PHD2 trick for BETTER GUIDING! (Not multi-stars)
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- čas přidán 9. 07. 2024
- Sorry for the meme-ish thumbnail :) Title is of course a parody of the "Doctors hate this trick" meme!
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00:00 Introduction
00:38 The symptoms
06:09 The solutions
08:05 The actual trick
11:06 The results
13:00 Conclusion - Věda a technologie
You are a legend Cuiv. Why am I only hearing about this now? Can't wait to give this a go. Thanks
Hope it works out for you!
You really do a great job of explaining things so that us newbies can understand the problem you are solving. Thanks for another great video.
Really happy to see such feedback, thank you :-)
I thought you were gonna talk about the east heavey method and almost didn't watch the video. Never heard of this method so thank you very much. Glad your back.
Great video as usual. Your contributions to amateur astronomy community have been incredible I can't thank you enough.
Thanks Rich! Although the PHD2 dev deserves all the acclaim!
Discovered this algorithm back when I had my CGEM, didn't help too much, but it really did when I got my EQ6R.
It's really mount dependent, glad it's working well now!
Note that KStars has this as well; I also just implemented a feature to decouple the predictive corrections from the guide camera corrections, so you can take long guide exposures if necessary, while responding to predicted PE much more frequently :)
That is awesome to hear Sophie, and yes that's a great feature, keeping with the predictive corrections while the next guide image is being taken :-)
So glad your back! You make my day. 😊
Thank goodness your back Cuiv, as well as turning me on to N.I.N.A your videos have steered me through most of the problems I have come across as a beginner astophotographer. Thanks for all your time ,effort , and enthusiasm.
Glad it's helpful!
Maan! So happy that you are back!! Thank you!
Glad to see you back Cuiv, rested and sharp. Great vid, as usual^^
I'm using it since its implementation on a SW AZ-EQ6 with a SC 8", which cut my RMS and peaks in half.
NB : polar alignment, weight distribution and calibration must be perfect.
I m so thankful that there are people like you out there. What a legend !!!
So great to have you back to making astrophotography videos again, Cuiv! I've always learned so much from you and this video is no different. I will be giving this a go next imaging session. Thanks for all of your help and tips over the past couple years. Take care, Cuiv.
Delighted you are back making videos Cuiv 😊
Keep up the fantastic work. Absolutely great video. Demystified some things for me! Gave me confidence to delve into the guts of PHD2.
Absolutely amazing to have to you back mate! Just learned something new from you (again)… Will implement this as some as weather improves here in Melbourne … now I have to remind myself how to turn off PEC corrections from my mount - EQMOD😂
That little change is amazing. My guiding went from about 0.85 arcseconds to about 0.55 arcseconds. absolutely amazing!!! thanks for the tip.
Awesome! Super happy it might such a large difference!
Thank you Cuiv ! As always useful information!
Another great video Cuiv I'll be using this setting in PHD2 next time I image as my guiding can be very hit & miss sometimes, thanks for your time uploading & explaining this clear skies!!
Good luck!
What a great guy! Thanks for still MORE helpful information I can put to work easily and quickly. And I’ll even sort of understand what I’m doing!
Brilliant, Cuiv! You’ve changed/ improved our imaging forever! Award this man a medal!
Thanks for the feedback as always Melvyn :-)
Excellent - cant wait to put this to use! As a beginner in the hobby I cant express enough appreciation for your videos - thank you Quiv!
Glad it's helpful!
Thanks Cuiv! What a brilliant educational vid. I will try out this PPEC on my SW HEQ5 Pro Mount the next time i'm imaging
I am happy to see your videos back. Theorical and practical is what I love. This is what defines an engineer. Keep going.
Thank you - I'm glad to hear my long-winded explanations are appreciated :-)
Thank you Cuiv, I have been using PHD2 for years but was not aware of this. I will try it next session. You have a great way of explaining things and this is very helpful.
Hope it works out well for you :)
Awesome! I've been using periodic error correction in EqMod up until now but I've had to manually re-record it every time I set up my rig for a night of imaging. Being able to tick a check-box in phd makes so much more sense. Thanks and keep up the great work - it's really appreciated by us noobs!
Enjoy the new lazy method ;)
This video dropped just in time! I literally looked up which PHD2 algorithms were better to use a couple of days ago and ended up settling for PPEC, which was one of the most recommended. Glad to know how that works now :)
Thanks for the informative video. I have a really beginner level mount and this trick seems to help. I'm glad that you are putting out video's again. Keep up the good work.
Glad it was helpful!
Fantastic information Cuiv. I have learned a lot from watching your videos. You rock it!
Thanks Vince, glad it's been helpful!
Amazing tip Cuiv! I cannot wait to try this. I've always suspected a slight issue with the worm gear on my EQ6. I had no idea about the Log viewer, now I can check it out and see what's going on. Thank you!
I hope it makes a difference!
You keep making us smarter! Thank you.
Thanks so much for sharing this Cuiv! I have some eccentricity in my EQ6R RA motor that causes a 120s PE that I can't get rid of with the mount's bulit in PEC, and this should be a great way to deal with that. BTW you probably know that is but you can use the "analyis" feature in the guidelog to look at the period of that sine wave.
Cuiv, there is nothing lazy about the depth of what you’re sharing and for the engineer audience you can’t say too much! Now i have to wait for the next clear night to give this a try. Thank you!
Hope it works out well for you!
Great video. I've known about PEC and PPEC since researching mounts when first getting into AP. But it all seemed too technical to get into and because my guiding (for the most part) was fine. After watching your video I realise that I can flick the switch in PHD and do the job there. Thanks Cuiv
Glad it helps!
As usual another great video Cuiv. Thanks for taking the time to pull it together. BTW - You should enable DEC Backlash Compensation and back-off on your Resist Switch Aggressiveness a bit.
Thanks Jim! I've had bad experiences with the backlash comp in the past, and with the CEM60 meshing that can be variable depending on the clutch I'm wondering if it would work well... I'll have a look!
0.51 RMS total is a great result. Thanks for going over this.
Thank you!
Appreciate all you do for the astro community. Thanks, Cuiv !!
Glad it's helpful!
Thanks for the tip. I will try this out. I am trying to guide out a C14 and the RA does show some periodic fluxes. I hope setting to predict PEC setting will help.
Cuiv, very well done explanation of cause and effect. This was done so well, I would suggest you consider doing slightly expanded version some Sunday on The Astro Imaging Channel (TAIC). They are always looking for great presentations.
Awesome! I will definitely do this. I have a CEM 60 and have really wanted to have it guide a little better. Thanks!👍
Go for it!
Great work putting this out there Cuiv! - I'll be giving it a go for sure! :-D
Clear skies!
Thanks Luke! I'll be curious how well it works out for you!
Thanks a lot!!
I use to have to record my pec in the beginning of all of my sessions and loose about 16 minutes ...
I can't wait to try this 👍👍
Excellent tip and explanation. Off to check my PHD2 log.
Have fun!
Great video, Cuiv!!! For those reading, it is possible to right click in the PHD2 log viewer to do a frequency analysis and it will tell you the periodic error to help in analysis. Great for talking with the PHD2 devs or mount support gurus as well!!
Thanks for the additional tip Steve, I didn't know that!
Thank you, Cuiv.
I will certainly give this a shot.
This is amazing sir...❤ always Crystal clear informations.. all the very best sir..❤
Fantastic tutorial with clear explanation! Thank s again!
Glad it was helpful!
Didn't know about that one Cuiv!. Thanks for that, I will definitely be giving it a go next clear night. I do have sine wave discrepancies on my guiding for sure.
Hope it helps!
Another pearl of wisdom. Great video, Cuiv.
Glad it's helpful!
Amazing video description Yannik. Thank you so much for making our hobby easier. Clear skies.
My pleasure, glad it's helpful!
Great job explaining what is going on with Permanent PEC. I was using Pempro for my PEC curves and I was guiding at the same time with PhD2.....I did not realize a battle was going on between the two software systems but that makes sense.....actually too much sense. Keep up the awesome tutorials and there is no need to keep them brief on my accord. R E T I R E D !
It really depends on the mount for how the guiding and the PPEC can fight... iOptrons are famously not great at it!
Thanks for the tip!! Will check my guiding graphs. Whether is crap so it’s a great time to fiddle around with settings and make improvements. Great video hope your skies are clear.
Enjoy!
Great tip! Never heard of it before! Gonna try it soon, thanks!
Enjoy trying it!
I simply love these types of astro hacks! Gonna give it a go on next opportunity! Thanks Cuiv!
My pleasure! Thank the PHD2 devs too :-)
Now if only the acronym for Predictive and Permanent Error Correction weren't both PPEC. Great video on a great phd2 feature, glad to see you're back!
Thanks Aaron! :)
Wow, I was actually thinking of predictive algorithms, more for my Equatorial platform. Didn’t knew PHD 2 already has it. Thanks a ton for this video.
My pleasure, glad it helps!
Very sophisticated and well explained!
Thank you!
Like every one here said: Another great video!!
We missed you !
Question could you explain the chart you show at 1:34 ?
Also, there's no advantage in getting a mount with built in PPEC?
Great video Cuiv. I've been using the PEC algorithm with both my AVX, and Losmandy Gm811G mounts, and found that it can give a tremendous improvement. The losmandy mount works much better when the PEC period is set to the worm period, with "auto" disabled. The AVX works best with the PEC programmed into the mount, and by using PHD2 PEC set to auto. The AVX has much more noise in the mechanics and benifits from using both.
It really does depend on the mount, thanks for the additional tips!
Ha! thanks for this 😊 didn't know about it 🙂
I am looking forward to implementing it into my next session :)
have done a lot of trials on lucky imaging and capturing with my guiding cam while unguided. been trying to figure out the best way to use livestacking as to filter the crappy frames and stacking only the very best using a FWHM filter and also an alignment filter!
Enjoy!
Even though I have a ZWO AM5, I still watched and past it in to the guy that bought my old iOptron iEQ30pro mount (a pretty nice mount too). But, what I appreciated is your comment about going out and do some testing during the full moon. I kinda pass on around 4-5 nights before and after the full moon. Makes sense, thanks!
Hope it works out well for the buyer of your mount!
This is a reason I get 0.5-0.6 on AVX with 25Lb load. I experimented with different algorithms; it gave best results.
That's excellent for any mount, even more so for an AVX!
@@CuivTheLazyGeek This is not “real” AVX. It is just AVX shell (made in 2016). Inside everything (bearing lubricant motor parts) US made, except electronics. I basically remade everything inside. One more thing, I guide with 0.5 sec interval. This very important.
Great information. Thanks for sharing.
My pleasure!
Great explanation! I use this feature but did not know why. Thank you for the theory. It really helps!
My pleasure Amy, nice to see you drop by :)
Fantastic! I’m definitely going to try this on my EQ8R Pro. Thank you! Seems odd that the guiding assistant doesn’t already have this as one of its suggestions!
That's one beast of a mount you have, enjoy!
Excellent video Cuiv! I kind of wondered if ppec and phd2 were fighting each other or not, so I quit enabling ppec. I will try this. Thanks!
Good luck!
welcome back !!!
Thank you!
I love the silly click-bait sub-title in the thumbnail!!!
I'm so glad you got the joke!!! Apparently some were a bit offended by the thumbnail, not realizing it is tongue in cheek!
That comment about looking at the DEC guiding to assess seeing across sessions is something I've noticed too.
It's so easy to get a great polar alignment with today's software that it seems like DEC corrections are few and far between - all that jitter on the guiding error graph is just "seeing" noise. I need to try this, or do the PPEC thing to try to get my RA error close to the DEC error. Thanks for the reminder.
Exactly - seeing... And wind!
Using PPEC and PEMPro together seems to work well with my Losmandy G11 with Gemini. The 240s error is reduced by PEMPro to some degree but the PPEC picked up the most of the residuals. But PPEC does not seem to have the ability to reduce multiple overlapping worm harmonics, e.g. it will handle the 240s error well but not the 120s, 80s or 60s; all fundamentals of the original worm period. A more advanced PPEC that could handle more frequencies at once would really be worth while.
Thanks again for your feedback.
John
Great tip, I will try this, thanks
Very helpful Cuiv .. I will give that a go!
Enjoy!
Great video, Cuiv!!
I've been using PHD2's PPEC algorithm for over 2 years with my iOptron GEM45 mount, and can't live without it now. The guide performance in RA axis is no match when you look at the guide graphs on the guide log side by side, and would highly recommend any of the beginning astrophotographers to use this algorithm on PHD2.
I usually guide with an OAG and the shortest focal length I use is about 900mm+. On such system, I use higher aggression and higher values for retaining the periodic error on the advanced (brain) settings due to terrible seeing conditions in the middle of Seoul.
I would also highly recommend not to use auto find setting for the worm period. I found that guesses the PHD2 is quite finicky, and I sometimes get something like 2.5 times the worm period (how does it guess such a figure!!) and get terrible guiding results if I leave it at auto. I use the worm period in the spec sheet of the mount, and it works perfectly
Thanks for the feedback! You're brave using such long FL in such poor seeing (I think Tokyo and Seoul have equally bad seeing...). Interesting on the worm period, thanks for the tip!
Thanks for this comment. I was going to ask about the gem45 as it is my understanding that it has built in encoders which Cuiv stated might make PEC suboptimal. Based on your experience I will try it myself.
Great advice Cuiv! I have the Orion HDX 110 Mount and routinely get around .52 arc seconds total error, which is already really good so I can imagine what predictive PE might do. I have been known to get a quarter arc second before but I'm not sure why it was so good. I did add around twelve new calibration steps. Perhaps that was it? Thanks for the advice.
thank you, very valuable information!
My pleasure :-)
With the EQ6-r and EQMOD, PPEC and guiding don't fight like they do on iOptron mounts. The combination works great together! The same is true or Astro-Physics mounts.
Thanks Linda,
That was my quesrion for Cuiv. So I’ll try both of them together. Without corrections on my EQ6-R, PHD2Guiding shows an RMS of 0,78”. Let’s try if I can ger this value lower.
Although to be fair, as far as I remember EQMOD does cut off some guide pulses when they conflict with the PPEC (Greenswamp Server has a specific mode to combat this). Might be misremembering though!
@@CuivTheLazyGeek That might be true if you are using EQMOD's PPEC, but I used PEMPro to write a curve to the mount so EQMOD isn't aware of it.
Very nice... Thank you.
Great tip Quiv, didn't know that so have to try this out if I can get some clear skies here in Belgium.
Question though, your title says "not multi stars" but in the video you write to enable multi star guiding ?
Just means that the trick isn't "multi-star", but something else (e.g. Predictive PEC). Basically clickbait :p
great explanation Cuiv, I wish the asiair had this function it would be an actual gamechanger!
I'm sure they'll get around to it :)
Thank You, Cuiv. Little Pearls like this make life better. I'd say after the multi-Star guiding, this can really help automate the guiding process. A friend of mine gave multi-star out as soon as PHD2 allowed it to be given. He was a part of the Beta team helping to work out the release. I do have a question though, why do you have your settings so broad where you show Plus/Minus of 30°? I try to run my graph much, much lower so my graph is choppier. Mainly just curious, because I've observed this a lot when folks start demonstrating their graph's. Or is it to get a much broader view of time? Love your tutorials! I've already applied this to my "Mount Computer" that I use outside. (I remote operate most of the time. I'm old, and the cold bothers me.) Again, Thank You!
You referring to the guide graph scale in PHD2LogViewer? I think the scale defaulted to that when I opened it - also I don't want to scale it too much because then I might start getting obsessed with the guide performance!
Many thanks!
Thanks for that Cuiv, I will give it a go next session. Pete.
On my Skywatcher HEQ5 mount which definitely exhibits PE in RA. I generally get good enough guiding total RMS around 1 arc sec but also annoying “random” excursions in RA up to +/- 4 arcsecs which does seriously affect my images. Pete.
Hope it fixes your issues, good luck!
You sir, are a scholar and gentleman!
Thanks Vipin!
Thanks for yet another great video! Can this be applied to mounts like harmonic drive or those belt driven Avalons? The term PEC still relates to something periodic… cheers
Works only for worm gear systems, so no Avalons or strain wave gear mounts!
I recently upgraded from DSLR to QHY 183 M with the 7 position filter wheel but I'm stuck finding the right fitting to connect my Televue Paracorr type 2 coma corrector to the QHY filter wheel. Any experience with that coma corrector and a Newtonian?
Been using Predictive PEC with my AZ-EQ6 for a while now and it seems to be the best algorithm of the bunch. My RA worm has a very aggressively bad part on it, maybe as much as 10 arcseconds within 30 seconds and it actually still works surprisingly well. I can see a dip in performance once every worm period but its corrected much better than with the simple hysteresis algorithm which really couldn't do anything at all to such a sudden change in tracking rate.
This is really great to hear!
Thanks for sharing this video Cuiv!
You mention "not multi-star" but wich is better to use with Predictive PEC, sigle star or multi star?
Multi-star is always better, regardless of what else is used!
Great video and explanation!
Is Phd2 smart enough to learn this while doing short exposures and dithers, or would it benefit from being left alone to guide uninterrupted for 10-15 min before you start imaging?
As long as you do this without slewing the scope, yes!
This is very useful Cuiv. Have you compared phd2 pec results vs doing a pec training within eqmod?
Heck no! That's far too much work and I already know from the result of the PHD2 PredictivePEC that there is very little room for improvement, so ROI on spending the effort to do so would be quite bad
Fantastic video!! Honestly this has been very useful and I look forward to seeing if I can improve my guiding with this method… however I use ASiair plus, do you know if the ASiair has this setting? I’ve not noticed in the settings, but I do notice a similar wave pattern on my guiding… I use an EQ3 pro mount. Thanks
I don't believe it's in the AA yet - you may want to petition ZWO to get it added ;)
@@CuivTheLazyGeek ah ok thanks Cuiv, I think I may have to try PHD2 guiding by itself in one of my next few sessions. My guiding has improved a lot recently by carrying out PA at least twice and making sure that I calibrate the guider everytime. But I do still notice the wave pattern. I could never figure out what could be happening so I’d try adjusting the aggression but ultimately because the guiding is usually around 0.7 arc seconds I haven’t been too troubled. But a fantastic video that really makes you realise there is much more to many aspects of AP than you would at first think. I never considered impurities in the worm and I do have one of the cheaper mounts too haha
@@Astroephotography see my reply to Cuiv, you Can access PHD2 log files in ASIair…
I have exactly this problem with AR, but I use ASI AIR, do you know if there is a way to correct it on ASIAIR as you did with PHD2?
Interesting Video. Just wondering do you keep it set on the "predictive PEC" option for all future runs or change it back to the other setting?
If it works for you, just keep it set (otherwise it just goes back to the old Algo)
Great video. One mystery for me on all these settings is which software does it in a multi-software environment? I run stellarmate as my core O/S but get it to use PHD2 as the guiding interface. Do I do these settings in PHD2 or Stellarmate, do you know if Stellarmate overides PHD2 settings?
I think Stellarmate would completely rely on PHD2 if setup to use PHD2, so it should be set there
Thank you for all your help with astro gear! I have learned so much from you!
Question: I have aa C14 on the CEM60EC mount (which has RA encoder) Do you know what PHD2 algorithm I should use with the encoder? Would I be better off to turn the encoder off and allow PHD2 to correct for both mount axis errors? I am running at F7 with the ZWO071MCpro camera at bin2 and off axis guider ZWO290mm mini. Thanks
I think a lot of people had issues with sub division errors with encoder + guiding forthe CEM60. You should check on Cloudynights
We love your videos….and you too.
I'm going to blush there Jane :😁
My hero
Does it have some sort of index system to track guiding one session to the next? I know my Celestron mount always seeks the gear index at startup. How does it know where in the cycle it is on a cold start?
It doesn't know, so it actually relearns each time. So it does mean that the first couple of worm cycles will be closer to Hysteresis performance.
Friend: What's that sinusoidal curve right there? Cuiv: I have a bad worm. Friend: Shouldn't you see a doctor for that, worms and all? Great job! I have put ups two todmorden piers so with a quick set up and take down I can now pay more attention to these things that will tighten things up! Thanks!
:D
Nice video as always. I looked for the optional algorithns in the settings and the pull down menu was inactive (greyed out if you will). Is this s version thing or is there another stting that inhibits this? Also, do you have the PEC playback (I have an AVX mount) active when you guide like this?
Did you try while it was guiding? Also PEC playback should be disabled if using that algorithm!
@@CuivTheLazyGeek Thank you. It was guiding. I just looked at it when unconnected and the menu option is there. Somethings seam more obvious in daylight. As soon as the weather cooperates I will disable PEC playback and give is a shot,
I have the same thing on cem26 :) thanks for the trick :)
Excellent!
Did you give up on Antlia ALP-T? I just got mine and can't wait to give it a go
Didn't give up on it - but it's just not a good match to a hyperstar setup!