Astro Farmers "Mastering an Avx" (guiding)
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- เผยแพร่เมื่อ 27 ส.ค. 2024
- Creator Notes below: In this video I describe some basic guiding techniques to use on an avx or other "budget" mounts that don't guide very well using traditional methods. Do not copy and use these mount settings as yours will be slightly different and I don't actually start tuning the guiding till later in the video. So stick with it.
At 22:45 If your seeing multiple corrections in the same direction after settling on your minmo..... Adjust the Agressiveness/Reaction up ..... If your seeing a back and forth movement but at long intervals... Bring the Agression/Reaction down a little... Experimentation is needed with "your" particular mount here to find the best settings.. Generally once set.. you won't need to make many adjustments... Further more if Dec is causing troubles after all this... Disable the backlash compensation... It can cause as many problems as it cures and is very dependant on how you've weighted your avx... Furthermore, Increase the guide rate in the Hand control (or CPWI) to a higher number in dec if needed (.6 to .8 is good) Increasing the step size can really help in the advanced button in the brain tab. Remember... Always East heavy.... And always Tail heavy..... Not alot... Just a little.. It's best to calibrate near the meridian and celestial equator (use drift align tool to slew there automatically).. When you Pec train the mount via hand control... Use the hysterysis algorithm using 1-2 sec exposures, run the guiding assistant. do everything it tells you. Don't worry about the error But be very picky with Polar alignment (drift align)..... Run PEC TOOL and average multiple runs, then upload to the Hand Controller. Enjoy ;-)
/ astrofarmer
At 22:45 If your seeing multiple corrections in the same direction after settling on your minmo..... Adjust the Agressiveness up ..... If your seeing a back and forth movement but at long intervals... Bring the Agression down a little... Experimentation is needed with "your" particular mount here to find the best settings.. Generally once set.. you won't need to make many adjustments... Further more if Dec is causing troubles after all this... Disable the backlash compensation... It can cause as many problems as it cures and is very dependant on how you've weighted your avx... Furthermore, Increase the guide rate in the Hand control (or CPWI) to a higher number in dec if needed (.6 to .8 is good) Remember... Always East heavy.... And always Tail heavy..... Not alot... Just a little.... When you Pec train the mount via hand control... Use the hysterysis algorithm using 1-2 sec exposures, run the guiding assistant. do everything it tells you. Don't worry about the error But be very picky with Polar alignment (drift align)..... Run PEC TOOL and average multiple runs, then upload to the Hand Controller. Enjoy ;-)
Thank you so much! Followed what you advise in PhD2 settings with my AVX (1s exposure works for me, instead of my previous 3s) and I am down from 1.7 arc secs Tot RMS error using PhD2's 'Multiple stars' option to 0.5 looking north-east. Happy nights! Thanks again. Chris
Dude: YOU ROCK!! Thank you so much for this video. It was great to see a video made specifically for the AVX mount. I was floundering around with total RMS of 3-7! I watched your video a few times and took a copy of it on my tablet to watch while I played with the Phd2 settings the other night. I managed to get my RMS down to .86. I'm still going to experiment to see if I can get it even better (multi-star guiding and more fine tuning of settings) but I'm delighted with the results I've gotten. Thanks again.
Glad it helped you... I have found for the vast majority of avx's... Predictive pec algorithm and multistar guiding combined with a pec trained mount with exposures between 0.2s and 1s will give the maximum performance. Clear skies!
Had several problems getting my AVX back -up again after hypertuning it on my own. Stumbled accross your video and managed to sort all things out... My tracking has greatly benefitted from using shorter exposures, my RMS (all of them) are now below my pixel scale and tracking is once again, spot-on. Thanks for sharing your experience and for reminding me that dogmas are not to be held for life.
Glad I could help. Originally the build video was just for a few folks that wanted to know how I carried the payloads I did... I need to update it at some point as a better backend bearing arrangement for ra has been found. High frequency guiding has been around a very long time. It really helps with servo/gearbox mounts. Thanks for stopping by!
Great video Jason! I like the way you explain the stuff that matters.
Thanks! It's easy to get lost in Phd2 that's for sure.
Thanks again for another fine video on the AVX. I do use the PHD2 both for guidescope and OAG. What i do miss in PHD2 is that fex. users could make recommendations for different mounts, just like you do in this video. That would be awesome. Its quite difficult to learn the PHD2 only by doing. Keep up your great work. Regards, Johnny from Norway
May be the best single video that will improve my image capturing...will have to rewind and watch this again...motivated now to go get parts for the tune up. I’m sure I’ll have some questions as I get time under a clear dark sky up here in central Iowa...
Fire away when ready!
Okay, so DM where you actually live so I can just bring it all to you and get a real jump start. Really though, I appreciate the heck out of this video. Will try everything you have demonstrated. Thank you.
Thank you Jason this was a big help to me.
Keep up the good work.
Hello, amazing video!! I got some improvement as I noticed I was way off. After making several adjustments, here is where I’m at. I am getting some double stars and elongated stars on longer exposures and I’m almost positive this is it. I’m currently 50 aggression, 0.10 mnmo and 2500 mx RA and 90 aggression 0.20 mnmo Dec with 3000 Mx Dec. I got my RMS to .08 (0.56px) RA, 0.07 (0.48px) Dec. total is 0.11 (0.74px) and Ra osc is 0.37. CCD calculator says 1.03. Peak to peak is 0.30 (1.97px) RA and 0.36 (2.40px) DEC. those do go down to mid/high 1 range but I keep getting random spikes that shoot the numbers up. RMS and RA osc generally stay the same when this happens. My exposure is 0.5
Those numbers sound fairly typical of what an avx is capable of.. if your still seeing doubles or elongation and one axis is not double the other in error, it's time to look elsewhere and do a sanity check for differential flexure.... If your seeing a large deflection occasionally in ra.... Predictive pec algorithm should be able to help with that. If it's really big pec training can help as well. If it's in Dec. You'll have to dither in Ra only, bias the weight considerably tail heavy, and loosen (bigger number) the minmo up. As your correcting/dithering into backlash it'll make a large deflection and a series of corrections... Also be sure your software allows adequate time to settle after a dither.. that'll sure do it. Those are some things off the top of my head before coffee...
Thank you for the quick reply! I apologize for my delay, it’s been a crazy work week. My question now is how tail heavy should I be? I noticed once in every 8 minute exposure declination would have an excursion of about 2 seconds and take about 5+ guide pulses to correct. I just tore out the worm gear and redid my old adjustment as it was very tight. I rotated by hand a full revolution adjusting the right spots to minimal backlash. Some areas have quite a bit, but still better than factory, but I’m not binding in any areas anymore and the “tight” areas now are very minimal backlash which I’m hoping will help smooth out declination. That excess backlash is normal for AVX from what I’m understanding.
@@Hidden.Light.Photography depending on how long your moment arm is would be the answer to how much bias to apply. I can say that often times it's more than people think. It's especially tricky on short setups (6"newt/sct). Dec can be a little tighter than Ra as it only moves when called upon to do so, Unlike Ra that ever moving westwards. So the main contributing factors to Dec movement are polar alignment (and some cone error) and having the minmo set too low for Dec. While it's best that not anything bind when your tuning, don't let it have too much slop in Dec or you find it correcting into the backlash and a telltale steady stream of corrections follow. It sounds like you e got a handle on the fundamentals going on here. It's just a matter of putting it all together and making a routine that's repeatable...
Loved the video and confirms what I have been experiencing with my AVX as well. My typical exposure time is 1.0s and if that is not working I will lower to .5s. Typical OSC is .25and spikes a tad with dithering. I will try your suggestion of dithering in RA only. Keep up the great videos
Thank you. I plan on doing a more comprehensive guide on it. And some pixinsight tricks that seem to be mostly paywalled tricks by most others.
Thank you for sharing. I am new here.
yea i also found my budget mount when guiding less at short time the performance is great and also i use the PPEC method
Excellent performance! I learned so much from this! Now to apply it to my Advanced GT and see if my results improve. I pretty much am having bloated ✨ and am trying to reduce the oscillation.
I hope it helps folks... ;-)
Incredibly helpful videos! My AVX has given me trouble from day one. Board went dead for no reason. Cheap Grub screws on Celestron diagonal came loose and dropped an expensive ep onto ground. Wild slewing towards the ground when trying to park in CPWI (and slewing past the RA/Dec limits!). Now, I have a situation where I seem to have good tracking in one part of the sky, then slew to another part but the tracking holds for a few seconds but then goes to hell. East/West trails in the image. Must be PA not holding. I think I will concentrate more on better East and tail heavy balancing per your instructions. Other then those fixes and some settings in PHD2 per your instructions, I'm done with the mount!
If you e been reading forums and taking advice from folks who own stepper mounts things will seem to be very wrong indeed. High frequency guiding with the proper imbalance has been tried and true for many years on servo mounts.. Celestron in particular. Checkout part 2 and beginners mistakes if you haven't. All my videos are very avx specific. Good luck on getting it tamed. I would ask what your payload is as too little weight is no good on an avx and no moment arm can be bad... Dec needs a pretty healthy imbalance if possible. Join the Celestron avx users group on Facebook if you haven't. Once a person gets their head wrapped around breaking all the rules and not following the bad information from the phd2 best practices guides, things usually start working better. Good hunting!
@@astro-farmer Thanks! As a visual user, off- balancing just wasn't first in my mind. During an imaging run, do you actually rebalance after a meridian flip or just avoid it? Anyway, It's about a 20lb payload with scope and accessories in hand. OEM weight is barely enough to balance. By the way, a decent spanner wrench on Azn is the "NEEWER Stainless Steel Lens Spanner Wrench". I use it to adjust my Maxbright bino's.
@@Ronbo765 generally you just end up moving the weights an inch or so after the flip. Thanks for the heads up. I've got a few spanners around now. Kids and tools... his argument is he works in an organic environment.. lol... I do not.. I like to know I'll find it where I put it.
@@astro-farmer Curious, with a well tuned PHD2, have you ever seen an out-of-the box AVX guide at
@@Ronbo765 yes. Most can get right around the 1"/pixel mark... but like anything, that's not entirely the whole story... it's the peak to peaks that get most folks... using that metric it's fairly rare to see an avx do under 1"/pixel. Usually 1.4" to 1.7" of peak to peak error is seen amongst the vast majority of avx's. Even modded and tuned avx"s have a hard time getting under 1" peak to peak. That the metric that actually matters and sadly it doesn't update between subs (dithers) on phd2 so you have to manually watch it. The beginners mistakes video covers this pretty in depth.
Hi Jason: This is a very interesting video about the PHD2 guiding. While I'm waiting for my parts to arrive for the AVX mount after watching your AVX rebuild I reviewed some of my old guiding logs for my AVX and will try applying what I saw here to the rebuild. On another note, I have a CEM60 that I spent a lot of time on tuning the guiding for the mount and it does extremely well with similar adjustments. I'm not chasing the seeing. I'm actually guiding at less than 1 sec exposures which like you say goes against the norm. It looks like I can make some more improvement and will give your methodology a go on my CEM60.
I use 2.5 second exposures on my cem120, But..... I can also "high frequency guide" it and get the same FWHM.. I live in an area with good seeing and bortle 3. Stepper mounts act much different in the fact that they don't have gearbox's and now days more often have belts. With that said.. Turning down your Guiding speed in the HC or commander is helpful. PHD's new multi star guiding (in beta under algorithms) works great. I can use fast exposures on my cem but have found it's really 6 one way and half a dozen the other so to speak... No real advantage either way... Just a different philosophy and method for the same end.... The new multistar guiding ( been around for years in other programs and is nothing really new) will give you lower rms values.... But again.... Your FWHM will be about the same "assuming" you were guiding right down to your seeing anyways... Glad you enjoyed the video :-) Clear skies!
Hi how do I get that toolbar where your graph is located I believe it is called the active controls mine doesn't display that . And thank you for the video
I believe the top drop down menus have the option
I understand you are down on the AVX mount. What is your opinion of the CGX-L mount?
I think the avx is great at it's price point although there is certainly contenders nearby that price.... I'm not a fan of the Celestron servo motors. The cgx is a pain to tune and much more difficult to really get right. You still high frequency guide it just like an avx.... Cgem is an eq6 in disguise... Just different firmware and servo vs stepper.... Syntax owns both skywatcher and Celestron so understanding that product name bias and marketing are a big factor. My main mount is a cem120 but my trusty avx is my portable rig. I enjoy them both for different reasons and use them to their strengths.
How do u connect with the computer and mount fiscally-- meaning how do run the wires ?
Also what drivers the computer needs to use the PHD2 program with the AVX mount
For physical connections the hand control has a usb connection on the bottom which simply plugs into your computer, the older ones have an RJ connection (they used a usb to serial adapter sold seperately to make the connection to your pc). CPWI is the driver/software you need to control your mount through software programs via a pc (including phd2).
I'm afraid to even mention this-- but this hand control idea to laptop has not worked at all. Could be a serial issue-- bottom line is I'm going with the Auto guide Port on the mount.
Yes almost manual and for each new target I'll need to reset the PHD2 program. Heck I lost the ST4 cable -- like totally vanished lol. So I tried looking for it on line--- and wow is it scarce to find one-- unless it's out of the US.
So basically ST4 cable to Mount direct to the Camera back port. This should allow for basic Auto Guiding as I see no other option that will work. Headed to the Mesa OK park near Kent this April should be very interesting
Hi Jason, I have another question about AVX. I use NINA as sequencer. I can slew and center using plate solving. NINA communicates with AVX via CPWI. However, when mount in home position and get command from sequencer, it doesn’t move. Sequencer is stacked. When I run simple sequence with final command Park. It doesn’t.
How do you set Parking in CPWI for AVX that will be recognized by other ASCOM sequence generators such as NINA?
I can't answer that one... But I can say that sequence generator pro and Apt both will park the mount just fine.... Maybe ask the Nina discord... I've never had any luck with Nina as it doesn't seem to like qhy gear.
@@astro-farmer Great. How do you set parking position for AVX in CPWI?
@@anata5127 I set it in in my capture software (sgp, apt)
@@astro-farmer Hmm. Thanks for this.
This is great info. Thanks for posting. What simulators are you using to test during the day? I’ve tried a few but I guess that they don’t move the stars and phd2 errors out.
This is just the phd2 standard simulator that comes baked into it....I use metaguide alot also... It too has a simulator mode.
Thanks again. I had been using the ascom ones. Have you tried CPWI? I’ve just been checking it out because I really dislike using the hand controller. And you can do PEC training from the app. It seems slick, but I’ve not tested it under dark sky’s yet.
@@Crozb07 Yes I use CPWI nightly and it works well.. The pec training portion works ok, but lacks the feature to take multiple runs and average them together... But yea it's a solid program. Love the xbox or ps controller capabilities and it now has the focuser added as well....
@@astro-farmer In the video you mentioned that you could be of assistance if running into a major problem. I’ve been having problems guiding for months now. Some nights is OK, others like last night it was absolutely horrible. My guiding literally looks like it’s a roller coaster. I actually changed software from Ekos/Kstars to Nina to see if running phd2 would help.
I’d like to send you my log file from last night if possible? Any help you could be is really appreciated.
@@Crozb07 Certainly, anytime
Do you have setting recommendations for the ZWO ASI Air?
unfortunately I do not. How ever there's alot of great info that can be found in the Celestron Avx Users facebook group. I know theres a good guide for the avx and a quick question on the group will get you off on the right foot.
Have you tried a raspberry PI 4 for speed? With USB 3 I find that it performs pretty well. I think that it's better than that Atom that I've used.
I've only helped others with the PI 4.... I generally recommend I3 or ryzen 3 minimum for fast exposure guiding and "tuning" your pc specifically for usb priority (disable all power savings and a few command line tricks) in Part 2 of this video I'll go over some of that. I hope to do more as time allows.
@@astro-farmer The RPI4 is pretty snappy and has USB3. I'd be interested to see if a faster computer really is required. For remote, I'm able to keep one running all night along with the mount etc on a PowerTank Pro (the bigger one). There is an issue with wifi interference while using USB3 though. I've worked-around it by turning off HDMI, but it's still quirky.
@@jamieamendolagine205 You can see if it's up to task by simply setting the guide exposure to .2 seconds and see if your actually seeing 4-5 frames per second rolling in...... The graph and star profile will come to life. If it's too slow... Lag will start playing havoc as it is attempting to make a correction at the time of taking an exposure and cannot keep up.. Bad oscillations will follow... And while you can still dial it in "some" it won't be near as good as actually getting that proper frame rate. Keep in mind your steppers on your eq6 will do much better with hysterisis and your guide speed turned down in eqmod. some experimentation is needed.. I generally tell folks, if you can have equal error in both axis then there's no need to expose any faster.... However.. There can be some benefit for those mounts that have alot of slop and/or backlash by utilizing fast exposures.. The trick is not to chase... Your numbers may be a little higher...... But measuring the FWHM of the output of the stars is the test.. For budget avx's and cg5's, etc... Guiding fast almost always helps. For my cem120... It's a wash.... So in the end just a tool in the toolbox for those that can't get round stars using the traditional method of guiding.. Cheers!
Jason. Phd2 issue. I have good guiding in the east. When I move to west sky the guiding goes down the tubes. What should I look for
Generally that's a balance issue.. However.. If heat producing roofs or lots of pavement is in that direction that can show up if it's bad enough... I'd double triple check the balance. If that's been done and adjusted and still problems arise.... Try recalibrating on that side of the meridian... If still bad..... Check worm lash ... Perhaps it's binding a bit over on that side of the ring gear where it wasn't on the other.
@@astro-farmer thanks. Balance is good. I haven't tried the re cali yet. Next clear night. As far as the motors and worm I'm waiting for the bearings to make there way across the pond before I tear it down. BTW Jason. I'll be relocating back to Kansas soon. Not to far from you. I'd like an opportunity to set up and let you pick apart everything I'm screwing up.
@@patrickdenning5986 Anytime! We are a small but very active group with a value mindset.. While there are some good equipment owners here you'll find no elitism or snobbery here.. We're a bunch of DIY'ers and love to view and image the night sky... Message me when you get all settled in and I'll provide the address.
Sorry to keep bugging you Jason. This time I'm asking about the hardware you use. I have an etc I can put in rings I'd like to mount that on top of my refractor. It has standard orion rings. The kind with studs. What dovetails and bases would I need.
Patrick what I've found in this hobby is that the industry really kind of reams you on hardware connections and ways of mounting things.. You can literally spend a fortune on mounting hardware.. The best money saver I have is a tap and die set.. I often just drill my own holes and use my own bolts that are readily found at most hardware stores.. And while it's not the "correct" way of doing things... I can't tell you how many hundreds of dollars it has saved me for all my weird concoctions that I come up with..... I like to bolt things back to back if I can't side by side them.. I have a farpoint astro side by side system.. For bolting back to back I've found that I just run the threads in the top of the lower scopes rings with the bottom bolts of the scope to be on top... Even if it goes very very tightly for a bit....... It will cut those new threads and when worked back and forth a few times go on smoothly and securely. So my ways aren't exactly "normal" I guess, but it works for me....