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GSRC8C

GSO Guan Sheng Optical
in stock
GSO 8" f/8 Ritchey-Chrétien - 203/1624mm RC - Carbon tube


1.379,00 EUR
incl. 19 % Tax
excl.Shipping costs


Description

8" f/8 RC Astrograph - 203mm aperture / 1624mm focal length
Ritchey-Chrétien telescope for demanding astro imaging and observing

TS best price guarantee! - Seen elsewhere cheaper? We appreciate making you an offer: info@teleskop-service.de

GSO RC8 Baffles
The elaborate, computer-optimized internal baffle system

Ritchey-Chrétien (RC) telescopes are known for their excellent optical performance, especially for photographical applications. At the same time however RCs were always notorious for being very expensive. To change this the well-known US-based distributor "Astro-Tech" asked GSO to produce true RC telescopes. GSO is best known for their excellent Newtonian optics which they have built for many years now.

The result of this joint venture is an instrument that is superior in most aspects to a conventional Schmidt-Cassegrain, and still comes at a very affordable price. Teleskop-Service is European distributor for these instruments from GSO.

The 8" f/8Astrograph was designed for full illumination of the "35mm format" (24 x 36mm). For cameras with a small sensor, particularly most CCD cameras, no field flattener is needed. For cameras with a larger sensor we recommend the use of a field flattening lens. (Currently under development.)

Since the optical layout of the RC uses no lenses or corrector plates there is no false colour at all. Also you will not need to use an IR cut filter, thus increasing the effective light-gathering power of the instrument.

How to bring a SLR camera into focus:
The GSO RC has a generous back focus allowing to attach many accessories like e.g. off-axis-guiders, filter wheels etc. If you want to take photos with a (D)SLR camera with the focuser in a moderate position, you need the following accessories:
- GSRCV50: 50mm spacer, to be placed between focuser and telescope
- TSFA240: T2 adapter with 40mm extension

Features and Specifications:

Optical Design:True RC (Ritchey-Chretien) with a hyperbolic primary and a hyperbolic secondary mirror. No glass corrector plates or lenses in the optical train.
Optical Characteristics:Aperture 8" (203mm), Focal Length 1624, Focal Ratio f/8
Primary Mirror:Quartz - surface quality 1/12 Lambda or better. The primary mirror has a 99% dielectric high-reflectivity coating.
Secondary Mirror:Quartz. The mirror has a 99% dielectric high-reflectivity coating. Robust collimatable cell. Obstruction is 42,5%.
Tube:CF tube with metal primary and secondary mirror cell - complete weight 6,1kg
Computer-optimized baffle system:The inside of the tube is lined with computer-optimized baffles for optimum suppression of stray light.
Focuser:1:10 Crayford focuser for extremely smooth focusing. The dual speed 1:10 focusing knob is particularly important for astro imaging. No image shift and up to 5kgs load capacity! The focuser accepts 2" and 1.25" accessories.
Dovetail mounting rail:A GP-style dovetail rail is mounted on the underside of the tube. It fits in all mounts that accept GP / Vixen dovetail plates.

GSO RC8 Monorail Auszug
The 2" Monorail focuser - much better, than a simple crayford design

Scope of Delivery:

-- 8" f/8 RC Astrograph
-- 2" Crayford focuser with 1.25" adaptor
-- 2x Vixen style dovetail plate (one on each site)

Technical Details:

Weigth: 6.2 kg
Obstruction: 97 mm
Tube length: 580 mm incl. focuser
Tube diameter: 230 mm
Prism rail length: 395 mm
Necessary extension tube for 2" diagonal mirror: 50 mm
" for 1,25" diagonal mirror: 80 mm

 


Optical Advantages of the GSO RC Astrographs

Optical Design: True Ritchey Chrétien / RC
The GSO Astrograph is a real Ritchey-Chrétien reflector telescope. Contrary to Maksutovs or Schmidt-Cassegrains which have spherical mirrors and need image correctors, and contrary to Newtonians that need coma correctors, the RC system is a well corrected photographical instrument that uses only mirrors (no false colour!) and does not require any corrector with many cameras.

The RC has a concave hyperbolical primary mirror and a convex hyperbolical secondary mirror.

The resulting image correction throughout the field as well as the sharpness on the optical axis are superior to typical Schmidt-Cassegrains or Newtonians.

It is for this reason that the Ritchey Chretien is very popular for astro imaging. The RC optical system (and a variant of the RC) is the most frequently used design for professional telescopes such as the 10 meter Keck telescope on Hawaii, or the VLT in Chile. Finally the RC is also available for amateurs without a "Nasa budget".

99% Dielectric High Reflectivity Coating
The primary mirror of the 8" RC is made of quartz which, similar to Zerodur, has practically zero thermic expansion for excellent optical properties during cool-down. Both primary and secondary feature a 99% high reflectivity coating which is well protected against scratches and against aging. Compared with similar instruments you get a much higher effective light gathering power.

Each optical set is tested by the manufacturer
For a constant quality level each optical set is tested and hand-corrected after the automatic production with state-of-the-art machinery. Then the optical set is tested with a Zygo interferometer. Here at TS we also test and collimate each instrument.

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Mechanical Advantages of the GSO RC Astrographs

Fixed primary mirror cell and computer-optimized baffle system
Most similar telescopes have a movable primary mirror cell. When focusing the telescope the entire mirror is moved. Unfortunately this technique invariably leads to a certain amount of image shift. Most manufacturers have controlled this problem to a fair extent, but the remaining image shift can be quite distracting for astro-imaging, particularly with cameras with a small sensor size or when taking series of frames with several hours of total exposure time.

In the GSO RC the mirror sits in a fixed mirror cell and focus is changed with a separate focuser. This eliminates the problem of image shift completely.

Computer-optimized baffles are placed inside the tube in order to eliminate stray light.

Collimation of the secondary mirror
The primary mirror is fixed in its precisely machined mirror cell. Collimation of the telescope is done through the secondary mirror. Collimation is rather easy and can even be done by an inexperienced amateur astronomer - we do however recommend to take your time with the collimation!

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upUser reports

NGC 891 durch 8zRC von GSO

This is a photographical result with the 8" RC from GSO

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Link to wonderful pictures from Mr. Jorge Garcia through the GSO 8" Ritchey-Chrétien

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Astrophotographic results with the 8" GSO RC from Rolf Wilmes

http://home.arcor.de/rolf.wilmes/Bilder/ST4000/Galaxien/M63.jpg

http://home.arcor.de/rolf.wilmes/Bilder/ST4000/Galaxien/M101.jpg

http://home.arcor.de/rolf.wilmes/Bilder/ST4000/Galaxien/NGC4565.jpg


congratulations to the good astro photos
Teleskop-Service


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E-Mail: info@teleskop-service.de · Telefon: +49 (0)89-1892870 · Fax: +49 (0)89-18928710
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