GSO 6" f/6 Newtonian Reflector Telescope with LB Focuser Upgrade - Steel OTA (White) # GS530-LRN

Our #: T-GS-GSSN06M6-W-LRN
Mfg #: GS530-LRN
Our Price: $389.00
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Out of Stock
Availability: Expected mid-April
Item Can Ship: Worldwide

The GS530 GSO 6" f/6 telescope (sold separately) comes with a very capable single speed Crayford focuser. While that included focuser is adequate for visual or light imaging use, serious astrophotographers might want to upgrade to this GS530-LRN version of the same scope that features the more robust and heavier-duty Dual Speed Linear Bearing Crayford Focuser

To learn about the advantages of the linear bearing focuser over the standard dual speed Crayford focuser, please see the "Eliminate Focuser Drawtube Slop" section at this link.

This linear bearing focuser has 50mm of tube travel compared to 40mm in the regular Crayford focuser and its body is a bit taller. Due to this you will also lose 5mm of available backfocus compared to the regular dual speed version. 

The linear bearing focuser on this telescope is NOT compatible with the ZWO EAF out of the box. It can be adapted for use with the EAF with Buckeyestargazer's 3d-printed adapter (see "Related Products" section above).

Other than the focuser, the GS530 and GS530-LRN are identical.

Quick Overview

This compact and affordable 150mm (approx. 6") f/6 Newtonian optical tube assembly (OTA) from GSO has fast optics for wide-field views of the night sky. Lightweight and easy to use, this Newtonian comes ready to go out of the box with a dual-speed 2" linear bearing Crayford-style linear bearing focuser, dual split-hinged mounting rings, and a Vixen style dovetail plate.

  • Fast 6" f/6 Newtonian optics for wide-field observations of the night sky
  • Fully and rigorously tested on site for cosmetics, mechanical operation, and optical performance by a master optician to ensure excellent overall telescope operation and customer satisfaction (an Agena exclusive service) 
  • Dual-speed 2" linear bearing Crayford focuser securely holds your eyepiece or lightweight camera with minimal wear and flexure
  • Includes 2" 35mm-long extension tube and 2"-1.25" eyepiece adapter
  • 13" Vixen-style dovetail bar with dual split-hinged felt-lined mounting rings to protect tube finish
  • Center dot on primary mirror for quick and easy collimation
  • Solid rolled steel telescope tube with gloss white exterior finish and matte black interior finish to increase contrast and minimize thermal effects

Product Details

1. Portable, Light Weight, and Economical

The GSO 150mm (approx. 6") f/6 Newtonian offers a fast focal ratio that's ideal for observing wide-field views of deep sky objects. The relatively short 900mm focal length keeps the tube length to a compact and easy-to-handle 32.8". With a total weight of only 14lbs 10oz (with all included accessories) this scope is ideal for use with compact and precision equatorial mounts such as the Celestron AVX, Skywatcher HEQ-5, or Orion Sirius. And with a price that's far less than a small ED refractor or Ritchey-Chretien scope, this OTA offers an economical alternative for imagers and visual observers on a budget who want a larger aperture.

While this scope has a smaller field of view than a faster f/4 Newtonian, it exhibits less coma and field curvature, especially when used for visual observing with long focal-length eyepieces or small cameras.

2. Full Optical and Mechanical Testing and Quality Control - An Agena Exclusive!

GSO telescopes are available from several suppliers, but Agena does much more than simply move the telescope boxes from GSO to you. Each GSO imaging Newtonian telescope at Agena undergoes a thorough physical, mechanical, and optical evaluation at our shop upon arrival - all at no extra cost to you.

Every GSO telescope is inspected to ensure good cosmetics, collimation, smooth focuser operation, and to make sure all parts are included by the manufacturer. Most importantly, we also check each telescope using a rigorous three-point on-site optical evaluation consisting of the following optical bench tests to ensure that your telescope delivers excellent optical performance:

  • Foucault Test: This knife-edge test is performed at the center of curvature of the primary mirror to evaluate the quality of the mirror's conic shape.
  • Ronchi Test: We then perform a Ronchi grating test at the center of curvature at inside focus, at focus, and outside focus. This is a qualitative method to evaluate primary mirror smoothness and figure.
  • Star test: Finally, we collimate the complete telescope and perform an autocollimation test with an artificial star to examine the overall system's image performance at the focus point.

This testing is performed and certified by a master optician to make sure each GSO instrument sold by Agena has excellent optical performance before it ships. Each telescope should be ready to go out of the box when you receive it.

3. Fast and Precision Optics

The precisely figured 6" f/6 primary mirror is made from BK7 optical glass for enhanced thermal stability. BK7 is far superior in thermal characteristics to soda lime float glass - the glass used in consumer products like cookware - that's used in many reflectors in this price range. The mirror is coated with enhanced aluminum to at least 92% reflectivity and coated with a protective layer of SiO2 (quartz) for durability. The primary mirror is mounted in a cell with six external push-pull collimation knobs on the back of the tube, and the center-marked primary makes collimation with a laser a snap.

4. Focuser and Accessories

The solid dual-speed 2" Crayford-style linear bearing focuser handles DSLR cameras, webcams, astronomy video cams, and large sensor CCD and CMOS cameras for astrophotography. It also has a tension knob to allow you to secure heavier loads. The ridged focus knobs give you a good feel and grip, even with gloved hands in cold weather, and the 10:1 fine focus knob lets you snap your image into perfect focus. The drawtube of the focuser is engineered to have minimal wear and very little flexure with most cameras. It offers 2" of focus travel and includes a focusing scale on the top of the drawtube to make it easy to return to the correct focus position during each observing session.

This OTA comes with a 1.25" eyepiece adapter with a compression ring to match 1.25" eyepieces and accessories, and it includes a 35mm-long 2" extension tube to let you achieve focus with a 1.25" or 2" eyepiece when using the telescope for visual use.

5. Tube and Mounting Rings

The tube of this Newtonian is made from rolled steel for good thermal stability and it's capped with end rings of die-cut aluminum for protection and rigidity. It includes a dust cap. The scope also comes with two split-hinged die-cast aluminum mounting rings to protect the finish of the tube. The bottoms of the rings have threaded mounting holes for a Vixen-style mounting plate (which is included). 

The tube also has an attractive outside gloss white finish and a matte black interior finish to reduce stray reflection and increase image contrast. The tube is 7" in diameter (7.2" at the end rings), 32.8" long, and it extends beyond the focuser to act as a shield to prevent stray light from entering the tube and reducing image contrast.

Please note: The tube rings included with GSO's 6" scopes are a bit smaller than they ideally should be. Hence, do not attempt to rotate the tube within loosened rings unless you completely open them or you will scratch the tube finish. Some customers resort to removing the felt lining and replacing it with a thinner alternative to allow the tube to rotate within the rings.

6. What's in the Box

  • 150mm f/6 Newtonian optical tube assembly
  • 2" dual speed linear-bearing Crayford-style focuser with 1.25" eyepiece adapter
  • Vixen-style finder dovetail base (bracket/finder not included)
  • Tube rings
  • 13" Vixen-style dovetail rail (color may be black or red, depending on stock)
  • 2" extension tube with 35mm extension
  • Front dust cover
  • 6x30mm straight-through finder with bracket
  • No instruction manual is included

7. Specifications

  • Optical design: Newtonian reflector
  • Aperture: 150mm (5.9")
  • Focal ratio: f/6
  • Focal length: 900mm
  • Primary mirror: Parabolic primary mirror; minimum 92% reflectivity; protective quartz layer
  • Secondary mirror: 50mm minor axis; minimum 92% reflectivity; protective quartz layer
  • Secondary mirror holder: 4-vane all metal spider
  • Secondary obstruction size: 33.3% by diameter; 11.1% by area
  • Tube outside diameter: End rings = 7.1"; tube = 6.75"
  • Tube length = 32.8"
  • Tube weight (with all included accessories): 14lbs 10oz
  • Shipped size / weight = 37"x13"x11" / 18lbs
  • Inspected for collimation and focuser operation at Agena AstroProducts
  • Warranty: 2 years

Other Information

  • Country of Manufacture: Taiwan
Description/photo copyright: Agena Astro - Reproduction without permission prohibited.