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Puzzling problem

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Hi everyone,

For two nights, I have had exactly the same thing happen. I am taking a four plate mosaic of M31. The first plate goes flawlessly, but when the command to move a small distance to the next plate comes, there has been a problem both nights. The slew takes an abnormal amount of time but finally ends. When the plate solving picture is taken there are star trails, indicating that the mount is still moving. After trying to resolve it my connecting and disconnecting the software, both nights I have finally had to resort to parking the mount at CWD and turning Gemini off and then back on. When I go out to the mount it is not at exact CWD position. The RA is off about 20 degrees.


When I correct the CWD and restart Gemini, everything works fine for the remaining three plates, including a meridian flip. I can find nothing binding on the mount that might have caused this problem, but to me that seems to be?the most likely culprit.


Does anyone have any other ideas?


Rob ?
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Futher update. Tonight it did the same thing on the third frame. This time I went out to check the mount before I sent it to CWD. I found that it had tried to "bend over backwards" or in other wards it had been sent looking for something in the Western sky?without?meridian flipping. The leg?of the mount stopped it, and, yes, I had put in safety limits. I believe this is what is happening every time.?On this particular time it had slewed to the new position fine and was only 97 pixtels from being centered. On the next move to bring it to within 50, it went flying off to the west.


For the last month and a half and through literally hundreds of subs, I have cold started the mount and let the plate solving software of SGP tell it where to go. This has gone on flawlessly until I left on a 5 day trip. When I came back, this problem began.?


I have gone line by line through the Gemini settings and found nothing amiss. I have no idea where to go with it now.


Thanks in advance for a suggestions you can offer.


Rob
 

Rob,

my guesses ...follow:

1. Use Gemini.net to look at the values of your Model (the "T-model").? When the errors occur, write down the parameyers and their values.? ?Then "reload model from PC" which should be your hood stored model from when you reboot your PC connection.? Compare the values:? do you see any whacky values there when the system misbehaved?

2. How can pointing errors come sbpit? If you left "Synch performs additional Align " checked on the Gemini.net then perhaps your simple slew could have resulted in a pointing model error.??

I'd further guess that when you rebooted the Gemini, it can reload you good stored PC model back and made everthing work swell.... til the next slew and synch...

3. My reasoning was:?

Physical cable snags, or clutch slips, are possible,? but your "long time to slew" was a clue the mount went somewhere else far away, as you discovered.? So it's a Gemini calculation error.? That error comes from bad model values...

best regards, and good luck,?
Michael?

On Oct 4, 2017 02:42, "sactowriter@... [Losmandy_users]" <Losmandy_users@...> wrote:
?

Futher update. Tonight it did the same thing on the third frame. This time I went out to check the mount before I sent it to CWD. I found that it had tried to "bend over backwards" or in other wards it had been sent looking for something in the Western sky?without?meridian flipping. The leg?of the mount stopped it, and, yes, I had put in safety limits. I believe this is what is happening every time.?On this particular time it had slewed to the new position fine and was only 97 pixtels from being centered. On the next move to bring it to within 50, it went flying off to the west.


For the last month and a half and through literally hundreds of subs, I have cold started the mount and let the plate solving software of SGP tell it where to go. This has gone on flawlessly until I left on a 5 day trip. When I came back, this problem began.?


I have gone line by line through the Gemini settings and found nothing amiss. I have no idea where to go with it now.


Thanks in advance for a suggestions you can offer.


Rob
 

Rob,?

Here are some initial thoughts:
  • Reset your Gemini by taking out the internal 3v battery for a few minutes. Replace it with a fresh one, just in case
  • Make sure you set all correct settings, including time zone and time, geo location, mount type?
  • Make sure you start as close to CWD position as you can
  • Double-check that your motor cables are plugged in well, making good contact.
  • Check that your oldham couplers are not slipping and the set screws are tightened down
  • Check that your clutches hold well and do not slip
Regards,

? -Paul
 

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Rob
Is this a Gemini-2, if so make sure you have the latest .

Tom H
On 10/3/2017 11:40 PM, sactowriter@... [Losmandy_users] wrote:

?

Hi everyone,

For two nights, I have had exactly the same thing happen. I am taking a four plate mosaic of M31. The first plate goes flawlessly, but when the command to move a small distance to the next plate comes, there has been a problem both nights. The slew takes an abnormal amount of time but finally ends. When the plate solving picture is taken there are star trails, indicating that the mount is still moving. After trying to resolve it my connecting and disconnecting the software, both nights I have finally had to resort to parking the mount at CWD and turning Gemini off and then back on. When I go out to the mount it is not at exact CWD position. The RA is off about 20 degrees.


When I correct the CWD and restart Gemini, everything works fine for the remaining three plates, including a meridian flip. I can find nothing binding on the mount that might have caused this problem, but to me that seems to be?the most likely culprit.


Does anyone have any other ideas?


Rob ?
 

¿ªÔÆÌåÓý

I¡¯ve had a similar behavior.

?

This appears to happen when I¡¯m pointing east, and the G11 doesn¡¯t swap the meridian on the way to parking.

I go out there and the weights are 30 degrees up in the east and the scope is 30 degrees buried in the west.

It hits the safety limit. Not the park position. The park request is initiated from SGP after a sequence is completed.

?

Another incident:

Last week while trying out a 3 hour run, a meridian auto flip was executed half way through, and a plate solve done, but then the mount went back to the west side again and hit the safety limit.

?

Doug Bock
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Thanks everyone,

Wish me luck tonight. I have reinstalled the firmware--it appears that I already had the most current, but I reinstalled anyway. I went line by line through every setting in Gemini to make sure that they were all correct--to the best of my knowledge. I confirmed that there is plenty of power in the battery.?I installed the latest version of the Gemini.net ASCOM driver. I am going to reinstall SGP, just to make sure it isn't the culprit. I had one other thought that maybe the network cable between my computer and Gemini might be faulty. If what I have done so far does not solve the problem, I will try changing that.


As far as the model goes, I'm not using modeling. I have for some time been letting the plate solving software in SGP direct the mount. This is why I suspect a communication problem, though PHD2 has performed flawlessly through all of this and it uses Gemini.net also...we shall see.


What are good safety settings for the mount. I have 124degrees on the?right and 114 on? left. These give left side safety position of 1881600 and right side of 365800. The Western goto limit is 2 degrees 30minutes. This does not seem to be working, as the camera hit the mount.


I really appreciate your responses.


Rob Fink
 

Rob, all sounds good.... the rest is experimentation.??

(I think you are saying your Gemini model shows all parameters at value 0.? This is what you get with a cold boot up.? There is no reason I can think of for your Gemini to go way off kilter from that.)

Good luck!

Michael?



On Oct 4, 2017 7:43 PM, "sactowriter@... [Losmandy_users]" <Losmandy_users@...> wrote:
?

Thanks everyone,

Wish me luck tonight. I have reinstalled the firmware--it appears that I already had the most current, but I reinstalled anyway. I went line by line through every setting in Gemini to make sure that they were all correct--to the best of my knowledge. I confirmed that there is plenty of power in the battery.?I installed the latest version of the Gemini.net ASCOM driver. I am going to reinstall SGP, just to make sure it isn't the culprit. I had one other thought that maybe the network cable between my computer and Gemini might be faulty. If what I have done so far does not solve the problem, I will try changing that.


As far as the model goes, I'm not using modeling. I have for some time been letting the plate solving software in SGP direct the mount. This is why I suspect a communication problem, though PHD2 has performed flawlessly through all of this and it uses Gemini.net also...we shall see.


What are good safety settings for the mount. I have 124degrees on the?right and 114 on? left. These give left side safety position of 1881600 and right side of 365800. The Western goto limit is 2 degrees 30minutes. This does not seem to be working, as the camera hit the mount.


I really appreciate your responses.


Rob Fink
[email protected]
 

Update: I believe that the problem is solved. It appears that it was a faulty network cable. Because of your comments, I had a lot of options to consider, now and in the future with other problems. Thanks to you, I have examined for the first time my safety limits and realzed that Gemini 2 default limits are way off from what I need for my telescope and camera,. Man, am I ever grateful for clutches.

Rob

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