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  #21  
Old 08-07-2014, 10:04 AM
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With the camera fitted to the corrector end of the OTA, its not intended to be use with a an OAG or filter wheel. As Rick has mentioned at 620mm focal length a guide scope will sufficient. My Hyperstar set up has a FL of 560mm, all
I use to guide is the Orion mini guide scope. Works perfectly.

The fact that the aperture is 11 inches and has 55mm of back focus suggests they have covered the DSLR market with the intention of making it "plug and play". You could still use a mono CCD using Starizona's Filter slider.

Greg is spot on, the SX 814 would be a great camera for this scope. I'm looking at getting one for my Hyperstar set up. Just need the cash
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  #22  
Old 09-07-2014, 10:36 PM
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Quote:
Originally Posted by Rod771 View Post
With the camera fitted to the corrector end of the OTA, its not intended to be use with a an OAG or filter wheel. As Rick has mentioned at 620mm focal length a guide scope will sufficient. My Hyperstar set up has a FL of 560mm, all
I use to guide is the Orion mini guide scope. Works perfectly.

The fact that the aperture is 11 inches and has 55mm of back focus suggests they have covered the DSLR market with the intention of making it "plug and play". You could still use a mono CCD using Starizona's Filter slider.

Greg is spot on, the SX 814 would be a great camera for this scope. I'm looking at getting one for my Hyperstar set up. Just need the cash
But why would Dave Rowe and Mark Ackermann design a telescope
corrector with so little back focus?
I like using an OAG - I don't want to throw away any subs from differential flexure.


My RCC coma corrector designed by Dave Rowe gives me 91.5mm of back focus for my Newt.
see here:
http://www.optcorp.com/ba-rcc-i-rowe...corrector.html

That is what allowed me to use an OAG , filter & camera.
It also allowed me to use a Baader Varilock spacer to adjust for coma correction.
see here:
https://www.flickr.com/photos/247194...in/photostream

What is it about this new design that does not allow for more back focus?
Surely Dave Rowe would have made a design to give more back focus if he could have?
That was the whole point of his Baader RCC corrector.

This major point is somehow hidden in the slick advertising here:
https://www.astronomics.com/11-f22-r...be_p20206.aspx
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  #23  
Old 10-07-2014, 06:12 AM
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The f/2.2 light cone is very steep. The front corrector would need to be larger and more expensive at longer back focus and it would cause a greater obstruction.

Cheers,
Rick.
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  #24  
Old 10-07-2014, 06:26 AM
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A back of the envelope calculation shows that increasing back focus from 55mm to 110mm would add about an inch to the diameter of the front corrector lens assembly. I'd say that the 55mm back focus was an economic decision...
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  #25  
Old 10-07-2014, 07:54 PM
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Quote:
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A back of the envelope calculation shows that increasing back focus from 55mm to 110mm would add about an inch to the diameter of the front corrector lens assembly. I'd say that the 55mm back focus was an economic decision...

Thanks Rick,
I knew there had to be a good reason for it.

cheers
Allan
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  #26  
Old 12-07-2014, 01:31 PM
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Quote:
Originally Posted by Rod771 View Post
With the camera fitted to the corrector end of the OTA, its not intended to be use with a an OAG or filter wheel. As Rick has mentioned at 620mm focal length a guide scope will sufficient. My Hyperstar set up has a FL of 560mm, all
I use to guide is the Orion mini guide scope. Works perfectly.

The fact that the aperture is 11 inches and has 55mm of back focus suggests they have covered the DSLR market with the intention of making it "plug and play". You could still use a mono CCD using Starizona's Filter slider.

Greg is spot on, the SX 814 would be a great camera for this scope. I'm looking at getting one for my Hyperstar set up. Just need the cash

Yes - the camera goes on the front corrector plate:

http://www.celestron.com/browse-shop...h-with-cgem-dx

How can you stop the fan from the peltier cooler from disrupting the air flow?
Also - the camera has to be connected by cables - so I take it that they
are placed across the aperture?
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  #27  
Old 12-07-2014, 05:47 PM
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Quote:
Originally Posted by alpal View Post
How can you stop the fan from the peltier cooler from disrupting the air flow?
Also - the camera has to be connected by cables - so I take it that they
are placed across the aperture?
You could just cut power to the fan if you dont want it to run during imaging.

Yes the cables run across the aperture just as with any Hyperstar set up. There is a trick to running the cables. If you run the cables in a curved configuration like in Gerald's picture here the result will be a nice image without odd diffraction spikes, which is what you're likely to get when running the cables off in a straight line.
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  #28  
Old 15-07-2014, 06:33 AM
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Quote:
Originally Posted by Rod771 View Post
You could just cut power to the fan if you dont want it to run during imaging.

Yes the cables run across the aperture just as with any Hyperstar set up. There is a trick to running the cables. If you run the cables in a curved configuration like in Gerald's picture here the result will be a nice image without odd diffraction spikes, which is what you're likely to get when running the cables off in a straight line.

Thanks - now I see how the Hyperstar works.

That's clever with the curves cables -
just like a curved spider in a Newt.

If you cut the power to the fan on the Peltier cooler the
temperature will rise.
You would increase the thermal noise.

Maybe at f2.2 you wouldn't notice the disturbed air in the light path?

Really - you need to have the camera attached to the rear as in a classical Cassegrain or RC scope.

I don't like the design of this new telescope.
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  #29  
Old 15-07-2014, 07:03 AM
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Quote:
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Maybe at f2.2 you wouldn't notice the disturbed air in the light path?

Really - you need to have the camera attached to the rear as in a classical Cassegrain or RC.
Atik sell a range of cylindrical ccd with fans for Hyperstar use, so maybe they "solved" the turbulence issue or maybe it isn't an issue at that focal length. There are a lot of people imaging with Hyperstar, it's pretty popular over the big pond.

And with the evolution of mirrorless DSLR, the body is shrinking all the time, and some models already barely cause any obstruction to the light path. I'd say this is a product looking forward...
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  #30  
Old 15-07-2014, 07:49 AM
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So, I take it, a 16803 chip with a 10-position filter wheel, is out of the question?

H
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  #31  
Old 15-07-2014, 08:45 AM
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Quote:
Originally Posted by Octane View Post
So, I take it, a 16803 chip with a 10-position filter wheel, is out of the question?

H
Works fine, just a bit of vignetting to sort out!

Greg.
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  #32  
Old 15-07-2014, 09:01 PM
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Quote:
Originally Posted by Octane View Post
So, I take it, a 16803 chip with a 10-position filter wheel, is out of the question?

H

Well actually, even though the Hyperstar is designed for a 27mm chip diagonal, Andreas has proved here http://astrob.in/78743/B/ with the correct flats it will work with 45mm chip. He's using the Atik 11000. Granted its not the 16803 but its pushing the boundaries.

Narrowband imaging is also possible at F2 where bandwith shift is present. Andreas is also testing new "High speed " 10nm Baader filters with his Hyperstar set up. See here http://astrob.in/99398/0/

But a 10 position filter wheel Might have to remove the secondary off Greg's 17''
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  #33  
Old 16-07-2014, 11:03 AM
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Hmm some thoughts come to mind.

1. The front corrector is going to be the main problem. An 11" corrector plate is going to dew up like nobodies business without a dew heater and using a dew heater will mean tube currents.

2. This appears to be a metal tube. Not a grand idea either. This sucker is going to move around like a mad woman's custard until it gets cold.

3. A QSI583WSG would fit the back focus but it is a narrow field of view. You would get an OAG with that camera.

4. No room for a rotator or fine focusor.

5. I have never liked the idea of hanging a camera off a piece of glass.

In short I don't see how this could be a great system. It could not be effective as a remote scope. Nice idea but I am uncertain how it would work well in practice.
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  #34  
Old 17-07-2014, 05:22 PM
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Quote:
Originally Posted by Paul Haese View Post
Hmm some thoughts come to mind.

1. The front corrector is going to be the main problem. An 11" corrector plate is going to dew up like nobodies business without a dew heater and using a dew heater will mean tube currents.

2. This appears to be a metal tube. Not a grand idea either. This sucker is going to move around like a mad woman's custard until it gets cold.

3. A QSI583WSG would fit the back focus but it is a narrow field of view. You would get an OAG with that camera.

4. No room for a rotator or fine focusor.

5. I have never liked the idea of hanging a camera off a piece of glass.

In short I don't see how this could be a great system. It could not be effective as a remote scope. Nice idea but I am uncertain how it would work well in practice.

Yes - how do you stop the weight of the camera from distorting the glass?

Yet alone - the air current disturbance?

You can't use an OAG or a filter wheel.

I can't see how such a system can work.
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  #35  
Old 17-07-2014, 06:03 PM
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I have no interest in buying one, but there is some info on Celstron's RASA webpage...

Glass is pretty rigid and doesn't have a great tendency to bend...ask any hyperstar users how they feel about loading up their corrector plate. Besides that, the secondary mirror assemblies in large SCTs aren't exactly light.

The biggest issue with the corrector plate is dew, and that is climate dependent. A dew heater tape should do a decent job of keeping the corrector clear.

And then the "12V MagLev" reduces cool down time (quote), and should keep the internal air somewhat equilibrated.

I'm surprised they didn't discard the corrector entirely and use some nice curved spider vanes.

Fine focus is accounted for with included 10:1 FeatherTouch.

I'm not trying to be smart, just quoting other info that's out there

Whether it all adds up to something you pros want to buy....sounds like a "no", but time will tell how it works out for others when they get out in the wild.

Btw, the picture on their website shows their Nightscape CCD on the front...maybe that's what they envisage people using with it
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  #36  
Old 21-07-2014, 07:07 AM
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This is like a built-in hyperstar. You wouldn't hang anything too heavy on the corrector, certainly not a filter wheel or a wide camera. Cylindrical Starlight Xpress would be ideal. Having said that the corrector would be quite thick to compensate the weight. I've never had any flexure or aberrations with my C11 at the front. It's always been primary flop originaly. I doubt very much the usable imaging circle would be very wide for a big sensor. Dew is less of an issue with these systems actually because the camera fan and heat tend to keep the moist out of the front if you have a dewshield long enough. That was my experience with the C11. Good pricing for what it is though.
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