Jump to content

Canada's top-tier Telescopes & Accessories
Be as specific as possible when reporting issues and *ALWAYS* include the full version number of the application you are using and your exact *CAMERA MODEL*
  • 0

Using PHD2 Log Viewer to analyse a BYE / PHD2 session





I am using PHD2 Log Viewer to examine a PHD2 log recorded recently while I was imaging with BYE.   In the viewer it is possible to have highlighted sections of the log that relate to data points acquired while the mount is settling following a Dither command.   It is possible in principle to identify the data points to be highlighted / ignored within Log Viewer either parametrically or by means of PHD2 Server API events recorded in the log by PHD2 Guiding provided that PHD2 Guiding is appropriately invoked by the calling application.


My understanding is that BYE does not used at present call PHD2 Guiding in Server mode so to exclude settle period data points  it is necessary to set appropriate values for the two parameters 'Settle at < x.x pixels'   and  'For yy seconds'  in the PHD2 Log Viewer, under the Settings menu.


My questions are:


a)  Should these two parameters be set exactly as the two parameters  'Settle dither at'  and 'Calm down period'  within the Dither Section of the BYE Settings Panel?


B)  Do you have any plans to amend BYE to call PHD2 in Server mode:  It occurs to me that it would probably not be a very major change to change the mode that BYE uses to call PHD2 guiding and possible also to include an option in the Dither Section of BYE whereby the user could choose which mode is used when PHD2 is called if this would be appropriate? 



Thanks for an excellent application.


Best regards




Link to comment
Share on other sites

  • Answers 3
  • Created
  • Last Reply

3 answers to this question

Recommended Posts

Hi Mike,


I do not have plans to amend the PHD interface as of yet, but plans do change over time :)


I'm not sure if these should be the same in PHD and BYE; I never used these parameters in PHD; I would guess they need to because otherwise BYE may start the capture sequence too soon.


I hope someone with PHD2 experience with these parameters and BYE can chime in.



Link to comment
Share on other sites

Hi Guy,   I had an email from Andy Galasso a while back on this topic which prompted my question to you.
PHD2 has two server modes -- the older PHD1 compatible mode and a newer mode.  In the older mode the imaging application is responsible for determining when settling is done after a dither. In the new server mode, PHD2 decides when settling is done and tells the imaging app.
Backyard EOS uses the old PHD1 style communication method, so although PHD2 knows about the dither it does not know when BYEOS has decided that settling is done.  Thus PHD2 Log Viewer does not have the information either.
There is a setting in PHD2 Log Viewer (File => Settings...) where you can enter the parameters to match BYEOS:

Image deleted


If you put in the values that match BYEOS then the log viewer will exclude the settling frames and it should correspond closely with BYEOS.
Link to comment
Share on other sites

I don't know how the PHD1 protocol worked, but IMO the PHD2 protocol is not optimal. Here's why...as soon as a client connects to the PHD2 server, PHD starts sending unsolicited messages that the client (BYE) must deal with, even if only to throw them away. I have rarely seen a server-side app work that way.  Usually the server is silent and waiting for a client request which it responds to.  The only exception may be when a client would connect and tell the server that they want to be notified when specific events occur. Only in that case would the server send event notifications to the client.


My point is that it may be slightly more than a simple change to for BYE/BYN to accommodate the updated protocol.  It is much simpler for you to keep the settling parameters between PHD2 and BYE in sync manually. I would not expect that they would change very much once set.


From watching how BYE does dithering, I believe that the correct answer to your question a) is YES.


BYE's "settle dither at" parameter and "calm down period"  seem to correspond to PHD2's settle parameters, as follows:

  • pixels - maximum guide distance for guiding to be considered stable or "in-range"
  • time - minimum time to be in-range before considering guiding to be stable

While settling, PHD2 measures the distance between the new lock position and the guide star. Once that distance has dropped below the "pixels" threshold, PHD starts the "calm down"
timer. Once the timer value exceeds the minimum "time" value, PHD2 sends a "Settle Done" event to BYE.


It is certainly simple enough for you to follow Andy's advice and sync up the values, and then see if the data points collected during dithering are correctly annotated in the Log Viewer output.

Link to comment
Share on other sites


This topic is now archived and is closed to further replies.

  • Create New...

Important Information

This site uses cookies to offer your a better browsing experience. You can adjust your cookie settings. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to the use of cookies, our Privacy Policy, and our Terms of Use