New Celestron Rowe-Ackermann F/2.2 Astrograph!

[Earl]

Very interesting looking scope, I wonder if there will be many adopters on this site.

[Gina]

That confirms my suspicions!  Remote control would require a very well designed and built robot!

[Gedan]

You don't need to remove the camera to change filters with hyperstar. The filter drawer is held in magnetically and just clips out. If you have a few of them these can be swapped round in a few seconds.

[Gina]

I guess that would be perfectly feasible if you have conditions where you have a good run of clear nights.  You could take one set of subs each night.  Chances of that in the UK seem rather limited.

[FLO]

I was on holiday last week when the new Celestron Rowe-Ackermann astrograph was launched and we have been closed over the Easter weekend so are busy catching up today but I will contact Celestron-UK for more info on this new model.

Steve  

[FLO]

So this is a hyperstar scope is it? Looks very nice:D

So what's the difference between this and simply putting a hyper star lens on a C11 or suchlike?

Those were my first thoughts too

My understanding is Celestron developed the 'Fastar' system which later became the 'Hyperstar' system now developed and marketed by the retailer Starizona in the US. (If I am wrong, perhaps it was a shared project developed by both Celestron and Starizona, I'll update this post straight way). 

Most regular SCT telescopes have an f2 primary mirror (f1.95 to be precise) and a secondary mirror at the front that amplifies this 5x to achieve f10. The Hyperstar system is essentially an optical component that replaces the secondary mirror so the f-ratio functions at it's original f2. The Hyperstar optic also corrects the spherical aberration and curvature normally associated with an f2 mirror. The ability to convert an existing SCT telescope into an ultra-fast wide-field telescope for imaging is attractive. Interestingly our American cousins are more receptive to this concept than us Europeans. 

The new Celestron C11 Rowe-Ackermann is different. It is a dedicated astrograph (not suitable for visual astronomy) with an entirely new optical system built around an f2.2 mirror (the original C11 uses a f1.95 mirror) and Rowe-Ackerman optics (4-elements) that achieves a wide/flat 70mm imaging circle. It can be used with a number of cameras, including of course Celestron's own, using the supplied T2 and M48 adapters. Focusing has also been enhanced with a 'linear brass focuser bearing' to reduce image shift and a pre-fitted dual-speed 10:1 FeatherTouch Micro Focus Knob. It also features a 12V MagLev fan to reduce cool-down time. 

As with the Hyperstar system, cameras with a slim profile are best because they fit within the central area of obstruction. Cameras from the new Atik 400 series, including the Atik 460EX, and the Starlight Xpress Trius cameras will work well. And, as has been discussed in this thread, it is best suited to one-shot-colour (OSC) cameras because there is no room for a filter wheel. It will be interesting to see what solution Celestron offer for those wanting to do narrowband imaging - possibly a filter drawer? 

Our first delivery is scheduled for "sometime this summer". We also now have a price so after posting this I'll bash some keys on our calculater then post it here. 

It is interesting to see Synta (the parent company of both Celestron and Skywatcher) establishing a more clearly defined separation between the brands with this new model. Skywatcher don't have anything even remotely like it. 

HTH, 

Steve 

[FLO]

 We also now have a price so after posting this I'll bash some keys on our calculator then post it here. 

I spoke too soon.

I think we'll need to wait until closer to the delivery date before setting and displaying our price but we'll update our website and this thread as soon as we can. 

Steve

[Sp@ce_d]

I spoke too soon.

I think we'll need to wait until closer to the delivery date before setting and displaying our price but we'll update our website and this thread as soon as we can.

Steve

Really.. That many zeroes !

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[Gina]

Thank you for your posts Steve   I await the price with trepidation   At least I already have a 460EX and would have no problem making a filter drawer - assuming the optical path requirements allow room for it.  The price will determine if I could afford one of these next year, the year after or not in my lifetime

The 460EX hardly makes good use of the enormous 70mm image size though.

[FLO]

...I already have a 460EX and would have no problem making a filter drawer 

I wouldn't be surprised if Celestron are already working on a filter drawer (I hear they have several new products in the pipeline) but if not we could ask John (our engineering wizard) to make one  

Steve 

[r3i]

Another option, at least for 1.25" filters, is this in-line adapter available from ScopeStuff in the USA: http://www.scopestuff.com/ss_tfa1.htm

[FLO]

We might already have a solution because Borg offer a Japanese-made filter drawer and separate filter holders for quick and easy filter change. It has the usual Borg M57 thread front and rear so we'll need to identify the adapter rings but it has potential and we have a while yet before the new telescope arrives. 

[Mike Hawtin]

Any filter drawer system used at this focal ratio would need to be very well engineered, the slightest filter misalignment (tilt) has a noticeable effect on the image quality, I'm speaking from direct experience here.

[DrRobin]

I would say that you would be best off using an OSC for the colour and a mono for the luminance/narrow band and change the camera, or just use an OSC. Exposure times are so fast that in no time at all you can get more than enough subs for a decent image, so changing the camera or the filter wouldn't be too much of problem. You are probably already having this as a permanent set up, so it would be very quick to re-align, even if you have to park the scope to make the camera/filter change.

I have used a Canon 600D on my C11 and Hyperstar, it sticks out over the secondary holder and the cable of course, but none of this is visible and I didn't get diffraction spikes on my pics. A filter wheel wouldn't be a good idea, it would be offset in the scop and block too much light defeating the advantage. A filter drawer would probably work fine, just a bit of a hassle changing filters. The Starlight Xpress cameras would be ideal as would the slim Atik as these have body sizes less than the size of the secondary holder. Given the image circle I would have thought that this scope was really suited to full frame cameras or even larger, a Canon 1D, 5D, 6D, SX35 or an Atik 11000 would be my preferred way to go.

As I undersand the history, Celestron first introduced the Fastar and then Starizona perfected it, at least for the C11 and above. At some point 2 or 3 years ago, Celestron dropped the Fastar lens, but continued to make SCTs with a removable secondary and so now they seem to have come full circle. It would be interesting if they drop the removable secondary from their C ranges, but Starizona will have that covered as they already make conversion kits.

I am intrigued by this scope, it will no doubt be better than a standard C11 and Hyperstar, but I am willing to bet the difference is not great and the addition of fans is something that all of the large Celestron's are long overdue, but here is the rub. Buy a standard C11 and a Hyperstar lens, probably for the same sort of money and you can use it for F/2 and F/10 imaging and by addition of an FR, F/7 and anything you like with a Barlow, something you can't do with this.

My C11 spends as much time with a Barlow imaging the planets as it does at F/10. It doesn't spend that much time at F/2, even less now that a front mounted camera won't fit in my obs. However, when the Hyperstar is fitted it does impress.

If your interest is wide field at lightning quick speeds then this with a full frame camera would certainly be the way to go.

Robin

[Gina]

Interesting   I wonder if I could rebuild a DSLR with Peltier cooling into a long narrow shape   I think it might be possible.

[Stu]

That would be an interesting one Gina, but please promise me not to start a 'Gina's build a life size, arduino controlled robot to change filters' thread, that one may be a bridge too far ;-)

Cheers,

Stu

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[Gina]

That would be an interesting one Gina, but please promise me not to start a 'Gina's build a life size, arduino controlled robot to change filters' thread, that one may be a bridge too far ;-)

Cheers,

Stu

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Very good   I love it

[FLO]

We are expecting prices early next week and probably delivery ETAs too. We'll post them here as soon as we know

I spoke too soon. 

I think we'll need to wait until closer to the delivery date before setting and displaying our price but we'll update our website and this thread as soon as we can. 

We have set our price for the new Celestron Rowe-Ackermann Astrograph telescope at £2,995  

Unfortunately the ETA of our first delivery is "Autumn" but we'll keep an eye on progress and update this thread when we know more. 

HTH, 

Steve 

[RobH]

Good price. How would one go about using a mono CCD and filters with this, without having to shoot new flats every time a filter is changed?

[harry page]

MMMM

Looks right up my street   , keep us informed

Harry

[FLO]

Good price. How would one go about using a mono CCD and filters with this, without having to shoot new flats every time a filter is changed?

With difficulty. I suspect it would be very hard to get a filter back to exactly the same position for doing flats. 

But at f2.2 we are in similar territory as Hyperstar users so I suspect, as with Hyperstar, the Rowe-Ackermann Astrograph will appeal mostly to users of OSC cameras. For them the super-fast f-ratio will be a dream come true. 

HTH, 

Steve 

[ChrisLX200]

Yes, OSC camera is generally the answer, although a filter slide/tray might do the job. I have a cunning plan to machine up a filter 'wheel' with a narrow profile that I believe would work and will attempt a prototype shortly.

ChrisH

[FLO]

I have a cunning plan to machine up a filter 'wheel' with a narrow profile that I believe would work and will attempt a prototype shortly.

That sounds like an interesting project 

I will be meeting with the people from Celestron at the IAS before the doors open to discuss this and their new Evolution models. They might have a solution in the pipeline. I'll ask them. 

[ChrisLX200]

That sounds like an interesting project 

I will be meeting with the people from Celestron at the IAS before the doors open to discuss this and their new Evolution models. They might have a solution in the pipeline. I'll ask them. 

Well this just for my own amusment/use, but there are two options - first is a 'Paddlewheel' arrangement with 4 blades, that would offer just 4 positions, and the additional obstruction would be the diameter of a single filter plus clearance for the center bearing, filter rim and casing (so not much more than a narrow-body CCD camera). The second option is a Rollodex type which would perhaps offer an additonal position due to more efficient stacking of unused filters but complicates registering of the filter in the optical plane. Not sure I can achieve that with sufficient accuracy. However, 4 positions would still give RGB&Ha (or RGB & Lum).

ChrisH

[FLO]

Our first delivery of Celestron Rowe-Ackermann Astrograph telescopes is scheduled to arrive end-Aug / early Sept