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Safest way to swap heavy accessories on alt/az mount?

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#1 betacygni

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Posted 25 November 2021 - 10:14 PM

I love alt/az mounts, but the problem I’ve always had with them is how to safely swap heavy diagonals, eyepieces, etc. I typically have a pretty extreme use case, heavy 2” diagonal, heavy binoviewers, plus 2 heavy eyepieces. Needless to say no friction clutch in the world would support this if these items were removed. So far I’ve come up with a few options, I think with varying risk. Wondering what other people do, or if they have any other ideas:

1) (my normal method): assemble everything off the mount, and mount scope in fully loaded out and balanced configuration. Downside of this is it’s a bit more heavy and awkward to mount, and of course any time I want to change accessories I have to dismount entire scope (which in itself always has some risk).

2) Utilize a strap between the guide handle and tripod leg. The strap would stop the scope from nose diving. But my fear is if somehow the strap slipped or failed, catastrophic nose dive, potentially into a tripod leg(!). My brain tells me such a failure is highly unlikely with right strap, but still. This would be the easiest solution from an accessory swapping standpoint.

3) Let it nose dive. Place scope in objective down position where it would naturally want to be without accessories. Worry though it might not want to balance there until you take off the accessories, so maybe have to temporarily hold scope while trying to one hand remove? Also hate leaving internals open to falling dust, etc, though I suppose only short duration.

Of these options I’ve only done 1) so far. Keep thinking there must be a better way. Wish mount makers would include some sort of fixed altitude stop one could rest scope on for this purpose. Suppose maybe I could fashion one myself…
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#2 luxo II

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Posted 25 November 2021 - 10:29 PM

...Wish mount makers would include some sort of fixed altitude stop one could rest scope on for this purpose. Suppose maybe I could fashion one myself…

Well, that's little different to your #2.

 

Why not DIY - a length of cord with a loop that engages something convenient on the back of the scope, and the other end is tied to a leg of the tripod. Do you know how to tie a bowline knot ? You could even put a hook on the lower end to engage with whatever your tripod has to offer.

 

Or a piece of velcro strap may be handy (available in long rolls, double-sided).

 

And while you are at it, use an elastic octopus strap so it has some elasticity...

 

Cost negligible, and hence why no-one would pay for it, either.

 

And yes I do use an altaz rig.


Edited by luxo II, 25 November 2021 - 10:33 PM.


#3 betacygni

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Posted 25 November 2021 - 10:49 PM

 

Well, that's little different to your #2.

True, was thinking of something metal, and without risk of breaking/slipping. But yes, you’re right, 2) would be nearly equivalent. And it’s not like an out of balance telescope would be applying much force to such a strap.



#4 Jethro7

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Posted 25 November 2021 - 11:44 PM

True, was thinking of something metal, and without risk of breaking/slipping. But yes, you’re right, 2) would be nearly equivalent. And it’s not like an out of balance telescope would be applying much force to such a strap.

Hello betacygni,

There is one other option. I use a magnet wrapped in Duct Tape, placed near the back of the scope tube. I used to carefully let the scope go vertical but the magnet works like a champ and is more practical.  

 

https://www.harborfr...pull-36904.html

 

HAPPY SKIES AND KEEP LOOKING UP Jethro



#5 Nicole Sharp

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Posted 26 November 2021 - 12:23 AM

I would recommend the Orion VersaGo II, which has locking clutches.  The Orion StarSeeker also has FreedomFind, which allows you to use it manually.

 

https://www.telescop...160/p/10105.uts

 

I have this problem on the Explore Scientific Twilight Nano with about 1 pound on the focuser.  I don't think there is anything that can be done about it without replacing the mount unfortunately.

 

I wouldn't recommend trying to hold the OTA in place, since trying to replace accessories on the focuser single-handedly increases the risk of dropping them.

 

Without replacing the mount, your best solution is a long dovetail bar.  Slide the OTA backward on the dovetail bar when you remove mass from the focuser.  This will keep it balanced.  You need to measure the centers of mass ahead of time and then remember how many inches you have to slide it back.  I use the Highpoint Apertura bar for this:

 

https://www.highpoin...t-vup11-2_1.jpg

 

https://www.highpoin...il-plate-vup11/

 

It has markings so you know how many inches along the bar the center of mass is located at.

 

Something else you can try is adding a heavy finderscope (if you are using a red-dot finder) to weigh down the rear of the tube when you remove accessories from the focuser.


Edited by Nicole Sharp, 26 November 2021 - 12:32 AM.


#6 castorpolu11

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Posted 26 November 2021 - 11:14 AM

Hello betacygni,

There is one other option. I use a magnet wrapped in Duct Tape, placed near the back of the scope tube. I used to carefully let the scope go vertical but the magnet works like a champ and is more practical.  

 

https://www.harborfr...pull-36904.html

 

HAPPY SKIES AND KEEP LOOKING UP Jethro 

Hey jethro hope you’re doing well. Can you post a pic of how you use the magnet?



#7 rhaskins

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Posted 26 November 2021 - 12:49 PM

As the happy owner of a Rowan AZ 100, I simply tighten the altitude lock. But the bungie cord solution stated above or a well trained large dog under the front of the scope could work well also.

 

In addition, although it is something else to lug around, try this: https://www.amazon.c...lv_ov_lig_dp_it

 

3/4 ton capacity, only weighs 34 lbs. That comes to mind as I am looking at it for another purpose. I am certain you can rig up a bogen tripod easier to do the same job, lighter also.

 

Some comments may be a little tongue-in-cheek. smile.gif

 

Rick


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#8 betacygni

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Posted 26 November 2021 - 01:14 PM

Picked up some black Friday harbor freight 16” straps, will report back on my results. Hope the 800 pound capacity is enough :)

#9 Jethro7

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Posted 26 November 2021 - 07:58 PM

Hey jethro hope you’re doing well. Can you post a pic of how you use the magnet?

Hello Castorpolu,

Every thing is great down here in Florida, and getting alot more Star Time in finally after a dismal Summer. I figured I owe you this explanation on how do you use a magnet on telescope with a aluminum tube? Simple, I use an aluminum magnet. lol.gif There is plenty of grip with the Duct Tape to just place the magnet on the back of the scope ahead of the focuser. On other scopes I will just lay it across the focuser it self. It will stay in place even at steep angles. These are the same magnets I use to balance my Dob when I use one of those huge 100° eyepices. I park the magnet on one of the back legs of my Astronomy chair till I need the magnet to swap out eyepieces. I paid $9.49 each for these magnets at Harbour Freight.

 

HAPPY SKIES TO YOU AND KEEP LOOKING UP Jethro

 

 
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Edited by Jethro7, 27 November 2021 - 08:33 AM.

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#10 betacygni

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Posted 26 November 2021 - 10:51 PM

Very clever idea Jethro, thanks for sharing it.

#11 betacygni

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Posted 28 November 2021 - 03:01 PM

Tried out my new solution today (16” Harbor Fieght strap and carabiner) with my lightest scope, worked flawlessly. With my mount and tripod there is zero chance of the strap slipping in any direction. Strap already has loops on either end, so just simple carabiner to connect.

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Edited by betacygni, 28 November 2021 - 03:41 PM.

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#12 weis14

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Posted 29 November 2021 - 12:29 AM

A very nice and simple, low cost solution. 

 

I often struggled with the same issue on my DM-6 and eventually just minimized eyepiece changes as a solution (though I also tended to use a big finder as ballast).  My Half-Hitch mounts have had altitude stops that work for this purpose.  Hard to implement that on a mount like that AZ-100 though.  




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