PHD2 Let's get better guiding! (but don't overthink it either!)
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- Опубликовано: 30 июн 2024
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00:00 Introduction
01:00 Multi-Stars
04:11 Guide Assistant
10:20 Bad Polar Alignment
14:00 Predictive PEC
15:35 Review PHD2 Log Viewer 
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Do you mean 10 arc mins not arc secs?
YES!!!
@@CuivTheLazyGeek mine is only 2 arc mins off and I get good drift for one way guiding….👍🏻
"Poor polar alignment of 10 arc seconds ..." - man, you have a different idea of 'poor' than I do 🤣
Not sure but imo it should rather be something like 10 arc minutes...
I usually find it harder to get it below an arc minute!
Sorry yes I meant arcminutes!!!!! So sorry about this!!
@@jimbob4484 I usually try to get it a below or around an arcminute, and then the final adjustment is just tightening up the knobs in the "error" direction, which gets me very close, and the bonus is that I know everything is tight too.
I have been all over the net looking for someone with your knowledge but also having the ability to explain and teach difficult concepts. As a professional life long teacher, my opinion is that you are outstanding. A hearty “thank you very much” is warranted.
I hope you are enjoying Japan. Just watch out for earthquake and tsunami and /or volcano or whatever else that poor island has to endure.
Guy.
Thanks so much Guy, that means a lot! Sometimes I wish I had been a teacher, since I do love teaching :)
Predictive PEC in PHD2 for me with an eq6 works equally as well as actually recording a pec curve - so highly recommended!
Excellent to hear!
i got 1 more tip ... if your guiding camera rotates even the slightest bit from your original calibration... like say you've been doing planetary and then want to stick it back in the guiding scope and start guiding, then you must do another calibration....
it will make a world of difference and it only should take a couple of minutes ( point your scope at a star along the meridian ... Dec 0 ... +/- 10-20 degrees)
my best results are when using 0.5 secs exposure with multistars enabled/ Svbony 305 using a 30/120 guider
Yes! That is something that is too often forgotten, thank you!
@@CuivTheLazyGeek most welcome Mon Ami!
Great information as always Cuiv!
fantastic video Cuiv, well done! thanks for sharing ....
Excellent job explaining these features as always, Cuiv. Thanks!
My pleasure!
Love tips and tricks!
I took your advice and now get much better guiding by turning off PEC on my AZ-EQ5 and now use predictive PEC within PHD2. Big difference. I now get around .4 to .5 all night.
That's awesome, great to hear!!
Awesome.. and the finalmost advice fully agree.. can try that during moonlight.. limited amount of clear skies. Thank you
Ashvn
This is the video I’ve been looking for. I’m pretty sure this is going to help my setup. Your explanations make complete sense. Thanks for these tips Sir!
Hope it does help, and don't forget to wait for the full moon to test so you don't waste time!
thank you for your continued videos. I am learning, slowly lol, from your great explanations. Love the look when you say "because the earth rotates".😅
I'm really happy to see my videos can be helpful!
Cuiv always delivers
Super video Cuiv!! 😀
Thanks Luke!!
thank you cuiv!
My pleasure :)
The additional tip to deselect "Auto-adjust period" at the 14:44 mark, made a huge difference for the better when using the Predictive PEC option. PHD2 was off by a bit in its calculation, and entering the value provided by the manufacturer was like magic for my guiding performance. Ioptron CEM70 worm period 348 sec. Thanks for the tips!
Awesome, thanks Michael!
Its great to see you back....
Great to be back ;)
Poor polar alignment is great idea. I’ve got to wrap my head around how to set it up to pull up from the east pre-meridian for example.🎉
Always enjoy your videos!
If I’m tracking with a non-go-to mount, and disabled the declination action, will the guiding assistant still help?
Another excellent video😊
It may be obvious but found in last few sessions phd2 was often complaining, (I had been very “lazy”with cables. Tidying up the cables improved phd2 results, images were better and even mount sounded happier when slewing to target
Great tip! Very true :)
Another excellent video
Thanks!
Genius! Thanks enormously!
My pleasure, as always!
Thanks!
Thank you for your support Nahid!
I had some issues with not enough stars as I am using an OAG on a SCT looking at galaxies or other things in sparse star fields. Brian (from PHD2 support) said to disable Star Mass Detection as it was not necessary any more. However, it seems to be on by default. I noticed you have it on. Thank you very much for that huge Dec drift issue mention. One of the other comments on it was before you run GA, give your mount a big nudge towards the north before starting GA as it means starting it without the DEC backlash having to be accounted for. Nice to have your videos as always.
Thanks for the additional tips Stephen! I've had star mass prevent situations when clouds came through and PHD2 locked on some part of the clouds rather than the guide star but I'll look into it!
Can't tell you how good it is to have you back making videos. We missed you, Cuiv!
May I ask how many of these things need to be re-done each session, if we don't have a permanent pier/setup? For those of us who have to setup and take down every time we shoot, should we have to run Predictive PEC and Guide Assist each time?
Guide assistant shouldn't be rerun, PredictivePEC works automatically afaik
Hi Cuiv,
The other shorter periodic errors you get are probably harmonics of the main 300s... you will notice harmonic#2 at 150s, harmonic#3 at 100s, harmonic#4 at 75s...
It means the error is not perfectly sinusoidal
Thanks Stephane!
Oh my! I saw subtitles as i was on your thmbnail. It said "Hi, Cliff the lazy geek here" lol.
Hahaha yeah the subtitles don't like my name (or my accent)
Excellent video, I have been guiding in one direction for some years now with my EQ8, which had bad DEC backlash….👍🏻
Good to hear it's been working for you on the EQ8! That thing looks like a monster though!
@@CuivTheLazyGeek yes it is, but it’s mounted in an obsy so all good….👍🏻
Never knew you could right click that graph!
Thanks! Your Videos are really useful. I just improved my guiding by 0,3" !
Great to hear! Glad it helped!
Thank you Cuiv.Excellent phd tips summary as usual.
I have a suggestion for a cloudy day/night video. What about making video about filter direction with your spectograph ? That could confirm that filters can be placed in any direction or not ?
All filters ? some of them ? We all have filter location and wonder the filter working direction. Your spectrograph can reveal the truth.
I've seen no difference in filter direction - direction really is about reflections and the AR coatings, which isn't something a spectrometer can check
@@CuivTheLazyGeek Thank you for the confirmation
Cuiv,
Thanks for all the great videos.
Questions:
1. Do you turn PEC (or PPEC) off when you run PHD2 calibration ?
2. Do you turn PEC off when you run PHD2's guiding assistant ?
I've been trying to find this information for quite a while !
thanks,
Monty
Another helpful video! Regarding polar mis-alignment, I was thinking the recommendation was along the lines of 5-10 arcmin for uni-directional guiding. No? Regardless, thanks again for the time you put into this for everyone's benefit! Here's hoping you get some clear skies soon.....
Yes! Thank you jonkjon, I got confused :(
More, more!
Haha, will do Melvyn :D
I use the ASIAIR, but still watched this all the way through, lol. Learning is fun, 😁 Thank you
Hahaha that's great to hear - thanks for watching despite it not being useful to you for the moment :)
Thanks for answering the question I was about to ask. Just learning ASIAIR. so wasn't sure if this was required learning. Never did get PHD2 to work properly with first gen Star Adventurer anyway. Again your videos are awesome, thanks!
Another brilliant vid Cuiv! You explain things so well!! But when you said poor polar alignment I assumed you were going to say 5 or 6 arcmin. Not 10”! I never bother getting any closer than 1’ anyway (and I consider that good PA)
Ok. No worries. I see the correction now 😊 I’m def going to try this as my EQ8R pro has a dec backlash of about 3500ms 😢
Superb video!
Unfortunately, backlash could be due to faulty motor. This is a main reason that mesh adjustment doesn’t work.
One more thing. Min-Mo numbers after guiding assistance often don’t work. Backlash size works very well, but not Min-Mo.
Thanks Ana! Interesting on the min-mo numbers - I've always just relied on them, but never really tried to change them
@@CuivTheLazyGeek Cuiv. I have a question not related to guiding. People often take L at 1x1 binning and RGB at 2x2 binning? I just wonder could RGB frames registered with L frame and then combine them all together?
Hi Cuiv, Unrelated question related to your 2 years old video. What do you think about asi294mc versus mm? 294mc has all sorts of drawbacks. Does 294mm have them? One more question. I have heard that asi has new camera with 9um/pixel. Did you know about it?
Thanks again Cuiv for an excellente and practical useful video! 👍🏻 I do currently have guiding issues with my dec axis after a belt mod. Weather has been terrible for weeks here in Norway, so I have not really been able to test properly, but one issue is probably binding. However, binding is not equal around the 360 deg rotation. One spot is tighter, and if I adjust backlash (as described in an older video from you) to avoid binding and no backlash here, I have a small backlash other places. So, if I should apply backlash compensation, and it is not evenly distributex around 360 degrees, what compensation should be applied...?
PHD2 will dynamically adjust the detected backlash to counter exactly that scenario. But remember, software solution to hardware problems!
big ups
Make sure to wait until full moon to test stuff out so you don't waste imaging time! Also, guiding is usually quite tolerant of oblong stars. The OAG naturally picks up the stars beyond the edge of the FOV, where they're wont to be oblong (depending on the scope optics). But in theory, guiding should still work quite well.
Hi Cuiv thanks very much for this video. I have an iOptron GEM28 and have tried the PHD2 PEC algorithm but no improvement in RMS. Just thought I would share my outcome with others. Cheers.
Thanks for sharing!
Any thoughts on recovery after a dither? Sometimes it seems to take too long and then has a negative impact on the frame immediately following a dither...
great video! thanks to your tip on Predictive PEC using this I got my guiding down to 0.28RMS with a CEM26
Awesome, I'm glad it helped!
I tried using predictive PEC but the jury is still out on that one. Still experimenting. But I have used the guiding assistant and have found it to be most helpful. My biggest challenge is working with my OAG. Seems you can never get round stars using an OAG. I have played with the prism to make sure it's as square to the OTA as possible. And that does help. But I'm guessing there is only so much you can do with a prism. If you have any tips using an OAG, I'd certainly be interested. Even w/o round guide starts I do on occasion get pretty good guiding. You just have to pick the smallest star you can in the limited star field you have.
Is the prism in front of or behind any filters? With my GT71 I had to stop using the OAG because my narrow band filters are screwed into the A6iii flattner and thus would block too much of the star light. But I also noticed the OAG worked great when I had my IDAS LP-3 or UV/IR cut filter in place.
@@yzr250jp Behind the prism. In front would be a lot easier, but I wanted the filter to be the last item in my optical train. So I figured out a way to do so, and not mess up my back focus.
I just did a 3-night session for the CN Goofi's monthly challenge, and I didn't re- polar align each night - so my polar alignment got worse each night for whatever reasons, which I could see from the increasing frequency of Dec corrections. My guiding got worse, even though the seeing got better each night (from PHD2 guide star data) - 0.55" average RMS on the first night to 0.70" on the third night. My Dec backlash is 4900ms (0.5 Sidereal guiding rate,) and normally PHD2 is excellent at guiding even when the Dec corrections reverse direction. So having poor polar alignment as the means of battling high Dec backlash may not work on all mounts. Mine is Sirius EQ-G with a 13 lbs load.
Interesting thank you!
Is there a 'best' direction for the offset in polar alignment to beat backlash? Is it better to offset the mount in elevation vs azimuth, for instance?
If that would even work for you, in the first approximation, it shouldn't really matter because of the rotational symmetry.
Adoré ! Spécialement le multi-star guiding machin. Tu m'as convaincu de passer du ASIAIR à Nina à cause de la flexibilité du guidage, jai un gros backlash sur ma monture, etc. Cependant, tu as un mini PC accroché au tube, si j'ai bien compris ? Quelle marque utilises-tu ? J'imagine que tu as un vidéo là-dessus aussi ?
Oui, c'est ici: ruclips.net/video/asSfA6HVHAc/видео.html
what are your experiences related to predictive PEC and harmonic drive mounts? if there are any?
I was going to ask the same question.
Honestly no real experience with strain wave gear/harmonic drive mounts PEC, so I can't really comment on this...
Do you prefer the O'l ways to the ASIAIR Plus? I bought it because the learning curve is/was so drastic on the O'l ways. One shout (Try) to keep up with tech, EVEN IF you had a hand in building the O'l stuff!! ROTFL... I want a comment or further video of the DWARF as I an considering one. And would love to learn all the ins/outs of the ASIAIR. But thanks for any and all of your content!!
Can't use the ASIAir anymore since I'm using non-ZWO stuff ... Yes I want to do a follow up video on the Dwarf II, but the weather isn't cooperating...
Step one. Never set your telescope up on a balcony. LOL
True! Lol
@CuivTheLazyGeek In the end we all do the best we can with what we have. While it would be nice to image from a dark site in New Mexico USA, reality is typically very different. I am blessed to have a permanent pier under a Bortle 4 sky. I enjoy your videos. Keep up the great work!
Hello Cuiv (real name?), how comes that you live in Japan? I hope that next time I am flying to Hong Kong and I have to make a stop in Japan, I can take time to meet you and take you out for lunch or dinner! It will be nice to meet you! (Jesus A. Ponce de Leon). I just came back from HKG and made a connection in Narita airport. But did not occur at that time to make a longer stopover (one day or two) and look for you!! Great work!
It is possible to take light frames between periodic pick errors? PHD can predict the periodic error so it can also synchrony time to take frames. Of course if exposure time is less than time between error picks. (Sorry for my English)
Mmmh theoretically possible but would require development on PHD2 side and capture software side...
Can I make these changes in PHD2 via my ASIAIR PLUS ?
I was told that multi star guiding doesn't help much with a big scope or OAG. Have you had any experience with this or any info to contribute to this? Thanks for the great videos I do apricate your opinion!
keep up the great work!
Helps a ton with my C8 and OAG. I’ve been running that config with PHD2 for over a year. Probably a .4” difference in guiding performance.
@@MrDirtyRod That's the same config I'm using. I'll have to give it a try. Thanks
Rod already answered but yes in theory it should also make a difference. That said many SCT + OAG users have good seeing to support their sampling, so they are statistically likely less affected by seeing in the first place!
I’m confused (as usual). With PHD2 following a star(s), how does doing PEC compensation help? At intervals the periodic error of the mount would cause the star to move and PHD2 would correct for this, true? Or is the PPEC advantageous at longer guiding times? In which case it seems that predicting the error means you better have the periodic error time accurate to better than 1/2 of your guiding exposure time.
It's all about predicting vs reacting in the end. When you're reacting, you're already off-track and need to spend time to bring it back on track. When you're predicting, you can avoid going off track in the first place (or at least limit the amount by which you go off track)
Is there a way to to de pecc while using the ASIAIR?
I don't think so - but if many people ask ZWO they might implement it ;)
PEC guiding for the AZ Gti seems to work so-so in my case. The old hystheresis algorithm works just way better. Maybe the errors of the AZ Gti are not that periodic and the PEC of PhD actually makes it go crazy and compensate incorrectly.
Well, in the end it's what works best for you that counts!
Great video. One thing that I've always wondered about PHD2 is the relationship between multi-star guiding and actually selecting a guide star using the mouse. With multistar turned on, does selecting a star override that? Or does it indicate a primary star? Or is it ignored?
Never mind. Figured it out. Selecting turns on single star.
Moving from just using the scope/mount/dslr to autoguiding. Watched your videos which are great. I get what and how to do things from your videos but translating that onto a real telescope and mount is proving impossible to do. No idea why it's not working.
Cloudy Nights and Stargazers Lounge forums would probably answer most of your questions on troubleshooting PHD2. The rabbit hole truly starts when you start autoguiding 😆
@bill murphy penguins thanks, I've 100s of questions. I've looked through both of those and got answers. They are great places for information. But it's putting into practice is the problem. Telling NINA to go to X target, and instead of going left the telescope goes right. Things like that.
I would allways recommend an offaxis guider :D improved my guiding extremly
OAGs are great, depending on the setup - of course not for Hyperstar :D
@@CuivTheLazyGeek thats right yep :D would be a little bit to much stuff in front of the scope
@@CuivTheLazyGeek Which guide scope and camera do you use with the C6 and hyperstar? Great video!