by default when you tell the guiding assistant to halt). If your setup is fixed, you shouldn't need to redo the polar alignment unless you change something. It's a bit catch 22 in that you need a good PA in order to do a calibration. But you have to do a calibration first so it's an iterative procedure. But with everything permanently setup you shouldn't have to do a calibration and PA each time.

Still, as I said, the avx does have DEC backlash and there isn't much you can do about it.

Louise

Yes - did the guiding assistant followed by the backlash which is when it came up with not worth bothering with.  But that was when I think I had a reasonable calibration.  Since then not been able to get that which is when I started to get the endless clearing backlash.  Unfortunately since I may have to rotate the guide camera most times to get a guide star I will need to redo calibrations more often.

Thanks

Colin

[Thalestris24]

The calibration just measures the relationship between the guide cam and the mount, so that shouldn't change.

Louise

[Stub Mandrel]

May I butt in?

I've just managed to get PHD2 to work with an HEQ5 using EQMOD, but to start with it was barely getting any movement.

I'm not sure what I changed (OK loads of things...)

What setting SHOULD I change to get the guiding movement to happen faster/coarser?

[Thalestris24]

Hi Neil

Are you calibrating ok? Have you set your guidescope focal length in PHD2 and used the calculate to get a calibration step size? Also, in eqmod there are ra and dec guide speed controls.

Hth

Louise

[Stub Mandrel]

I tried using calculate but got in a mess, I just guessed some of the numbers until it sort of worked...

In the end I left it to look after itself. I got two decent subs and it stopped tracking completely... I will try and look up the calibration data properly, but I think this needs more data!

 

[Thalestris24]

Hi again

The calculate function is very simple! You just enter the data for your guide scope and guide cam plus a few other bits. The guide speed is from the slide controls in eqmod, that I mentioned before. Generally you'll have that set to .8 or .9. Number of steps - about 15 should do. The dec is from where your pointing - I think phd2 picks that up automatically, as well as the eqmod settings. I think, generally, pointing at a dec of about 30 deg is good. Anyway, it just returns a value in ms that it uses to step time the calibration ie the value in the box next to the calculate button. The actual calibration should only take about 5 mins. It can have trouble getting back to it's calibration start position if you have a lot of backlash.

It sounds like your power died or you hit track limits? (Again something you can set in eqmod).

Hth

Louise

ps there is a useful eqmod pdf here 

[Stub Mandrel]

Well, disconnecting the power by sitting on the battery in the dark didn't help...

The calibration was so far out the mount wasn't moving far enough to calibrate it at first.

In the end I got it working, came back and it stopped tracking after 10 minutes.