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

Spring tension vs Counterweight Parallelogram

Equipment Mount
  • Please log in to reply
3 replies to this topic

#1 Robin Clarke

Robin Clarke

    Lift Off

  • -----
  • topic starter
  • Posts: 1
  • Joined: 21 Jun 2021

Posted 21 June 2021 - 01:52 PM

I enjoy tinkering in my workshop when it's too cold to be standing outside at the eyepiece in -40 temperatures.  I built myself a parallelogram for my 10X50 binos a couple years ago and then modified it slightly when I got a pair of big binos.  It has been working well except for the portability factor.
 
I am in the process of thinking of P-mount version 2 design and am trying to figure out how I might incorporate springs into the p-mount in order to eliminate or at least significantly reduce the size and weight of the system.  Does anyone have p-mounts that use springs instead of counterweights?  How do you determine the right springs and spring placement?  How can a spring-loaded p-mount be made adjustable to suit different sized/weighted equipment?  
 
Photos, plans, sketches, advice, criticism and comic relief all welcome.
 
Robin Clarke
Manitoba, Canada



#2 jmillsbss

jmillsbss

    Viking 1

  • *****
  • Posts: 723
  • Joined: 03 Dec 2018
  • Loc: New Albany, Mississippi, USA

Posted 21 June 2021 - 02:13 PM

JMO, too much math, using springs.  Too many variables.  I'd stick to a counter-weight.  Too simple to mess up.


  • B 26354 likes this

#3 B 26354

B 26354

    Surveyor 1

  • *****
  • Posts: 1,994
  • Joined: 05 Jan 2017
  • Loc: Southern California semi-desert (NELM mag 5.3)

Posted 21 June 2021 - 03:12 PM

Hard to imagine being able to significantly reduce the size of a P-Gram. The main P-Gram has to extend far enough away from the center of its tripod to be useful... otherwise you'd constantly be running into the tripod legs, or tripping over the tripod feet.

 

For use with my 9.4-lb APM MS 25x100 EDs, I did reduce the amount that the counter-balance arm needs to extend, by adding an extra 10-lb weight to the two 5-lb weights that were supplied with the P-Gram:

 

APM MS 25x100ED on Farpoint P-Gram.jpg

 

Not exactly an "ultra-portable" system... but I'm lucky enough to be able to do all of my observing and AP from my driveway.

 

biggrin.png



#4 Couder

Couder

    Apollo

  • *****
  • Posts: 1,109
  • Joined: 24 Feb 2014
  • Loc: Mansfield, Missouri in the Ozarks

Posted 21 June 2021 - 03:47 PM

Just a thought - you may already know this, but the longer the arm the counterweight is, the less weight you have to lug around.




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





Also tagged with one or more of these keywords: Equipment, Mount



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics