Description

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.

Specifications

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

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