Refractor on top of reflector, possible?

[emadmoussa]

Hello guys,

I'm not sure this is unorthodox or not, but I've been thinking about mounting a 70mm (say, MERCURY-705 70MM) refractor on the top of my Skywatcher 200p tube - or maybe both togther on the same mount (EQ5). I'm actually after a readily made maginifcation set-up instead of constant changing of the eyepieces. I would use the reflector as a powerful finderscope, that's not to say I'm getting rid of the original 10x50 finderscope. Or Mayb I am?!!

Do you think it's an extreme thought? Has anybody seen something like that? Any extra accessories required to fit the refractor? Any suggestions?

I created a graphic below to explalin my point:

Thanks!

Imad

[furrysocks]

I'm thinking of mounting a 3 inch reflector on my 8.5" reflector as a finder, so I've been thinking about this myself.

In your case, what is the combined weight of the two scopes? Up to what weight is your mount rated? Are you visual-only, or do you do astrophotography? How does the weight move when your scope moves and/or rotate the reflector in its rings? Would you need to be able to rotate the refractor around the reflector for comfortable viewing? Is the refractor heavy enough that it would put undue stress on the reflector tube (depends on mounting system, I guess)?

Just some thoughts - good luck.

[Catanonia]

Quite common to do and thinking about doing it myself again.

My OAG is a pain for my SuperNewt, so currently I am side by side with a refractor, but it weighs alot and needs an extra 5kg on the bar.

So thinking about this setup, but will introduce flex causing guidance issues.

Luckily I am @ F2.8 so can get away with short exposures. But normally people move away from the fract on top because of flex.

[Uplooker]

yes, this is very easy to do. The scope rings on your SW 200P have 1/4 inch threaded holes at the top. Use these to attach the dove-tail bar from the refractor you want to dual mount.

I use this method to attach a SW ST80 to my SW 150P to use as a guidescope.

Ian

[emadmoussa]

yes, this is very easy to do. The scope rings on your SW 200P have 1/4 inch threaded holes at the top. Use these to attach the dove-tail bar from the refractor you want to dual mount.

I use this method to attach a SW ST80 to my SW 150P to use as a guidescope.

Ian

Thanks Ian, that's genius. So all I need is the guide scope?

[Carbon Brush]

Assuming you have an equatorial mount, piggy back balance is easy.

The SW200P is though supplied usually with EQ5. Adding extra weight is pushing this mount a bit. Some would say too far.

I have mounted scopes piggy back and side by side, usually for comparison purposes.

The weight soon builds up so I only do it on D6 mount.

Hope this helps.

[StuW]

I explained in your other Identical post that your mount would be highly overloaded. I'm at the limit of my HEQ5 with just the 200p, an EQ5 wouldn't cope with the extra weight.

[emadmoussa]

I explained in your other Identical post that your mount would be highly overloaded.

I appreciate your advice. The guidescope is not very heavy though. I tried to overburden the mount to test, it seems OK. I'll see how it goes though.

[Keiran]

It should be quite easy to do as the 200P has a mounting area on the top of its tube rings, simply bolt a dovetail bar to the top of the rings and the frac to the bar.... Make sure the balancing is right and away you go. The only problem, as pointed above, is the weight of both scopes. That setup will be quite heavy, and maybe too heavy for an EQ5.

Keiran

[emadmoussa]

Assuming you have an equatorial mount, piggy back balance is easy.

The SW200P is though supplied usually with EQ5. Adding extra weight is pushing this mount a bit. Some would say too far.

I have mounted scopes piggy back and side by side, usually for comparison purposes.

The weight soon builds up so I only do it on D6 mount.

Hope this helps.

How do you fit it side by side?

[Keiran]

If you do go down the road of putting a frac on the newt, i really wouldnt mount them side by side.

This is my side by side bar

IMG_9705 by Keiran Bernstein, on Flickr

and piggyback

IMG_9707 by Keiran Bernstein, on Flickr

but obviously for smaller scopes

[madatter]

Just a thought, but couldnt you use one off the scopes as a guide scope for the other?

[emadmoussa]

If you do go down the road of putting a frac on the newt, i really wouldnt mount them side by side.

This is my side by side bar

IMG_9705 by Keiran Bernstein, on Flickr

and piggyback

IMG_9707 by Keiran Bernstein, on Flickr

but obviously for smaller scopes

Thanks Keiran, do you know where to get the side-by-side adaptor?

[emadmoussa]

Just a thought, but couldnt you use one off the scopes as a guide scope for the other?

I thought about that, but apparently I've got a pair of Celestron 15x70 binoculars for this purpose. I'd like the two scopes to be together, easier to handle and aim.

[Carbon Brush]

Here is a side by side on thew D6 with 8" & 10" newts.

[emadmoussa]

Here is a side by side on thew D6 with 8" & 10" newts.

Where can I buy this mount extension?

[Carbon Brush]

If you look here...

http://www.firstlightoptics.com/adm-guidescope-rings-and-systems.html

These are the components I am using.

They big and heavy and expensive. But very well made.

[emadmoussa]

If you look here...

http://www.firstligh...nd-systems.html

These are the components I am using.

They big and heavy and expensive. But very well made.

Thanks David, very helpful. Unfortunately, they're quite pricey. I guess it's cheaper to buy the Skywatcher Mercury 70mm and use it as a guide scope. The problem, I don't have a clue how to attach it to the 200p tube. Sorry for the non-stop questions, but do I just screw them into the tube rings, like Ian ''above'' suggested?

[emadmoussa]

yes, this is very easy to do. The scope rings on your SW 200P have 1/4 inch threaded holes at the top. Use these to attach the dove-tail bar from the refractor you want to dual mount.

I use this method to attach a SW ST80 to my SW 150P to use as a guidescope.

Ian

Do you have a photo for this?

[Peter Drew]

You're going to have to add extra weights as well as the second telescope in order to get good balance, the combined weight might be too much for the mount. As far as "possible" is concerned, I mounted a 8.7" F12 refractor on my 30" Dob for a while.

[laser_jock99]

I have an ST80 guide scope sitting on top of 12" Newtonian. Side by side mounting presents too much of a balancing challenge unless scopes are of similar sizes/weights.

[emadmoussa]

Hi there,

I think I'm going to settle for the Skywatcher StarTravel 80mm as a guide scope. It seems to me that the Skywatcher StarTravel 102mm could do the job as well. the 80mm is 1.3 Kg - does anybody know the weight fo the 102mm?? Also, what is the best webcam for this?

[furrysocks]

It seems to me that the Skywatcher StarTravel 102mm could do the job as well. the 80mm is 1.3 Kg - does anybody know the weight for the 102mm??

teleskop-express.de quotes 2.5kg for the OTA.

[michael.h.f.wilkinson]

As a giant finder a 70mm F/5 can be used very effectively, see my post here:

I could find WAY more objects like that than with the 6x30 standard issue Celestron finder. I intend to use this as a guider as well. A fast little frac like the Mercury-705 is much better than the slower 709 type, certainly as a finder (the latter gives at most 1.7deg FOV). The larger FOV also makes finding guide stars easier.

[emadmoussa]

Do you recommend a certain webcam?