A REALLY good DSO imaging rig for my obsy?

[rocketandroll]

So, this is all somewhat hypothetical at present as I'm at least 1year off moving to somewhere I can even build the observatory.... but I do plan on building one and setting up a pretty sexy imaging rig in there.

I will keep my current range of equipment for star parties and for imaging larger targets... but I want to spend some money on a rig for imaging smaller DSO's at really good resolution.

So... if I said the budget was about £10K in total for the pier, mount, scope and camera... what should I be thinking about?

I am certainly thinking a BIG fast reflector would be the way to go on a static pier-mounted rig... am I stuck with a large newt or am I mad for thinking about trying to stick a reasonable sized Dob on an equatorial pier?

I've seen pics of the so-called 'Eq-7' or 'EQ-8' that are due out... I am guessing trying to stick a 12"+ Dob on an EQ6 is way beyond it's reasonable loading capacity... so... is the cost of a larger mount with a higher load capacity really going to be the big cost issue? Assuming one of these new larger SkyWatcher mounts comes in at under £5K and could handle the weight of say a 16" truss Dob... I could theoretically at least have a few grand spare for a dedicated CCD.

Mental?

I hasten to add I do have some engineering knowledge and access to some fairly high end machining facilities of this is going to need some custom hardware.

Anyway... was just day-dreaming and wondered what people's thoughts were?

Ben

[RobH]

JohnH uses an Orion optics 14 inch newtonian on an EQ6 without any trouble, and I know he's been getting 20 minute subs, so the EQ6 will handle a 12 inch.

[rocketandroll]

...hmmmm, wonder if it'd handle a 16"? :-)

[Rossco72]

The Dob is a Newt but on a John Dobson base.

You could look at something like an RC based optical system if you wanted the camera at the back, something like a 10" or maybe 12"

To get the magnification you seem to desire on smaller objects, you will be imaging at long focal lengths. For this you will need a REALLY good quality mount and I'd suggest ooking at an AP or Tak system rather than a Skywatcher one.

The mount will make all the difference in getting a useable large scale image at focal lengths of say 3-4m and probably f15-20 at least.

Cheers

[shaunster]

orion optics AG8

EQ6

Atik 11000

ahh just seen you want smaller DSO's!

In that case the choices ive suggested probably arent the best

[FraserClarke]

The Dob is a Newt but on a John Dobson base.

Very good point about the Dob. It *may* not be as trivial as taking a dob off it's alt-az mountings and strapping it on to an equatorial mount. Quite often the mirror support system on a dob is built on the basis that it is an alt-az telescope, and it won't take happily to slewed around the sky. Probably better to stick with a Newtonian (or other) design built specifically to go on an equatorial mount.

Here's how I got to your "ideal" scope**;

For maximal resolution, you'll want to be sampling at around 0.7"/pixel (1.5" is I think the best image quality you can regularly expect in the UK, and that's using a well tuned system at a good site). So, if you have a 8300-chipped camera (say £2k) with 5.4 micron pixels, you'll need a focal length of 1500mm. That's about a f/4 14" scope. AG14 from Orion Optics seems to fit the bill (no recommendation -- just a quick google search) at £7500. That scope is within the rated capacity of an EQ6 or a G11 (£1k and £3k respectively), but you'd maybe want to go up to the Losmandy-Titan (again, just a google search) at £5k. Ideally you'd put it on a Paramount at £10k. £1k on a good set of 2-inch filters, £1k for misc cabling and software etc, and you're away Unfortunately I've just blown your budget by at least £5k...

Anyway, that was pretty pointless as I have used none of that kit (apart from the Paramounts) -- but maybe useful to see the thought process??

I think 10k is probably a tricky price range to be honest. You could drop 10k on the mount alone, if you want to push out to the really capable mounts like the Paramount... Equally, you can probably come up with a system for £5k that would match what you can do for 10...

** ideal DSO rig in the UK is probably a 20-inch f/3 with a hyperbolic primary, a Wynne corrector and the camera at prime focus -- but no-one makes those to my knowledge

[ollypenrice]

I wouldn't want all my eggs in the long focal length basket. There are many, many nights when a long FL is simply not workable, notably in the wind or just when the seeing is bad.

For me the fantasy setup is all about depth and speed, so nothing slower than F4 and possibly a tandelm rig, eg two FSQ85s and two 11 meg cameras in parallel.

Olly

[rocketandroll]

I wouldn't want all my eggs in the long focal length basket. There are many, many nights when a long FL is simply not workable, notably in the wind or just when the seeing is bad.

For me the fantasy setup is all about depth and speed, so nothing slower than F4 and possibly a tandelm rig, eg two FSQ85s and two 11 meg cameras in parallel.

Olly

Which reminds me... having seen that 'W.A.S.P' exo-planet earcher using 6 Canon 200mm f1.8 lenses... got me thinking.... has anyone ever built a rig which uses four scopes to take L,R,G,B or four narrowband images of the same subject similtaneously on one mount?

Obviously it's four times the cost just to get the extra speed... but it did occur to me you could effectively capture 16hrs of data on one subject in a single 4hr session.

That's be awesome :-)

Ben

[ollypenrice]

Which reminds me... having seen that 'W.A.S.P' exo-planet earcher using 6 Canon 200mm f1.8 lenses... got me thinking.... has anyone ever built a rig which uses four scopes to take L,R,G,B or four narrowband images of the same subject similtaneously on one mount?

Obviously it's four times the cost just to get the extra speed... but it did occur to me you could effectively capture 16hrs of data on one subject in a single 4hr session.

That's be awesome :-)

Ben

I'm on the case: I have two Atik 4000s and am aiming to rig the TakFSQ85 up to shoot One Shot Colour while a parallel WO ZS66 collects the optically much eaasier Ha. Not a full on WASP but a good start.

I'm also very tempted to buy a second used Canon 200L lens, at least for a while, to make a shorter FL 'two shooter'.

Buying a second FSQ or TEC140 is a nice idea but, and this is a big but....

Olly

[rocketandroll]

Buying a second FSQ or TEC140 is a nice idea but, and this is a big but....

Olly

but.....KERCHING!$!$!$! :-)

It's a nice idea... I was thinking something like 4X 80ED's would be financially viable... possibly even 4X 120ED's if we're talking about 'fantasy rigs' here :-) Doesn't help my desire for longer FL, but it'd still be cool as anything.

I guess having 2 or 4 scopes the same would help with re-combining the channels later?

Ben

[martin_h]

I have 2 QHY9's one mono and one osc, just waiting for another ED80 to be delivered (1st one was damaged) and I will have a "double shooter" One for RGB and one for Lum and or Ha/narrowband

[ollypenrice]

I have 2 QHY9's one mono and one osc, just waiting for another ED80 to be delivered (1st one was damaged) and I will have a "double shooter" One for RGB and one for Lum and or Ha/narrowband

Machine gun!

In fact this approach is probably cheaper than paying a bomb for fast flatfield apos and mega chip cameras.

Olly

[Zakalwe]

I have 2 QHY9's one mono and one osc, just waiting for another ED80 to be delivered (1st one was damaged) and I will have a "double shooter" One for RGB and one for Lum and or Ha/narrowband

I aim to do similar.

As soon as I get the kit to build a finderguider, I'll move my DSLR onto my ED-80, and use the new OSC QHY8L on the Equinox 80.

I'll eventually pick up a mono CCD and field flattener for the ED-80.