PHD2 Unveiled: A Guide to Understanding Your Guiding Data 📊✨

[@LiamMcDermott-r9w]

Another great vid! Looking forward to Part 2!

[@Hidden.Light.Photography]

Thank you! I am hoping for very soon and then follow that up PEC training :)

[@NeilW210]

Thank you Tony, this is the most useful PHD2 I've seen (so far). Can't wait to see the "live" one.

[@Hidden.Light.Photography]

Thank you and you are very welcome! This means a lot :) I will put out a community post when I start producing it.

[@gerardford1116]

Anthony, this was excellent! Clear and concise definitions of the data and settings!

[@Hidden.Light.Photography]

Thank you!! I appreciate your kind words :)

[@Daniel_DP83]

6:30 The total RMS is like the pythagoras formula c² = root (a² + b²) = 0.10 = root (0.06² + 0.07²)

[@Hidden.Light.Photography]

That is exactly how total RMS is calculated, awesome job :)

[@kgid8011]

Thank you so much for the video and your very clear explanations. Guiding has been taking the fun out of it for me, feels like when I finally get a clear night I’m looking just at the computer screen, never the beauty above. I get that sometimes there will be times of dealing with the equipment but lately guiding troubleshooting has just consumed me. I really appreciate your help on this subject!

[@Hidden.Light.Photography]

You are very welcome and I am very happy this has helped! Have you had a chance to try any of this since watching?

[@kgid8011]

@ no I have not

[@Hidden.Light.Photography]

No worries, let me know when you’re able to try and if you need any help :)

[@michaeltweedy4370]

Thanks for this. Its something i have also been meaning to address for quite a while.

[@Hidden.Light.Photography]

You are very welcome! Are you getting consistently high total RMS?

[@richardcullip8468]

Thanks for the PHD2 Guiding parameter walkthru. Looking forward to the recorded live session to see your on-the-fly adjustments

[@Hidden.Light.Photography]

You are very welcome! I’m looking forward to recording it :)

[@darle94]

Bonjour. J'utilise le PecPredictif dans l'onglet algorithmes...cela fonctionne très bien. Merci à toi pour tes excellentes vidéos.. Patrick de France

[@Hidden.Light.Photography]

Good evening, yes, the PEC training does work very well :) We will also be doing a video on that after this. I’m happy to hear you are enjoying the content. Let me know if you have any requests :)

[@paulsmaglik5063]

Awesome intro

[@Hidden.Light.Photography]

Thank you!!

[@jimwaters304]

Useful PHD2 video. For my Losmandy G11G I need to set my DEC Aggression to between 70 to 80 to get acceptable guiding and dithering. Thanks Tony.

[@Hidden.Light.Photography]

Thank you and you are very welcome! Yes, that is a very good point. It’s truly amazing how different mounts have different “personalities” and prefer to be handled certain ways. DEC is one that should rarely move, but some mounts prefer high aggression whereas others prefer lower aggression :)

[@AstroCapture325]

Thanks for the video Tony. What are your thoughts on how long the exposure time should be for the guide camera? I see in your scenario it is set at 1.0 seconds.

[@Hidden.Light.Photography]

You are very welcome! I like to use 1 second. I feel I get much better guiding off of that and that is going between either my Orion Starshoot camera or ASI585MC with Orion 50mm guide scope and either my EQ6R Pro or AVX. I like to think of FWHM or lucky imaging. During bad seeing, our FWHM during deep sky can grow because the turbulence is distorting our images. The longer exposures give enough time for the turbulence to “smear” the stars thus increasing our FWHM and hindering the quality of the night’s captures. During lucky imaging, we’re using video because those short exposures are quick enough to sneak past turbulent moments and we use the captures that were able to get through the turbulent atmosphere (seeing). Using 1 second exposures allows the opportunity to reduce the seeing effects. Yes, we are picking up more movement, but we aren’t distorting the guide star. This is also where multi star guiding comes in because even though the shorter exposures pick up more guide star movement from seeing, but it’s being averaged out over multiple stars. I hope this helps :)

[@KJRitch]

Will you be discussing the other algorithm, Predictive PEC? I use that on my AVX. I find it seems to work better than Hysteresis. I’m still plugging away with my AVX. I get semi random DEC spikes. dEC will be cruising along nicely at 0.6” then suddenly spike up to 4” or greater then flatten out then drop down to the zero line. pHD2 is sending pulses like crazy. The spike looks like a table top mesa. I’ve decided to strip down the DEC and R, clean the parts and lube and reassemble. I installed my C8 on the saddle while setting the worm. I haven’t had an opportunity to test due to weather. I’ve decided guide exposures between 0.5 secs and 1.5 seconds work the best however one night I found 2 seconds worked better. My guiding is harder due to using an OAG. Will you discuss the calibration procedure? 99% pf the time my AVX fails calibration, orthogonal angle and backlash are out of spec. After several attempts I just accept the calibration out of frustration. Despite these issues I manage to get 5 minute exposures without loosing too many frames. I check each frame focusing on a couple of stars and comparing them with the preceding frame using ASIFitsViewer. I can “blink” through the frames. Each frame gets autostretched. I use the RMS error number in the frame title from NINA and if it gets above 1.20” I check very closely. Any frame under 1” seems to have round stars although they could be bloated.

[@Hidden.Light.Photography]

Absolutely :) I plan on a PEC video as well. The AVX is a very temperamental mount and takes some careful adjustments to guide. The scenario almost sounds like a setting issue fighting with PHD2, except the fact you are getting guide commands to try to correct. There’s a few possibilities. I used to get similar and what I found was in CPWI, there is an option to track in RA and DEC or just RA. I selected to track in just RA and that resolved mine. Another possibility is DEC may be losing connection periodically. That would cause DEC to drift off (even though DEC is rarely guided, the AVX DEC axis is the most troublesome). PHD2 sees that and issues commands to recenter, but the mount isn’t responding and then connection restores which results in the guide commands finally being obeyed and the axis brought back to 0. I wouldn’t say stiction since the axis isn’t overshooting. Have you tried another cable that connects to the DEC axis? In other words, the “phone jack” cable that the AVX has that plugs the DEC encoder to the main board?