Jump to content


Photo

Digital Circles for an old Cave mount?

  • Please log in to reply
11 replies to this topic

#1 Mike Boessen

Mike Boessen

    Lift Off

  • -----
  • Posts: 9
  • Joined: 31 May 2010

Posted 11 January 2013 - 08:00 PM

I am building a 16" newtonian reflector. I have a huge old 1974 Cave mount I am going to put it on. I am looking for some way to equip this with digital setting circles. Curious if anyone has a suggestion for how this might be accomplished.

Attached Files



#2 Tom and Beth

Tom and Beth

    Soyuz

  • -----
  • Posts: 3714
  • Joined: 08 Jan 2007
  • Loc: Tucson, AZ

Posted 11 January 2013 - 10:20 PM

I was going to use USDigital S2 encoders with timing belts...then picked up an AP1200. Lost interest in the conversion...

#3 detector

detector

    Explorer 1

  • -----
  • Posts: 74
  • Joined: 20 Apr 2007
  • Loc: douglasville ga.

Posted 12 January 2013 - 09:30 AM

hey mike

I to am restoring a cave 16 inch mount and putting a 16 reflector on it. I added a object locater to another cave I owned from JMI worked great have contacted them about putting together another one for me.

#4 EFT

EFT

    Vendor - Deep Space Products

  • *****
  • Vendors
  • Posts: 2550
  • Joined: 07 May 2007
  • Loc: Phoenix, AZ

Posted 12 January 2013 - 03:09 PM

You might also be able to work with Sky Engineering to come up with something to attach a Sky Commander system.

#5 Mike Boessen

Mike Boessen

    Lift Off

  • -----
  • Posts: 9
  • Joined: 31 May 2010

Posted 12 January 2013 - 05:37 PM

Outstanding! A few years back I put a Lumicon Sky Vector on my Mead LX5 and it worked great. I called them and they said they had never heard of this being done. Glad to hear there might be an option. I'll google JMI and call them Monday. Appreciate the help!

#6 orion61

orion61

    Aurora

  • *****
  • Posts: 4752
  • Joined: 20 Oct 2007
  • Loc: Birthplace James T Kirk

Posted 12 January 2013 - 09:54 PM

Jims Mobile (JMI) sells computer systems called the JMI Max.
They have settings for all types of mounts and you can get hardware packages for those types of mounts. I use one all the time with my German EQ, it doesn't even have to be Polar Aligned, just roughly N. They are push to so you can slew to your hearts desire by hand without worrying about
realigning.
Mine is very very accurate, 2 stars and it is up and running in 3 minutes or less.

#7 Mike Boessen

Mike Boessen

    Lift Off

  • -----
  • Posts: 9
  • Joined: 31 May 2010

Posted 13 January 2013 - 11:16 AM

Sounds perfect. I'll call them tomorrow. I'm waiting for a spider, secondary mount and focuser so I can finish the optical tube, get it balanced and figure out a mounting point. Then I'm going to cut the pier so it nearly scrapes the floor. I need to know how the DSC are implemented before I can commence restoration of the mount and pier, so this is a crucial component of the restoration and is holding me up at this point.

#8 orion61

orion61

    Aurora

  • *****
  • Posts: 4752
  • Joined: 20 Oct 2007
  • Loc: Birthplace James T Kirk

Posted 13 January 2013 - 11:27 AM

You will need to take the mount apart to put the gears on A and Dec shafts, there is a belt that rund to the encoder box. from there choose the mount type and encoder ratio in the handbox and BAM! you are there! Be advised they are kind of expensive, $300.00 + but the only way I know to
computerize that old mount.
I know a guy that has the basic Mini Max computer and hardware for a Schmidt that he is going to sell for about $125.00 you could then just buy the hardware?
Their support is outstanding! and easy to work with.
If you don't buy new PM Me and I'll hook you guys up.

#9 Geo.

Geo.

    Mercury-Atlas

  • *****
  • Posts: 2952
  • Joined: 01 Oct 2008
  • Loc: Upstate NY

Posted 13 January 2013 - 01:02 PM

The encoder on the Dec axis will probably have to be belted or geared off the CW shaft near the mount. I have seen kits that directly couple the RA encoder on the end of the RA axle. The least expensive solution is the contruction of the Dave Ek encoder - PC interface. $24 for the PCB and most components and AMT102 encoders, about $25 a piece from DigiKey. The AMT102s are very flexible, but with that flexibility comes the need to create some of your own mounting solutions.

Here's an Ek/AMT102 set up I did for a Meade LX50. The sketch lead to CAD drawing and more than two versions for brackets, etc. A foot or two of aluminum angle was sacrificed in the process. The control panel was scavanged from a dead Meade DS2000 mount's motor control board.

Attached Files



#10 orion61

orion61

    Aurora

  • *****
  • Posts: 4752
  • Joined: 20 Oct 2007
  • Loc: Birthplace James T Kirk

Posted 13 January 2013 - 08:41 PM

If you decide to build your own I have a pair of 4000 click
encoders, they are older but you can have them both for $40.00 if it will help you. I might even have a couple gears and belts. It is pretty nice to put a computer on those old gals..

#11 Mike Boessen

Mike Boessen

    Lift Off

  • -----
  • Posts: 9
  • Joined: 31 May 2010

Posted 26 January 2013 - 04:16 PM

Hi, Orion61. Thank you very much for the help! I called JMI. You are correct. Very helpful. They are making one up for me. I bought the middle of the three offerings. Goes down to 16 mag. Since I don't live on Palomar, I figured that would be a practical limit. You were also right that it ain't cheap. Nearly 800 bucks. I don't know if I could have used the other guy's system, but I had already ordered this before I read this post. (Couldn't find it back.) Oh, well. If I get it all working, it's going to multiply the times I go out by about 10 having a permanent observatory. Sure do appreciate the help. I'm working on trying to drive the RA with a stepper. The old, *BLEEP* 7w synchornous motors both had stripped gears. Lots of learning going on. Still no spider, secondary mount or focuser. You'd think this being a slow time of year they'd get this stuff out faster. 3 weeks so far on both of them

#12 Mike Boessen

Mike Boessen

    Lift Off

  • -----
  • Posts: 9
  • Joined: 31 May 2010

Posted 26 January 2013 - 04:22 PM

I have ordered the middle price system from JMI. They are making gears to go on the 2 5/16 shafts that will drive the encoders at 2-1. I'm currently working on building an RA drive with a stepper motor since the old 7w synchronous motors were shot. This will probably force me to take off the setting circles, but, what the heck, 8 years in an astronomy club with over 200 instruments and I've never seen anyone use them. Thanks a lot for the help!






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics