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SCTs

Ben Ritchie

By Ben Ritchie
in EEVA - Reports

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Ben Ritchie

Ben Ritchie

Posted
Posted

Vaguely pondering equipment (...as I often do when the weather stops me from using what I have... :) ) and I was wondering how well SCTs work as video astronomy 'scopes?

It seems to me that it might be quite a good system, with the Meade f/3.3 reducer giving a decent speed/image scale and a reasonably compact OTA that would fit my EQ6 nicely - e.g. C9.25 or C11, maybe Meade 10" - and a piggybacked refractor for the wider stuff. I've seen Peter's comparison with a C8 (?) and assorted reducers with a terrestrial target and that looks promising, but any other reports under the stars? I guess the obvious alternative is a fast 8" or 10" Newtonian, but they're a bit of a pain to collimate at f/4, the focuser is at the 'wrong end' and the lunar/planetary abilities of the SCT focal lengths are also quite interesting.

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Psychobilly

Psychobilly

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Yeah mines a CPC800 the f3.3 reducer should work a treat with these small sensors especially the 1/3" one in the 2000 series cams..

The pics I posted the other day were with a cheapo 1.25" 0.5X reducer ...

The SCT hadn't been used for a coupel of seasons other than as a mount for the Megrez72 that was used for most of the imaging that I had been doing...I saw these Intergrating cams as a way of getting some use from it again...

Peter...

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Electron

Electron

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Hi Ben,

I have a C11, with hyperstar (f2) and 6.3 reducer for the other end.

I am flying to UK tonight and will be picking up a Mintron camera,

72S85HP-EX from Bernard at Modern Astronomy.

With a DSLR and Hyperstar, max exposure I have used is 30secs for deep sky, so I'm dying to get the Mintron home and see what it, and I, can do.

I am still learning the basics of the C11/Hyperstar but I'll post some of my first attempts with the Mintron that may give you more of an idea, won't be until after the 17th though.

About collimation I would say that, like most telescope related tasks, it seems to be a daunting thing for most of us but as always practise makes perfect and so reduces the time needed.

So I would guess it would become no issue for either type of scope, with use.

As Peter's pics posted the other day shows, a cheap reducer may be enough, I am certainly going to go that route first.

I love the C11, but it is very heavy, I have just had a set of "wheely bars" made locally so I can now just wheel it outside.

Takes about 30 mins to set up, minus polar align, now. before the bars it took about an hour to move everything outside.

Just some things to bear in mind.

Denis

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Ben Ritchie

Ben Ritchie

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Thanks guys, interesting - i'm not sure about Hyperstar, but only because i've always been terrified of something happening to the SCT secondary, but weight shouldn't be an issue per se as it would be observatory-mounted on the EQ6. A C9.25 might be a good balance, but the aperture of the C11 is attractive. With the relatively small sensors of the video camera strong focal reduction should work well and the disadvantages of the classical SCT vs. the newer aplanatic SCTs aren't an issue.

Peter, any idea how the f/3.3 reducer works with the 1/2" chip? I've been down that route for a SCT + Meade f/3.3 + cooled CCD in the dim and distant past, but my memory fails me...

Managed a 'first light' of sorts with the SBC-2000P (...the hedge at the bottom of the garden...!) and quite excited about the prospects.

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Macavity

Macavity

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I think, with VIDEO astronomy - Smaller chip size etc., many "deprecated" (re. imaging!) scopes work rather well. I had a fair degree of success with Skymax MAKs and, ad-hoc reducers, stuck on the end of the Camera nose-piece... :)

I struggle (slightly) with my, albeit-laudable, F4 Newt, and yearn for the solidity and simplicity of a "Catadiopteric" system. If I had the dosh, I'd be looking at a 7", F10, "Russki" MAK - Albeit with 2" focusser... As my ONE and only scope. :)

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Ben Ritchie

Ben Ritchie

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and yearn for the solidity and simplicity of a "Catadiopteric" system

It's been six years since I owned a SCT and maybe rose-tinted hindsight is playing tricks on me, but I have similar feelings - over the last year or so i've been backtracking towards simplicity on the grounds that after work/family etc. the less effort something is to use the more likely I am to actually use it. So that's my real hope for video, and i'm vaguely starting to think about other kit options to support it.

Heck, I remember my *fork mounted* LX200 as being really simple to use.... :)

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philj

philj

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The C11 / Mintron 12V6 combo worked for me. I used it at F10, F6.3 and F5, (never had a 3.3 reducer). to great effect.

Below is M51 at F10 in the Mintron, somewhere around 1 to 2 minutes grab, stacked and thats it.

Enjoy the scope and cam Im sure you will.

Philj

PS Oh and the Watec in the C11 is awesome, (as an oldy I never use that word except when applicable and its applicable, itll blow your socks off)

post-14930-133877659799_thumb.jpg

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Helen

Helen

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The C11 / Mintron 12V6 combo worked for me. I used it at F10, F6.3 and F5, (never had a 3.3 reducer). to great effect.

Below is M51 at F10 in the Mintron, somewhere around 1 to 2 minutes grab, stacked and thats it.

Enjoy the scope and cam Im sure you will.

Philj

PS Oh and the Watec in the C11 is awesome, (as an oldy I never use that word except when applicable and its applicable, itll blow your socks off)

I wish you hadn't said that Phil.....I was all set to part with my C11 as it doesn't get enough use :)

Helen

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Helen

Helen

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The C11 / Mintron 12V6 combo worked for me. I used it at F10, F6.3 and F5, (never had a 3.3 reducer). to great effect.

Below is M51 at F10 in the Mintron, somewhere around 1 to 2 minutes grab, stacked and thats it.

Enjoy the scope and cam Im sure you will.

Philj

PS Oh and the Watec in the C11 is awesome, (as an oldy I never use that word except when applicable and its applicable, itll blow your socks off)

I wish you hadn't said that Phil.....I was all set to part with my C11 as it doesn't get enough use :)

Helen

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Macavity

Macavity

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Some real-time limiting magnitudes for the GSTAR-EX (ref. Massey & Quirk):

80mm F5 refractor: 14.2

15cm/F5 reflector: 15.6

20cm/F5 reflector: 15.8

20cm/F4 reflector: 16.2

20cm/F10 SCT: 15.5

28cm/F10 SCT: 16.2

31.5 F4.5 reflector: 16.9

c*u*m grana salis perhaps? But impressive, nonetheless! I think my "Mag five point something" skies would have a theoretical "background" of around Mag +18? Still a bit to go, with an 8"/F4 Newt then - Notwithstanding noise. <G> But whatever, this gets interesting... :)

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