New, improved version of Blue Fireball's X-04 eyepiece extension tube - with twist-lock, self-centering mechanism!
This high-quality Blue Fireball extension tube can be inserted into any 2" telescope focuser to gain an additional 50mm (1.97") of back-focus travel. With this, eyepieces and accessories that you may not have been able to use because your telescope tube was too short are usable again!
Lack of sufficient back-focus travel is a common problem with many of today's fast f-ratio telescopes, especially if you have a low profile focuser or a short telescope tube that is optimized for binoviewer viewing. The 50mm extension tube alleviates this problem. This tube can also be used with 1.25" accessories with the use of commonly available 1.25"-2" adapters (sold separately).
With this adapter, you can forget about fumbling with thumbscrews in the dark. Just twist and lock the knurled twist lock ring at the top, and your 2" eyepiece or other accessory will be centered precisely. The helical centering mechanism is controlled by an inner polypropylene compression ring that will not mar your eyepieces. Its long length ensures that the adapter works well with smooth and recessed eyepiece barrels.
It also includes a large thumbscrew should you feel the need to provide added security for heavy items after you have tigthened the twist lock ring; however, use of this screw is optional and not required for regular use.
This practical and superb quality adapter is made from precision machined aluminum and is black anodized. The inside surface of this tube is black-matted to enhance contrast by reducing stray light reflections and is threaded to accept standard 2" telescope filters.
- Total length = 82.5mm (3.25")
- Extension provided = 50mm (1.97")
- Weight = 4oz (113g)
- Compression band depth (from top edge) = 16.2mm (0.64")
- Compression band length = Approx. 16mm (0.63)
- Maximum diameter = 62mm (2.44")
Manufacturer part number: X-08
Sep 18, 2018
Very nice self centering eyepiece extension tibePros: Cons: Comments:
I bought this for the specific purposes to center my laser collimatot in my newtonian's focuser. This helped me achieve the very best mirror alignment I have ever seen! No set screws to make the tube go askew. I also used a threaded adaptor ring to attach this extension tube to my focuser. Perfection!!!
We'll build and sturdy. And Agena is by far the best vendor on the web to order these kind of items from. Lightening fast shipper as well, as no hassle returns.
This review was provided courtesy of AgenaAstro.comDec 31, 2016
Works just ok.. a bit cumbersomePros: Cons: Comments:
This is a cheaper in cost alternative to the expensive baader turn lock accessories. Instead of what appears to be metal band which compresses inward on turning, it uses a beveled hard plastic band, which compresses to hold the barrel. I found it a bit cumbersome as the band catches on the barrels a bit which requires a bit of force to seat, and needs a whole half turn of the lever to tighten it fully where the bader is I think a 20 degree turn to lock it very securely. But it’s definitely an alternative for much lower cost if you like the turn rather than thumbscrews. A word of warning, is that I had a hard time fully tightening a diagonal in the holder to the point where I felt confident it wouldn’t come out. Since I have both I’ll say the Baader is much better for this kind of function. I think in the future I’ll either pony up the $ for the Baader or go with traditional thumb screws.
This review was provided courtesy of AgenaAstro.com
- Skill Level
- Time with Product
Apr 2, 2015
- User Notes:
- Review by C6R User of OH.
Easy to Use,Strong ConstructionCons: Comments:
I bought this for my Celestron C6R with a GSO linear bearing Crayford focuser.
The unit is well machined and locks up easily and securely.
Bottom line: Excellent
This review was provided courtesy of AgenaAstro.comAug 23, 2014
Well Made,Strong ConstructionCons:
This extension allows me to achieve focus with a CCD, filterwheel and flattener hanging off a small fast refractor. Fit and finish are excellent. There is no slop at either the telescope or the camera end. The price is just right and Agena's service was top-notch.
One minor point is that the safety screw (which need not be used normally) may mar the barrel the nose-piece of your equipment. Replace this with a plastic-tipped screw and you will still be ahead of the competition.
This review was provided courtesy of AgenaAstro.comApr 23, 2014
Blue Fireball 2" twist lock extensionPros:
Strong Construction,Easy to Use,LightweightCons: Comments:
Haven't had a chance to use it yet. But I'm sure it will work perfectly. Seems well built. I'd give it 9/10. Shipping was great, thank you. I'll be shopping here again.
This review was provided courtesy of AgenaAstro.comSort by