Hows anyone attached an 80mm refractor to 6SE goto mount?

[yeletah]

Hi,

Hows anyone attached an 80mm refractor to Nexstar 6SE goto mount?

I imagine the slew travel limits would need to be adjusted to avoid any contact between refractor and the 6SE goto mount.

The refractor is a 600mm focal length (evostar ED80)

[ronin]

Someone put a WO Megrez 72 on one some years back. Looked very good, actually looked better with the WO72 then the proper Celestron tube.

Not sure of the spec of the ED80, need to work out the balance and what protrudeds either side of that, overall length is only part of the setup. As the ED is a refractor the weight is towards the front so you may need to shift the OTA backwards to get balance right and then the diagonal could impact the mount. Think the ED80 is f/7.5 so there is reasonable length behind the balance point. Weight should be OK the original tube is about the same weight and the mount takes the 8" tube anyway.

Concern is the balance and length to the rear of that for viewing overhead.

I could see it not quite working as well as it would appear at first glance. Suppose the other question is why has Synta not done it already, they stick just about every scope on every mount combination they have.

[yeletah]

Can I find the balance point of the ED80 by hanging by a string?

and position this balance point on the centre of fork arm of the 6SE

[johnno]

I've done the same but with a SW az mount, what I did was use a old round broom handle cut it down to about 12'' lay it on a table and place the tube on it and just roll the tube along it till you find a balance , I know its a bit crude but it seems to do the job, and marked the c.o.g on the tube with tipex. I did 2 markings, 1 for just the diagonal and eyepiece and finderscope and clamps fitted and the other for the flipmirror and camera finderscope and clamps.

[ronin]

Doesn't need to be totally accurate as in to 0.001mm, 5mm either way will be fine.

It is just that the refractor has the weight at the front and a SCT is I think towards the rear.

So you will have a reasonable amount more of the ED 80 OTA to the rear of the pivot and that length could easily hit the mount base if you tried to view something like Albereio at this time of year.

The mount is stupid and will simply try to drive on immaterial and so motors burn out and cogs get stripped.

Check if there is a handset input option to limit the elevation of the scope, would add safety to it all.

[yeletah]

Thanks for the posts, in the photo it looks like it will clash?

It is just an idea just to get an occasional photo, nothing serious.

I would need to get confident with setting the elevation limit, make sure it's reliable!

[Herbig]

I 've done the same as Johnno with an 80mm Equinox, bolted a medium length ADM dovetail to it to have flexibility with balance, had no problems with clashes (yet) but have a 2" diagonal and heavy Meade EP's that help with balance.

[yeletah]

Thanks for the info

Did you adjust any goto limits?

[Cath]

Thanks for the posts, in the photo it looks like it will clash?

That's the big problem that you would have I think with using the SE mount. Useful for horizontal work but would have a limited vertical movement.

[johnno]

I've just had a look at the degree marker scale and it looks like 70 degree's looks like a safe limit maybe 75 at a push if you remove the controller handset bracket. I've not set a limit as I never go up that far. 2 photo's with it at 70.

[yeletah]

Thanks for the photos, good to see.

My main concern is if the 6SE or enter the wrong target! hence adjusting the limit.

I'll have to balance the ED80 - match that point to the fork arm and give it a try manually and see what freedom is allowed.

and then test the limits work as expected,.

If it does work - I use it for short exposure astrophotography no higher than about 45 drgrees

[Cath]

I've just had a look at the degree marker scale and it looks like 70 degree's looks like a safe limit maybe 75 at a push if you remove the controller handset bracket. I've not set a limit as I never go up that far. 2 photo's with it at 70.

Not to bad. But the 6SE mount is a bit different though, it will limit the vertical movement by a great deal.

[Donkeiller]

I regularly mount my Kson 1026ED (focal length 612) on my 6/8SE mount.

I place a short extension tube (Celestron x2 Barlow with the lens cell removed) into the diagonal and this allows me to reach zenith and not collide with the mount base ;-)

Gotos are accurate and the scope is pretty much balanced.

I'm sure something similar could be done with any short focal length refractor under 100mm.

One other point my scope is carbon fibre so it is very light (OTA =5.7lbs). Makes a great G&G.

I'll post a photo when I get home.

[Donkeiller]

See attached piccies- 102mm refractor on SE mount. P.S. the little pouch strapped to the mount arm contains 10x 1.2v NiMh rechargeables. Enough for 4-5 hours viewing. No cordwrap either!

[Donkeiller]

Rats- here it is- hopefully

[Cath]

Well, that works

[yeletah]

Brilliant !

Thanks

[LukeSkywatcher]

Rats- here it is- hopefully

Looks good to me. Must try my 70mm travelscope on my 8SE mount.