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Dual TEC 140 - the plan.


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Since Tom repossessed his Atik 11000 for use in his new robotic observatory (based here) our well known Twin Tak FSQ has become single barreled again. However, Tom happens to have a spare TEC140 stored in our linen cupboard (as you do) and Gnomus happens to have a Moravian camera so the plot is to try a dual high resolution rig. We now have all the metal bits to bolt this monstrosity together but with guests coming this afternoon I can't disturb the working rigs for another seven days.

The Moravian has a larger FOV and slightly lower resolution than my Atik 460 currently in number one TEC, so maybe we won't need our Cassady tilt-pan device to get a fully overlapping FOV. This would save considerable weight and remove one source of flexure (though the Cassady thing is remarkably stiff.)

Will it work? We just screwed the dual Tak FSQ106 rig together, aligned the scopes and started imaging. It was as simple as that and we never touched it again. But that's at 3.5 arcsecs per pixel. My TEC is running at 0.9"PP. Will we get flexure or other gremlins? Watch this space.

Olly

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I snapped this quickly on my phone while we stood back to admire Its a beast of a set up. Cant wait to get data from it. Tom

Since Tom repossessed his Atik 11000 for use in his new robotic observatory (based here) our well known Twin Tak FSQ has become single barreled again. However, Tom happens to have a spare TEC140 store

Nope. Just checked- and I don't have one. Very disappointed.

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On ‎02‎/‎03‎/‎2019 at 13:15, ollypenrice said:

 Tom happens to have a spare TEC140 stored in our linen cupboard (as you do)

A must have accessory, a magic cupboard filled with astro bits and bobs :)

 

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My friend has a food magic cupboard from which she can rustle up all sorts of delights from seeming nothing but bare shelves!! Is this something similar?  ?

Good luck with this, it sounds very exciting and I am sure that it will work just fine!! Just need to find another 106N now to get back to a dual Tak rig.... I'll keep my eye out like I did for your last one LOL!!!

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17 minutes ago, swag72 said:

My friend has a food magic cupboard from which she can rustle up all sorts of delights from seeming nothing but bare shelves!! Is this something similar?  ?

Good luck with this, it sounds very exciting and I am sure that it will work just fine!! Just need to find another 106N now to get back to a dual Tak rig.... I'll keep my eye out like I did for your last one LOL!!!

We already have one sitting doing nothing for want of a camera but I'm not sure how many dual rigs I'm up for running here!!!

Olly

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32 minutes ago, swag72 said:

My friend has a food magic cupboard from which she can rustle up all sorts of delights from seeming nothing but bare shelves!! Is this something similar?  ?

Good luck with this, it sounds very exciting and I am sure that it will work just fine!! Just need to find another 106N now to get back to a dual Tak rig.... I'll keep my eye out like I did for your last one LOL!!!

Ultimately I hope to run a dual Tak robo set up. I have not got the single one running yet though.

Dual Taka nd Dual TEC data will be enough to keep me swapped.

T.

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Just now, Tom OD said:

Ultimately I hope to run a dual Tak robo set up. I have not got the single one running yet though.

Dual Taka nd Dual TEC data will be enough to keep me swapped.

T.

You're not wrong there! I find that with only 1 Tak and the TMB running it's too much data!!!

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Actually Olly, I also have something in my cupboard: an Atik 460 that never got to be used before I went CMOS. Are you interested to attach it to that other TEC140 to get a perfect match? It is potentially up for sale but I could be equally interested in offering it in exchange for receiving good data from a dream dual rig in a place with clear skies! PM me if interested.

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  • 3 weeks later...

Update: Tom and I loaded the pair of scopes up onto the Mesu using the Cassady tilt pan adjuster for the lighter one (without guidescope.) With two people on the job getting the dynamic balance wasn't too terrifying but you wouldn't want to lift the pair on and off the mount together. It's a combination of weight and cumbersomeness (is that a word?)

We then waited for darkness and aligned one to the other, set the cameras orthogonal to RA and Dec, focused and tried a 15 minute sub in both. The guide trace was superb and stars tight and round on both sides.  It works! A second test the following night confirmed this.

The camera is off again while Steve configures it in SGP over the net and while we source a full set of filters from a supplier who has them in stock. When it's all back together I'll post some pics and a video but, trust me, it looks darned tasty!

Out of tidy mindedness we nearly set both scopes to exactly the same fore-and-aft position in their rings but forgot to do so. We were then glad we didn't because it means we can take off either camera without disturbing the other: the filterwheels miss each other when rotated.

Olly

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That’s great!

Once I have retired and got the dome up and running with the Esprit 150 and Altair 102, myself and Tomatobro have a notion to replace the Altair with another Esprit 150 (pension lump sum permitting), this thread confirms it is a practical proposal.

If dual rigs make any sense, it has to be under UK skies?

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24 minutes ago, tomato said:

That’s great!

Once I have retired and got the dome up and running with the Esprit 150 and Altair 102, myself and Tomatobro have a notion to replace the Altair with another Esprit 150 (pension lump sum permitting), this thread confirms it is a practical proposal.

If dual rigs make any sense, it has to be under UK skies?

Twice as fast is twice as fast under any skies, including ours. They are not always helpful and I never claim they are! Unlike fast F ratios (a minefield for any number of reasons) a dual rig does what it says on the tin. Even the fanciest-dancing of theorists are unable to argue with the fact that a dual rig is more or less twice as fast as a single. There are hidden benefits as well. Sky looks dodgy? Set up to shoot RGB on one side and BGR on the other.

I like dual rig imaging!

Olly

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On 04/03/2019 at 22:45, gorann said:

Actually Olly, I also have something in my cupboard: an Atik 460 that never got to be used before I went CMOS. Are you interested to attach it to that other TEC140 to get a perfect match? It is potentially up for sale but I could be equally interested in offering it in exchange for receiving good data from a dream dual rig in a place with clear skies! PM me if interested.

Sorry Goran, I missed this. It would have been a good offer but Steve got in first with his Moravian. Personally I'd give that 460 a try...

 

Here's another pic. You can see the Cassady T-GAD device on the right hand scope as seen in the pic. (It's bolted to the almuminium-coloured dual bar.) So far it has been able to carry the scond scope without flexure. To be on the safe side we have the guider on the 'rigid' scope side with the higher resolution camera.

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It will be interesting to see how consistently the difference in system resolution translates into real and perceptible image resolution.

Another benefit of the change is that the smaller Tak 106 is now in the smaller observatory. It was a bit cramped in there with the TEC!

Olly

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Looks like a dream team!

Ideally I assume you could add more counter weights so they do not have to be so far from the centre - but as we all know they are ridiculously expensive and your guiding is probably fine in any case.

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Watching this closely Olly as Alistair and I are hot on your heels with both of us getting our APM TMB 152 dual rigs going too.  We both tried using Optec Libras as we couldn't source a Cassady, but the Optecs just weren't man enough for our 152s - so had to resort to feeler gauge shims instead!  We're almost there now.  I'm getting differential flexure on the second scope and so I'm off back to Spain on Monday to fit extra tube rings fore and aft, bolted the tubes together with ADM Vixen dovetails in the hope that will fix it. The prospect of capturing 20+ hours each night has a certain appeal!

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1 hour ago, AstroFD said:

That looks like the perfect set-up. Hw do you mange in SGP the dual set-up in terms of dual camera, focusing, dithering etc... I thought SGPro was only set-up for single camera.

You can run two instances of SGP on one PC - we have done this at home - dithering needs to be switched off though. We set up and save different equipment profiles for both sides of the rig and then make sure that one profile is active in one instance of SGP and that the other profile is active in the second instance. Only one profile controls guiding and doing the meridian flip. You will obviously lose a sub on the secondary camera when the mount flips.

I believe that Olly is using one PC/laptop per camera - we have run that system at home as well with one PC purely taking care of data capture and focussing on the ‘dumb’ side of the rig. Once again you can’t have dithering switched on and you will still lose a sub if you are doing automated meridian flips.

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3 minutes ago, MrsGnomus said:

You can run two instances of SGP on one PC - we have done this at home - dithering needs to be switched off though. We set up and save different equipment profiles for both sides of the rig and then make sure that one profile is active in one instance of SGP and that the other profile is active in the second instance. Only one profile controls guiding and doing the meridian flip. You will obviously lose a sub on the secondary camera when the mount flips.

I believe that Olly is using one PC/laptop per camera - we have run that system at home as well with one PC purely taking care of data capture and focussing on the ‘dumb’ side of the rig. Once again you can’t have dithering switched on and you will still lose a sub if you are doing automated meridian flips.

I've even managed to run three instances of SGP on one PC!  However I'm struggling without dithering.  How do you address hot pixels?

I'm contemplating running long (30 mins Ha/OIII) subs on the master scope, and shorter (LRGB 5 mins) subs on the slave scope so that I can still dither, but accepting that around 1 in 6 LRGB subs will be sacrificed.

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I've found the same make ASCOM auto focusers don't like running on multiple rigs.

Wont bother Olly though as he doesn't believe in that new fangled stuff :grin:

Dave

Edited by Davey-T
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2 minutes ago, Davey-T said:

I've found the same make ASCOM auto focusers don't like running on multiple rigs.

I've got 2 Optec FocusLynx focusers running ok, but Optec is limited to just 2.  As mine is a triple rig I'm using a Lakeside for the third focuser.

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