Eyepiece weight unbalance issue

[bomberbaz]

Hello all.

I recently got a hold of a Celestron Axiom 31mm beast eyepiece. Calling it that as it weights in at 3.5 pounds weight, thats a hefty piece of kit.

I am a little concerned the extra weight might put too much strain on the goto dob base on my 300P, so i was looking at getting a couple of large magnets weighing in at around 1.5 pounds total (.75 each) to stick on the OTA at the bottom when using said EP to help bvalance out things a little.

Can anyone tell me if there is a reason to not do this. Thinking about the magnetic field, distortions to mirror etc!

Thanks for any help

Steve

[Adrian]

I hope you're enjoying that one

I wouldn't have thought that the magnetic field would affect the mirror because the coating is aluminium, so shouldn't be particularly affected by the magnetic field. Also the steel tube should shield the contents from exterior magnetic fields (I think...maybe )

Anyway, loads of other dob owners do this, usually by attaching a magnetic knife rack to the tube so you can slide the weights up and down to tune the balance - if there was a problem doing this (other than allowing the use of weighty, expensive, high quality eyepieces and the damage to the bank balance that ensues) then it would probably have come to light by now.

[bomberbaz]

Cheers adrian, i did not rhink there would be an issue but cant be too careful with your baby can you ;-)

I found a place selling these magnets weighing in as stated and these would be fine for use and are cheap as chips. 2 for £12 delivered

[John]

I use the magnetic knife rack approach (e.bay - £5) attached to the top of the tube of the mirror end of my dob. I then stick iron kitchen weights to it as needed to counterbalance heavy eyepieces. I find I need a 2lb weight at the lower end of the tube to counterbalance my heaviest eyepiece which is the 31mm Nagler at around 2.2 lbs. The Axiom 31 sure is a heavy beast - I thought 2.2 lbs was quite enough !.

[bomberbaz]

I could always get a hold of some extra weight to stick to the magnets if needed but I will see how I get on. The main concern is the added strain to the motors when slewing to targets, although I do most of that myself to help it get there quicker.

Theory being of using the added weight is the manufacturer must make an allowance for the additional weight of EP's when designing the system but probably not to the extent of beasts like the Nagler or axiom 31mm.

[Moonshane]

should no problems on all counts I think. stick some felt/flocking on the fixing side maybe to prevent scratches?

[John]

Theory being of using the added weight is the manufacturer must make an allowance for the additional weight of EP's when designing the system but probably not to the extent of beasts like the Nagler or axiom 31mm.

True. Additional finders, dew / glare shields, light shrouds etc also add weight to the top end of the scope. It must be difficult for a manufacturer to pre-guess what modifications potential customers will make to their scopes.

[faulksy]

wow cant belive they weigh that much, I thought my nagler/nirvanas were heavy 2 kg each