emutz
sage
Reged: 02/15/06
Posts: 354
Loc: Pensacola, Fl
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I hope that someone here on the forum might be able to help me with a problem I am having with calibrating PHD.
I have a StarShoot Autoguider (SSAG) attached to an off-axis guider on my LX200 10" scope. The camera connects to the autoguider port on my AP1200 either via the SSAG built in guider relays, or via a GPUSB. I can connect both the camera and the autoguider relays or GPUSB in PHD without problem.
The difficulty I am having is the apparent lack of movement in all four directions when calibrating. After selecting a star to calibrate on, PHD moves the mount to the west (West 1). The second command is East 1. However, instead of moving back to the original starting position, the mount moves again in the same direction as the first West 1 movement. The same holds true for the N-S axis. North 1 movement moves the mount in one direction. The corrective South 1 movement continues the mount's movement in the same direction. It is almost as if the mount is not receiving commands to reverse directions. This problem occurs if I connect via the built in autoguider relays on the SSAG, or if I connect via the GPUSB.
The settings for PHD are the default with the exception of decreasing the movement for calibration to 150ms (to keep the star from flying off the camera chip).
Any help would be greatly appreciated!
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Fabio Papa
Pooh-Bah
Reged: 03/01/05
Posts: 1460
Loc: Piacenza, Italy
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You're saying that PHD only sends 1 guiding pulse in both west and north before switching direction? That's way way too low a number. It should give from 10 to 20 pulese to obtain a good calibration.
Also, another clue could be you saying a 150ms pulse is required or else the stars jumps off screen. This makes me think you have a too fast speed set into your mount computer. Usually a 0.5x sideral is used as guide speed.
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Fabio Papa
Celestron C8 F/10
Vixen ED81SWT F/7.7
Orion Atlas EQ-G
Gruppo Astrofili di Piacenza
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emutz
sage
Reged: 02/15/06
Posts: 354
Loc: Pensacola, Fl
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Thank you for the suggestions, I will try and set them tonight.
Another person suggested that I need a RJ-12 crossover cable. It may be that the Orion SSAG/GPUSB uses one set of connections and the autoguider port on my AP1200 uses the opposite connector arrangement.
Does anyone know where I can buy a crossover cable to fix this problem on the internet? I cannot believe I am the first one to run into this problem! Any advice would be appreciated!
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LLEEGE
Running out of Oxygen
Reged: 03/03/05
Posts: 9082
Loc: Cloud-chester,NY
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Sounds like a cable issue. IIRC, the GPUSB uses a straight through configuration and the SSAG is a cross over.
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"Okay! You draw the straws. I'm-a taking the parachute."
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LLEEGE
Running out of Oxygen
Reged: 03/03/05
Posts: 9082
Loc: Cloud-chester,NY
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The 1200 is a standard ST4 port. You can make your own with parts from RAdioshack or Shoestring Astronomy sells them.
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"Okay! You draw the straws. I'm-a taking the parachute."
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quantumac
sage
Reged: 12/17/07
Posts: 389
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Bought my RJ-12 cable from Shoestring Astronomy. Works great, and I didn't risk a mistake making my own.
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Scope: Meade 10" LX200R
Guide/Planetary Camera: Imaging Source DBK41AF02.AS
DSO Camera: QHY8
Guide Hardware: Celestron OAG, Shoestring Astronomy GPUSB
Software: Mac OS X, Starry Night Pro, Nebulosity, PHD Guiding, PixInsight, Astro IIDC. No Windows anything.
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DanB
scholastic sledgehammer
Reged: 12/05/07
Posts: 837
Loc: Pacific Northwest
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Quote:
Bought my RJ-12 cable from Shoestring Astronomy. Works great, and I didn't risk a mistake making my own.
Yea, Shoestring is fast too. I typically get my items in 3 days when I order from them:-)
Dan
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AT8RC astrograph
AT80ED refractor (guidescope)
10" Meade f4.5 reflector
8" Meade f6 reflector
EQ6 Skywatcher/Synscan
Meade DSI (Guide camera)
CCD Labs Q453 (Main imager)
Nebulosity 2
PHD guiding
"In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual".
- Galileo Galile -
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emutz
sage
Reged: 02/15/06
Posts: 354
Loc: Pensacola, Fl
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An update to see if you all can help me more.
I found an old SBIG autoguider cable that seems to have been a crossover cable. The small blue wire is on the left on one end and on the right on the other (when holding the cable in the same orientation). I swapped this cable out with the straight through cable that I had been using. After that, the mount did not move at all in response to calibration commands from PHD. So, I guess that is not the problem.
Since I have never gotten PHD to work quite right I am not sure what the normal star motions are during calibration. How do the stars move for you usually? Do you see distinct motion in all 4 directions? Or do the motions seem to be along only 2 axis?
Last night I decreased the ms movement time to about 50ms and PHD seemed to be able the calibrate the mount. While the stars did not move cleanly along the calibration axes during the calibration routine, the star did stay in the small green box. Afterwards I received a "now guiding" message. PHD did guide on the star for several minutes. After 4 or 5 min however, it lost the star and stopped tracking. The motion of the star was slight but noticeable while guiding. What settings would help keep the guide star in the box? Some progress however!
I am not sure what to try now. The crossover cable did not work but I can get marginal guiding on a star using my existing GPUSB and cable. Buy a replacement cable? Alter settings in PHD?
Any help would be appreciated!
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Fabio Papa
Pooh-Bah
Reged: 03/01/05
Posts: 1460
Loc: Piacenza, Italy
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50ms is way too low! Something is strange. Have you checked the guiding speed in your mount computer? What's its setting?
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Fabio Papa
Celestron C8 F/10
Vixen ED81SWT F/7.7
Orion Atlas EQ-G
Gruppo Astrofili di Piacenza
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blueman
Vendor Blue Sky Accessories
Reged: 07/20/07
Posts: 1435
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Let me get something straight.
Do you plug the cable provided with the SSAG into the SSAG and then into the ST4 guide port (which is the way I do it) or do you plug the SSAG into a GPUSB and then into the ST4 guide port? I do not think the SSAG will work using the GPUSB.
I use two different cables with my SSAG, one is a coiled cord that I used with the GPUSB and the other is the one that came with the SSAG. Both work well and I just checked them both, they are not a reversed or Null Modem type cables, just a straight through type.
You may have to increase the min movement until you see movement. I assume that you reduced it because you saw it "jumping off of the screen"?
Guide rate? I used .5 for a while, but recently increased it to .8 which I feel does seem to work better.
I have a G-11 not an AP mount, but they both use the ST4 guide port. But maybe there is something different about the AP mount?
Blueman
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14.5" Starmaster with ServoCat and Argo Navis
AT 8" RC
TV NP101 f/5.4 APO Telvue .8 Focal Reducer
WO 80mm f/6 APO Televue .8 focal reducer
SBig ST2000xm with CFW-9 filter wheel
Astrodon Gen2 filters RGBL
Baader HA,O-III, H-Beta, S-II Filters
Losmandy G-11 Gemini Auto-guided
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Mike Clemens
Post Laureate
Reged: 11/26/05
Posts: 4289
Loc: Wasilla, Alaska 61N
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I am using a GP-USB with an AP1200 with great results from PHD.
I did make a custom cable to the specs in this:
http://www.store.shoestringastronomy.com/User_Manual_GPUSB.pdf
I have guide speed set to 0.5x make sure your guiding speed is good on your AP1200.
I'll get all my calibration settings from PHD today.
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blueman
Vendor Blue Sky Accessories
Reged: 07/20/07
Posts: 1435
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Hi Mike,
Why would the GPUSB be needed with the SSAG? It does not require the interface to work with the ST4 port.
Blueman
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14.5" Starmaster with ServoCat and Argo Navis
AT 8" RC
TV NP101 f/5.4 APO Telvue .8 Focal Reducer
WO 80mm f/6 APO Televue .8 focal reducer
SBig ST2000xm with CFW-9 filter wheel
Astrodon Gen2 filters RGBL
Baader HA,O-III, H-Beta, S-II Filters
Losmandy G-11 Gemini Auto-guided
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ZMass
sage
Reged: 11/07/07
Posts: 269
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It sounds like your settings are crazy. Post an image of your settings like I have below. Use the correct straight cable as mentioned by others. My settings are for an f5 scope with a DSI pro attached - yours will be different, but not ridiculously so.
The important setting for calibration is "calibration step (ms)" - set lower than mine (maybe 400-800?). Key is for it to count out maybe 5-10 steps as it calibrates in each direction.
When mine calibrates, here is the routine it goes through:
1) East or West (not sure which is first) counts to 7ish.
2) West or East (the other one) counts to 7ish
3) Clearing backlash...
4) North counts to 7ish
5) South counts to 7ish (I actually get very little movement in the south direction - it seems to just clear backlash for south then starts guiding.)
6) Guiding
The direction it moves during this time depends on the angle that your camera is attached to the scope but doesn't matter, PHD will figure itself out.
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-Zeke Mass
Encinitas, CA
6" Custom Newt on CG5
CCD Labs Q285M (Qhy2 Pro)
ST-80 guide-scope with DSI Pro
Edited by ZMass (11/04/09 05:01 PM)
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emutz
sage
Reged: 02/15/06
Posts: 354
Loc: Pensacola, Fl
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I have both the direct cable that connects the SSAG to the ST4 port on my AP1200. I also have a GPUSB with the coiled cable. I can swap them out and have tried one or the other, but not both plugged in at once.
I might need to cut my guide rate to .5x. Will that help with guiding? I am just confused as to why the callibration routine moves well in 2 directions and not so well in the other two directions.
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Bert Burch
member
Reged: 01/06/09
Posts: 79
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I am having the same problem. I have both a CGE and a CG5, same results on both if I use the ST-4 port. nothing works, but if I use ASCOM and conenct via my hand controller, all works well. Not sure why it is not controlling directly via the ST-4 port,
could it be that I am not polar aligned enough and that the ST-4 can go only up to 1x Sideral but going thru the HC it can go faster, therfore catching up with the bad alignemnt?
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EspacioProfundo
Vendor-Espacio Profundo
Reged: 02/16/07
Posts: 30
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Maybe this helps, I had the same problem, tested the SSAG with several scopes with no luck, the problem is that the SSAG is broken. In PHDGuide connect the camera to the ST4 port and do a "manual guiding", check if the mount works moving the E,W,S,N arrows, mine only work on E and S. The cable is ok, the SSAG seems to be broken since it's not sending pulses on W and N.
Regards
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Ricardo Contreras
Espacio Profundo
Buenos Aires
Argentina
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emutz
sage
Reged: 02/15/06
Posts: 354
Loc: Pensacola, Fl
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As a followup I discovered that the problem was partly due to the guiding rate being set too high on the hand controller on my mount. Setting the guide rate to .5 or .25 produced about 20 steps in each direction. Just as Fabio said!
While I got the PHD guiding to work ok, I found a manual callibration for maximDL. This works great and allowed me to callibrate the guider and then guide in Maxim.
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