I purchased the RASA 8 in December 2018 and my experience with the astrograph has been excellent.
I highly recommend the RASA 8. I also have a SCT 9.25 and not sure if I will use it again due to the amazing RASA 8.
The main reason for purchasing the RASA 8, was to increase the sky coverage from 21.9 x 16.4 arc-minutes (SCT 9.25 f/6.3 with Atik Infinity) to a sky coverage of 107.3 x 85.8 arc-minutes (RASA- Atik 460ex).
The other reason was to have a faster exposure. For example, a 1 hour RASA F/2 exposure is equivalent to 9 hours at F/6.3. Life is short and time is precious.
I see more of the universe and faster and that is a great incentive to get the RASA.
The RASA 8' is light and portable. I have some of the best dark skies, one hour from my house. The RASA 8 was the right size for this task and for me.
My cameras are CCD's and I can't comment on Cmos-camera & RASA at this time.I am currently using two cameras, The Atik Infinity and the Atik 460ex.
Most people say that the pixel area should be between 1 and 2 for good imaging, however, I get very good results with the RASA 8 at 3.3 (under sampling).
The RASA 8 with the Atik infinity with a pixel size of 6.45 x 6.45 produces a pixel area of 3.3 pix and great photos.
The square shape of the Atik infinity camera is larger than the 'lens group cell' and creates very large diffraction spikes. Kind of cool actually!
The RASA 8 with the Atik 460ex with a pixel size of 4.54 x 4.54 produces a pixel area of 2.3 pix and amazing photos.
The round shape of the Atik 460ex is perfect for the RASA 8 and the diffraction spikes are small.
I will share some images with you later on, but before I do this, I would like to share a few observations and details.
First item, Dylan O has a great review of this astrograph, you may want to review his information. I want everyone to know, the light pollution Filter is not included with the RASA 8 as stated in the review.
Also, the feather touch focuser is not a component of the RASA 8. For myself, I got confused between the RASA 11 and RASA 8 spec. sheets.
As for the focusing system of the RASA 8, I have not had any problems even when imaging at -20 C here in Canada.
Using a Bahtinov mask, I would start an imaging session at FWHM= 3.0 to 4.5 and have the same FWHM value 6 hours later. This information indicates to me, nothing move, nothing shifted on all of my observations sessions with the RASA 8.(9 sessions 6+ hours per session so far...)
I had one minor issue with removing the optical window. Make sure you use an appropriate tool to remove the window. It is impossible to remove the optical window, just with your finger or a sharp object.
This optical window removal tool should have been provided with the astrograph, but it is what it is.
I give the Celestron RASA 8, a very high 5/5 rating, including the service I received from Celestron and All-Star Telescope (https://www.all-startelescope.com) where I purchased the RASA 8.
Images produced with RASA 8 are in my opinion,amazing if I compared them to my SCT 9.25 F6.3, using the same camera.
Links to 'RASA 8' images taken in a city with Bortle index=8:
RASA 8 Images :
A summary for January
The Monkey Head Nebula in Orion:
IC 5146 with Atik Infinity:
Hope this information is useful.
I am not a promoter of any of the co or products listed above. This review is my own experience with RASA 8 for the pure enjoyment of discovering the universe.
Edited by FWHM, 10 February 2019 - 06:18 PM.