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SPECIAL ORDER
These instruments are special order only - please contact us for availability.
- A breakthrough 36 cm aperture, f/2.2 optical system designed for professional applications that require both a wide field of view and resolution, such as space surveillance and other scientific applications
- 4-element lens group utilizes extra-low dispersion (ED) glass for images free of false color, coma, and field curvature, the Rowe-Ackermann Schmidt Astrograph (RASA) 36 cm is also an excellent choice for advanced astroimaging
- 60 mm optimized image circle maintains pinpoint stars to the far corners of the largest available sensors
- Extended spectral range takes advantage of sensor response in the 700-900 nm range, allowing a brighter overall signal to be detected
- Redesigned focusing system minimizes focus shifting or other unwanted motion of the primary mirror, enabling easy and stable focus
The Rowe-Ackermann Schmidt Astrograph (RASA), is a cost-effective optical system for space surveillance, Space Situational Awareness (SSA), other scientific applications, and advanced wide field astroimaging. It offers unprecedented value in aperture, speed, field of view, and optical performance. The RASA design has a convenient external prime-focus image capture location with a flat focal plane, providing small spot sizes to the edge of a wide field. The result is images free of optical defects like field curvature, off-axis coma, and astigmatism.
The 36 cm aperture version is the largest RASA Celestron manufactures; it is the biggest and fastest (f/2.2) optical instrument of its kind available “off-the-shelf.” Unlike most telescopes, which only focus visible light (400-700 nm), the RASA 36 cm focuses an extended spectral range (400-900 nm), allowing a brighter signal to be detected by a camera sensor. The RASA 36 cm also features a redesigned focus system, which ensures easy and stable focusing.
RASA 36 cm’s ample back-focus distance (77.5 mm) accommodates a wide variety of imaging sensors. A custom camera adapter can be added for a field of view up to 4.4 degrees.
Optical Performance
The Rowe-Ackermann Schmidt Astrograph features newly designed optics with 4-element rare-earth glass for images free of false color and aberrations like coma and field curvature. The optical quality and spot size across the entire image circle is unprecedented for an astrograph in this price range—or even that of a much more expensive instrument. The design also provides minimal vignetting.
Advanced Features
Advanced features like a custom engineered linear brass focuser bearing and FeatherTouch Micro Focus Knob allow you to make the fine adjustments you need to capture the perfect shot. Meanwhile, a12V MagLev fan reduces cooldown time and provides optimal airflow through the dust filtered optical tube.
Engineered as a complete astroimaging system, every component of the Rowe-Ackermann Schmidt Astrograph is optimized for peak performance with DSLR and astronomical CCD cameras. Down to the thickness of the glass used in the included fully-multicoated optical window or an optional imaging filter, every component of the system has been taken into careful consideration to work together seamlessly.
| OPTICAL TUBE INFO: | |
|---|---|
| Optical Design | Rowe-Ackermann Schmidt Astrograph |
| Aperture | 355.6 mm |
| Focal Length | 790 mm |
| Focal Ratio | f/2.2 |
| Central obstruction diameter | 158 mm (44% of aperture diameter) |
| Light Gathering Power (Compared to human eye) | 2581X |
| Resolution (Rayleigh) | 0.39 arc seconds |
| Resolution (Dawes) | 0.36 arc seconds |
| Image circle | 60.1 mm Ø, 4.4° |
| Useable field | 70 mm Ø, 5.1°, only minimal performance loss at edge of FOV |
| Wavelength range | 400 – 900 nm |
| Spot size | < 6.3 μm RMS across FOV |
| Optical coatings | Enhanced aluminum, XLT multi-coatings used throughout |
| Off-axis Illumination | 83% at 30 mm off-axis |
| Optical window | 104 mm Ø |
| Back focus with included camera adapter | 55 mm |
| Back focus from top of threaded collar | 77.5 mm |
| Optical Tube | Aluminum |
| Optical Tube Length | 42.5" length, 16" diameter |
| Focuser | New focuser design, minimizes focus shift |
| Finderscope | Not included |
| Optical Tube Weight | 75 lbs |
| Other features | Ventilation fan, dual dovetail mounting bars |
| Included items | 48 mm camera adapter, fan battery pack |