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Old 25-10-2010, 07:31 PM
TrevorW
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PHD and Orion SSAG

I've been having some issues lately where it's taking several tries before PHD will track in DEC

RA hasn't been an issue

has anyone experienced similar problems

scope balance is not an issue

once sorted PHD will track perfectly for several shots and then for no reason I can think of lose DEC tracking


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Old 25-10-2010, 07:45 PM
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Always had problems with PHD; and still often come across problems using MaxDL as well.
Could be anything; comms issue; software issue; guider issue; config settings.

What do you mean by several tries before it gets going. I assume you mean several re-calibrations?

Best to post any issues over at the Stark Labs Yahoo Group; plenty of folks over there that could assist.
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Old 25-10-2010, 07:54 PM
TrevorW
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Thanks Dan

yes, several re calibrations DEC just goes off the graph

I have Maxim will it recognise the Orion SSAG or do I need to get drivers
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Old 25-10-2010, 08:03 PM
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Yes maxim will recognise the orion guider. You should also have the disk that came with it that has the system drivers on it

Mark
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Old 25-10-2010, 08:29 PM
TrevorW
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Thanks Mark will check
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Old 25-10-2010, 08:34 PM
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multiweb (Marc)
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Quote:
Originally Posted by TrevorW View Post
once sorted PHD will track perfectly for several shots and then for no reason I can think of lose DEC tracking
When you track in RA your scope balance in DEC changes. As a result PHD DEC tracking will drift north or south. If this happens, stop tracking, re-calibrate in place on the same star, load the worm in DEC and start guiding again. I garantee you that your DEC drift will be gone.
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Old 25-10-2010, 08:47 PM
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Thanks Marc, what do you mean by load the worm in DEC ??
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Old 25-10-2010, 08:53 PM
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Thanks Marc, what do you mean by load the worm in DEC ??
You always load the worm whether in DEC or in RA so you have no backlash and you always push the load. If your DEC drifts north or south guide in the opposite direction until it settles then reduce the max dec duration value to smooth out the corrections then you're good to go until balance shifts again.
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Old 25-10-2010, 09:02 PM
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Ok, thanks, I get your drift
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Old 30-10-2010, 02:48 AM
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Well tonight for the life of me I could not get PHD to track in DEC either direction.

Even resintalled it, in the end I gave up and went over to using Maxim well the instructions in the PHD booklet are for an earlier version of Maxim but I just set exposure length, expose, picked a star, calibrated the set too track, was all I needed to do and it works no problems.

Why didn't I use it sooner
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Old 30-10-2010, 11:00 AM
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Quote:
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Why didn't I use it sooner
Dont know Trev but I reckon you were very lucky to get it working with no tweaking


Mark
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Old 30-10-2010, 02:01 PM
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Hey Mark send me some instructions for tweaking, the graph was up and down a bit but seemed to track Ok although last night the easterley wind really picked up

Cheers
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Old 30-10-2010, 03:27 PM
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Trevor if the graph was over shooting the guide point your corrections are too aggressive or backlash is comming into play. The best thing about maxim is that most of the following changes can be made on the fly so you adjust in real time and get instant feedback on any changes made. There are 3 main windows you can use to tweak guiding in ver 5.

Window 1: This is the first window you see when you select the guide tab from the camera control window. If you open the options tab click on the "fine aggressiveness" to enable it. This allows you to adjust the correction aggressiveness in 0.1 increments rather then 1.0 which means much finer tunning. You should also set the camera for simple dark calibration under the options tab as it applies darks on the run and there is less noise for the program to sift through. If you then click on the graph tab in the guide window to open the graph, click on the arrow at the bottom and another menu appears. Choose plot --> set telescope axes. The graph plots these rather then the the Dx, Dy of the camera. The X axes is usually RA but you will need to verify this as it depends on which way you have the camera set. I find this really useful as it allows you to diagnose which axes is playing up (eg bad balance, snagged cables etc). You can also set the scale of the graph in this tab (usually use +/- 1 pixel). If you start at the recommended 8.0 (80% correction) and tweak away until your curve is as flat as possible. My mount also has guide rate correction settings ( 0 - 2x sidereal) in the controller which I also use to flatten it some more. I set the RA to 0.6X and dec is left at 1.0X (getting nice round stars).

Window 2: If you select the settings tab from the main guide window you will open the guider settings window. At the top left are the cal time tabs for x and y. I find my guiding is best when I set these so the scope slews at least 30 pixels in the x and y directions during calibration ( I usually aim for about 50 pixels with a time setting of about 15 - 20 secs). Next to these are the backlash settings which I leave at 0 - 0.2 mostly as my mount has very little backlash. You should always have all backlash settings turned off on your mount control as they will interfere with the guiding and set any backlash compensation from here. You can leave all the guider enables x and y boxes ticked unless your mount has shocking backlash in which case you may wish to correct against the drift only. It also pays to have the mount connected through the telescope window as this will supply all the info to maxim and you wont have to use the manual calibration settings and scope dec is automatically read as is pier flip etc so you do not need to recalibrate if you move to a different target. You can also bin the camera 2 x 2 here which makes it more sensitive.

Window 3: If you click the advanced tab in the guider settings window you will be presented with even more options. Under the guiding settings (top left) I usually leave the standard settings with the exception of delay between corrections. I often set this to 1.5 - 2 sec delay but it really depends on the seeing and the exposure time you are using with the guide cam, just adjust to get the best results. I also leave the move command settings alone as well. Under guider motor control uncheck both "y is RA and enable simualtaneous x and y corrections". I dont know about how the EQ6/EQmode responds to simualtaneous corrections but it plays merry hell on the SXD and is not really necessary.

As with all things in maxim you are never just working from one window. I have already mentioned having the mount connected in the telescope window as this supplies necessary info to the guiding function. Another very useful feature I also use is in the camera control window under the autosave tab. Here you have a "delay between" function that will set an interval between the camera downloading an image and the start of the next exposure. This is handy with the QHY camera's running the ascom driver with the "No USB During Download" checked. When the camera is downloading the guiding in maxim is stopped and when it commences again the program can sometimes impose large movements if the guide star has moved too much during the down time depending on the aggressiveness used in the correction settings. I set a 1 - 2 min interval between downloading and starting a new exposure as it gives the mount time to settle and the guiding to get back on track. Of course if you are using a mono camera with filters the autosave window is bliss. You could also use the autosave for a OSC sequence (including darks and flats) and that way it is set and forget allowing you to concentrate on other things (like beer wine and spirits).


Hope that helps

Mark

Last edited by marki; 01-11-2010 at 10:36 PM.
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Old 30-10-2010, 03:43 PM
TrevorW
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A bit to digest

thanks
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Old 14-11-2010, 10:29 AM
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I'm still having issues and was wondering has anyone had a cable problem with their guider
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Old 15-11-2010, 03:56 PM
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Quote:
Originally Posted by marki View Post
Yes maxim will recognise the orion guider. You should also have the disk that came with it that has the system drivers on it

Mark
It does, but I seem to recall some period a year or so back where Orion brought in new drivers and so Maxim updated to use them and stopped using the old ones. No problem if you update everything, or have an earlier version of Maxim.
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Old 15-11-2010, 11:31 PM
TrevorW
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Well I don't know what I did spent some time with Alignmaster tonight although the AZ adjustments on an EQ6 is useless just no movement at all in it (do you have to take the head off an adjust the nut up or what) and the ALT is a PITA I got it reasonably well aligned although I don't have a horizonal view I had to wait for any of the suggested stars to rise high enough for me to align on.

Anyhow I set PHD working again and its going along very well with a relatively small sawtooth pattern in the graph.
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