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GSO 2" Linear Bearing Crayford Focuser for SCTs - Dual Speed
| Brand | GSO |
| Part Number | PAF-GS-LBSCT |
| Availability | available |
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Product Info
Manufacturer Description
PLEASE NOTE: Due to its larger size and length, this focuser can only be used on equatorial mounted SCTs. It is NOT recommended for fork mounted SCTs.
This GSO Dual-Speed Linear Focuser for SCT telescopes features the most recent innovation in focuser design to hit the astronomy market in recent years. It is designed specifically to meet the heavier equipment and stability requirements of astrophotography equipment and heavy eyepieces. The linear stability and repeatable quality of focus reached with this focuser will have you returning night after night for more spectacular views, sharper images, and consistent enjoyment!
Eliminate SCT Image Shift
Many users find the primary mirror focusing mechanism of Schmidt-Cassegrain telescopes (SCT) cumbersome to use. There is some amount of image shift and precise focus cannot be found easily. This is inconvenient for visual use and a serious problem for astrophotography. By relying on this focuser for fine focusing instead of the telescope's movable primary mirror, image shift is completely eliminated, and you will experience very smooth and precisely controlled focuser motion.
Eliminate Focuser Drawtube Slop
In conventional Crayford focusers, the drawtube is held in place by four roller bearings. Because of the small area of contact between the focuser tube and these bearings, changes in load or telescope orientation can cause some amount of slop in the focuser drawtube. The new linear bearing focuser is built with a cutting-edge rail system made of stainless steel which provides extended, consistent, and linear contact with the focusing mechanism and the inside of the focuser body, even when the focuser is fully extended. The result is zero flexure throughout the focus travel range, even in the worst case scenario when the focuser is parallel to the ground and carrying a heavy load such as a large CCD camera. This linear bearing rail mechanism also allows the use of heavier loads (GSO's rated load capacity for their linear bearing focusers is about 9 lbs (4.1 kgs)).
Smooth Focusing Action
The ultra-smooth focuser adjustment knob is only topped by the 10:1 fine adjustment knob which yields superior fine-tuning that will stay in place without slippage for hours on end. You'll feel as if the focuser is gliding on air as you meticulously seek the perfect focus. For critical imaging applications, the focuser position can be locked in place via the large thumbscrew provided for this purpose on the top of the focuser. The focusing tension can be controlled by another large screw on the underside of the focuser. The drawtube features a laser-etched measurement scale for quick and repeatable focusing.
Rotatable for Maximum Comfort
This deluxe model features a 360-degree rotatable ring that allows you to orient the focuser (and hence your diagonal/eyepiece/camera) to the most comfortable viewing or imaging position.
Very High Quality Construction and Features
The highly polished, anodized black aluminum is complemented by the meticulous CNC machining. Every part is carefully selected and designed to deliver a linear focusing system that will provide both beauty and quality for years to come. The 2" focuser barrel features a brass compression ring and can accept standard 2" refractor-type diagonals and other 2" accessories (Note that the use of this focuser converts your telescope's rear SCT thread to a 2" visual back. As a result you will not be able to use an SCT-type diagonal with this focuser; you will need a refractor-type diagonal instead). Also included is a 2"-1.25" adapter with brass compression rings and threads to accept standard 2" filters.
Easy Installation and Use
Installation is a simple matter of threading the focuser’s flange onto the standard male SCT thread (which is a 2" x 24 TPI thread) on the rear of your SCT telescope. Please note that some Celestron telescopes made in the late 1970s and early 1980s did not have a standard thread pitch. This focuser will not fit those, and there is no way for us to know what threads you might have on your telescope.
To focus, simply use your main SCT focusing knob to bring your scope into the ballpark range of focus, then fine tune with the focusing knobs built into your linear focuser. It’s that simple! With a generous 2" focus travel range, you may never need to touch your SCT's main focuser knob again!
Specifications:
• Minimum focuser height (without 1.25" adapter) = 4.65" (118mm)
• Maximum focuser height (without 1.25" adapter) = 6.65" (169mm)
• 2"-1.25" adapter height = 0.39" (10mm)
• Tube travel = 2" (50.8mm)
• Drawtube outside diameter = 2.32" (59mm)
• Steel rail width = 0.56" (14.1mm)
• Focuser weight (with 1.25" adapter) = 1lb-15.3oz (887gm)
• Focus knob diameter = 1.57" (40mm)
• Microfocus knob diameter = 1.06" (27mm)
• Maximum outer body diameter = 3.23" (82mm)
• Flange thread: Standard SCT female thread (2" x 24 TPI)
• Measurement scale on focuser drawtube: Yes
• Rotatable: Yes
• Dust plug: One 1.25" dust plug included
Additional Comments
• The focuser is shipped in a foam-fitted padded box.
• No instruction manual is included.
Reviews
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Mar 29, 2019
Quality Focuser
Pros: Cons: Comments:Excellent addition for my C8. Takes the focus gear hysteresis of the C8 out of the picture. Very fine fit and finish with smooth operation. Can not achieve focus with the f6.3 focal reducer and a star diagonal on the C8.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Dec 3, 2017GSO SCT linear bearing focuser
Pros: Cons: Comments:I have not had the time to try the focuser in the field. It installed easily and appears to be well built and designed. Very slight pressure is needed to lock the focus position. The linear bearing also appears to be worth the extra cost. So it is a keeper.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Dec 3, 2017Very well costructed focuser
Pros: Cons: Comments:Received this Crayford focuser last week and I am very impressed with its construction and ease of operation.
Bottom Line: Would you recommend this item? Yes
This is my second GSO product and I am still impressed with there products.This review was provided courtesy of AgenaAstro.com
Jan 16, 2017Linear Bearing Crayford focuser for SCTs
Pros: Cons: Comments:Very smooth consistent operation, easy installation, solid construction, and an excellent value. 5-Stars !
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jun 16, 2014Excellent Focuser - a pleasure to use
Pros:Accurate,Strong Construction,Easy to Use
Cons: Comments:I have been using the focuser for about 3 months now. It has helped me get some great photos of Jupiter, Mars, the Moon, and Saturn with my Nexstar 8se SCT! It is especially helpful for making focusing with a barlow lens MUCH easier (a lot less turns on the mirror knob). I set the GSO at about mid range (2"), then do rough focus with the SCT's mirror knob. After that, I do coarse and fine focus with the knobs on the GSO. The GSO is also nice for visual use as well.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Mar 28, 2014Great Focuser
Pros:Strong Construction,Easy to Use
Cons: Comments:These GSO Linear Bearing focusers work exceedingly well. I have two of them now and love them. Being able to rotate the focuser is a big plus also.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
dvoprvb New Member
- Skill Level
- Unknown
- Time with Product
- Unknown
- User Notes:
- Review by dvoprvb of CT.
Nov 29, 2013Hardworking focuser
Pros:Easy to Use,Strong Construction
Cons: Comments:I wanted/needed to replace a focuser on a 6inch homemade refractor. It was new to me but is several years old. To have one machined would have been real expensive. I had Agena measure with a micrometer the shaft. I gave it a try and this fit into the plate. Now I have a focuser that is really heavy duty (locks up) and dual speed.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
brunono2 New Member
- Skill Level
- Unknown
- Time with Product
- Unknown
- User Notes:
- Review by Bruno of Sydey Australia.
Sep 28, 2013Excellent focuser-value for money
Pros:Strong Construction
Cons: Comments:Linear bearing enables heavy eyepieces and focuser to be carried without slipping. Far superior to non linear focuser. Value for money when compared to competitors
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Aug 12, 2011Great solid focuser
Pros:Strong Construction,Accurate
Cons:Strong Construction,Accurate
Comments:I bought it for my Meade 10in SCT & SBIG ST2000XM. Even when fully extended, there is absolutely no wobble. SCT/focal reducer/focuser/ccd camera remains as one solid unit. I'm sure there are better focusers out there, but probably not at this price.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
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Manufacturer GSO Focuser Telescope Type SCT
