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What is a good way to lock the altitude in place on a Truss dob for moving outside?

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#1 JoshH

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Posted 20 October 2017 - 09:55 PM

I have a 16" F4.5 Telekit dob and I'd like to start using it more for observing more at home. My skies aren't the best but I can still do a lot, planets, double stars etc. I have a M703, and while it is a great scope, almost every time I get it out I'm always thinking, this would look so much better in my dob. Plus it isn't exactly a quick setup with the tripod mount etc. I'm hoping that if I can easily wheel my dob out when I get home from work, I'll observe more this winter. I can leave my dob setup in my basement but I need to make a 90 degree turn when going out the door, and to make the turn I need the altitude at just the right angle. I've seen one guy drilled a hole in the bearing into the base so he could put a nail in there to lock it in place. Curious if anyone has any other ideas?

 

I know I can always just take the upper cage off, but often my problem is motivation or lack of time. I want to observe more, the easier and quicker it is to do the more often I'll do it.

 

Thanks! 


Edited by JoshH, 20 October 2017 - 09:56 PM.


#2 rockethead26

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Posted 20 October 2017 - 10:58 PM

I had Rob at Teeters Telescopes drill holes thru the rocker boxes and mirror boxes of the 16" and two 12" scopes he made for our public program that used a captive 1/4" metal pin with a ring pull on the end to solve that exact problem for us. It was designed to hold the UTA at a 45° angle to make it easy to get thru door of the storage closet and keeps the mirror box from jumping out of the rocker box while rolling it around. The pin hangs on the outside of the rocker box with an attached cable so it's always there and cannot get lost. Same idea, but a little more elegant than a nail. The ring pull helps extract the pin easily.


Edited by rockethead26, 21 October 2017 - 10:09 AM.

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#3 JoshH

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Posted 20 October 2017 - 10:59 PM

I had Rob at Teeters Telescopes drill holes thru the rocker boxes and mirror boxes of the 16" and two 12" scopes he made for our public program that used a captive 1/4" metal pin with a ring pull on the end to solve that exact problem for us. It was designed to hold the UTA at a 45° angle to make it easy to get thru door of the storage closet and keeps the mirror box from jumping out of the rocker box while rolling it around. The pin hangs on the outside of the rocker box so it's always there and cannot get lost. Same idea, but a little more elegant than a nail. The ring pull helps extract the pin easily.

Thanks. I'd love to see a picture of that. 



#4 Bro061

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Posted 20 October 2017 - 10:59 PM

Hi Josh,

 

I have a Obsession 15. I use 4  bungee cords, which are wrapped around the truss pole blocks bolts/Knobs and hook up to the opposite  wheel barrow eye bolts. You could uses the bungee cord wrap them around the truss pole and connected them to the wheel barrow eye bolts.The Yahoo Obsession Groups shows a picture of an altitude clamp by m_barsotti, 

 

David



#5 SeaBee1

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Posted 21 October 2017 - 07:40 AM

I use pull pins for my ATM 10 inch, same as Jim uses in post #2. Easy peasy... picture as follows...

 

gallery_241784_6248_54292.png

 

I just put them in my pocket when I pull them out...

 

Clear skies!

 

CB



#6 Jon Isaacs

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Posted 21 October 2017 - 09:09 AM

Josh:

 

There are several ways to do this.. 

 

The point I want to make is to be very aware when making tight turns (or whenever moving an assembled Dob) that if you raise the handles there's a critical angle where the scope will slide forward and out of the base.  When you're trying to make a tight turn,  the tendency is to lift the handles to provide maneuvering room. 

 

If the scope is well attached to the rocker box this probably won't happen but if it's held by friction or held only on one side,  it's still possible.   It's happened to me a couple of times,  I didn't understand exactly what was happening but you are actually dumping the scope like a wheel barrow.. 

 

Bill Meyer's thread "Dissent on Dob Wheels" is a good read.  

 

https://www.cloudyni...s/#entry4349792

 

The JP Astrocraft Sweet 16 is an example of this technique.. 

 

http://www.jpastrocr...com/sixteen.htm

 

rolling_0048a_web.jpg

 

Jon


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#7 rockethead26

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Posted 21 October 2017 - 10:20 AM

 

I had Rob at Teeters Telescopes drill holes thru the rocker boxes and mirror boxes of the 16" and two 12" scopes he made for our public program that used a captive 1/4" metal pin with a ring pull on the end to solve that exact problem for us. It was designed to hold the UTA at a 45° angle to make it easy to get thru door of the storage closet and keeps the mirror box from jumping out of the rocker box while rolling it around. The pin hangs on the outside of the rocker box so it's always there and cannot get lost. Same idea, but a little more elegant than a nail. The ring pull helps extract the pin easily.

Thanks. I'd love to see a picture of that. 

 

Here's one from the user manual that I wrote, hence all the labeling:

 

Teeter scope with locking pin.jpg



#8 stargazer193857

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Posted 21 October 2017 - 11:32 AM

Good design ideas in here.

#9 Pinbout

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Posted 21 October 2017 - 02:42 PM

https://www.youtube....h?v=Wlx7kWby6J8



#10 JoshH

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Posted 22 October 2017 - 04:32 PM

Thanks everyone, very helpful. 



#11 tomykay12

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Posted 23 October 2017 - 01:11 PM

Look at Advel (sp?) pins used for yachts; it's a variation of the "pull pin" with a very positive ball action using a push button on the end. The come in different lengths. Very classy


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#12 Jon Isaacs

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Posted 26 October 2017 - 05:51 PM

Look at Advel (sp?) pins used for yachts; it's a variation of the "pull pin" with a very positive ball action using a push button on the end. The come in different lengths. Very classy

I think it's spelled Avdel..  Seems to be a company with a number of products. 

 

Jon




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