About this product
Part Number: 91075
"The [Rowe-Ackerman Schmidt] Astrograph’s performance was extremely good. Using a DSLR with an APS-C sensor, the scope gave us a measured field of view of 1.6x2 degrees. We found our images went deep very quickly, a five-second test at ISO 1600 showing a tremendous amount of detail in and around the Orion Nebula, M42. The billowing nebula had lots of fine structure in it and this was even more impressive when we compared the shot with a similar field taken by a 4-inch apochromatic refractor. The larger aperture of the RASA really delivered a tremendous improvement in resolution. The start were sharp across the entire field and showed no serious distortion right to the frame corners. The four-element lens group in the centre of the corrector really did its job well; the quality of the field was quite superb." Pete Lawrence writing for BBC Sky at Night magazine.
The NEW Celestron astrograph telescope features 11" f/2.2 Rowe-Ackermann Schmidt optics and rare-earth glass for images free from false colour, coma and field curvature.
52 mm imaging circle ensures pinpoint stars to the edges of the largest imaging sensors.
Custom engineered linear brass focuser bearing reduces image shift and a dual-speed 10:1 FeatherTouch micro focuser ensures precise, smooth focussing.
Built-in, quiet, high-output 12v MagLev fan to reduce cooldown time and block dust.
Capturing impressive deep-sky astroimages is easier than ever with Celestron’s new Rowe-Ackermann Schmidt Astrograph, the perfect companion to today’s top DSLR or astronomical CCD cameras. This fast, wide-field f/2.2 system offers two huge advantages over traditional f/10 astroimaging: better apparent tracking and shorter exposures. That means you’ll create better-looking astroimages in a fraction of the time, even without the use of an autoguider.
The Rowe-Ackermann Schmidt Astrograph builds on the legacy of Celestron’s Schmidt Camera, which allowed astrophotographers to produce images on film in the 1970s.
Today, with CCD sensor sizes as large as film—or larger—the Schmidt Astrograph offers a full 52 mm optimised image circle to capture pinpoint stars on the largest imaging chips. Combine this large image circle with a focal length of just 620 mm and you have an instrument suitable for wide-field imaging, creating huge mosaics of the night sky, surveying, and even comet hunting.
The Rowe-Ackermann Schmidt Astrograph features newly designed optics with 4-element rare-earth glass for images free of false colour 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 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 optimised 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.
Telescope Field of View Simulator
|Optical Design ||Rowe-Ackermann Schmidt |
|Aperture ||279 mm |
|Focal Length ||620 mm |
|Focal Ratio ||2.22 |
|Backfocus from front lens assembly ||73 mm |
|Backfocus from included camera adapters ||55 mm |
|Central obstruction diameter ||114 mm |
|Finderscope ||Not included |
|Light Gathering Power (Compared to human eye) ||1588x |
|Optical Coatings ||StarBright XLT |
|Total Telescope Kit Weight ||35 lbs |
|Average Rating (1 Review): |One of the finest light buckets you can buy
Friday, 12 June 2015 | Mark
I remember the late 1970's when I dreamed of either a Celestron 5 or 8" Schmidt camera which used film which you had to bend around a specially crafted holder in a light bag then place back into the focal plane of the camera. I never did realise that dream & I'm glad I waited until now.
The RASA has none of the previous follies bestowed on the earlier cameras. It is a monster- sucking up vast amounts of light &squirting it into your chosen camera.
If you have a Celestron 11" OTA be prepared for a surprise. The RASA seems much bigger. I would suggest you make sure you have a medium class of mount with a very sturdy tripod or pier- nothing less will carry this beast adequately. I don't think the issue is just weight it is the extra length of the OTA.
The RASA comes with a battery adapter to power the Maglev fan on the back of the OTA. This power-pack is functional but is very cheap & is not becoming of the rest of the instrument quality. You get 2 camera adapters to fit most popular CCD cameras like Atik & a larger 48mm adapter for DSLR cameras.
If you use the RASA in a light polluted location you will need the 72mm LPR filter which whilst being expensive (made by Astrodon) is pretty much an essential accessory. The existing glass filter is replaced with this filter in a matter of seconds and you are good to go. This filter leaves no noticeable image cast on the CCD subs from what I've tested.
The short focal length of 640mm (f2.2) means exposures for deep sky objects are counted in seconds & not minutes. The field of view is simply amazing- swarms of stars in quantities never envisaged with a lessor instrument. The field is very flat although the light drop off at 20% on the corners will require flat field correction. This can be problematic as the camera is on the front & not the back like a traditional telescope. Use a dew shield on the front so not as to contaminate from oblique light sources.
You will enjoy this imaging super power but you need to pay careful attention to the quality of the mount to get the best results.
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