GSO 2" Dual Speed Crayford Focuser for Refractors with 86.4mm Base Adapter
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||GSO 10:1 Dual Speed Crayford Focuser for Refractors - 86.4mm Base Flange Diameter
|Item Ships in US Via:
||USPS Priority Mail with delivery confirmation
1. Detailed Product Description
Please do not order this item unless you have read all the information below and are sure that you are ordering the correct item. This is especially important for “Section 6: Selecting a Focuser Model for your Telescope” below. We will not accept returns if you buy the wrong size/item.
This listing is for an 86.4mm 10:1 Dual Speed Crayford Refractor Focuser.
This very high quality, dual-speed Crayford focuser for refractor telescopes from Guan Sheng Optical (GSO) is beautifully machined and a joy to use. You will wonder how you ever lived without it once you install it!
1. Smooth Focusing Action
The 10:1 dual speed microfocuser control makes achieving precise focus for visual observations and astrophotography a breeze and you will experience very smooth and precisely controlled focuser motion with zero backlash and zero image shift.
2. High-Quality Construction and Features
CNC machined from aluminum and anodized black, this focuser comes with a base plate adapter to attach to refractor telescopes. The inner drawtube glides on 4 precision bearings and a roller shaft and provides 79mm (3.11”) of focus travel. The inner barrel is baffled and painted a flat black to minimize reflections for maximum contrast.
The 2" focuser barrel features a brass compression ring so your eyepieces and other accessories will not be marred by the set-screw. Also included is a 1.25"-2" adapter with brass compression rings that is threaded to accept standard 2" filters.
The inner draw-tube barrel is anodized black and features a laser-etched scale.
Please note: Most GSO Crayford
focusers have or will soon develop two bearing marks/lines on the upper
side of the drawtube. This is caused by wear on the barrel anodizing
where is makes contact with the roller bearings. In some focusers, you
have to look hard to find these marks. In others, it is very prominent,
even for brand new items received from GSO. This does not indicate a
defective or used product and is essentially just cosmetic.
3. Tension Adjustment and Focus-Lock
The focuser has two large thumbscrews on the underside. The thumbscrew on the telescope side can be used to lock the focuser, allowing the use of heavy accessories or cameras without fear or slippage or losing focus. The other thumbscrew on the eyepiece end can be used to adjust the tension of the focuser to achieve a focusing "feel" that you like. At the easiest (lightest) setting, the focuser moves extremely smoothly. At tighter settings, you can still use heavier accessories without sacrificing much of the smooth focuser action. GSO's rated load capacity for their Crayford focusers is about 6 lbs (2.7 kgs).
4. 360-degree Rotation
These focusers are rotatable, i.e., you can turn the entire focuser body/diagonal/eyepiece combination into a better observing position by loosening or tightening a large silver thumbscrew on the top of the focuser. However, please note that this is a relatively weak feature of this otherwise excellent product. We inspect every single focuser and tweak/lube it as much as we can, but the rotation is often not smooth over the entire 360-degrees and may bind in a few spots, requiring additional effort to rotate it. This is probably a minor annoyance since most people will not use this feature very often.
5. Focuser Installation
The focuser is easily attached to a telescope tube with three M4 screws (not included) spaced 120 degrees apart on the flange. Installation is usually a 5 minute job that involves removing your old focuser, sliding in the new Crayford focuser, and screwing it on to the telescope tube. In almost all cases, the original screws used on your OEM focuser will also work for this Crayford focuser. If not, you will have to buy the M4 screws from a local hardware store. You will just need a Philips (cross-slot) screw-driver to perform this upgrade.
We strongly recommend that you make sure that you can remove your old focuser from your telescope tube before buying this item. Some OEM R&P focusers can be very hard to remove.
6. Selecting a Focuser Model for your Telescope
The focuser comes with a base plate adapter. This adapter is available in 3 different flange sizes [86mm (3.39”), 96mm (3.78”) or 112mm (4.41”)] to fit inside many popular telescope tubes sold today.
We have provided a telescope compatibility table below for your convenience based on feedback provided by our customers. We will, however, not be responsible for any errors or problems if you do not measure your own telescope tube. Manufacturers sometimes change tube specifications, so the ONLY way to correctly determine which size adapter you need is by removing your existing focuser, measuring the inner diameter of your telescope tube, and then making a choice. If your telescope model is not listed below, then we do not know which model will work for you. In such cases, please contact us with your tube dimensions and we will work with you to find a solution.
Focuser Compatibility Table:
|GSO 86mm Focuser|
Celestron 80mm f/5 ST, Celestron NexStar 80 SLT, Celestron 80ED/100ED (requires additional screw-on adapter sold separately in our eBay store), Discovery 90mm f/5.6 Short Tube, Konus KonusMotor 90mm f/11, Meade Model 390 90mm f/11, Orion ST80, Orion 80mm f/11.4 OTA, Orion 90mm f/5.6 Short Tube, Sky-Watcher 80mm f/5, Stellarvue AT1010 NightHawk, Synta 90mm f/5.6 Short Tube
|GSO 96mm Focuser
Celestron C4R 102mm f/9.8, Celestron 102mm f/5, Celestron C-102HD 102mm f/10, Celestron C6R 150mm f/8, Orion 80ED, Orion 100ED, Orion Astroview 100mm f/6, Orion Astroview 120ST EQ (mounted into collar on tube; 112mm model if mounted into tube), Sky-Watcher 80ED, Sky-Watcher 100ED, Sky-Watcher 120ED, Sky-Watcher 102mm f/9.8
| GSO 112mm Focuser
Celestron Omni XLT 120, Orion 120mm f/8.3, Orion Astroview 120ST EQ (Mounted into tube; 96mm model if mounted into collar on tube)
7. Focus Travel Issues
Most Crayford focuser units are shorter than existing R&P focusers. So while you will typically have more in-focus travel with a new Crayford focuser (which is great for imaging applications), you might not have sufficient out-focus travel to reach focus with all your eyepieces/accessories. In such cases, the problem can be easily fixed with 2” extension tubes that are available in our eBay store.
8. Finder Mounting Options
In many existing focusers, the base for your finder bracket is molded onto the focuser body. When you replace the existing focuser with a Crayford focuser, you will lose this base to mount your finder. We sell an optional Synta/GSO-compatible dovetail base modified to fit GSO focusers so that you can attach your Synta/GSO-compatible finder brackets again. You can purchase this dovetail base from our eBay store.
Click on any image below to enlarge.
9. Focuser Specifications
- Flange outer diameter on telescope adapter: 86.4mm (3.40”)
- Minimum focuser height (with 1.25" adapter and base flange) = 118mm (4.65”)
- Maximum focuser height (with 1.25" adapter and base flange) = 197mm (7.76”)
- Minimum focuser height (without 1.25" adapter but with base flange) = 108mm (4.25”)
- Maximum focuser height (without 1.25" adapter but with base flange) = 187mm (7.36”)
- Tube travel = 79mm (3.11”)
- Focuser weight (with 1.25" adapter) = 1lb-13.8oz (844gm)
- Focus knob diameter = 40mm (1.57”)
- Microfocus knob diameter = 26mm (1.02”)
- Laser-etched scale markings on focuser drawtube: Yes
- Rotatable: Yes
- Dust plug: One 1.25" dust plug included
Specifications are subject to change without notice. Please verify with us if necessary.
10. Customer Installation Photos
Note: Occasionally, the product you receive might have a slightly different cosmetic appearance or labeling than what is shown. This can often change from batch to batch according to the whims of the manufacturer. However, you will always receive a brand new, original product as described above.
Text and photos - Copyright Agena AstroProducts. Reproduction without permission prohibited.
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Sales Tax: 8.5% sales tax added if your Ship-To address is in California.
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Delivery Time: Most orders ship within 1 business day of receiving payment. First Class shipments will take 3-5 days to arrive after we ship it. Priority Mail shipments will take 2-3 days. However, these delivery times are NOT guaranteed by the USPS. Delays of up to 2 weeks can occur in about 5% of the shipments.
Tracking/Delivery Confirmation: We will send you a Delivery Confirmation number in the shipment notification email after your order ships. This is not detailed tracking, but it provides some very basic tracking info en route. Sometimes, the USPS neglects to update this info for a few days but your shipment is not affected.
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Handling Fee: For all international orders, we charge an additional handling fee of 3% of the purchase price of the item(s). This will be added to your order total when you check out.
1) USPS First Class International: Delivery takes about 3-4 weeks after we ship your package. This can frequently take 4-6 weeks or more for several countries (up to 8 weeks for Brazil, Germany, Italy and South Africa). THERE IS NO TRACKING FOR FIRST CLASS SHIPMENTS. The information shown in your eBay account is just a customs form number - it is NOT a tracking number as incorrectly indicated by eBay. Once your package ships, we can do nothing but wait until your package arrives. Please do not become impatient and contact us in 2-3 weeks if your package has not arrived. If you don't receive the package in 6 weeks, contact us and we will work with you to resolve the issue. If you don't want to take the risk of this delay, then DO NOT USE First Class mail - use Priority or Express shipping instead.
(2) USPS Priority Mail International: Delivery takes 1 - 2 weeks after we ship your package. This can sometimes take 3-4 weeks to several countries. The USPS provides some basic tracking information for Priority shipping.
(3) USPS Express Mail International: Delivery usually takes 5-10 business days after we ship your package. You will receive a tracking number with which you can track your shipment from USPS.com. Note: If you use this option, you must send us your phone number when you check-out or else your shipment will be delayed. This is required for international postal forms.
Again, these delivery times are NOT guaranteed by the US Postal Service. The most common reason for delays is slow customs inspection and clearance in your country, and can be very long, even for Express mail packages. Upon shipping your order, delivery delays are beyond our control, so do not leave us negative feedback or file a Paypal claim if your package is delayed. Delays are quite common but losses are very rare, so your patience/cooperation will be greatly appreciated.
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US Orders: We must receive any returns within 14 days from the time you receive it. A minimum restocking fee of 10% will be levied for all returns and exchanges. A larger amount will be deducted if there is evidence of use or wear, dirt, scratches, missing packaging/parts, etc. Shipping fees are non-refundable and you are responsible for all return shipping costs. Please contact us first before returning an item.
International Orders: No returns/exchanges accepted unless the item we shipped is defective. Please research the product and ask us any questions BEFORE you purchase to make sure you are buying the correct item for your needs.
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