Click here if you are having trouble logging into the forums Cloudy Nights - Official Forums of the 2009 International Year of Astronomy Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu.... uh, User   You are not logged in. [Login] Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar Astrophotography and Sketching >> Beginning Imaging Previous   Index   Next   Threaded   Pages: 1 DaemonGPF Pooh-Bah Reged: 03/22/08 Posts: 1452 Loc: New Mexico PHD autoguiding and DEC issue       #2557491 - 08/03/08 11:27 AM Edit   Reply   Quote Quick Reply   I just seem to be cursed with technical glitches lately, but I imagine this one is more simplistic: This happens just randomly, but probably almost 40% of the time when I head out for an evening and I start PHD, it runs through its calibration steps and decides that Declination guiding has failed and disables it. I can't figure out why. I always calibrate on one of the bright alignment stars or on Jupiter or one of its moons before I head off into the sky and guiding on real targets. When it works, it works flawlessly, when it doesn't it seems like I can't get it going that night and just have to bag it up. Thoughts? -------------------- -Josh *Orion Starblast Imaging 150mm OTA *Orion Starblast Imaging 114mm OTA *Meade 50mm AR short tube OTA *Meade DSI Pro IIc *Orion Starshoot DSCI *CG5 mount http://cleardarksky.com/c/AlbuqNMkey.html My Messier Project Gallery Post Extras:       zAmbonii sage Reged: 01/19/08 Posts: 215 Loc: Ypsilanti, MI Re: PHD autoguiding and DEC issue [Re: DaemonGPF]       #2557568 - 08/03/08 12:16 PM Edit   Reply   Quote Quick Reply   I only played around with PHD guiding a little bit, but I suspect your problem is with the backlash in DEC. You may want to increase the calibration step size in the options menu. From what I gather, the program will try to move the guidestar X number of pixels in DEC so it can calibrate. It will send pulses to the mount to move it, but it only tries a set amount of times. If after the set number of times it sends pulses, the guide star does not move X number of pixels it will give a fail message. It is possible that increasing the calibration step size will help alleviate this. Otherwise you may need to do some tweaking in your mount to reduce the amount of backlash in DEC (this would probably be the best) Maybe some others will have other ideas. -------------------- Celestron C6-N 150mm f/5 Newtonian Celestron CG-4 mount Canon 300D unmodded Meade 70AZ-Z + Philips SPC900NC for autoguiding Post Extras:       chutch44 sage Reged: 02/23/07 Posts: 330 Loc: Pontotoc, Ms Re: PHD autoguiding and DEC issue [Re: zAmbonii]       #2557594 - 08/03/08 12:38 PM Edit   Reply   Quote Quick Reply   I ran into the same thing. I increased the calibration step size from the default size of 500 to 1450 and it has not failed since. I honestly don't know what this does other than it calibrates much faster and I haven't had any negative affects since changing it. -------------------- Hutch Celestron ASGT C8 William Optics Z66SD Meade 3.3 Focal Reducer Meade Dsi-c Meade Dsi-Pro II Plillips SPC900NC Post Extras:       DaemonGPF Pooh-Bah Reged: 03/22/08 Posts: 1452 Loc: New Mexico Re: PHD autoguiding and DEC issue [Re: chutch44]       #2557716 - 08/03/08 02:06 PM Edit   Reply   Quote Quick Reply   Thanks for the tip guys, I didn't even change the step size come to think of it. I'll give it a go tonight and see what happens. I did adjust the backlash settings as much as possible on the CG5 and it's about as good as it will get without modification right now. The backlash seems to be negligable since I put shorter and lighter OTAs on top. -------------------- -Josh *Orion Starblast Imaging 150mm OTA *Orion Starblast Imaging 114mm OTA *Meade 50mm AR short tube OTA *Meade DSI Pro IIc *Orion Starshoot DSCI *CG5 mount http://cleardarksky.com/c/AlbuqNMkey.html My Messier Project Gallery Post Extras:       DaemonGPF Pooh-Bah Reged: 03/22/08 Posts: 1452 Loc: New Mexico Re: PHD autoguiding and DEC issue [Re: DaemonGPF]       #2557723 - 08/03/08 02:09 PM Edit   Reply   Quote Quick Reply   Quick question, what exactly does the "Dec Algorithm" settings do? It has "low pass filter" and "resist switching" as options. -------------------- -Josh *Orion Starblast Imaging 150mm OTA *Orion Starblast Imaging 114mm OTA *Meade 50mm AR short tube OTA *Meade DSI Pro IIc *Orion Starshoot DSCI *CG5 mount http://cleardarksky.com/c/AlbuqNMkey.html My Messier Project Gallery Post Extras:       Nils_Lars scholastic sledgehammer Reged: 01/04/08 Posts: 977 Loc: Santa Cruz Mountains , CA Re: PHD autoguiding and DEC issue [Re: DaemonGPF]       #2557910 - 08/03/08 04:08 PM Edit   Reply   Quote Quick Reply   I have the same mount and opened the cases and tightened the worm gear mesh a tiny bit and it on both motors and get much less backlash. I also added some foam inside the cases where they wont touch the motors and cuts the noise alot , people still call me the coffee grinder at star partys though -------------------- Erik Orion ED 80 Orion Atlas GOTO mount Williams Optics reducer Various eyepieces and other gear Baytronix 80mm guidescope Orion Starshoot Autoguider PHD guide Canon 400D (unmodded) Stilleto Focuser Tamron 75-300mm&28-80mm lenses NexImage webcam http://home.comcast.net/~eriknlarsen/site/?/photos/ Post Extras:       DaemonGPF Pooh-Bah Reged: 03/22/08 Posts: 1452 Loc: New Mexico Re: PHD autoguiding and DEC issue [Re: Nils_Lars]       #2557924 - 08/03/08 04:21 PM Edit   Reply   Quote Quick Reply   ROTFLMAO! I can see how they would.. My CG5 makes considerable noise. The foam idea sounds great, I might try that. I'm hesitant, but I've been tempted to try the astronomy boy mods to see if I can clean up the gears a bit. The backlash is tremendously improved after swapping to a 6" OTA from the 10", but there's room to improve. -------------------- -Josh *Orion Starblast Imaging 150mm OTA *Orion Starblast Imaging 114mm OTA *Meade 50mm AR short tube OTA *Meade DSI Pro IIc *Orion Starshoot DSCI *CG5 mount http://cleardarksky.com/c/AlbuqNMkey.html My Messier Project Gallery Post Extras:       Nils_Lars scholastic sledgehammer Reged: 01/04/08 Posts: 977 Loc: Santa Cruz Mountains , CA Re: PHD autoguiding and DEC issue [Re: DaemonGPF]       #2558684 - 08/04/08 12:50 AM Edit   Reply   Quote Quick Reply   Yes I used his site but I didnt actually take anything apart , I just tightened a few things and some of them tighten by going counter clockwise so read his site for sure. -------------------- Erik Orion ED 80 Orion Atlas GOTO mount Williams Optics reducer Various eyepieces and other gear Baytronix 80mm guidescope Orion Starshoot Autoguider PHD guide Canon 400D (unmodded) Stilleto Focuser Tamron 75-300mm&28-80mm lenses NexImage webcam http://home.comcast.net/~eriknlarsen/site/?/photos/ Post Extras:       scully1234 super member Reged: 09/04/07 Posts: 144 Loc: Rush, NY Re: PHD autoguiding and DEC issue [Re: Nils_Lars]       #2558965 - 08/04/08 08:06 AM Edit   Reply   Quote Quick Reply   Hey guys, I use PHD frequently. The "Calibration step size" in PHD refers to the DURATION of the pulse sent to the mount during the calibration phase. If you increase this number, it allows PHD to run the motors on the mount for a longer pulse during the calibration so that PHD can see the guide star begin moving a greater distance for each pulse it sends to the mount. This can compensate for sloppy gears, or if you are pointed near the NCP the mount will need to moved a greater distance for each correction pulse before PHD will see the guide star move in response to the correction. You can tell if the DEC gear backlash on the mount is excessive if you set the calibration step in PHD to greater than 1500 and PHD indicates that it took more than 5 or 6 steps in the "CLEARING DEC BACKLASH" portion of the calibration routine. I have the CG-5GT mount and with my backlash settings in the CG5 menu set for 10% it only takes PHD about 3 steps to clear the dec backlash before it begins calibrating North and South. -------------------- Astrophotographer wannabee ! Celestron C8 XLT on the CG-5 mount Meade 70mm AZ guide scope Nikon D50 DSI color Canon A530 point-n-shoot Post Extras:       DaemonGPF Pooh-Bah Reged: 03/22/08 Posts: 1452 Loc: New Mexico Re: PHD autoguiding and DEC issue [Re: scully1234]       #2559077 - 08/04/08 09:23 AM Edit   Reply   Quote Quick Reply   I didn't get a chance to test this out last night as the clouds rolled in out of nowhere. Looks like I won't have a shot at it until Tuesday night. -------------------- -Josh *Orion Starblast Imaging 150mm OTA *Orion Starblast Imaging 114mm OTA *Meade 50mm AR short tube OTA *Meade DSI Pro IIc *Orion Starshoot DSCI *CG5 mount http://cleardarksky.com/c/AlbuqNMkey.html My Messier Project Gallery Post Extras:       zwoof sage Reged: 06/11/07 Posts: 222 Loc: NC Re: PHD autoguiding and DEC issue [Re: DaemonGPF]       #2563637 - 08/06/08 10:45 AM Edit   Reply   Quote Quick Reply   Make sure DEC guide mode is set to auto. I had the same problem and after rebooting the PC and starting PhD again it worked every time with DEC set to auto. -------------------- CPC800 XLT DSI -C Orion ST80 CG-5 GT mount Orion 120 ST Celestron 80ED Canon Rebel XT unmodded STI focuser HD wedge on homemade pier 1965 Corvair Corsa Turbo - For Sale! Post Extras:       DaemonGPF Pooh-Bah Reged: 03/22/08 Posts: 1452 Loc: New Mexico Re: PHD autoguiding and DEC issue [Re: zwoof]       #2564671 - 08/06/08 06:55 PM Edit   Reply   Quote Quick Reply   I was wondering about that. Does it work better than just setting it to "North"? -------------------- -Josh *Orion Starblast Imaging 150mm OTA *Orion Starblast Imaging 114mm OTA *Meade 50mm AR short tube OTA *Meade DSI Pro IIc *Orion Starshoot DSCI *CG5 mount http://cleardarksky.com/c/AlbuqNMkey.html My Messier Project Gallery Post Extras:       Qkslvr Pooh-Bah Reged: 06/23/06 Posts: 1052 Loc: NE Ohio, US Re: PHD autoguiding and DEC issue [Re: DaemonGPF]       #2565279 - 08/06/08 11:53 PM Edit   Reply   Quote Quick Reply   The only time I have that problem is if my Dec balance is way off. Do you dismount the scope between sessions? -------------------- Mike N8/CG-5/40D Coming sometime/Maybe FrankenRebel Post Extras:       DaemonGPF Pooh-Bah Reged: 03/22/08 Posts: 1452 Loc: New Mexico Re: PHD autoguiding and DEC issue [Re: Qkslvr]       #2566801 - 08/07/08 06:11 PM Edit   Reply   Quote Quick Reply   I always tear down the optics and weights each session. I rebalance every time I set up. -------------------- -Josh *Orion Starblast Imaging 150mm OTA *Orion Starblast Imaging 114mm OTA *Meade 50mm AR short tube OTA *Meade DSI Pro IIc *Orion Starshoot DSCI *CG5 mount http://cleardarksky.com/c/AlbuqNMkey.html My Messier Project Gallery Post Extras:       Qkslvr Pooh-Bah Reged: 06/23/06 Posts: 1052 Loc: NE Ohio, US Re: PHD autoguiding and DEC issue [Re: DaemonGPF]       #2566921 - 08/07/08 07:14 PM Edit   Reply   Quote Quick Reply   Try making the down end of the scope a little heavier in balance than the up end. -------------------- Mike N8/CG-5/40D Coming sometime/Maybe FrankenRebel Post Extras:       Pages: 1 Previous   Index   Next   Threaded   Extra information 7 registered and 8 anonymous users are browsing this forum. 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