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

Why am I wrong? Synscan upgrade on a CI-700....

This topic has been archived. This means that you cannot reply to this topic.
34 replies to this topic

#26 Falcon-

Falcon-

    Aurora

  • *****
  • topic starter
  • Posts: 4,950
  • Joined: 11 Sep 2009

Posted 16 May 2012 - 11:08 PM

I think 47T vs. 48T difference is just 2% so it is possible the tracking rate adjustment may/would work flawlessly.


Ahh yes.... "possible" and "may"... :p That makes it worth ordering the gear from the UK instead of the US if I can get the 47 tooth I think!

#27 ccs_hello

ccs_hello

    Voyager 1

  • *****
  • Posts: 10,739
  • Joined: 03 Jul 2004

Posted 21 May 2012 - 10:54 PM

Now that I figured out how Synscan intelligent motor controller achieves its precision timing, I guess the 4:1 belt-n-pulley is quite doable. See this CN post in ATM subforum.

Clear Skies!

ccs_hello

#28 Falcon-

Falcon-

    Aurora

  • *****
  • topic starter
  • Posts: 4,950
  • Joined: 11 Sep 2009

Posted 21 May 2012 - 11:16 PM

Thanks for the update - and thanks on behalf of the community in general for the work you are doing in that other thread! :)

#29 Falcon-

Falcon-

    Aurora

  • *****
  • topic starter
  • Posts: 4,950
  • Joined: 11 Sep 2009

Posted 29 August 2012 - 01:21 PM

Ok - so hopefully resurrecting this old thread is the way to go instead of starting a new one...

I have now ordered the EQ6 Synscan upgrade kit from KW Telescopes and went to go order the pulley gears from hpcgears.com (as they make 47tooth versions).

However.... turns out the 47tooth pulley (part number 47PT25-10) has an OD of 36mm, the existing 80-tooth spur gear has a diameter of 31mm and a clearance of only 2mm to the mount. In other words the 47tooth pulley will not fit!

:foreheadslap:

So - my plan is to use a transfer shaft with a 1:1 pulley ratio between the transfer shaft and the worm shaft.

So the motor output shaft would have a 12-tooth pulley connected to a 47tooth pulley on the transfer shaft preserving the radio the synscan HC expects. There would then also be a 30-tooth pulley on the transfer shaft connected to another 30-tooth pulley on the worm shaft. Picture with arrangement attached.

So... any arguments against this or suggestions for better alternatives?

Attached Thumbnails

  • 5393344-ci-700_pulley_plan.png


#30 Falcon-

Falcon-

    Aurora

  • *****
  • topic starter
  • Posts: 4,950
  • Joined: 11 Sep 2009

Posted 29 August 2012 - 01:28 PM

This now leads to the question of how to physically set up the transfer shaft.

My plan was to use a retangular aluminium extrusion as the motor mount, similar to how the stock CI-700 drive is done. Can anyone point me in the right direction for sourcing a drive shaft and appropriate bearings that could be used here? On this aspect I am a little bit lost and could use suggestions. :confused:

The default bore on the 47tooth and 30tooth pulleys is for a 5mm shaft, though that can be modified if something else is recommended.

#31 orlyandico

orlyandico

    Cosmos

  • *****
  • Posts: 9,892
  • Joined: 10 Aug 2009

Posted 29 August 2012 - 02:32 PM

how much is the synscan upgrade kit?

i'm in the middle of hacking on my Littlefoot Elegance Photo. the PEC upload tool hasn't been updated for the LFEP's 1024-PEC-cell system (the older Littlefoots only had 256 PEC cells) so i'm actually updating the tool myself.

it is a well thought out system and quite flexible, as all the ratios can be defined. the catch is that it has a very simple-minded GoTo pointing model - one star align, just like the AP GTO hand set.

#32 Falcon-

Falcon-

    Aurora

  • *****
  • topic starter
  • Posts: 4,950
  • Joined: 11 Sep 2009

Posted 29 August 2012 - 03:25 PM

The synscan upgrade kit is $399 cdn

http://www.kwtelesco...Accessories.htm

That is *with* steppers, motor controller, hand controller, & cables. If you have an EQ6 it is a no extra parts needed direct upgrade (not quite the case here of course). I will be making a mount bracket for the steppers, longer cables to go from the steppers to the motor controler board, and an enclosure for the motor control board so it can hang from the Losmandy drive-controller mount point (where a #492 or gemini electronics box would normally hang).

I did consider the various littlefoot goto systems initially but after purchasing steppers and so on it ends up expensive so I would rather go with the more common synscan system w/ its EQMOD support. I would have needed to make my own motor mounts for a littlefoot based system anyway.

#33 orlyandico

orlyandico

    Cosmos

  • *****
  • Posts: 9,892
  • Joined: 10 Aug 2009

Posted 29 August 2012 - 07:47 PM

I am using $33 (each) Vexta spur-gearhead steppers on my littlefoot system now :p (these motors do cost $220 each new... so if I had to get them new my materials cost would bloat alarmingly)

I did have to fabricate new motor mounts but I just copied the AP motor bracket. The new motors are the largest that can fit inside the AP600, and even so can only muster 160X GoTo speed, which is slow but tolerable.

The downside is that the Vexta gearhead has a sizable amount of periodic error, probably in the +/- 2" range. I've been PEC-training it and that's the best I can get after PEC. Not so bad, my CGEM's gearhead has about +/- 4" of PE (quite apart from the +/- 25" from the worm fundamental).

#34 skywolf856

skywolf856

    Viking 1

  • -----
  • Posts: 722
  • Joined: 25 Jan 2008

Posted 29 August 2012 - 07:49 PM

Falcon,
Try these links for mechanical components.
All good.

http://us.misumi-ec.com/
http://www.sdp-si.com/
http://www.wmberg.com/

#35 Nils_Lars

Nils_Lars

    Voyager 1

  • *****
  • Posts: 10,056
  • Joined: 04 Jan 2008

Posted 02 September 2012 - 11:28 AM

Looks like its coming along , keep us updated with pics :)


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