Can PHD2 Determine Mount P.E.?

[Jim Waters]

Can PHD2 Rel 2.6.3 determine a mounts RA Periodic Error?  

 

If so how?  Thx

[Andy Galasso]

Hi Jim,

Can you clarify what you are looking for?   PHD2's Guiding Assistant will measure the magnitude of your PE and estimate the steepest slope of the curve, but if you are looking to program the PE in your mount then you'd need some other tool for that. On a related note, PHD2 has a new guide algorithm that can measure and predicatively correct for PE on the fly.

Andy

[Jim Waters]

Just curious to know the P.E. of my mount. Is the Guiding Assistant 'Right Ascension Peak-Peak' the same as P.E.?

[Andy Galasso]

Jim,

The Guiding Assistant RA Peak-Peak measure will tell you roughly how large your PE is, but the overall magnitude may not be the most important factor for how effective your RA guiding is going to be. For example, you could get better guiding with a mount that has a large but smoothly varying PE versus a mount that has lower total PE but has "spiky" rapidly varying sections of the PE curve. (The Guiding Assistant's RA Max drift rate value estimates the steepest part of your PE curve.)

Generally speaking, it can be very helpful to look at a graph of your PE.  If you have run the Guiding Assistant, open your PHD2 Guide Log in a log viewing app such as PHD2 Log Viewer. Look at a graph of your un-guided RA tracking (the section of the log where the guiding assistant was running) to get an idea of how your mount's RA tacking behaves.  Make sure you run the Guiding assistant for at least a full worm cycle.

You can also load your PHD2 Guide log into a dedicated PE tool like PECPrep to get a frequency analysis of the PE curve.  But for starters, just looking at the curve can be very informative.

If you want to upload a guide log from a session where you did a Guiding Assistant run, then we could help you analyze it.

Andy

[Jim Waters]

Thanks for taking the time to reply.  

Jim