Jump to content

Banner.jpg.39bf5bb2e6bf87794d3e2a4b88f26f1b.jpg

Improving my PHD2 calibration.


Recommended Posts

I've been getting by seemingly ok with a calibration I did a while back but its time to improve. I've been looking into where I can make improvements today which lead me to read that you can bring up your last calibration details, I've done that and can now see that it wasn't great even though it seems to have got me by - see picture below. I've been watching a good video by 'The Astro Imaging Channel' which has explained  some good things about PHD2 and showed what the calibration details should look like for a decent calibration. So along side doing my own reading up which can easily confuse me still, I would like to get an understanding of my next steps to improving the calibration when next out. I'm still to this day a little confused about the settings I need, and i need to get a simpler understanding of the exact settings in PHD2 to allow me to get the best calibration for my setup. I know I need to calibrate at the celestial equator and towards the south, it also appears I could have some dec back lash which I've been reading how to clear before proceeding with the calibration so it's mainly getting the settings in PHD2 right. My main confusion is getting the calibration steps to the right amount, from reading the very good 'understanding PHD2 and getting it to work properly' document on here, for my guide pixel scale of 3.44 (225mm fl 3.75 um) I need a calibration step setting of around 2500 and above, but my computed values seem to calculate 1000  It obviously calculates from what I put in above so what should I set for 'calibration steps' and 'calibration distance' to get it to calculate a higher calibration steps setting in the computed values section!? . I'm still also confused over the sidereal setting and guide speed and what they should be set to in both the mount and PHD2, should the guide rate siderale setting in the advanced section of PHD2 guiding, match the sidereal rate of the mount!? 

Anything you can see and can help with from the above info and image provided would be greatly appreciated. I have been doing alot of my own reading but I still get very confused, and still to this day I haven't grasp what the settings should be. 

IMG_20210126_150754.jpg

Edited by Rustang
Link to comment
Share on other sites

I can only make specualtive guesses without the guide log but start here to set a more appropriate guide rate. I assume you have EQMOD. I'd suggest you start over with a new profile using the profile wizard.

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

Then read the best practices:

https://openphdguiding.org/phd2-best-practices/

And always provide a guide log when you need help:

https://openphdguiding.org/getting-help/

  • Thanks 1
Link to comment
Share on other sites

7 hours ago, kens said:

I can only make specualtive guesses without the guide log but start here to set a more appropriate guide rate. I assume you have EQMOD. I'd suggest you start over with a new profile using the profile wizard.

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

Then read the best practices:

https://openphdguiding.org/phd2-best-practices/

And always provide a guide log when you need help:

https://openphdguiding.org/getting-help/

I appreciate your help, thanks. I didn't provide a log because its just the initial calibration that I'm looking to sort then I can continue with improving guiding later. I thought the photo would be enough to do so, so apologies. I will look into what you have mentioned. 

Link to comment
Share on other sites

The guide log includes the calibration and also what equipment you are using. Based on experience I'm guessing you are using the EQMOD driver which has the quirk of defaulting to a guide rate of 0.1x sidereal since that is what I see on the screen shot. That guide rate is way too low. The guide log would confirm that you are using the EQMOD driver in which case the instructions I linked are relevant. If some other sort of mount then you still need to increase the guide rate but the linked instructions would not help you.

The log also contains the raw data for the calibration which does not necessarily graph the same as shown on the screen shot. The raw data helps with the diagnosis.

In any case, adjust your guide rate to between 0.5x to 0.9x then try another calibration.

If you use the profile wizard and enter the correct values it will calculate the right calibration step size for you.

  • Thanks 1
Link to comment
Share on other sites

1 hour ago, kens said:

The guide log includes the calibration and also what equipment you are using. Based on experience I'm guessing you are using the EQMOD driver which has the quirk of defaulting to a guide rate of 0.1x sidereal since that is what I see on the screen shot. That guide rate is way too low. The guide log would confirm that you are using the EQMOD driver in which case the instructions I linked are relevant. If some other sort of mount then you still need to increase the guide rate but the linked instructions would not help you.

The log also contains the raw data for the calibration which does not necessarily graph the same as shown on the screen shot. The raw data helps with the diagnosis.

In any case, adjust your guide rate to between 0.5x to 0.9x then try another calibration.

If you use the profile wizard and enter the correct values it will calculate the right calibration step size for you.

Thanks, I plugged my mount (HEQ5 Pro) into the laptop and yes the the guide rate was 0.1 for both RA and DEC in EQMOD so will keep an eye out to change that each session to what you have mentioned, i will probably start with 0.5x and I'm guessing that needs to be the same setting in the advanced guide settings in PHD2!?.  For now, with what you have mentioned and what Ive read I think Ive got enough to go on to try and get a better calibration, if i cant then I will post the logs of my next attempt. Thanks again for you help, I had a massive struggle at the beginning to begin my guiding journey and I was bound to miss some settings etc and its hard to decipher what I need out of the internet sometimes because i still find it over whelming, this forum has made the journey possible though, I owe my recent images to everyone on here!.

Edited by Rustang
Link to comment
Share on other sites

Once you've changed guide rate in EQMOD it should stay that way for future sessions.

Going on memory, I think PHD2 only reads the guide rate when you create the profile with the wizard. After that you would have to change it manually, in the advanced settings calculator, to the value in EQMOD One of the many reasons for creating a new profile with the wizard.

PHD2 is constantly being imprved so a lot of what is on the internet is out of date. The best place for information is the official web site and support forum.

  • Thanks 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.