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Anonymous
Unregistered




Sand in alu tripod?
      #191685 - 09/08/04 01:39 PM

Hi ppl

Yes, again a question about mounts but I want to get my telescope (8" Newt on EQ5) more stable to try some astrophotography.
I saw on astronomyboy that you can fill the aluminium tripod legs with sand to get better stability (and more weight ). I was just wandering if this works (almost) as good as a (home-made) wooden tripod.

Thanks again for your always kind help!!!
Pieter



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ArizonaScott
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Reged: 04/29/04
Posts: 5864
Loc: Scottsdale, AZ
Re: Sand in alu tripod? new [Re: ]
      #191709 - 09/08/04 02:08 PM

Definitely works. Can't get a much cheaper fix-up than a bag-o-sand

--------------------
Scott
10" LX200 Classic, Konus 200, Orion ST80, ETX90 OTA, 60mm Celestron alt-az, Obie 20x80's, Meade 10x50's




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dgs©
Postmaster


Reged: 03/29/04
Posts: 15091
Loc: West Monroe, Louisiana
Re: Sand in alu tripod? new [Re: ArizonaScott]
      #191762 - 09/08/04 03:19 PM

Could you get the same results suspending a sandbag (or bag of lead weights) from the accessory tray. Seems like it would be easier than filling the legs. All you are looking for is to increase the mass of the system to decrease its natural frequency right?

--------------------
- david
8"Ø Newtonian on SVP, Moonlite CR2, Telrad
PST Oberwerk Ultra 15x70 Orion Ultraview 10×50
Hand-me-down Sears Refractor (Discoverer) 60mm×900mm



"What we have done for ourselves alone dies with us; what we have done for others and the world, remains and is immortal." --Albert Pike


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ArizonaScott
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Reged: 04/29/04
Posts: 5864
Loc: Scottsdale, AZ
Re: Sand in alu tripod? new [Re: dgs©]
      #191783 - 09/08/04 04:00 PM

Good suggestions David. I've even seen a gallon jug of water hung from a rope from the center of the mount. Seems like the sand would be a more esthetically pleasing option

--------------------
Scott
10" LX200 Classic, Konus 200, Orion ST80, ETX90 OTA, 60mm Celestron alt-az, Obie 20x80's, Meade 10x50's




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Anonymous
Unregistered




Re: Sand in alu tripod? new [Re: dgs©]
      #192245 - 09/09/04 02:29 AM

Quote:

All you are looking for is to increase the mass of the system to decrease its natural frequency right?




I think it works this way, indeed.
If I have to increase weight, then, sand in the legs must give the same effect as weight on the accessory tray.
I'll try this definitly.

Thanks for the help!
Pieter


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Greg K.Administrator



Reged: 12/11/03
Posts: 17634
Loc: Clifton Park, NY
Re: Sand in alu tripod? new [Re: ]
      #192693 - 09/09/04 04:46 PM

It should have an additional effect of making the legs somewhat stiffer.

--------------------
Astro-Tech AT111EDT f/7 | AT72ED f/6 | Celestron CGEM
NexStar 11 GPS | Orion SkyView Pro 8EQ (w/ Autostar mod)
Canon EOS Rebel T2i (modded) | QHY5L-II mono

astrophoto gallery


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Todd
Carpal Tunnel


Reged: 02/23/04
Posts: 1674
Re: Sand in alu tripod? new [Re: ]
      #192715 - 09/09/04 05:15 PM

It helps a bit but IME it doesn't make the aluminum legs as stable as wooden.

Todd


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Tim2723
The Moon Guy


Reged: 02/19/04
Posts: 5762
Loc: Northern New Jersey
Re: Sand in alu tripod? new [Re: Todd]
      #192793 - 09/09/04 07:12 PM

I tried this trick, and except for fairy short, light scopes, you'll have limited results. Doesn't cost anything to try though. Just make sure the sand stays away from the glass.

--------------------
Intes MK-66 Deluxe (6" f/12 Maksutov)
Celestron C-102HD (4" f/10 achromat)
Celestron C-102AZ (4" f/5 achromat)
Orion 6LT (6" f/8 classic Newtonian)
Orion Apex 90 (90mm Mak spotter/grab-n-go/little fun scope)



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erik
telescope surgeon


Reged: 01/30/04
Posts: 24789
Loc: Hawaii
Re: Sand in alu tripod? new [Re: Tim2723]
      #192857 - 09/09/04 09:03 PM

besides making the scope more solid and reducing dampening times, it can also help prevent a top heavy scope, such as the 10"SN or AR6 LXD55 series from tipping over. filling the legs with concrete would probably work better than sand because it'd be a solid mass. i've heard of people using the water jug trick, but it seems like a bit of wind might cause the jug to move slightly and introduce its own vibrations....

--------------------
-Erik Wilcox
Starstuff
Homebuilt 16" Truss Dob in Ohia Forest Observatory
(12' X 12' rolloff under Mag 7 skies)
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos
Homebuilt 80mm f/5 refractor
Mirador 60mm f/12 1960's refractor


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mikeb57
Grand Pooh-Bah


Reged: 01/03/04
Posts: 1661
Loc: Central Maine, USA
Re: Sand in alu tripod? new [Re: erik]
      #193214 - 09/10/04 10:39 AM

Then again another point to consider... Unless you plan on leaving the tripod extended forever, the sand in the legs will cause an undo amunt of wear and weakness in the legs... That pretty much covers any and all aluminum leg tripods...

--------------------
Mike B
Meade ETX-70EC
Homemade PowerTank


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Anonymous
Unregistered




Re: Sand in alu tripod? new [Re: mikeb57]
      #193286 - 09/10/04 12:31 PM

I filled the lower legs of my Meade ETX field tripod with Plaster of Paris some three years ago. It was a cheap (if not somewhat messy) mod that has proven to be very effective.
I intend to do the same with my LXD75 tripod this weekend.


Phil


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dgs©
Postmaster


Reged: 03/29/04
Posts: 15091
Loc: West Monroe, Louisiana
Re: Sand in alu tripod? new [Re: ]
      #193358 - 09/10/04 01:55 PM

Sand in the legs adds mass, to lower the natural frequency, but won't do much to stiffen the legs. The Plaster of Paris will harden and brace the aluminum tubing to help cut down on the flexiblity of the legs, but probably doesn't add as much mass. Hard to say which would be more effective.

--------------------
- david
8"Ø Newtonian on SVP, Moonlite CR2, Telrad
PST Oberwerk Ultra 15x70 Orion Ultraview 10×50
Hand-me-down Sears Refractor (Discoverer) 60mm×900mm



"What we have done for ourselves alone dies with us; what we have done for others and the world, remains and is immortal." --Albert Pike


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ccs_hello
Postmaster


Reged: 07/03/04
Posts: 5224
Re: Sand in alu tripod? new [Re: dgs©]
      #193457 - 09/10/04 03:08 PM

My tripod lower side has 1' rebar secured by the Silicon caulk. Then the rest of the space, including the upper legs were filled with the "Great Stuff" gaps and crack filler. During the filling, it's VERY messy (seal every holes first .)

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jack savard
professor emeritus


Reged: 05/26/04
Posts: 516
Loc: quebec canada
Re: Sand in alu tripod? new [Re: ccs_hello]
      #193474 - 09/10/04 03:40 PM

do your leg are join togeter by a triangular at midle
mine are and that is very stable
also may be combine sand and water ;
the last way renforce leg like the sailer pole whit a kind of rope tention betwing the tow end whit a little piece in the midle that top vebration on a sailer



--------------------
nobody made it I AM INTEREST
46,49 N 71,14 O Québec canada 2\L100 2\D100 0\S100


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erik
telescope surgeon


Reged: 01/30/04
Posts: 24789
Loc: Hawaii
Re: Sand in alu tripod? new [Re: jack savard]
      #193726 - 09/10/04 10:22 PM

i'd say concrete mix would be the best of both worlds. it has the mass that sand has, and will stiffen the legs like the plaster does. but i've only read about it, i've never done it myself, so what do i know...

--------------------
-Erik Wilcox
Starstuff
Homebuilt 16" Truss Dob in Ohia Forest Observatory
(12' X 12' rolloff under Mag 7 skies)
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos
Homebuilt 80mm f/5 refractor
Mirador 60mm f/12 1960's refractor


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ccs_hello
Postmaster


Reged: 07/03/04
Posts: 5224
Re: Sand in alu tripod? new [Re: jack savard]
      #193755 - 09/10/04 10:43 PM Attachment (67 downloads)

Quote:

do your leg are join togeter by a triangular at midle
... sailer pole ....







Hmmm....
We have sand, we have water, bucket, sail, wind, and rope. Can't imagine summer is over

Indeed mine has a wooden spreader as suggested in the Meade4504Telescope.

ccs_hello

Attachment


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Anonymous
Unregistered




Re: Sand in alu tripod? new [Re: ccs_hello]
      #193882 - 09/11/04 02:53 AM

The legs are indeed joined together with a triangle.
I also discovered something very useful for increasing stability:
1. I have tightened as hard as possilbe the top screws of the legs (the screws that attach the legs to the mount)
2. I added my accessory tray, which made the 3 legs be joined together very well

I will still try adding some sand in the tripod, but these 2 'discoveries' increased the stability dramatically!


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Don W
demi-god


Reged: 05/19/03
Posts: 19226
Loc: Wisconsin, USA
Re: Sand in alu tripod? new [Re: ]
      #194010 - 09/11/04 10:42 AM

Another good quick fix for these tripods is to remove the screws, go to a hardware store and buy the next larger size. Seems that the holes are drilled a bit too large for the screws they use.

--------------------
DON'T PANIC!-Hitchhiker's Guide to the Galaxy

Don Wyman
Obsession 18" f/4.5 #1166
W/Argo Navis DSC and Torus Primary


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Anonymous
Unregistered




Re: Sand in alu tripod? new [Re: Don W]
      #195318 - 09/13/04 10:07 AM

Actually, the Plaster of Paris adds substantial weight to the tube in comparison to what an empty tube weighs. I did not weigh the tubes after filling them but my guess is that each tube now weighs over a pound, adding at least 3lb's to the tripod. Cement would add even more. I stll have to test the results but I expect damping time to come down from 5+ seconds.


Phil


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john strnck
super member


Reged: 07/07/04
Posts: 127
Re: Sand in alu tripod? new [Re: ]
      #195346 - 09/13/04 10:58 AM

it may help a little bit- fiberglass or steel reinforcing rods is a better choice filled with expando foam- but whatever you do wont make it any stonger, youll still have flexure, best option is to ditch the stamped aluminum completely and upgrade to wood or stainless steel

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