PHD Guiding Help

[AlistairW]

Hello,

I am trying to learn what to do with PHD - I am guiding a 81mm refractor with a 210 focal length 50mm finderscope and QHY5L-II guidescope. The graph I got last night is below. I have a few questions:

- This screenshot shows Dubhe - it is very bright - is this correct, or is my focus out ?

- The tracing on the graph looks ok to me, are these values ok for a HEQ5pro and the 210 focal length finderscope I am using ?

- Although I found it easy to guide on this particuar star. I did try others only to get the message that they were not moving enough. I put the calibration steps up to 3000 (from 1050) but just did not have any luck last night.

any comments appreciated ....

Thanks

Alistair

[Zakalwe]

The graph looks fine, but the real test is how the stars look in the actual image. They should be tight and sharp.

• Try upping your guide exposures a bit. 1.5 seconds is a wee bit short and you can end up "chasing the seeing".
• Don't guide on an everly bright star- you can open a window (under Tools) that shows the star profile. Pick one that doesn't have the top of the FWHM profile chopped off. Alternatively just let PHD pick a star for you.
• You will have to up the calibration steps for a finderguider as the FoV is very wide.
• Make sure that PHD is communicating with your mount. You can open a Manual Guide window (again under Tools) which will open a mount control box. Click and hold the arrows and watch the guide window. You should see the star starting to drift. If not, then the guide commands aren't getting through to the mount.
• Finally, make sure that you aren't trying to guide on a hot pixel. I've been there and done that . Taking darks helps a lot too, and it only takes a few seconds.

[red dwalf]

looks ok to me, bright stars will look big on the screen, a good idea is to fit a cheap ir cut filter to the guide camera, this helps sharpen the stars and cut down the bloat.

as for the calibration steps, PHD 2 does a good job of working them out for you, click on the brain, bottom middle of picture, and go to the guiding tab, PHD will sense what size the pixels are on the guide camera and they should be displayed in the box, then enter the focal length of the guide scope in the relevant box and PHD will work out the steps needed, don`t forget also that scopes balanced on the mount well help, but looking at your graph it doesn`t look bad, i would add that poor seeing conditions will affect the graph, i usually go for 2 second exposures, also darks help will a better picture, it should have asked you if you want to do darks when you first set up PHD, if not you can add them by clicking the darks tab.  

[AlistairW]

Thanks for those suggestions - will give them a try.