Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

EQ8 broken?

  • Please log in to reply
8 replies to this topic

#1 starhopper-de

starhopper-de

    Sputnik

  • -----
  • topic starter
  • Posts: 26
  • Joined: 18 Apr 2009
  • Loc: Germany, EU

Posted 15 September 2019 - 03:54 AM

Hello forum,

 

I got a EQ8 for 2 years in my garden observatory, yesterday a great issue appeared.

After a successfull one- or two star alignment, the displayed current coordinates are wrong and a goto fails in any case. Moving the mount with the handbox does not update the coordinates well. It seems to hang randomly.

I had to disable "auxilary encoders" to get it work again. A factory reset had not worked.

 

Has anybody encountered such a behaviour? Can I repair it myself?

 

Thomas

 



#2 StrStrck

StrStrck

    Viking 1

  • *****
  • Posts: 970
  • Joined: 19 Mar 2017
  • Loc: Denmark

Posted 15 September 2019 - 02:09 PM

Perhaps the electronics have corroded? Or is your power source kaput?



#3 macdonjh

macdonjh

    Skylab

  • *****
  • Posts: 4383
  • Joined: 06 Mar 2006

Posted 15 September 2019 - 08:57 PM

I had trouble with my HEQ-5, similar to what you describe, but not exactly the same.  When I talked to Orion tech support they recommended updating the hand controller firmware.  That seemed far fetched to me, but I tried it and it worked.  Perhaps it will help you, too.



#4 starhopper-de

starhopper-de

    Sputnik

  • -----
  • topic starter
  • Posts: 26
  • Joined: 18 Apr 2009
  • Loc: Germany, EU

Posted 16 September 2019 - 02:15 PM

Somebody told me, that the encoders are not sealed. Dust and oil can degrade performance of the encoder.

Is there a way to clean it?

Thomas



#5 EFT

EFT

    Vendor - Deep Space Products

  • *****
  • Vendors
  • Posts: 5274
  • Joined: 07 May 2007
  • Loc: Phoenix, AZ

Posted 17 September 2019 - 06:45 PM

Not only are the encoders not sealed, but the DEC encoder "wheel" (sticker on disk) can end up sitting in water when it gets into the metal housing around the encoder wheel.  Even a heavy dew can result in water in the housings.  That ends up ruining the stick-on encoders strip.  I have replaced a couple of those and drilled holes in the lowest part of the housing so that water can always get out.  The disks are a pain to get and a pain to install.



#6 OzAndrewJ

OzAndrewJ

    Mercury-Atlas

  • *****
  • Posts: 2884
  • Joined: 30 Nov 2010

Posted 17 September 2019 - 07:14 PM

Gday Thomas

As Ed noted, the encoders are not sealed at all and get covered in grot/deteriorate/corrode badly

They are not required for normal operation so you should just turn them off.

 

Andrew Johansen Melbourne Australia



#7 StrStrck

StrStrck

    Viking 1

  • *****
  • Posts: 970
  • Joined: 19 Mar 2017
  • Loc: Denmark

Posted 18 September 2019 - 12:26 AM

Gday Thomas

As Ed noted, the encoders are not sealed at all and get covered in grot/deteriorate/corrode badly

They are not required for normal operation so you should just turn them off.

 

Andrew Johansen Melbourne Australia

Gday, Andrew. What are the encoders for? Why are they not important?



#8 OzAndrewJ

OzAndrewJ

    Mercury-Atlas

  • *****
  • Posts: 2884
  • Joined: 30 Nov 2010

Posted 18 September 2019 - 12:41 AM

Gday Bjorn

The true position of the mount is determined by the motors microstep count relative to home, but this "home" can be changed as required

The encoders in the EQ8 ( And EQ6/5) are very coarse ( around 80 arcsec/ pulse for the EQ8 and 250 arcsec per pulse for the others )

They are only really used when "freedom finding", ie if you declutch the axes and manually slew around, they will keep your alignment "roughly" accurate ( by changing the microstep datum point ), but it may be several arcmins off. This is OK if rubbernecking, but not if you are synchronised with a planetarium program and require accurate positioning data.

The encoders have nothing to do with tracking rates etc, but as noted above, they can automatically change the microstep baselines if they trip certain limits, ie even tho the mount hasnt moved from target, the encoder can tell the system it has moved and adjust its datums without asking :-)

 

 

As such, unless you are rubbernecking, they really are not required.

 

Andrew Johansen Melbourne Australia


Edited by OzAndrewJ, 18 September 2019 - 12:42 AM.


#9 StrStrck

StrStrck

    Viking 1

  • *****
  • Posts: 970
  • Joined: 19 Mar 2017
  • Loc: Denmark

Posted 18 September 2019 - 05:12 AM

Gday Bjorn

The true position of the mount is determined by the motors microstep count relative to home, but this "home" can be changed as required

The encoders in the EQ8 ( And EQ6/5) are very coarse ( around 80 arcsec/ pulse for the EQ8 and 250 arcsec per pulse for the others )

They are only really used when "freedom finding", ie if you declutch the axes and manually slew around, they will keep your alignment "roughly" accurate ( by changing the microstep datum point ), but it may be several arcmins off. This is OK if rubbernecking, but not if you are synchronised with a planetarium program and require accurate positioning data.

The encoders have nothing to do with tracking rates etc, but as noted above, they can automatically change the microstep baselines if they trip certain limits, ie even tho the mount hasnt moved from target, the encoder can tell the system it has moved and adjust its datums without asking :-)

 

 

As such, unless you are rubbernecking, they really are not required.

 

Andrew Johansen Melbourne Australia

Ah, thanks for the clarification! Good on ya!




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics