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Astronomy > Telescopes > Celestron > CGEM II > Celestron Telescope Astrograph S 203/400 RASA 800 CGEM II GoTo
Product no.: 62859

Telescope Astrograph S 203/400 RASA 800 CGEM II GoTo

$ 5,300.00 incl. VAT, plus shipping costs
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Right of return up to January 31 2025!


Product description

More about the series CGEM II...

Digital Schmidt camera for wide angle astrophotography!

This astrograph makes it very easy to create stunning photos with a modern DSLR or astronomical CCD camera. The new optical design has a four-lens corrector, incorporating rare earth glass, which suppresses chromatic aberrations and other problems such as coma and field curvature. Never before has an astrograph in this price range delivered such optical quality and spot size over the entire image field. The design also allows for a very low vignetting.

  • super-fast 11" f2.2 optics - sharply images APS format and is even optimized for sensor sizes up to a 70mm field diagonal.
  • extremely short exposure times - the RASA Astrograph acquires images twenty times faster than at f10! Thirty seconds at f2.2 correspond to ten minutes at f10 - tracking control is hence superfluous!
  • huge field of view - with a 620mm focal length, makes wide-angle shots a piece of cake and you and always have an overview
  • excellent focusing mechanism - new bronze bearings reduce image shift, the 10:1 FeatherTouch micro-focuser allows highly precise focusing!
  • innovative Features - quieter 12V MagLev fan reduces the cooling phase, keeps out dust and allows optimum air circulation in the OTA. Various adapters for popular camera brands are included. Back focus for the camera supplied adapters: 55mm, back focus for the front lens group: 69.26mm

RASA stands for Rowe-Ackermann-Schmidt Astrograph - Dave Rowe and Mark Ackermann are renowned optical instrument designers. Together, they hold numerous patents on their inventions. The RASA astrograph combines their expertise and experience.

Note: The RASA 800 doesn't work with regular DSLR cameras (because of a short backfocus). It is recommended to use the RASA 800 with mirrorless cameras or small dedicated CCD or CMOS astronomical cameras.

CGEM II mount

Celestron has updated its popular CGEM mount. Version 2 features a sturdier tripod, USB port, dual dovetail clamp for Losmandy and Vixen standards, improved ergonomics and firmware!

But it has not changed the tried and tested features of the CGEM, which continues to be a highly reputable mount for astrophotography - safely carrying Celestron SC OTAs of up to 11-inch (279mm) aperture for astrophotography purposes. Of course, you can also use the CGEM with telescopes from other brands, whether refractors or medium-sized Newtonian telescopes. The dual saddle clamp is suitable for the two common prism rail formats (also known as dovetail rails). The saddle clamp has two large, handy screws that can even be easily operated when wearing gloves. Since the clamp engages over its entire width with the prism rail and not just the screws themselves, no damage to the rail can occur during setting up.

Additional advantages of the CGEM II

  • the tripod legs are marked, allowing you to extend the legs to a consistent length and easily remember your preferred length.
  • built-in All-Star Polar Alignment by Celestron to align the mount using any star. So you do not need a polar finder and do not have to separately north align. You do not even need a clear view of the Pole Star! The screw for adjusting the polar height is large and convenient. This is an important advantage, as the polar height adjustment must be done with the weight of the OTA present.
  • large database of all popular deep sky objects, catalogued by name and catalogue number; the most famous double, triple and quadruple stars as well as variable stars and objects within the solar system.
  • Permanently Programmable Periodic Error Correction (PPEC)
  • double-line, 16-character LCD hand control with backlit buttons. The hand controller has a USB port for easy connection to the PC for firmware updates of the mount and hand controller.
  • tracking beyond the meridian by up to 30° - so that long-term exposure astrophotography does not have to be suddenly interrupted.

The CGEM II is between the AVX and CGX mounts in Celestron's range of modern equatorial GoTo mounts. For beginners, we recommend the low-priced AVX - which has all the advantages of NexStar + electronics, but is not mechanically designed to carry large OTAs. The CGX mount meets the highest demands of astrophotographers, even when carrying heavy equipment. Finally, the CGEM II is an excellent compromise between carrying capacity, performance and price. It is the workhorse of sophisticated astrophotographers.

It not only matters which telescope you buy but also where you buy it. Our additional services:

  • We are a leading telescope dealer and know the devices we sell. Our customer service team will gladly help you after your purchase if you have problems with assembly or operation.
  • We provide a copy of the 80-page Telescope ABC beginners handbook with every telescope.

Specifications

Optics


Type
Reflector
Type of build
Astrograph
Aperture (mm)
203
Focal length (mm)
400
Aperture ratio (f/)
2
Resolving capacity
0,68
Limit value (mag)
13,3
Light gathering capacity
843
Coating
Starbright XLT
Tube material
Aluminium
tube diameter (mm)
235
Tube length (mm)
628
Tube weight (kg)
7,9
Tube construction
Full tube

Reflector


Secondary mirror obstruction
46
Ventilation for central mirror
yes

Focuser


Gear reduction
without
Type of build
Linear Crayford
Backfocus (mm)
29 & 25

Mount


Mounting type
Equatorial
GoTo control
yes
Polar elevation setting (°)
15 - 70
Motors
Servomotors
Encoder
yes
Weight (kg)
18
Load capacity (kg)
18
Power supply
12

GoTo control


GPS
optional
Software
NexStar
GoTo Language
German, English, French, Spanish, Italian
Alignment method
2-Star Align, Quick Align, 1-Star Align, Last Alignment, Solar System Align
Database
40.000
Interfaces
2x Aux, USB 2.0, Autoguider
Remote
Celestron PWI

Tripod


Tripod leg diameter (mm)
51
Type
Tripod
Material
Steel
Weight (kg)
9

Included accessories


Counterweights (kg)
1x 7,7
Power pack
no
cigarette lighter socket
yes
Prism rail
Losmandy-Style
Polar finder scope <p>
no
Transport cases
no
Camera adaptor
M42 & C-Mount
Miscellaneous
Filter holder
Battery compartment
yes

General


Series
CGEM II

Area of application


Astrophotography
yes (very good)
Moon & Planets
yes
Nature Observation
no
Nebulae & galaxies
yes
Sun
no

Recommended for


Beginners
no
Advanced
yes
Observatories
no

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*All prices include VAT plus shipping costs.

Celestron Telescope Astrograph S 203/400 RASA 800 CGEM II GoTo
Rear View - the telescope has been optimized for astrophotography and has no focuser.
Celestron Telescope Astrograph S 203/400 RASA 800 CGEM II GoTo
Cross-section through the light path
Celestron Telescope Astrograph S 203/400 RASA 800 CGEM II GoTo

Typical application 1

Celestron Telescope Astrograph S 203/400 RASA 800 CGEM II GoTo

Typical application example 2

Celestron Telescope Astrograph S 203/400 RASA 800 CGEM II GoTo
Example - Comet 46P/Wirtanen taken by Michael Jäger with an RASA 800

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