Sky-Watcher Evostar 80ED DS-Pro Dovetail on the AZ-EQ6 Pro

[oymd]

Morning everyone

I would be very grateful if you can offer some advice about a mounting issue I face.

Last month I bought the Sky-Watcher Evostar 80ED DS-Pro and the new AZ-EQ6 Pro mount. The OTA comes stock with a very well made, but very short, dovetail. It has 2 recessed parts to fit the nuts that hold the tube rings.

I have struggled to balance the OTA in DEC, especially with the heavy 2" diagonal and with 2" eyepieces. With attached camera it becomes even more backend heavy, and impossible to balance.

To fix this problem, I bought the LONG Skywatcher dovetail, 33.5cm, also in green. Part number: MPN: 20759

I tried to fit it yesterday night to the OTA, but was surprised to see that on its underside it has no RECESSED holes, and the stock nuts which I removed from the stock dovetail and rings DO NOT FIT through the new dovetail's holes?

Can you please advise what to do? I have attached pics of the STOCK short 21cm dovetail, and the LONG 33.5cm new dovetail.

Many thanks

[johninderby]

Get one of the ADM or StellaMira dovetail bars with proper recesses and long slots.

https://www.firstlightoptics.com/dovetails-saddles-clamps/stellamira-universal-vixen-style-dovetail-bar.html

 

[joe aguiar]

Since u have that long 13 inch sw green bar u can just drill 1 or both holes and just use a nut and bolt that fit the hole.

It wont be tap or screw in but it doesnt have to be.

If u can find least 1 hole that work that's half the job then just drill 1 hole out.

Joejaguar 

[oymd]

5 hours ago, joe aguiar said:

Since u have that long 13 inch sw green bar u can just drill 1 or both holes and just use a nut and bolt that fit the hole.

It wont be tap or screw in but it doesnt have to be.

If u can find least 1 hole that work that's half the job then just drill 1 hole out.

Joejaguar 

I prefer this option. By drilling, do you mean take it to a shop, or drill it myself? I have a power drill, and possibly can try widening the pre existing holes with a thick bit I have. 
 

but won’t that risk rust etc?

[johninderby]

The dovetail is aluminium so no problem with rust.

I did modify one a few years ago but used a drill press but as it’s aluminium not hard to drill with a power drill. Drill out the holes then use a countersink bit and buy some countersunk stainless screws. Makes it easy that way. Oh yes and buy a new drill bit if needed which can be had for a couple of quid off Amazon.

Edited February 14, 2020 by johninderby

[Danjc]

Apologies if you have already done so but have you tried moving the OTA up the tube rings ?

Also one of the rings can be moved on the dovetail bar to allow for even more movement of the OTA. 
When I first got my ED80 I had a DSLR and FF/FR on the back and managed ok to balance with a little adjustment. 

[Skyline]

Buy one of these.

https://www.firstlightoptics.com/dovetails-saddles-clamps/primaluce-lab-240mm-plus-vixen-dovetail.html

[oymd]

16 hours ago, Danjc said:

Apologies if you have already done so but have you tried moving the OTA up the tube rings ?

Also one of the rings can be moved on the dovetail bar to allow for even more movement of the OTA. 
When I first got my ED80 I had a DSLR and FF/FR on the back and managed ok to balance with a little adjustment. 

I have

i moved the OTA all the way forward until the rings get caught on the screws of the focuser assembly. It’s still very back heavy. Also, because of the 2 safety screws on the bottom of the dovetail, I cannot move the dovetail completely forward to its very edge. 

[oymd]

5 hours ago, Skyline said:

Buy one of these.

https://www.firstlightoptics.com/dovetails-saddles-clamps/primaluce-lab-240mm-plus-vixen-dovetail.html

The one that comes stock it 21cm. Not sure a 24cm will make a big difference. 

[geeklee]

If you don't want to drill, I got the 11inch version (recommended by FLO) for my 80ED - same challenge - and it was perfect:

https://www.firstlightoptics.com/adm-vixen-type-v-series/adm-vixen-style-universal-dovetail-bars.html

(was also mentioned above)

[ollypenrice]

Remember that you don't have to have the focuser the 'right way up.' If it helps to do so you can rotate the scope till the focuser is on the top. You can also add a weight to the front of the bar if it's rear end heavy.

Olly

[joe aguiar]

On 14/02/2020 at 16:00, oymd said:

I prefer this option. By drilling, do you mean take it to a shop, or drill it myself? I have a power drill, and possibly can try widening the pre existing holes with a thick bit I have. 
 

but won’t that risk rust etc?

sorry iam normally not around on weekends much but yes try it yourself , its just a hole if you are not handy its a great way to learn.

Joejaguar