A Triple Rig, sort of

[tomato]

My new RASA 8 is now riding on the Mesu along with the dual Esprit 150s. The all up weight is 56 kg, still inside the 75 kg imaging limit for the mount. As the scopes have to look through the dome aperture, I had no choice but to mount the RASA piggy back between the refractors which means it is quite some way from the centre of axis, good job it is only 7 kg.

I have it all balanced, it is not my intention to image with all three scopes at the same time, I don’t think my laptops or my brain could cope, and there wouldn’t be much point any way. If the mount can take it  the main advantage will be not having to tear down and build up the rig each time I want to change imaging scopes.

The real test will be the guiding error when imaging at 0.9 arcsec per pixel, time will tell.

 

 

 

Edited August 30, 2020 by tomato

[andrew s]

Look FAB. Regards Andrew 

[rubecula]

😲

How do you focus the RASA?

 

[tomato]

Focus is adjusted just like a regular SCT, by moving the primary mirror. Celestron claim to have improved the stability of this arrangement on the RASA, and I saw no indication of mirror flop over a 2 hour session, at least visually.

[wimvb]

The more, the merrier. Looks very nice. But what is the cardboard for?

[gorann]

That is something else! Good idea to either run the RASA or the refractors not to make your brain and computers to melt down. Mine would. Looks sturdy enough.

Regarding focusing the RASA, this has been one of my main surprises with this f/2 scope. It is very easy and it keeps all night (I see on Chuck's Atrophotography on youtube that he found the same). I just zoom in on the smallest stars and make them as small as possible on the screen. When I put the Bathinov mask on after having focused on the computer screen, focus is always spot on, so I have now retired the Bathinov.

Good luck!

[tomato]

22 minutes ago, wimvb said:

The more, the merrier. Looks very nice. But what is the cardboard for?

That’s for when the Astrozap dewshield I have to hand doesn’t go all the way around.😜The cardboard fits neatly where the dovetail is located.

PS I once made a Mesu mount replica out of cardboard, but that’s another story.

[Ken82]

Looks great, how are you aligning all scopes ? 

[wimvb]

7 hours ago, tomato said:

PS I once made a Mesu mount replica out of cardboard, but that’s another story.

Interesting. I once made a refractor out of wooden sticks, paper and two simple lenses. Maybe we should start a business together. I bet we would be hefty competition to SkyWatcher.

[tomato]

8 hours ago, Ken82 said:

Looks great, how are you aligning all scopes ? 

One of the Esprits is on an adjustable saddle, I won’t attempt to align the RASA as I don’t intend to image with this scope at the same time as the refractors.

[tomato]

It was guiding at 0.5” total RMS, on Andromeda low down in the East. The guiding was steadily improving as the target climbed higher in the sky.

It sure is tight now, inside the dome, especially as there is some equipment mounted inside, high up. I check before initiating a big slew.

[wimvb]

16 minutes ago, tomato said:

It sure is tight now, inside the dome, especially as there is some equipment mounted inside, high up. I check before initiating a big slew.

You know, Göran solves such a problem by building a new obsy now and then. Sometimes I wonder if he’s secretely competing with Deep Sky West (not Midlands).

ps

don’t let him know I told you that. 🤫

[tomato]

Well, I definitely cannot consume any more real estate for observatories, but it looks like my brother @Tomatobro will be getting a dome. Maybe we could set up our own Not So Large Array?😁

[Tomatobro]

Long baseline inter photography.....sounds good

[wimvb]

9 hours ago, Tomatobro said:

Long baseline inter photography.....sounds good

You'll need a watch. An accurate one.

[callisto]

You've got some gear there my friend 👍

[tooth_dr]

Very nice setup - but I'm not used to all the cables now - the integrated cabling feature of the new mesu is something I really like.  I'm trying to fit my solar scope onto the mount somewhere, as it's just handy having it all there ready to go.  It did have a spot, but then I mounted another lens and camera there, so looking for another spot 😂 

 

[tomato]

Just keep bolting it on somewhere, the Mesu can take it.😎

[ampleamp]

On 31/08/2020 at 08:59, tomato said:

One of the Esprits is on an adjustable saddle, I won’t attempt to align the RASA as I don’t intend to image with this scope at the same time as the refractors.

Which saddle are you using for adjustment, and does this avoid and trailing in the secondary scope?

[tomato]

It’s an ADM saddle, the lateral adjustment has been modified to allow all adjustments to be done from the one side and with an adjustment tool, as the saddle is heavily loaded and the standard knobs were not up to it.

There is a floating bracing plate linking the two sets  of scope rings together on the top, this is carefully tightened down once the scopes are aligned, this has eliminated flexture between the two scopes, it does take a bit of setting up initially though. The RASA is now bolted to this, I will have to see how this affects the stability of the set up, but the scope can be taken off easily if it is a problem.

[ampleamp]

Thank you, sounds fiddly, but worth it.