PHD2 Let's get better guiding! (but don't overthink it either!) 

Do you mean 10 arc mins not arc secs?

"Poor polar alignment of 10 arc seconds ..." - man, you have a different idea of 'poor' than I do 🤣

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.

Predictive PEC in PHD2 for me with an eq6 works equally as well as actually recording a pec curve - so highly recommended!

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

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.

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!

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!

Excellent job explaining these features as always, Cuiv. Thanks!

Great information as always Cuiv!

fantastic video Cuiv, well done! thanks for sharing ....

Awesome.. and the finalmost advice fully agree.. can try that during moonlight.. limited amount of clear skies. Thank you Ashvn

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

Love tips and tricks!

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".😅

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.🎉

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?

Super video Cuiv!! 😀

Excellent video, I have been guiding in one direction for some years now with my EQ8, which had bad DEC backlash….👍🏻

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

Its great to see you back....

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.

Cuiv always delivers

Oh my! I saw subtitles as i was on your thmbnail. It said "Hi, Cliff the lazy geek here" lol.

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.

Genius! Thanks enormously!

thank you cuiv!

Another excellent video

Thanks! Your Videos are really useful. I just improved my guiding by 0,3" !

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!

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

I use the ASIAIR, but still watched this all the way through, lol. Learning is fun, 😁 Thank you

Never knew you could right click that graph!

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 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.....

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)

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.

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 ?

great video! thanks to your tip on Predictive PEC using this I got my guiding down to 0.28RMS with a CEM26

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!

big ups

More, more!

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.

Step one. Never set your telescope up on a balcony. LOL

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.

I will dare to propose an idea for better guiding, even if it is so silly that could make someone to get his abs ripped by laughing: What if an in-software memory (through a driver - or whatever - that creates it), by storing the best star value after n (let's say 10) exposures of the guiding camera, could keep the best value and then this driver, by communicating through a dedicated algorithm, could compensate in such a way that could use the difference from each next value so it could always keep the best one and use only this best value? Then the algorithm copying the image of the star in the best value and creating an artificial, second star in the field of the guiding camera, telling the crosshairs of the software to lock there? This could probably help even on a flat guiding-error graph (on windless nights), on both axis. I was thinking of this solution as a "pseudo-corrector" or "guide boost" functionality with the software's guiding error graph assigned to the copied star (that its value doesn't change) so the error graph would be as flat as flat as possible, constantly, for as long as a certain target is photographed. What are your thoughts?

I would allways recommend an offaxis guider :D improved my guiding extremly

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...?

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!!

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...

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.

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?

what are your experiences related to predictive PEC and harmonic drive mounts? if there are any?

Can I make these changes in PHD2 via my ASIAIR PLUS ?

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)

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.

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!

Is there a way to to de pecc while using the ASIAIR?

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.

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?