Aligning two scopes on an AZ EQ5GT

[osbourne one-nil]

I'm toying with the idea of getting a nice 6" or 8" Newtonian to join the Tak FC-100DS on my AZ EQ5. I already have an 8" Portaball, which is wonderful but I'm not happy leaving it outside to always be at ambient temperature so it doesn't really offer "grab and go"; I'd be ok leaving something cheaper in the shed. 

I've never had two scopes mounted before, so I'm wondering if they would be aligned so the view in one scope matched the view in the other; I'm assuming they would be otherwise the goto ability of the mount would be compromised, but the precision necessary seems high. Is there some adjustment available/required to make this happen?

Thanks. 

[Stu]

I'm afraid the answer is often no! I had an AZEQ6, and it has altitude adjustment between the two sides, but not azimuth. If I wanted exact alignment then I used to use a guide scope mount like this which gives the adjustment needed. It works ok unless you are using a heavy scope, I've used with 4" refractors no problem.

http://www.firstlightoptics.com/guide-cameras/skywatcher-guidescope-mount.html

[brantuk]

Yup - those alt/az shoes are fine for lightweight guide scopes - though you do have to watch the flexure and ensure everything is tightened up firmly. But not really effective for larger heavier scopes. The best I've had with side by side scopes comes from using a wider angle eyepiece in one of them - at the cost of slightly lower magnification.

(I hasten to add I was using a side by side mounting plate - not tried it on the AZNEQ6 yet)

[ollypenrice]

For visual use I wouldn't have thought that perfect alignment were necessary. 

I would use the refractor as the definitive or fixed scope because the Newt will, almost certainly, exhibit image shift due to mirror movement, so it will tend to be slightly variable at the best of times. Once mounted on a standard dual saddle setup you could shim the dovetail slightly to refine alignment on the Newt. After that they'd be pointing close enough to make only a small handset nudge necessary.

I'd be wary of undersized guidescope adjusters for carrying a 4 inch. On our dual Tak 106 rig I use a massive Cassady T GAD adjuster on one scope but these cost the Earth, are no longer in production and add a vast amount of weight. FLO were looking into making an alternative and I seem to recall seeing something on offer, though I don't remember the details. The Cassady would probably overload an EQ6 with two scopes as well, though, let alone a 5.

One fly in the ointment: Where would you orientate the eyepiece on the Newt? Wouldn't the other scope tend to be in the way in some positions? Certainly in GEM mode it would?

Olly

[osbourne one-nil]

Thanks all - sounds like it might be more straightforward to simply mount one or other scope perhaps or simply, as Olly says, accept that they're not perfectly aligned. I suppose wouldn't matter a jot. All the versions I've seen place the eyepiece on the left of the scope which means I'd have to mount my Tak on the right, which seems to be on some sort of extendable shaft, which again, probably doesn't matter. 

Of course, if I could find a way to safely store my Portaball in the shed, that would be perfect. I did so over Christmas but when I took a look one night, the mirror had condensation on and the wooden mirror cover had mould on the edge! Not ideal. 

[ollypenrice]

If you put the Portaball in the shed, in an almost but not absolutely sealed insulated container with a pet-warmer pad inside it, or even just a dew heater strip placed in there and left on, might that not be close enough to ambient yet sufficiently higher than the dew point to work perfectly? 

http://www.ebay.com/bhp/pet-heating-pad

Olly

[osbourne one-nil]

I've wondered about something like that (I was going to use a lightbulb) and could probably easily knock up a small timber unit with some insulation and vapour barrier, get a cheap coffin on Ebay. It would certainly be a lot better than stored in my office which is kept at 21 degrees! 

I was hoping my shed would be ok - it's actually a double stable (which is weird as I don't think the original owners had horses) but it's very open and very ventilated, so seemingly doesn't offer much protection. 

Thanks Olly - I'll have a think. 

[osbourne one-nil]

Something like this might be just the job. 

http://www.keter.com/products/store-it-out-ultra#measurements