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6" Cassegrain Telescope by GSO
YOU ARE HERE >> HOME| Telescopes with Motor & GoTo| GSO 6" RC on EXOS-II Dual Axis Motor

6" F/19 Ritchey-Chrétien Telescope with EXOS-II Dual Axis Motor & HPC
D=152mm / F=1370mm F/9 - MADE IN TAIWAN Telescope OTA
85800 + 18% GST
GSO 6" Classical Cassegrain Telescope GSO 6" Classical Cassegrain Telescope
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IC 405 SHO  

6" f/19 Ritchey-Chrétien Telescope by GSO
6" F/9 RC Astrograph Telescope is not only perfect for Astrophotography but also for observing.
It is extremely portable and offers a superb image quality and visual observing power too.
 
Advantages of RC Telescopes compared to MAC and SCT
  • Aperture 6" / 152mm.......Focal Length 1370mm
  • f/9 is faster than a 6" SC or Mak
  • illuminated field is much bigger
  • you can attach 2" eyepieces and full size SLR/DSLR cameras without vignetting
  • two hyperboloidical mirrors with 96% reflectivity lead to a bright image
  • faster cool-down time and no dew problems because of open tube design without front correcting plate
  • enough back focus for all kinds of accessories
  • M90 extension tubes for easy reaching of the focus are optional. Spacer, to be placed between focuser and telescope
  • fixed mirrors and 2" Crayford focuser with 1:10 dual speed transmission - no problems with mirror shift
  • Rotatable, 2" dual-speed (10:1) machined Crayford focuser provides precise focus adjustment control
  • Features one dovetail finder scope bases
  • corrected field is much bigger compared with a 6" SC
  • Computer optimized internal baffle system
 
EXOS-II Special Features
  • weight EXOS II Goto: 4.5kg (without counterweight shaft, which weights 1.0kg)
  • load capacity: 13kg
  • weight Tripod: 4.9kg
  • maximum height tripod: 108cm
 
In The Box
  • 6" f/19 Ritchey-Chretien Telescope
  • Choice of two eyepiece (Any ONE from : 4, 6, 9, 12mm and any ONE from 15, 20, 25, 32mm)
  • Mirror Star Diagonal 1,25"
  • 6x30 Achromatic Finder Telescope
  • 2" focuser with reduction to 1.25"
  • Dovetail GP Level
  • Dust protection cap for the focuser and front aperture
  • Finder shoe (mounted)
  • M90 extension tubes
  • German Manual
  • BRESSER EXOS II EQ-5 Mount with Motor
  • Hand Pad Control
  • Height Adjustable Tripod
  • 2x flexible shaft
  • Polar Finder Scope
  • 4.5 kg counterweight
 
TELESCOPE SPECIFICATION
Country of Manufacturing TAIWAN
Best for viewing Bright Deep sky
Best for Imaging Deep sky
Astro-imaging capibility Lunar, planetary and long exposure
RC 6 6" f/9 Ritchey-Chrétien Telescope
Optical Design Ritchey- Chretien with a hyperbolic primary- and secondary mirror.
Diameter Primary Mirror 152 mm Primary Mirror 96% reflectivity dielectrically coated/minimum 1/12th wave, Quartz glass
Focal Length 1370 mm
Focal Ratio f/9
Optical type Hyperbolic
Accepts Eyepiece Barrel Ø 50.8mm (2") to 31.7mm(1.25")
Resolving power 0.76 arc sec.
Limiting Stellar magnitude 13.6
Optical quality Diffraction limited
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.
Other features Vixen style dovetail mounting bar, 360-Degree rotating camera angle adjustment collar
Standard Eyepiece(s) Your choice of any two GSO Premium Plossl Eyepiece 1.25''
any one from series:: 12mm / 9mm / 6mm / 4mm
any one from series:: 15mm / 20mm / 25mm / 32mm
[ subject to availability in choices ]
View Finder Scope 6x30mm Fully multi-coated achromatic finder
Star Diagonal Mirror Star Diagonal 1.25"
Computer-optimized baffle system The inside of the tube is lined with computer-optimized baffles for optimum suppression of stray light.
Tube materila Aluminum
Lengt of optical tube 19.1"
diameter of tube 191 mm
Weight, optical tube 12.1 lbs. ( 5.5 kg)
EXOS-II GENERAL TECHNICAL DATA
Colour white
Material Metal
Product series Messier
EXOS-II DIMENSIONS & WEIGHTS
Net weight (without access.) 4500 g
Net Weight total (incl. accessories) 14500 g
Net weight tripod (incl. accessories) 4.9 kg
Shipping Weight 20 kg approx
 
Instructions for use in ENGLISH
Bresser Operating Manual for EXOS-II EQ Mount
 
Optical design
True Ritchey-Chrétien two-mirror Cassegrain optics, with hyperbolic primary and secondary mirrors. 6" aperture, 1370mm focal length, f/9 focal ratio. For more details, click on the “optics" icon above.
 
Hyperboloid Primary Mirror
Made of BK-7 optical glass. Polished to diffraction-limited or better surface accuracy. Unlike catadioptric designs (SCTs, Maksutovs, etc.) that move the primary mirror to focus (which can lead to image shift as the mirror moves), the GSO RC mirror is fixed to eliminate potential image shift. The fixed primary mirror also eliminates the frequent primary mirror collimation requirements of a Newtonian reflector.

GSO RC fixed primary and secondary mirrors “eliminate image shift, which has been the bane of Cassegrain scopes with moving-mirror focusing systems . . . It also keeps the effective focal length of the system constant, and the infinity focal point remains at a fixed point outside of the telescope, neither of which is the case with moving-mirror systems that change the separation between a Cassegrain’s primary and secondary mirrors."
 
Hyperboloid Secondary Mirror
Made of BK-7 optical glass. Polished to diffraction-limited or better surface accuracy. Mounted in a four-vane spider and fully collimatable.
 
Enhanced aluminum optical coatings
Both primary and secondary mirrors have enhanced aluminum mirror coatings, overcoated with a protective layer of quartz for long life. Reflectivity is in the 96% range, the same as the larger multi-thousand dollar R-C scopes.
 
Optical tube
Painted rolled steel, 7.5" o.d. x 19.25" long, with die-cast and machined aluminum front and rear cells.
 
Internal light baffles
Computer optimized primary and secondary baffling. Eight contrast-enhancing glare-stop baffles in the optical tube, multiple glare-stop microbaffles in the secondary mirror light shield, and four baffles in the primary mirror baffle tube provide truly dark sky backgrounds during imaging.
 
Dual-speed Crayford focuser
A 2" Crayford focuser is threaded onto the 90mm x 1mm pitch rear cell of the 6RC. The non-vignetting focuser has dual-speed focusing. There are two coarse focusing knobs. The right knob also has a smaller concentric knob with a 10:1 reduction gear microfine focusing ratio. This provides exceptionally precise image control during critical CCD imaging. All focus knobs are ribbed, so they are easy to operate, even while wearing gloves or mittens in cold weather.
 
Focuser travel
Focuser drawtube travel is 34mm, while back focus between the focuser's 2" accessory holder and the focal plane is 150mm. The 6RC falls 9-3/4" outside the back of the telescope, allowing plenty of room for all types of cameras, filter wheels, and ancillary equipment."
 
Extension Rings
Two extension rings (one 1" and one 2") areoptional to thread onto the rear of the scope (singly or in combination) between the scope rear cell and the focuser. These form a very rigid and tilt-free extension that moves the focuser out from the rear cell to accommodate the varying back-focus requirements of webcam/Deep Sky Imager-type cameras versus DSLRs. Typically, both rings (one 1" and one 2") will properly position most DSLRs at the 6RC focal plane. The “1- and 2-inch extensions, as well as conventional extension tubes that fit in the 2-inch focuser, mean that you can always assemble the system so it comes to focus with whatever camera and accessories you're using."

For even more impressive coma-free DSLR imaging with the GSO-6RC, consider adding field flattener. This modestly-priced imaging accessory essentially eliminates the residual field curvature inherent in all reflector telescope designs, so that the coma-free star images remain point-like all across the field of the APS-C size imaging chip used in most DSLR cameras. Use of field flattener with a DSLR will typically requires one optional 2" extension ring, instead of the two rings generally needed with a DSLR camera alone.
 
Compression ring accessory holders
The focuser drawtube ends in a 2" accessory holder that uses a non-marring soft brass compression ring to hold 2" imaging accessories in place. The compression ring won’t scratch the barrel of your accessories as an ordinary thumbscrew can. Also supplied is a 1.25" accessory holder that slips into the 2" compression ring holder to let you use 1.25" imaging accessories. Like the 2" eyepiece holder on the eyepiece holder rotation mechanism, the 1.25" adapter also uses a non-marring soft brass compression ring.
 
Mounting dovetail
Vixen-style dovetail bar runs the length of the underside of the optical tube. The dovetail can be removed, if desired, so the 6RC can be installed in optional user-supplied mounting rings for piggyback mounting on a larger scope.
 
Finderscope dovetail
A Vixen-style finderscope bracket dovetail base is installed on the upper left side of the optical tube. It can easily be removed if not needed. It will accept Vixen-style finderscope brackets as well as red dot-type finders.
 
WARNING
Buy BAADER Solar Safety Film
Buy 1000 OAKS Solarite Safety Film
 
The following items are FREE with the telescope listed above.
Magnitude 5 STAR Atlas
Directional Compass  FREE
Micro Fiber (Anti-Static) Cleaning cloth
Optics Cleaning Fluid
The Moon Map Poster B/W chart unfold to 22"x26"
110 Messier Object Locator     A4 size front back colour print
109 Deep Sky CALDWELL Catalogue A4 size front back colour print
Star Dial - Identifying Stars & Constellations
Various Astronomical Post-Card (SET-3)
Desiccant Cap - Refillable desiccant cap to protect fine optics
Astronomical Telescope - user guide
 
Suggested Accessories with this Telescope
    SOLAR FILTER
  • SOLARIX Solar filter (Explore Scienfific - USA) provide more pleasing and natural Yellow-Orange image of the Sun . . . . Rs 1470
    EYEPIECES (Super Premium Plossl for GSO) EYEPIECES (Super Premium Plossl for GSO)
  • 40mm Plossl Eyepiece 1.25" . . . . Rs. 2820
  • 32 mm Plossl Eyepiece 1.25" . . . . Rs 2640
  • 25 mm Plossl Eyepiece 1.25" . . . . Rs. 2550
  • 20 mm Plossl Eyepiece 1.25" . . . . Rs. 2460
  • 15 mm Plossl Eyepiece 1.25" . . . . Rs. 2280
  • 12 mm Plossl Eyepiece 1.25" . . . . Rs. 2100
  • 9 mm Plossl Eyepiece 1.25" . . . . Rs. 2100
  • 6 mm Plossl Eyepiece 1.25" . . . . Rs. 2100
  • 4 mm Plossl Eyepiece 1.25" . . . . Rs. 2100
  • GSO SuperView 15mm 1.25" Wide Angle Eyepiece . . . . Rs. 3000
  • GSO SuperView 20mm 1.15" Wide Angle Eyepiece . . . . Rs. 3000
  • GSO SuperView 30mm 2 " Wide Angle Eyepiece . . . . Rs. 4800
  • GSO SuperView 42mm 2" Wide Angle Eyepiece . . . . Rs. 4800
  • GSO SuperView 50mm 2" Wide Angle Eyepiece . . . . Rs. 4800
    DIAGONAL
  • GSO 1.25" Mirror Diagonal . . . . Rs.2100
  • GSO 2 inch Mirror diagonal . . . . Rs 5700
  • GSO 2 inch 99% Dielectric mirror Diagonal CNC . . . . Rs 7500
  • GSO 2 inch 99% Quartz Dielectric mirro Diagonal CNC . . . . Rs 9300
  • GSO 45 Degree Erecting Image Diagonal . . . . Rs 2640
    FINDER
  • GSO 6x30 Straight finder . . . . Rs.2460
  • GSO 8x50 straight finder . . . . Rs 3900
  • GSO 8x50 RA finder . . . . Rs 4800
    BARLOW
  • GSO 2x ED-Barlow-Lens (Multicoated) . . . . Rs.4800
  • GSO 2X Achromatic BARLOW LENS- fully multicoated 1.25" . . . . Rs. 1470
  • ED 3X Barlow Lens GSO 1.25" . . . . Rs. 2640
  • 3 Elememt 2.5x Barlow GSO 1.25"  . . . . Rs. 2370
  • 3 Elememt 5x Barlow GSO . . . . Rs. 2820
    CAMERA ATTACHMENTS
  • T-RING Nikon . . . . Rs. 840
  • T-RING Canon . . . . Rs 840
  • T Adapter 1.25" . . . . Rs. 750
  • Super ACHROMATIC (MultiCoated /High Colour corrected) 2X BARLOW 1.25" OD, 2 ELEMENT LENS with T-thread for direct camera attachment /with Brass compression ring / GSO. . . . Rs. 3,000
  • 2 inch T-2 Camera Adapter . . . . Rs 1650
  • GSO 40mm Camera adapter 2 inch . . . . Rs. 1560
  • Eyepiece Projection Camera Adapter . . . . Rs. 2100
  • Mobile Cell Phone Adapter . . . . Rs. 1830
  • GSO 1.25" 32mm Camera Projection Lens (CPL) eyepiece ... Rs. 3900
  • GSO 1.25" 40mm Camera Projection Lens (CPL) eyepiece ... Rs.4080
  • GSO 2" 30mm Camera Projection Lens (CSV) eyepiece ... Rs.5700
  • GSO 2" 42mm Camera Projection Lens (CSV) eyepiece ... Rs.5700
  • COMA Corrector 2 inch . . . . Rs 5700
  • GSO....0.5X Focal Reducer 1.25" with 25mm extension tube ....Rs 1560
  • GSO.....0.5x Focal Reducer 2 inch ....Rs 2100
  • GSO Planet View filter each . . . . Rs 660
  • GSO 2 inch EXTENSION TUBE
    35mm . . . . Rs 1470
    50mm . . . . Rs 1560
    80mm . . . . Rs 1650
  • GSO....0.5X Focal Reducer 1.25" with 25mm extension tube ....Rs 1560
  • GSO.....0.5x Focal Reducer 2 inch ....Rs 2100
  • GSO Planet View filter each . . . . Rs 660
 
 
 
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