Weighty problem 200p Dob

[Sirius Starwatcher]

Hello All help please,  my 200p Dob is top heavy what with RA finder, telrad and focus train.  Scope will not stay put and drops. Can anyone

suggest what type of magnets I can buy to put on lower end of the tube to counter balance the heavy top.?

[astronymonkey]

Hi, can you tighten the handle more to stop it dropping ?

Cheers

 

[brantuk]

Or you could try re-balancing it which will involve sliding the dovetail down a bit in the mount shoe.

[Joseki]

5 minutes ago, brantuk said:

Or you could try re-balancing it which will involve sliding the dovetail down a bit in the mount shoe.

I don't think that is possible with the 200p dob

[Joseki]

I wonder if anyone's tried moving the mounting points (? - black plastic bits bolted to the OTA) to re-balance the scope.  Other than another set of holes in the tube it should work.

[DevonSkies]

If tightening the handle doesn't work, perhaps you could find some way of attaching a counterweight to the bottom end? You probably wouldn't need to add much to balance it out.

[brantuk]

Thanks John - senior moment - it's a dob d'ohhh!

[Mark at Beaufort]

Garry when I had a Skywatcher 10" Dob I used something like this  - http://www.ebay.co.uk/itm/Magnet-Taxi-Sign-small-Magpad-77mm-x-52mm-x-12mm/331585238011?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D35308%26meid%3Dd5f8ea644e684d4e9ca3d35944046aa6%26pid%3D100005%26rk%3D5%26rkt%3D6%26sd%3D271121678995

I added a small counterweight and placed it at the bottom of the tube. It worked even when I used heavy Ethos EPs

I just looked on Astroboot and saw this weight (see attached photo) which could easily be fixed to the magnet mentioned above.

 

[Floater]

I use magnets meant for taxis and the like, which I bought on eBay. I had the 'sticking out' bits buffed away and my wife sewed them into a kind of belt. This means I can put them on only when needed. I guess I could also just slide the 'belt' up and down the tube.

Works a treat but, sorry, can't remember the suppliers.

[John]

I use a kitchen magnetic knife strip fixed along the lower part of my dob tube and a couple of iron kitchen scale weights as needed. My heaviest eyepiece is the 2 1/4 lb 21mm Ethos.

[Sirius Starwatcher]

Thanks everyone for the help and advice. Will look at the magnetic strip. Axminster tools sell them so a little experiment will be needed.

 

[N3ptune]

I don't know which one could be the best but I found some examples.

Sliding type

http://www.marklessastronomics.com/counterweight%20products.html

Weights and screws on the back

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p2980_Dobsonian-tube-balance-weight-system--for-12--GSO---Meade.html

Home made solution with hinges

http://www.orion-xt10.com/telescope-counter-balance-weights.html

The hinges solution is nice and inexpensive.  (:

[N3ptune]

I don't know which one could be the best but I found some examples.

Sliding type
http://www.marklessastronomics.com/counterweight%20products.html

Weights and screws on the back
https://www.teleskop-express.de/shop/product_info.php/language/en/info/p2980_Dobsonian-tube-balance-weight-system--for-12--GSO---Meade.html

Home made solution with hinges
http://www.orion-xt10.com/telescope-counter-balance-weights.html

The hinges solution is nice and inexpensive.  (:

====================

I also had this idea a few weeks ago for my own weight problem on my instrument. It consists of a 50mm strap with various weights sizes holding with Velcro. It could work for almost no money. Although, I didn't figure which weights to use from various items found at the hardware store.

I publish the idea just in case.

[Kenny Fowler]

If you have an old microwave oven you can salvage big round magnets which are similar in shape to the weight that Mark at Beaufort has posted. I use them for lots of things as they are very strong.

[Charic]

Just ensure that both handles are just tight enough to to hold the OTA rigid,  then when the nearside tensioner is loosened, the scope moves freely. The far side handle could/can come loose, allowing for your OTA to drop. 
My Skyliner  with the standard 9x50 finder, Telrad,  even a  DSLR,  I  detect no movement unless  imputed. 

If you want to add weights, speak to your local auto tyre dealership. They use smallish stick-on weights, I have them on my alloys?

[BGazing]

if it is not too much weight that you need, you can try with the tennis lead tape, it's used to change the balance of the racquet.

http://www.tenniswarehouse-europe.com/descpageUNIQUE-PSLT.html

[Sirius Starwatcher]

I settled on the kitchen knife wall magnet from Axminster tools. Cut it into three and wrapped electrical tape around them as an anti scratch surface. They work a treat. Thanks all for the advice

regards Garry

[Sirius Starwatcher]

On 20 February 2016 at 14:51, Kenny Fowler said:

If you have an old microwave oven you can salvage big round magnets which are similar in shape to the weight that Mark at Beaufort has posted. I use them for lots of things as they are very strong.

 Mmmmmm how many microwaves do you have ? And where do you get them from 

[Kenny Fowler]

You can pick them up from lots of places. I even picked up a couple from my work when they renewed the old ones. The local dump AKA recycling centre has loads, just ask nicely and you will get one.