Celestron Advanced VX 8 inch RASA

Celestron Advanced VX 8 inch RASA

RASA 8" - Rowe-Ackermann Schmidt Astrograph
Rasa 8" DiagramThe transportable astrograph from Celestron, the 8" Rowe-Ackermann Schmidt Astrograph (RASA), can capture spectacular deep-sky wide-field images in seconds. This incredibly fast f/2.0 system is the perfect telescope for modern astronomical CMOS color cameras, smaller CCD cameras and mirrorless cameras.

Thanks to the large focal ratio and the patented optical design, you can produce sharp, detailed images and in many cases completely dispense with an autoguider. With a weight of only 7.7 kg (17 pounds), it is easy to transport the 8" RASA to even the most remote locations.

RASA performance for everyone
The 8" RASA is a telescope designed purely for photography, providing a flat field of view with no optical aberrations to show extremely sharp stars over a wide field of view. It provides astronomical images with impressive "depth" and avoids the problems typically associated with longer focal length (and slower focal ratio) instruments.

The latest addition to the RASA family is a much more portable and affordable 8" aperture version of the RASA 11, which was launched in 2014 to great acclaim. With the 8" RASA, the benefits of the RASA design are now available to a wider range of astrophotographers. It shares many features with its "big brother" RASA 11, including the integrated cooling system, the internal filter holder and the robust CGE dovetail mount.

The 8" RASA is designed exclusively for photography and cannot be used visually. The focal plane is located at the front of the optical system, so the telescope cannot accommodate a conventional eyepiece.

Shorter exposure times and virtual "real time" observation
As it is an f/2.0 optical system, astrophotographers can use shorter exposure times to capture details in faint objects. In combination with sensitive cameras and the right "live stacking" software, the 8" RASA also makes near-live observations possible: you can instantly view and stack the images on a computer, making them brighter and more detailed than with the naked eye - even compared to much larger telescopes!

As shorter exposure times are possible, your mount does not have to track with high precision over long periods of time. The relatively short focal length of 400 mm of the 8" RASA further reduces the tracking requirements. In many cases, autoguiding is not necessary. With a weight of only 7.7 kg (17 pounds), this telescope fits perfectly with a large number of commercially available mounts.

Ultra-stable focusing system
With the introduction of the 8" RASA, Celestron introduces a new focusing mechanism that reduces the backlash of the primary mirror when focusing, slewing or tracking the astrograph. Focusing is easier, more accurate and more stable than ever. The key to this ultra-stable focusing system is two sets of precision bearings that are precisely aligned and tested during assembly for optimal results.

Unique optical design
The patented RASA design (US 2016/0299331 A1) consists of a Schmidt plate, primary mirror, lens group and optical window. The lens group consists of four elements and uses rare earths. In contrast to many other telescopes, which only perform well in visible light (400-700nm), the 8" RASA is designed for a wider spectral range, from 390-800 nm. This allows more light from celestial objects to be collected and imaged sharply.

With many optical systems, it makes no difference to the image quality whether an additional flat glass such as a filter is used. With extremely fast systems such as the RASA, the situation is different. Our developers have solved this problem by providing the RASA with an optical window that can be removed and replaced with a filter. This means that the image quality remains at the highest level even if you use a filter or the camera has its own optical window. Celestron offers a filter against light pollution which was specially developed for the 8" RASA and which replaces the optical window.

All refractive optical surfaces are StarBright-XLT coated, the primary mirror has an improved aluminum coating. This ensures high transmission for the entire system. Compared to the HyperStar system for Schmidt-Cassegrains, the RASA 8 delivers better optical performance and superior illumination.

Developed for the most modern cameras
In contrast to the larger RASAs, which are optimized for DSLR and large CCD cameras, the 8" model was developed for astronomical CMOS colour cameras, smaller CCD cameras and mirrorless cameras. The telescope does not work with standard DSLR cameras due to the available back focus. It is optimized for sensors with a diagonal of up to 22 mm and still offers good performance on sensors with a diagonal of up to 32 mm. The APS-C format sensors used in many mirrorless cameras are a good choice. 42 mm full-frame sensors also work in principle, but performance visibly degrades at the edges of the sensor and field illumination is reduced. Furthermore, we do not recommend combining the RASA 8 with a camera body with a diameter of more than 10cm.

You can use the following table to determine whether your camera is compatible with RASA 8:

The Advanced VX mount
The Advanced VX telescopes set the standard for medium-sized telescopes. The mount was developed with the requirements of astrophotography in mind. The Advanced VX offers many of the features of the large Celestron equatorial mounts at a very attractive price.

The Advanced VX is designed as an ideal platform for astrophotography with smaller telescopes. For telescopes up to approx. 13.6 kg (depending on the lever), you now have the sophisticated functions of our large equatorial mounts at your disposal. Thanks to PEC (Periodic Error Correction), the periodic worm error that occurs with all mounts with classic worm gears can be compensated, so that long-exposure images are also possible. In addition, you can track objects far beyond the meridian without having to turn around immediately. This allows you to observe the most interesting part of the sky without interruption. The Advanced VX also has a much wider base than its predecessor, which further increases stability even with heavy loads. The improved motors have greater torque and are better able to compensate for a slight imbalance.

State-of-the-art technology for mobile use

Celestron Advanced VX mounts set the standard for medium-sized telescopes up to approx. 13.6 kg. The mount was developed with the requirements of astrophotography in mind. It offers many features of the large Celestron mounts at a very attractive price - and the axis cross weighs only 7.7 kg!

Solid cast parts and heavy-duty mechanics

Based on the proven Advanced GT mount, the Advanced VX not only offers large, easy-to-grip adjustment screws and stronger motors that cope even better with unevenly distributed loads, but also a wider base for the tripod connection and an improved dual dovetail mount with two clamping screws. No premature tilting! Tracking is possible up to 20° beyond the meridian passage.

State-of-the-art software

The AVX mount is supplied with the cold-resistant, significantly more powerful NexStar+ hand controller. This provides you with modern computer control - with over 40,000 objects and German menu navigation. Thanks to the built-in clock, commissioning is even faster than before. The software automatically moves to the reference stars, all you have to do is center them in the eyepiece. Even the sun can be used as a reference object.

Advanced VX mounts can be controlled via Celestron PWI Telescope Control software using the PC connection on the hand controller.

Polar alignment made easy

With the AVX, you no longer have to laboriously adjust the pole star using the polar finder: Point the mount roughly north, perform a 2-star alignment - and then call up the All-Star Polar Alignment. The software will now help you to align the mount precisely, even if you cannot see Polaris. You can look comfortably through the telescope and do not have to kneel under the polar finder (still available as an option).

Versatile and expandable

In addition to a USB port on the hand controller, the AVX also has an autoguider input and two AUX ports. Here you can connect additional, separately available expansion modules - for example the SkyPortal WiFi module for control via WLAN with iPhone/iPad/Windows PC or the StarSense module, with which the mount automatically approaches and perfectly centers its reference stars.

Experienced photographers will appreciate how easily this mount can be transported to a dark observation site. If you are new to astronomy or astrophotography, the Advanced VX will help you get started and can serve you well for many years to come.

Avoid electronic damage - remember the right power supply unit!

To ensure trouble-free operation of the device, please only use high-quality power supply units that also meet the specifications for astrophotography, i.e. for outdoor use - cheap power supply units often only deliver the specified voltage and power at room temperature and can even damage the electronics in the worst case. Suitable high-quality power supply units can be found on the left under Optional accessories.

Accessories included:
The Advanced VX RASA 8 is supplied complete with an M42 camera adapter, C-mount camera adapter and a battery holder for fans.