Another hallmark reference video for beginners like myself, thanks James!
@HeavenlyBackyardAstronomy
3 жыл бұрын
This is very helpful to me since I have the same equipment. I will put some of these suggestions into practice the next clear night ... whenever that might be. Thank you, James. (Patrick Prokop, Savannah, GA)
@Aero19612
3 жыл бұрын
Glad you found it useful, Patrick. Do you see the same magnitude of periodic error (25 arc-sec)? Also, for a typical night, what do you get for rms errors for the RA and DEC axes? Thanks for watching!
@HeavenlyBackyardAstronomy
3 жыл бұрын
@@Aero19612 ... currently, I am around 0.85" RMS. I will let you know what the new values are WHENEVER these skies clear up. Just had tropical storm "Danny" pass through.
@jlecomte0719
3 жыл бұрын
Hey James, I just discovered your KZitem channel. Your videos are very well made and informative. Thank you!
@Aero19612
3 жыл бұрын
Thank you very much, Julien! Glad you found them. The internet is a big place.
@davidaylsworth8964
3 жыл бұрын
Only an engineer …. Always interesting to watch your explanation of these things. I have a CGEM-DX and I’ve seen similar behaviours with my guiding graphs. I’ll need to watch this again a few times to really absorb the various factors. I don’t use OAG for my guiding but I have made it a practice to setup the guider near the object I’ll be photographing. Another very useful video James.
@Aero19612
3 жыл бұрын
I know the CGEM has it's issues and it's not manufactured with the tightest of machining tolerance, but a well-tuned PHD2 can span the gap. Thanks for watching, David!
@JoesAstrophoto
3 жыл бұрын
Super informative as usual James! I never thought about doing this to see how much of it was mechanical and how much was seeing. With my EQ6 w/PPEC , OAG on the Edge8 I get .4 Total RMS on good nights and .7 on really bad nights so I just have learned (actually assuming) from experience that my mechanical contribution is about .4". Looking forward to what you find out in the advanced features.
@Aero19612
3 жыл бұрын
0.4"!!!! Wow. I would weep tears of joy if ever I saw that kind of performance. I've been thinking about the EQ6, now I'm going to seriously think about it. A question: On a typical night, what do you see for RA and DEC rms? My RA is about 50%-70% higher than DEC because of the mechanical contribution. Thanks, Joe!
@JoesAstrophoto
3 жыл бұрын
@@Aero19612 Thanks James, it's not .4" that often unfortunately lol only really good nights. I can tell you from looking at my guiding video as I don't pay a lot of attention to my separate RA and DEC rms, just try to make sure they are as close together as possible, that my RA was at .48" and DEC was at .30" with a total rms of .57". I think my RA is always a little higher than my DEC just as you presented in your video. I love the EQ6, and with a good PEC curve recorded to the mount it's just super solid. It really is an amazing mount for the price. Thanks again for this video and all your videos, I learn so much watching them!
@TheCassese
3 жыл бұрын
How about multistar guiding? Would it work with an OAG?
@Aero19612
3 жыл бұрын
Hey, Marcelo Multistar guiding will reduce "chasing the seeing" error but not mechanical gear/bearing noise error. In the former, the stars move randomly with respect to one another. In the latter, the stars move the same. In theory, multistar will work with an OAG. There are two issues though: (1) for long focal lengths, there may only be one suitable guide star in the OAG field of view and (2) multistar works best with widely separated guidestars, but with an OAG at high focal length, the very small field of view means the separation of any two stars (where their light passes through the atmosphere) is not that great so the seeing-induced motion may be similar. Thanks for watching!
@psuaero100
3 жыл бұрын
Another great analysis and video James. I'm surprised your PA was off by 3 arc-min, that's quite a bit. Just curious... what are you using to PA the mount/scope? I've been using SharpCap Pro for over a year and very happy with it's capabilities. If you believe the SharpCap software then I'm typically in the 10-30 arc-second PA error range. I usually see 0.1-0.5 arc-mins. reported by PHD2 so that gives me hope that SharpCap is accurate. Knowing that you have a long FL setup and also use a OAG, maybe SharpCap won't work. I think you still could use it but you'd need a extra guide scope/guide camera on the side of your main scope. That obviously has it's own drawbacks like extra weight, equipment, power, etc. just for 3-5 minutes of work each night. Just a thoughtclear skies!
@Aero19612
3 жыл бұрын
Yeah. I haven't polar aligned the mount since my last imaging session 7 months ago. If I'm going to be doing imaging, I'll polar align using the PoleMaster. I knew I wasn't going to do any imaging that night with clouds rolling in. I will sometimes leave a little miss-alignment if I'm going to use one-sided DEC guiding to avoid DEC backlash.
@pmasters2
3 жыл бұрын
Hi James, Have a look at PECPrep as it has the FFT built in. It also has a db of popular mounts and their various gear periods. If you’re looking to get your mount tuned up, I’d also recommend DarkFrame as they’ve done wonders for my mount.
@Aero19612
3 жыл бұрын
Thanks for the suggestion, Peter. I looked it up. Might be worth a go. I have PEMPro which does similar things. I guess the nerd in me wants to play with the numbers. Come to think of it, I think I got the worm gear period of 478 sec from the PEMPro database. Thanks for watching!
@davidf9494
3 жыл бұрын
Thanks again for a great video James! I was getting about 0.6-0.8 rms with my CGEM and EDGE 8 w/ OAG but since March, my orthogonality has been awful and my rms has been >1. DEC backlash for this mount is really bad so PHD2 has always struggled. My new iOptron GEM45 will arrive next week (ordered last Dec) and I'm hoping to leave some of the backlash and guiding issues in the past. Nevertheless, your video had really good pointers and I may try your Stellarium trick and see if I can implement it with SGPro. I'm hearing good things about NINA and may considered switching over. Looking forward to your next video- Clear Skies!
@Aero19612
3 жыл бұрын
Hey David. I could have written these exact words: "I was getting about 0.6-0.8 rms with my CGEM and EDGE 8 w/ OAG but since March, my orthogonality has been awful and my rms has been >1." At the moment you were typing your comment, I was looking at the GEM45 on iOptron's website. Please fill me in on your experience with it. I notice it only comes with 1 11-lb counterweight. Will you be able to use a counterweight from the CGEM?
@davidf9494
3 жыл бұрын
@@Aero19612 Will do James. I'm getting an extra 5kg counterweight. Unfortunately, the GEM counterweights are 28mm so I can't use my smaller OD CGEM weights. I bought the mount and their tri-pier since I didn't like the 1.5" tripods it comes with (not very robust -from owners). The GEM45 mount is a featherweight at 15lb compared to the 41lb CGEM mount. That's going to be easier for setup and teardown for sure! Will report back when the unit arrives and setup. Clear Skies!
@claude77573
2 жыл бұрын
At about 9:22 into the video, it looks like you created some spreadsheet to summarize your data. Would it be possible to get a copy of those spreadsheets?
@Aero19612
2 жыл бұрын
Hey Claude. That's not a spreadsheet. It's a plot of some analysis I did in Python so I'm afraid it's not in a user-friendly format, otherwise I'd post it for you to use. Thanks for watching!
@oq17
Жыл бұрын
Hello - excellent video . Thank you Do you know how I could use phd2 to evaluate my mount's tracking performance ( not while guiding)? The catch here is, the mount is a homemade . I am using an Arduino to control a single Ra axis stepper motor . The mount has no ability to talk to a camera or phd2 . I only use this mount to track ( not guide), but I am curious how well it does tracking. I basically want to mount my guide camera on this mount - and let phd2 tell me what the tracking errors are . I do not have the ability to run a calibration routine , as phd2 cannot talk to or control this mount . Any help would be appreciated. Thanks !
@Aero19612
Жыл бұрын
Not sure. If you can mount a guide camera to your scope, you might be able to run PHD2 in "guiding assistant" mode where it simply records the motion of a guide star without sending commands to the mount. I'm just not sure if PHD2 will let you get this far if you don't have a mount connected. Give it a shot if you can. Good luck
@oq17
Жыл бұрын
@@Aero19612 Thank you for your reply . I do appreciate it .
@guntergeorgi1347
Жыл бұрын
Hi James, do you happen to know how to delete PEC data in CGEM mounts?
@Aero19612
Жыл бұрын
Hi Gunter. I don't think you can. You can (a) turn off PEC with the handset or (b) write over the data with a new PEC curve. So, you really don't have to delete it.
@guntergeorgi1347
Жыл бұрын
@@Aero19612 thanks
@MrBebopbob
3 жыл бұрын
Hi James. Listening to you is like talking to myself. I was going to drop you a note after testing during my last session (but I didn't want to sound like a whiner). I think I learned one thing from that session, 3D balancing is killing me. I was getting >0.9" until I got near the meridean where my guiding finally settled down to ~0.55". This happens to be the only area where my balancing is good(ish). I decided to buy an electronic filter wheel as an adjustable weight to offset the SCT focused. Btw, with my I option mount you can't use PEC with guiding. I used PemPro to generated a PEC curve for my AVX mount. This helped but was no where near the quality of the PHD2 correction. Whew, thanks for letting me air my complaints. I feel like I owe you for counseling. Clear skies.:-)
@Aero19612
3 жыл бұрын
Ha. Whining is my favorite past-time when doing astrophotography. I don't think I've ever seen 0.55". Interesting use for a filter wheel, Bob!
@MrBebopbob
3 жыл бұрын
@@Aero19612 Hi James. I wasn't implying that you whine. Just that we seem to share a lot of the same equipment issues. Thanks for all the great videos.
@Aero19612
3 жыл бұрын
@@MrBebopbob Haha. I know you weren't. I just meant that whining goes with the dinner in astrophotography. I don't think I would have a KZitem channel if all I had was one awesome image after another.
@gothicm3rcy426
Жыл бұрын
I use a crayford on my sct
@sirmeowcelot
3 жыл бұрын
Thank you so much for another great contribution to education.
@Aero19612
3 жыл бұрын
Ha. I'd prefer to get great guiding performance and be stupid.
@anata5127
2 жыл бұрын
Did you rid off this mount and got another? Is there a way to fix it?
@Aero19612
2 жыл бұрын
Yes. Replaced the CGEM with the EQ6R. No, I don't believe the CGEM can be improved. Mine is hypertuned. There is just too much machine tolerance error in the gears so adjusting the meshing can only do so much-too much backlash. The EQ6-R is working very well.
@anata5127
2 жыл бұрын
@@Aero19612 Thanks for info. Problem is that EQ6R may also not last. Maybe it is better to get AP 1100GTO right away? Additionally, you can enhance your capabilities by putting 12-14” RC on it.
@danjensen9425
3 жыл бұрын
I bought the cgemll , sent it back they sent me another I had that one hypertuned and it was super to balance no stiction at all but the ra bar still had play and the dec error was still terrible. Sold it and bought a EQ6-R pro and now headache free guiding. The harmonics in those motors are the issue. But if you can get to work that’s great.
@Aero19612
3 жыл бұрын
Excellent feedback, Dan. I've had the EQ6-R in my "cart" for some time. You're making it easier to push the button. Still a long wait time though. Thanks!
@bdykes7316
Жыл бұрын
It seems like this would be an ideal application for a traction drive gear reduction. Since a cylinder is a much simpler shape than a gear or worm gear, they can be made more accurately.
@Aero19612
Жыл бұрын
I don't know anything about those drives. Avoiding gears, backlash, and metal-on-metal contact would be a good start. Particularly for the CGEM type mount. The harmonic drives that are coming on the market seem interesting, but their guiding performance is worse than the EQ6-R. Thanks for watching!
@MethiasZa
3 жыл бұрын
When you dig into the advanced options, if you find anything useful, would you be able to make a video on it please. I need to try improve my guiding and am looking for all ways I can optimise and improve at this point.
@Aero19612
3 жыл бұрын
Will do. Thanks for watching, Wayne!
@Aero19612
3 жыл бұрын
Follow up: I posed a few questions about those settings on the PHD2 forum and I think I was politely told to "go outside and play with my little friends".
@MethiasZa
3 жыл бұрын
@@Aero19612 HAHAH I see what you mean. I went to the forums now and saw the reply. Now I want to go see if its possible just because :)
@louisrosner7902
3 жыл бұрын
Another great video. Just as an aside do whatever you can to repair your own guiding. My mount just had a pier crash. CGX otherwise similar to yours and I made the mistake of sending it back to Celestron. One month just to get an RMA and now 2 1/2 total months and they won’t even answer my calls. Just told me they’re very busy and they will get back to me when they can. Totally unacceptable.. their service has become abysmal. I’m looking into Ioptron CGEM70
@Aero19612
3 жыл бұрын
That's terrible, Louis! I'm not surprised to hear that about Celestron service though. I wouldn't even consider sending my mount into Celestron for my minor guiding issue. The CEM70 looks like a good mount with a high payload capacity. I'll have to start looking into other mount options. Can't say that Celestron is at the top of that list. Good luck. I'd be really interested to hear what you think of the iOptron when/if you get it.
@gothicm3rcy426
Жыл бұрын
I had similar on my cgem ii but i got the hypertune diy kit..... incredible difference now. The bad friction wasnt enabling me to balance correctly which was the main part.... but I did worm gear adjustments too. Its performing 100% better now
@Aero19612
Жыл бұрын
That’s great! I moved on to a Sky Watcher EQ6-R and am very happy with it. I did have my CGEM hyper tuned along with repair to re-attach an encoder. I could balance it much more accurately but really didn’t see much improvement in guiding. I’m glad your experience was more positive. Thanks for watching!
@gothicm3rcy426
Жыл бұрын
@@Aero19612 I was thinking of getting the eq6r also, I could use 2 mounts really as my wife is very interested in the hobby too..... the eq6r being belt driven is remarkable value. I got my cgem working really well with PEC. I get around .4 to .5 rms which is a huge improvement to was I was getting pre hypertuning. Ever so slightly off balancing helps a lot with backlash too. Also, I replaced the nylon gears in the motor for metal ones, the motor model 33GN2732 has metal gears which are identical to the nylon gears in the cgem motor. The good thing is the motors were cheap..... also replaced the encoders with us digital encoders, slew runaway is a thing of the past.... The grub screws in the cgem motor encoders are lock tited in, but often there can be movement ooff the shaft and encoder wheel... the us digital encoders lock a completely different way. Thing is though.... celestron could easily intergrate upgrades to make the cgem much better out of the box. Its disappointing that they dont
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