leaving tracking - DDM85 standard

[astrobry]

I notice a strange behavior of the DDM85. When I do an imaging run during the night, I see almost every night that some images failed in tracking.  I couldn’t reproduce that phenomenon , by putting the telescope on the same position and see what happens. I thought there is some problem with balance or so. Nothing happens, just perfect tracking, until I yesterday morning during a imaging run, I was just near the telescope while the imaging run was busy for a while, suddenly,  I see the DEC axis was leaving his position for few seconds for a couple of degrees then came back to the correct position. Very strange, I don’t know why ? I did'nt touch anything.

 

I use a windows 7 PC 64 bit, with The Sky 6 Pro, CCD-Commander (last version), MaximDL (last version), Ascom Poth, and a FLI Atlas focuser (via ASCOM controlled -via MaximDL)

 

Anybod an idea why this is happen ?

 

thanks for reading,

 

best regards

Erik

[Jay]

Hi Erik

 

I'm afraid you might have a problem. I noticed similar behavior with my DDM60 sometime ago. Couldn't figure out why I lost frames every know and then (trailing stars) even everything seemed to be functioning well. Then one night noticed that the RA axis suddenly moved forward while tracking and returned to the same exact position right after.

After a while I also started getting "position error" messages which caused the motors to shut down. Had a remote session and the mount had to be sent back to service. I was told one of the bearings was defected. 

 

You might want to record some CLservo logfiles to see if there are current peaks during the night while the mount is tracking. I had high current peaks that stalled the motors because the current limit was reached.

 

Jay

[astrobry]

Hi Jay,

 

Hmmmm..., Sounds not so good...  I'll check first the logfiltes and then contact ASA-support.  Thanks for the tip !!

Erik

[astrobry]

still no answer or reaction from ASA-support...

 

The mount was checked few days ago from ASA Support. Dietmar Weinzinger

[Jay]

Hi Erik 

 

Did you check out the CLservo logfiles. Any current peaks ? Because if the problem is there the peaks are easily noticeable.

 

Best

Jay

[astrobry]

Hi Jay,

 

Thanks for your reply! i checked the log files and i see increasing current, then i see a sort of repositioning of the mount, the current is dropped for a while and then it is increasing again until about 5 AMPS.  On 3 dec. i get answer from ASA support and recommended me to send the mount to ASA, what i did on 3 dec. Now i'm waiting until the mount is back. Possible problem is the bearing, but we wait and see...

 

cheers

Erik

[jfd]

Erik, Have you received  back the mountt repaired from ASA? Were the bearings the problem?

 

Joaquin

[astrobry]

Hi Joaquin,

 

I have my mount back since 2 days, they told me that the bearing of the DEC was the problem and is changed.  I must install my moun this weekend, but i see now a problem with the GALV connectors. On the DEC axis is this now a 6-pin connector. Before it was a 4-PIN connector. On the RA axis is this still a 4-pin connector. trange, don't now how to connect my camera, because i use this connector for power of my CCD-camera.  I'll try to make some measures to see how the pins now are configured. I don't know why this is changed... but it is a mystery how these connectors GALV on RA and GAKV on DEC) are now connected.

[Sebastian]

Salut Eric,

 

I have a fairly new DDM85 which came with the 6-pin connector - I expected it to be a 4-pin.

 

What I found out is, there are now two additional pins for +/-12V comming from the OK3 +12V gray and GND yellow.

 

I was told it was a modification for things to come in the future.

 

Regards

 

Sebastian

Belegungsplan_ASA_DDM85.pdf