BRESSER Extension Tube 37,5 mm for 2.5" HEXAFOC

Are you having trouble focusing your eyepiece or camera? Then use this BRESSER 25 mm extension sleeve to increase the distance between the 2.5 inch HEXAFOC eyepiece extension and the eyepiece or camera. The extension sleeve has an M68x0.75 mm internal and external thread and can therefore be screwed directly onto the HEXAFOC draw tube.SPECIFICATIONSIncreases the distance to the eyepiece/camera Suitable for 2.5 inch HEXAFOC Optical length: 25 mm Internal and external thread: M68x0,75 mmInside black matt coated Material: aluminium, black anodized SCOPE OF DELIVERYExtension sleeve 25 mm (1 piece)

With the introduction of the 68° Series we are pleased to make two important improvements in eyepiece manufacture, the first being 15 layer Enhanced Multi-layer Deposition (EMD™) coatings on all glass-to-air surfaces to gain maximum contrast, and waterproofing the eyepiece with the use of Argon gas purging instead of standard Nitrogen gas. Although Nitrogen is a fine choice that will last for many years, Argon is a larger molecule that maintains its protective properties over a wider range of temperatures, and is even more resistant to diffusion thereby further extending the protective waterproof environment of the eyepiece body. Through computer-optimized design, a careful selection of optical glasses, and enhanced multi-layer deposition coatings, the Explore Scientific 68° Series™ eyepieces produce long eye-relief and ensure high image-correction, a flat field, and high contrast across the entire image field. An excellent choice for those who make extended visual studies of detail with subtle variations of brightness, and for those who must wear glasses while observing. All 68° Series eyepieces are fully EMD (Enhanced Multi-Layer Deposition) coated and edge-blackened to produce superior contrast.

For astrophotography it is essential to achieve the correct focus point with great precision. With the 1:8 Gear set precision focussing is easy. The gear set can be installed easily without difficulties and upgrades a 2,5" Hexafoc to a full 2,5" Hexafoc DeLuxe.Installation video:  https://www.youtube.com/watch?v=RCnsn2o-B94&t=144s

Universal 60mm viewfinder and guide telescope with a focal length of 250mmExcellent 10x60 viewfinder telescope with removable eyepiece unit and crosshairs with adjustable red illumination. The larger aperture and focal length, provide an even brighter field of view and more accurate tracking due to the higher resolution. The precise helical focuser and the 1.25 inch /31.7mm plug-in connection, as well as the T2 camera connection thread (M42x0.75mm), allow the autoguiding required for long time exposure to obtain a point-shaped star image. It can also be used as a mini travel telescope.High quality 10x60 viewfinder telescope with adjustable crosshair illuminationImage sharpness and viewing characteristics lift this viewfinder well above the level of the usual 10x60 viewfinder scopes. The visible image is bright and crisply sharp. Furthermore, this viewfinder has a very large field of view (FOV) of 6.0 degrees. This makes finding and adjusting objects much easier. The existing scale markings (pitch=0.85 degree) on the crosshair are a good reference for estimating distances, and the open centre markings also make it easier to centre objects precisely. All lens surfaces are protected against weathering by multi-coating and guarantee a bright viewfinder image due to the high light transmission values. The adjustable red LED illumination unit is powered by two LR41 coin batteries. The main lens and the crosshairs can be focused independently of each other, giving you perfect focus for your eyes.Compact tracking unit for autoguidingOne of the main applications for this telescope is the so-called autoguiding. Here the usually larger photo-taking optics are actively corrected by a smaller guiding telescope with a second tracking camera. This means that the mechanical fluctuations in the tracking accuracy, which are present in all astronomical telescope mounts, are measured by the tracking camera and compensated accordingly. This is necessary in order to obtain a point-shaped star image on the astrophotos during long time exposures and to avoid unwanted star trails. For this purpose, the guiding telescope is inserted into the existing viewfinder shoe of the photo-taking optics and aligned parallel. If the existing viewfinder shoe is not compatible, a suitable viewfinder shoe is also included. With the 1.25 inch / 31,7mm plug connection at the rear end or via T2 thread connection (M42x0,75mm), a tracking camera can be mounted afterwards. This is held securely by a brass ring clamp and 3 clamping screws. Please note the required back focus for your tracking camera. The focal plane (backfocus) is approx. 22mm behind the T2 thread. The sensitive focusing on the guiding star is done by a large knurled wheel of the mechanically precise manufactured helical focuser. For easy reproduction of the point of focus, this has a white millimetre scale from 0 to 28mm, which is attached by laser engraving. After the tracking camera has been connected directly or via computer to the telescope mount and the necessary basic settings have been made, the first astrophotos with long time exposure can be taken.Use as mini travel telescopeThis viewfinder and guide telescope can also be used quite simply as a mini travel telescope. With the optional eyepieces, a magnification of 9x to 50x can be achieved. Nearly all eyepieces with a focal length of 5 to 26mm and 1.25 inch/31.7mm plug connection are suitable. Especially recommended are the EXPLORE SCIENTIFIC eyepieces of the 52 degree (Art. 02195xx) and 62 degree (02196xx) LER series. Note: Only straight view use is possible.Metal viewfinder holder and viewfinder shoeThe mount of this viewfinder and guide telescope is completely made of aluminium and is a stable base. The viewfinder mount is suitable for many common types of telescopes, such as EXPLORE SCIENTIFIC, BRESSER MESSIER etc. If the existing viewfinder shoe is not compatible, a matching viewfinder shoe is also included. This can be attached to the telescopic tube by means of four M5 screws. The bore distances of the viewfinder shoe are 31.7mm on the longitudinal and transverse axis. The six large adjustment screws with non-slip knurling make it easy to align the viewfinder, even with clammy fingers. All adjusting and clamping screws have plastic tips that effectively prevent the viewfinder housing and viewfinder mount from being scratched.FEATURESExcellent 10x60 viewfinder and guiding telescopeCan also be used as mini travel telescopePerfect image sharpness and good viewing comfortFMC Multi-coated lens surfacesLens focal length: 250mmMax. possible camera weight: 550gRemovable eyepiece/cross hair unitCamera connection via 1.25 inch / 31.7mm plug connection or T2 threadT2 thread: M42 x 0,75mmPrecise helical focuser for focusing the visible imageFocuser travel range: 28mmClose focus distance: 3 mLaser engraved millimetre scale from 0 to 28mm on the focuserFocal plane (backfocus) is approx. 22mm behind the T2 threadSeparate focusing of the crosshair at the eyepieceVery large field of view FOV of 6.0 degreesWith adjustable red cross-hair iillumination Scale markings crosshair with 0,85 degree graduationPower supply of illumination unit: coin battery type LR41 (2pcs)Brass ring clamp and 3 clamping screws on the 1.25 inch plug connectionWith optional eyepieces magnifications from 9x to 50x can be achievedSuitable are almost all eyepieces with 1.25 inch/31,7mm shaftMounting of the viewfinder telescope is completely made of aluminiumViewfinder mount with 6 large adjustment screws with knurled head for easy gripFinder shoe suitable for EXPLORE SCIENTIFIC, BRESSER MESSIER etc.Additionally a suitable viewfinder shoe is includedBore distances of the viewfinder shoe are 31.7mm on the longitudinal and transverse axisAdjusting and clamping screws have plastic tipsWHAT'S INCLUDED10x60 viewfinder/guiding telescopeEyepiece unit with crosshairCrosshair illumination unit incl. batteriesViewfinder holder with viewfinder shoeInstruction manual

With the usage of barlow lenses, you can extend the equivalent focal length of telescopes and hence increase the magnification of your observed targets. Subsequently, you can use lower power eyepieces in Barlows to act as much more powerful eyepieces, but retain the larger ocular size and more comfortable viewing that comes with lower power eyepiece designs.Due to their two lens design, these Barlow lenses provide a brilliant image quality for the whole visual field and are suitable for observations and photography.  The black coloured Barlow element cell in this BRESSER Barlow Lens 2x 31.8mm/1.25," can be unscrewed and has the same thread as 1.25" filters, allowing it to be mounted in 1.25" eyepieces, t-adapters and other accessories, giving you flexibility of use and the ability to vary magnification in different accessories.  For instance, the black Barlow cell screwed into the average length nosepiece of a standard push fit t-adapter will give around 1.6x magnification on an attached DSLR.  This can be very useful when trying to get to photographic focus with some Newtonians and Solar Telescopes, which lack the necessary amount of in focus travel to get a camera to a prime focus position.FEATURESsuitable for observations and photographydoubling of the focal lengthtwo lens designfully multi-coatedWHAT'S INCLUDEDBarlow lens (1pc)

The "Wow-effect" eyepiece: You see deep sky objects as if you were in space! It makes you forget that you are looking through a telescope. This makes up for an unforgettable observing experience, that even exceeds the expectations of demanding amateur astronomers. Of course it has the same specifications as the already well established 100° eyepieces: inert gas purged, and waterprrof, the high end EMD coatings are protected from the outdoors.  Dust, fungus, humidity and cleaning solutions cannot harm the precious eyepiece for years of observing to come!