New Celestron Scope - 11" f2.2 Schmidt Camera (Astrograph), RASA

[jolasa]

New Celestron scope:

http://www.optcorp.com/celestron-11-rasa-rowe-ackermann-schmidt-astrograph-ota.html

 

An 11" f2.2  fixed Fastar/Hyperstar configuration - wide-field obviously - basically a Schmidt camera.  70mm image circle.  Shipping in May they say.  $3500!

 

Should be great with a DSLR on the front!

 

JonS

[jimwc6491]

JonS

 

I can see some Pros and Cons.

 

 

First the Pros.

 

1. F2.2 WOW

2. very little if any Guiding needed with a good mount.

3. Hyperstar already configured

 

Now (IMHO) the Cons

1. the weight 35 lbs. (oh My back)

2. need for a heavy mount CGEM DX Class or better.

3. may be tough to align with no eye piece focuser.

 

 

 

[astroman133]

Plus, it is fixed at F2.2

 

You can purchase any of the Edge HD optical tubes and separate HyperStar. That way you can use it at F/10 or F/2.  That way you don't give up the flexibility that is inherent in the SCT.

 

I predict that this offering will not be spectacularly popular.

[s3igell]

I think that the biggest concern would be the largish size and odd shape (rectangular, lopsided, and thick cables coming off only one end) of the Central Obstruction generated by the DSLR.  These have been bugaboos for Fastar/HyperStar configurations, and would be the same for the Schmidt Camera configuration.  This is the same reason why Mono Cameras with obstructive Filter Wheels are not readily used on these SCT variants.

While the "Shadow" could be counteracted with Flats during Stacking, the wild Diffraction Patterns would make all Bright Stars look quite misshapen.  And the overall increased Central Obstruction would work to significantly reduce the Sharpness and Contrast of the resulting Images (this is the reason that serious AP Imagers favor the Expensive Large-Aperture APO Refractors).

[jimwc6491]

JonS

 

I forgot one of the Pro's is the price you save about $450.00 over buying the OTA and HyperStar separately.

 

 

  

[s3igell]

JonS

 

I forgot one of the Pro's is the price you save about $450.00 over buying the OTA and HyperStar separately.

 

 

  

But that "savings" is at the expense of Not having an actual SCT, which can also be used at it's native F/10 and/or reduced F/6.3. You'll notice that the "Schmidt Camera" doesn't have a Visual Port on the back, rather it's sealed off for use as a Cooling Fan.

[jimwc6491]

s3igel

 

That was one of my "Cons" mentioned above. "may be tough to align with no eye piece focuser"

 

the only way to do a polar align is with the camera. because the only visual port is at the front of the scope. and you would be standing in front of the scope to look through the eyepiece.

 

I guess you could use a modified web cam to do your alignment so your imaging camera doesn't get too hot.

 

and we don't know if the primary mirror even has a hole for a focuser because it doesn't need one because there is no secondary because it is removed when the HyperStar is installed.