Orpington Astronomical Society

Astronomy => Technical => Topic started by: Fay on Mar 04, 2011, 15:28:22

Title: Scope Bottom heavy
Post by: Fay on Mar 04, 2011, 15:28:22
The QSI has made the scope bottom heavy. Has anyone any idea what I can do?

THanks
Title: Re: Scope Bottom heavy
Post by: Tony G on Mar 04, 2011, 15:35:50
What scope are you using it on?

Tony G
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 04, 2011, 15:42:47
ed80,
Title: Re: Scope Bottom heavy
Post by: Tony G on Mar 04, 2011, 15:46:43
Can't you just move the rings right down tight towards the crayford?

Tony G
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 04, 2011, 15:49:40
the rings are right down
Title: Re: Scope Bottom heavy
Post by: Rocket Pooch on Mar 04, 2011, 15:59:59
You must have the QSI583F model not the QSI583M model, most people think the M means mono, it does not, its Male, the Female version is bottom heavy due to the maturity of the product.
Title: Re: Scope Bottom heavy
Post by: Mike on Mar 04, 2011, 16:02:02
Use another ring to screw a small weight to the lens end or wrap a strip of lead around it.
Title: Re: Scope Bottom heavy
Post by: PhilB on Mar 04, 2011, 16:06:43
Quote from: Fay on Mar 04, 2011, 15:49:40
the rings are right down

You're either going to have to add some counterweight up by the dew shield (MORE expense!) or you'll have to switch to your 120 equinox which probably won't give you such a wide field  :roll:

Title: Re: Scope Bottom heavy
Post by: PhilB on Mar 04, 2011, 16:09:37
Looking at the sky, I assume you were hoping to go out and play tonight?
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 04, 2011, 16:13:50
Well, I had another 1/2" to move it up & it is just about balanced now on the ED80. I may have to start to piggy back with that scope. It will be ok with the 120 as so top heavy
Title: Re: Scope Bottom heavy
Post by: PhilB on Mar 04, 2011, 16:20:17
Here's a thought, if you're that close to getting things to balance, if you move the mounting rings closer together, by drilling another hole in the dovetail plate and remounting one ring, this should enable you to reach balance. If that makes sense?
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 04, 2011, 16:33:29
I will think about that Phil. I will have to do something. I have found a spare, the bit that the dovetail holder, may be able to fix that to the ed80 rings.

It will be fun when I attach the QSI to the WOZS66!!!!!!!! It will have to be piggy backed.

Chris is that a joke male & female camera?????? :radiation:
Title: Re: Scope Bottom heavy
Post by: mickw on Mar 04, 2011, 16:41:03
This is what Phil means - or use a longer dovetail - This is on my ETX

(https://lh5.googleusercontent.com/_VTfcx7bG__M/TXEVJxE8ZsI/AAAAAAAABMo/L77UzUP90_Q/dovetail.jpg)

Chris is using the QSI on the TS Quad which is about the same size as ZS66
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 04, 2011, 16:52:16
I was wondering how Chris gets a balance with that. I am sorting thru my bits to see if I have the parts to piggy back. Thinking about a longer dovetail as well

Title: Re: Scope Bottom heavy
Post by: PhilB on Mar 04, 2011, 16:55:35
Ignoring the balance point, the photo shows just what I' referring to, Fay. Basically, by moving one ring you make the dovetail plate project out at one end. You then mount the telescope so that the projection is up by the dew shield which means that you can then move telescope further towards the mount.

Quote from: Fay on Mar 04, 2011, 16:33:29
Chris is that a joke male & female camera?????? :radiation:

Nah, I think it's a reference to the the great British Pear Shape!
Title: Re: Scope Bottom heavy
Post by: Rocket Pooch on Mar 04, 2011, 17:05:22
Fay,

What I did with mine was to get another set of tube rings, put them the other way around with the same difference at the other end, obviously this means at the new out of balance ends I had to balance the both to keep it all working. 

I did toy for a while about getting another QSI583M and ED80 and putting it the around the other way around on a Gemini bar to ensure it was all in balance, anyway the origional version worked well, and was approx £3k cheaper that the latter solution.

Chris
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 04, 2011, 17:18:22
can't picture that Chris, if you have a photo

Not sure I will get anything tonight, as I have spent hours trying to figure out the auto filter bit & not sure I have got it right. Also hope it downloads quickish when focusing
Title: Re: Scope Bottom heavy
Post by: PhilB on Mar 04, 2011, 17:30:08
Ooops, I'm having trouble picturing it too. My earlier post is upside down!! The scope is bottom heavy so the dovetail projection needs to be towards the focuser so you can move the telescope objective further away from the mount. Sorry  :oops:
Title: Re: Scope Bottom heavy
Post by: Rocket Pooch on Mar 04, 2011, 20:40:04
Fay,

I was joking, I never have had the thing in balance, its too light to worry about.

The camera will do 2 second downloads, will take a little getting used to, but its good enough for focusing.

Chris
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 05, 2011, 09:04:17
seen a picture of scope on long dove tail, with rings right at the top end, this looks good idea.

But, I will have to piggyback when using WOZS66 & QSI

Chris, I found that it was not bad to focus with Nebulosity, before changing over to AA. in AA the rectangled star did not even show in the focus box
Title: Re: Scope Bottom heavy
Post by: Mac on Mar 05, 2011, 14:14:41
Can you not just slide the dovetail forward??
to balance, rather then move the scope in the rings?

Mac.
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 05, 2011, 16:30:36
I have ordered a longer dovetail, then I can put the rings further up
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 10, 2011, 17:49:51
Balance ok now.

Bought a longer dovetail, moved the rings, but it was still bottom heavy, thought I had wasted my money, so moved the dovetail so the screw underneath was the other side of the dual bar instead of before it. Moved the WO back a bit & it was ok.

It went on for a while, as I am not logical & could not figure out what I was supposed to be doing.............John is the logical one, so I had to call upon him. We had to have one brain in gear!     
Title: Re: Scope Bottom heavy
Post by: RobertM on Mar 10, 2011, 20:21:14
So are you no longer bottom heavy or is there still a problem?
Title: Re: Scope Bottom heavy
Post by: Fay on Mar 10, 2011, 20:23:11
My bottom is lightweight now! :lol: