Has anyone sucesfully used PHD2 and an EQM-35 Pro ....together....at the same time?

[Astro_mark_c]

I've just gotten the EQM 35 pro, ZWO 40 f/4 mini scope and zwo asi120mm mini camera for guiding.  Just waiting for my USB cable to arrive so I can update the handset.  If I have any issues I'll be sure to ask here!

[Astro_mark_c]

On 29/08/2020 at 06:42, Seelive said:

The camera connects to one PC USB port and the hand controller to another (or if you're short on PC USB ports you can use a USB hub). If you have the newer hand controller version with the USB socket then the PC can be plugged directly into it.  If it has the older RS232 interface then you will need to get a USB to RS232 converter (unless your PC has a RS232 port). In both cases you will need to download and install the ASCOM driver from the Skywatcher website https://skywatcher.com/download/software/ascom-driver/ before PHD2 will talk to it.

i missed this that's great to hear!

[MartinB]

I have finally managed to get out with my EQM 35 Pro for a guided imaging session. I have previously done some observing and have tweaked the backlash.  I was unfamiliar with EQmod.

I was using a zwo mini guide scope with a 120mm f/l and a Lodestar camera to guide an asi 1600 cam with a Canon 200mm lens.

I chose a star near the celestial equator to calibrate and did a North nudge with eqmod prior to starting calibration.  Also I turned off Dec backlash compensation in eqmod since phd sorts out backlash.  The calibration went OK with phd doing a nudge at the end of the dec calibration to bring the star back into position  exactly as expected.

After sorting out a couple of gremlins (a severe saw tooth pattern as phd oscillated between guide star and a rogue hot pixel, and undercorrecton in ra  owing to too low guide correction rate set in eqmod, things ran pretty smoothly.

I have now done a bad pixel map and next time will run guide assistant to help optimise settings.  However I am happy with the way the mount performed.  It did have a lot of dec backlash when I first got it but I reduced this without too much trouble.

For some reason guide logging was turned off.  I have corrected this and have downloaded Andy Galasso's log inspector program.  I will report back with more objective info after another session, hopefully soon!

[JoeRPatrick]

On 25/09/2020 at 08:25, MartinB said:

It did have a lot of dec backlash when I first got it but I reduced this without too much trouble.

How did you do this?

[Newforestgimp]

12 hours ago, JoeRPatrick said:

How did you do this?

Yes how indeed?

I saw mention in an earlier post of the guide rate setting in EQMOD being low at 0.2.... what should that setting be ? So far im going with the Trevor Jones school of thought and not stressing too much about the numbers but would like to get a stable flat saw tooth rather than a sine wave saw tooth hunting above and below the centre axis. Been happy with the images so far but its nice to know what settings to use to start out with.

[JoeRPatrick]

1 hour ago, Newforestgimp said:

Yes how indeed?

I saw mention in an earlier post of the guide rate setting in EQMOD being low at 0.2.... what should that setting be ? So far im going with the Trevor Jones school of thought and not stressing too much about the numbers but would like to get a stable flat saw tooth rather than a sine wave saw tooth hunting above and below the centre axis. Been happy with the images so far but its nice to know what settings to use to start out with.

So I had a look for myself and took the cover off the DEC motor.  

The gears had a fair bit of play so I adjusted the screws and nudged things about a bit and now it seems to have a fair bit less play.

Going to have to wait to Wednesday by the looks of it for a clear night to see if this actually makes any difference though

Edited February 19, 2021 by JoeRPatrick

[MartinB]

1 hour ago, JoeRPatrick said:

So I had a look for myself and took the cover off the DEC motor.  

The gears had a fair bit of play so I adjusted the screws and nudged things about a bit and now it seems to have a fair bit less play.

Going to have to wait to Wednesday by the looks of it for a clear night to see if this actually makes any difference though

Yep, that was pretty much what I did.  This took out the slop in the system and PHD was easily able to take up the backlash after doing this.  It is important not to over do things because the gears can bind.  Best fully slew to check everything still runs smoothly.

 

[MartinB]

3 hours ago, Newforestgimp said:

Yes how indeed?

I saw mention in an earlier post of the guide rate setting in EQMOD being low at 0.2.... what should that setting be ? So far im going with the Trevor Jones school of thought and not stressing too much about the numbers but would like to get a stable flat saw tooth rather than a sine wave saw tooth hunting above and below the centre axis. Been happy with the images so far but its nice to know what settings to use to start out with.

I'm fairly new to PHD2 myself having used the excellent guide tool incorporated in Maxim for years.  With my widefield imaging outside the observatory I am using SGP with links with PHD2.  Far and away the best guide I found was this video on youtube https://www.youtube.com/watch?v=LXFGRta98rs  It is long but well worth watching, all the way through and taking a few notes.  There are no "magic settings" so it is difficult to advise on optimal guide rate settings and such like.  Generally the default settings will do the job but if you have a more demanding situation e.g. long focal length, or a problematic mount you will need to tweak.

 

[MartinB]

The EQM-35pro is an excellent little mount and will work very well provided it's limitations are respected.  Obviously it shouldn't be overloaded.  Make sure to turn off any dec backlash corrections in Eqmod!  Mine doesn't track quite as well as my CGEM but is much easier to lug around.  I am using it for short, widefield imaging using a 200mm lens and a ZWO mini guider scope.  It behaves very well in this undersampled situation.  I wouldn't put my 10" SCT on it!  Short focal length refractors are perfect.

A picture paints a thousand words so here  is IC1396 taken with this set up.  The mount never missed a beat.  

 

[Newforestgimp]

1 hour ago, MartinB said:

The EQM-35pro is an excellent little mount and will work very well provided it's limitations are respected.  Obviously it shouldn't be overloaded.  Make sure to turn off any dec backlash corrections in Eqmod!  Mine doesn't track quite as well as my CGEM but is much easier to lug around.  I am using it for short, widefield imaging using a 200mm lens and a ZWO mini guider scope.  It behaves very well in this undersampled situation.  I wouldn't put my 10" SCT on it!  Short focal length refractors are perfect.

A picture paints a thousand words so here  is IC1396 taken with this set up.  The mount never missed a beat.  

 

WOW ! something to shoot for indeed !!
How do I turn off any backlash corrections in EQMOD ?

[michael8554]

22 hours ago, Newforestgimp said:

I saw mention in an earlier post of the guide rate setting in EQMOD being low at 0.2.... what should that setting be ?

The PHD2 site has  many links to instructions and fault finding, but few people go there, instead they look at random videos on YouTube..........

https://github.com/OpenPHDGuiding/phd2/wiki/EQASCOM-Settings

Michael

[MartinB]

3 hours ago, michael8554 said:

The PHD2 site has  many links to instructions and fault finding, but few people go there, instead they look at random videos on YouTube..........

https://github.com/OpenPHDGuiding/phd2/wiki/EQASCOM-Settings

Michael

That is a nice link.

Worth saying that the youtube link I gave is not a random video but is Andy Galasso, one of the key PHD2 developers, giving an in depth talk on all the features of PHD2 and how to fully optimize guiding.  Some people will find this easier to work through than the written documentation.

[Newforestgimp]

48 minutes ago, MartinB said:

That is a nice link.

Worth saying that the youtube link I gave is not a random video but is Andy Galasso, one of the key PHD2 developers, giving an in depth talk on all the features of PHD2 and how to fully optimize guiding.  Some people will find this easier to work through than the written documentation.

Thank you both, FLO gave me a basics check sheet which pointed also an ASCOM EQMOD starting point too.

so I’ve gone back to basics, reset phd2 and just changed the tracking rate in ascom as advised by the articles.

will run a guiding assistant session next time I have relatively clear skies, to see what setting suggestions to backlash and aggression etc phd makes.

[michael8554]

19 hours ago, MartinB said:

Worth saying that the youtube link I gave is not a random video but is Andy Galasso, one of the key PHD2 developers,

I was generalising, your Andy video is not at all spurious.

Michael

[Newforestgimp]

Just thought I'd provide a little feedback after applying the best practices advised in the link. I had clear skies last night so rather than gather subs I decided to do a pure guiding analysis and fine tuning.

My EQM-35 is un-fettled, as is, out of the box but I'm pleased with the results so far, no Sine Wave tracking in evidence just pulses hunting along the central 0" reference line. I started by making sure the balance was slightly counter-balance heavy & checking and setting the guide speed in EQMOD Toolbox as suggested to between 0.5 & 0.9, I chose 0.8, it was set at default value of 0.1. I didn't make any further adjustment to this value on this occasion, I may reduce by 0.1 next time out and see if it makes any improvement.

I then ran several (at least 4) guiding assistant runs and adjusted the focus, min/max values and exposure value as suggested by the assistant. I then proceeded to run a guiding session for 2 or 3 hours making changes to the exposure value trying to discern which seemed to give the most consistently low RMS value, I settled on 2.5 seconds. This seemed to achieve a very steady 1.10 - 1.20 RMS value, whilst not superstar noteworthy sub second, it was the consistency that I was after and therefore consider last nights session a success.

Baby steps....

[MartinB]

1 hour ago, Newforestgimp said:

Just thought I'd provide a little feedback after applying the best practices advised in the link. I had clear skies last night so rather than gather subs I decided to do a pure guiding analysis and fine tuning.

My EQM-35 is un-fettled, as is, out of the box but I'm pleased with the results so far, no Sine Wave tracking in evidence just pulses hunting along the central 0" reference line. I started by making sure the balance was slightly counter-balance heavy & checking and setting the guide speed in EQMOD Toolbox as suggested to between 0.5 & 0.9, I chose 0.8, it was set at default value of 0.1. I didn't make any further adjustment to this value on this occasion, I may reduce by 0.1 next time out and see if it makes any improvement.

I then ran several (at least 4) guiding assistant runs and adjusted the focus, min/max values and exposure value as suggested by the assistant. I then proceeded to run a guiding session for 2 or 3 hours making changes to the exposure value trying to discern which seemed to give the most consistently low RMS value, I settled on 2.5 seconds. This seemed to achieve a very steady 1.10 - 1.20 RMS value, whilst not superstar noteworthy sub second, it was the consistency that I was after and therefore consider last nights session a success.

Baby steps....

A text book description of how to properly get to grips with PHD2, excellent!

[Newforestgimp]

Thank you, Appreciate the confidence boost 👍