The Celestron RASA 11" Rowe-Ackermann Schmidt Astrograph is an incredibly fast f/2.2 optical system designed for imaging with modern CMOS cameras. The RASA 11" provides a flat field free of optical aberrations across a 43.3mm field of view, with usable performance up to 52mm making it suitable for full frame sensors.
As the RASA 11" is a fast f/2.2 system, you can use much shorter exposure times than usual to capture faint objects. This combined with the 620mm focal length means that you don't need to have super-accurate tracking over extended periods, making the RASA 11" suitable for use on a wide variety of higher capacity equatorial mounts.
The RASA 11" includes Celestron's Ultra-Stable Focus System which utilizes two sets of precision sealed ball bearings to virtually eliminate lateral movement of the primary mirror when focusing, slewing or tracking. An additional top-mounted CGE dovetail allows you to easily mount accessories such as or guide scopes.
Building on the legacy of Celestron's Schmidt Cameras of the 1970's, the RASA 11" allows astrophotographers to capture incredible data with minimal exposure times. The 4-element lens group with rare-earth ED glass provide images free from aberrations that are inherent in other types of telescopes.
The RASA 11" performs best once its optics have reached thermal equilibrium with the ambient air. To aid this, the telescope is equipped with cooling fans which direct air through the tube and around the primary mirror.
Note: The RASA 11" is designed for astrophotography and cannot be used visually. The focal plane is at the front of the optical system so it is not possible to use an eyepiece. It is recommended to only use narrowband filters that are optimized for fast systems such as the or .
Specifications
| Optical design | Rowe-Ackermann Schmidt Astrograph |
|---|---|
| Aperture | 279 mm (11") |
| Focal length | 620 mm |
| Focal ratio | f/2.2 |
| Resolving power | 0.41 arc seconds |
| Image circle | 43.3 mm, 4.0° |
| Usable field | 52 mm, 4.8° with only minimal performance loss at edge of FOV |
| Light gathering power | 1588 times the human eye |
| Central obstruction diameter | 114 mm (41% of aperture diameter) |
| Wavelength range | 400 - 700 nm |
| Spot size | < 4.4μm RMS across image circle |
| Optical coatings | StarBright XLT |
| Off-axis illumination | 83% at 21 mm off-axis |
| Optical window diameter | 68 mm |
| Backfocus with included camera adapter | 55 mm |
| Backfocus from top of threaded collar | 72.8 mm |
| Mount attachment | CGE dovetail plate on top and bottom of tube |
| Focuser | Ultra-Stable Focusing System |
| Included connection adapters | M48 x 0.75, M42 x 0.75 |
| Tube length | 838.2 mm |
| Tube weight | 19.5 kg |
| Tube diameter | 330.2 mm |
| SKU | CE-91076 |
Items included
- RASA 11"
- 2 x CGE dovetail
- Dew cap
- M42 camera adapter
- M48 camera adapter
- Fan battery pack
Filter solutions
The RASA 11" has a much greater backfocus than the smaller 8" version, so it is possible to use standard filter drawers and DSLRs. We recommend the for most applications.
Usage with Baader UFC
In order to connect DSLR cameras with Baader T-Rings, you will need the following pieces:
In order to connect common CMOS cameras with 17.5mm of backfocus, you will need the following pieces:
- UFC RASA 11" adapter - BA2459126
- UFC 15 - 20mm variable extension - BA2459145
- UFC 15mm extension - BA2459142
- UFC 5mm extension - BA2459141
- UFC filter slider - BA2459112
Downloads
 Celestron RASA 11" manual |
For all orders exceeding a value of 100USD shipping is offered for free.
Returns will be accepted for up to 10 days of Customer’s receipt or tracking number on unworn items. You, as a Customer, are obliged to inform us via email before you return the item.
Otherwise, standard shipping charges apply. Check out our delivery Terms & Conditions for more details.
