Balancing the ED80/350D on the EQ6

[iceman]

Hi all

I figured out that my lack of being able to do more than 30s exposures without trailing was partly due to not properly balancing the ED80/350D on the EQ6.

In fact, I didn't really balance it at all. I didn't realise how much it would affect the tracking.

But the other night when I took my NGC253 image I did make attempts to balance the scope properly and was able to get 60s exposures without trailing, and went 90s with just a little trailing.

But balance still wasn't 100% right. I couldn't get the balance right in DEC. With the 350D and finderscope attached to the ED80, I moved the dovetail as far forward as it could go in the mount, and I moved the scope as far forward as it could go in its rings, but it was still too heavy towards the camera end.

It's like I need a counterweight on the dewshield end of the ED80.

How do I balance it properly? What do I need to/what can I use to balance properly in DEC by adding more weight to the objective end?

Thanks

[h0ughy]

you could get a guide scope and use that at the counterweight but keeping it a little bit forward - maybe an excuse to get a 66mm scope?

[JohnG]

I found that I had to remove the short rail on the underneath of the scope to get the tube far enough forward to balance out the camera setup.

Simply took the focuser off (3 screws around the end) and removed the internal nuts from the rail, then plugged the holes with rubber covers. The scope now has plenty of movement.

Cheers

[[1ponders]]

There is nothing wrong with adding counterweigths Mike. Sticky Velcro and then get some bits of lead (Surf sinkers and flatten them if necessary with a hammer :bashcomp: :) ) and attach sticky velcro to them. Works a treat. Or get a smaller bolt for the front ring so it doesn't stick up so far and hit the bottom plate.

[acropolite]

Handy you raised that Mike, I'm going to have the same problem with the ED80/20D, given the 20D is heavier the balance will be more of a problem.

[RB]

Use magnets as counterweights Mike.

[dugnsuz]

I may have the same problem with my ED80/40D combo too!
Is this where a dovetail and mini counterweight system similar to the attached pic would be handy?

[ballaratdragons]

Andrew, magnets would be the ideal solution, except that everything up front on an ED80 is aluminium. The OTA, the Dewshield, the Dovetail etc.

Mike, if Kate doesn't mind sewing things up for you (or you could try yourself), you could sew up an item like a miniature money-belt. It could velcro around the Dewshield, and in the little pockets you could add or take lead weights (sinkers etc).
Just an idea :thumbsup:

[iceman]

hmm good idea Ken! Kate is quite the seamstress ;)

[RB]

:confuse3: I had a quick look at my Orion ED80 and I can attach a magnet to the OTA (but not the dew shield). :shrug:

[iceman]

I'll try my Saxon!
Thanks for the suggestions guys, will let you know next week (i'm away for the weekend).

[iceman]

Well my Saxon doesn't let magnets stick to it.. I've had to use duck tape to tape a counterweight to the front end of my ED80 to balance it when the cameras (350D on the ED80 and DMK on the guidescope) are in place.

Any other suggestions?

[[1ponders]]

Sticky velcro.

[iceman]

Sticky velcro only weights a few milligrams, Paul ;) j/k

How much weight can a piece of sticky velcro hold? I wouldn't want the weight slipping back down and knocking my 350D or something.

[[1ponders]]

Ha Ha Ha !!!! Funny guys :P

My thought was a ring of sticky around the tube, then each weight has a piece stuck to it on both sides and then a piece of velcro wrap over the top. Aint nothing going to move then. That velcro wrap is brilliant stuff

[[1ponders]]

I need to do something similar but I haven't gotten round to it. I just make sure I shoot either directly east or west, that way I can balance it using my counter weights :lol:

[iceman]

hmm ok I get it, thanks Paul will try that.
I've got some old gym weights that will do the trick nicely.

[[1ponders]]

Another option with the velcro would be to stick strips of it (about 100mm long or longer if needed) about 3-4cm apart from the cell back towards the focuser all around the circumference. That way you could put velcro wrap lengthwise over the top of each weight and if you needed to lighten the load you could remove individual weights much more easily.

[iceman]

yeh another good idea.

Only problem is, it makes a nice looking refractor look ugly. Much like the weight taped on with grey/silver duck tape does :)

[[1ponders]]

Ugly! Ugly!!! No way. This is like Dob Modding (remember that grasshopper :lol: ). It gives your scope character. It gains you notice when you are out on the imaging field "Gee Mike that is a great idea. I'll use that on my setup". Ugly Pfft. It's all in the eye of the beholder.

But silver duck tape, now that is just chincy and crass. Black if fine, but silver....puhlease. :rolleyes:

:lol:

[Kal]

Could be worse. Ugly is a big blob on playdo stuck on the end of your tube! :lol2:

[[1ponders]]

Or a sledgehammer head attached to the end of your counterweight shaft (http://www.iceinspace.com.au/forum/attachment.php?attachmentid=3047&d=1121577886). :lol:

[Lee]

Ouch! I couldn't even stand Losmandy's nasty counterweights, had to get a couple of Mick's shmick ones :D

[[1ponders]]

Now there's an idea Mike. Playdo, plasticine or better yet, bright yellow U Tac with small lead sinkers mixed in with it. ;) Would work a treat.

[joshman]

i had this very problem the other night when trying to balance the 400d with battery grip (who needs AC mains when you've got two x 1200mAh batteries powering your camera? puts the canon 720mAh batteries to shame), which i fairly heavy, attached to teh ed80. my though was to get a longer dovetail made up so that it would stick out backwards over (under?) the focuser, or possibly drill and tap another hole into teh existing dovetail so that i can adjust teh ring spacing and allow the dovetail to sit back under the focuser a bit more....

but velcro and weights seems a more elegant option.

[[1ponders]]

Of course probably the easiest way to deal with this is to get another 400D with a nice heavy 135mm lens or similar, that can be mounted on the forward piggyback point to help counterbalance. Sort of like a seesaw. :D

I'll just settle for an SBIG at the back and the 300D at the front shall I. :lol:

[Lee]

I've thought of this - what I was thinking of is making a small plate from some aluminium, and joining it to the pair of camera mount spots on the top of the ED80 rings - then mount the camera on the plate, more towards the middle.....

[[1ponders]]

You mean like this :D

What works well is instead of using just the ball head, use the manfrotto video adapter that can slide with the ball head on top. Or position the camera further out along the aluminium. You just have to be careful of flexure in the aluminium bar then.

Except that Mike is imaging at prime focus. ;)


But Mike you could try mounting the weights to the end of the Aluminium bar. Yours is thick enough and as long enough.

[Lee]

:doh:

[[1ponders]]

:lol:

[joshman]

hahah, i think you might be onto something!!!!!! or i get a 40d and use that prime focus and put the 400d on the forward piggyback!!!

oh noes....i might catch the buying frenzy!!!

not likely, i have negative mulah, lol