BRESSER Extension Tube 37.5 mm for 2.0" R&P Focuser

The three-lens design of the EXPLORE SCIENTIFIC ED-Apochromats provides everything an amateur astronomer desires - at a reasonable price. The construction with Hoya FCD-1 ED glass has two air spaces and provides a level of correction so superior to the two-lens constructions, that are common in this price class, that you will see the difference immediately. This excellent optical performance teams up with a high precision mechanics - the result is a telescope on a level that is setting a new standard in it´s price class. Astrophotographers will love this telescope - a optional field flattner is available and makes the telescope perfect even for cameras with a large chip format.These very popular EXPLORE SCIENTIFIC Triplet ED APO Refractors we do offer in 3 different product lines:Essential Line: HOYA FCD-1 Glass lens, AL-Tube, 2.0" Rack&Pinion Focusser with 1:10, 2.0" Star Diagonal 99% Reflectivity (see Part No. 0112084(AL), 0112106(AL), 0112132(AL)), 0112155(CF + 3"FT)) Professional Line: HOYA FCD-100 Glas lens, AL/CF-Tube, 2.5" HEXAFOC Focusser with 1:10, 2.0" Star Diagonal 99% Reflectivity (see Part No. 0112086(AL), 0112108(AL), 0112109(CF), 0112134(AL), 0112135(CF))High-End Line: OHARA FPL-53 Glass lens, Carbon(CF) Tube, 3.0" Feather-Touch Focusser with 1:10, 2.0" Star Diagonal 99% Reflectivity (see Part No. 0112165(CF))FEATURESthree lens air-spaced ED-apochromatHoya FCD01-ED glasspolystrehl of above 0.9weight: 2,6kgbackfocus: 165mm above 2" adaptorSCOPE OF DELIVERYOptics with dovetail plate and finder slot 2" Star Diagonal 99% reflectivityDust caps for front-lens and focuser

Highly corrected 80mm air-spaced triplet apochromat (with three lenses) and aluminium tube and a 2.5" high-precision HEXAFOC focuser.   Apochromats are the ultimate choice in small to medium sized telescopes: the combination of compactness, transportability, very high image contrast and sharpness together with the possibility to make excellent astrophotos cannot be bested. The advances in glass manufacturing during the last few years have made true apochromats available to more astronomy enthusiasts than ever before. The new Explore Scientific FCD-100 Alu Hex represents another major improvement in this field - the overall correction (color and spherical) is setting new standards in this price class. The optical design shows a polystrehl value of 0,97 indicating a level of correction that is absolutely top of the line.This small excellent apochromat is a very versatile telescope: the fast f-ratio makes short exposure times possible. The high contrast and sharpness of the image provide breathtaking views of large objects like the North america nebula or the Andromeda galaxy as well as tack sharp planetary images. The telescope is lightweight and compact - the dew shield slides down the tube to minimize size for transportation. Revolutionary glass and precision manufacturing created a telescope that offers observing joy on the highest level. This does not only qualify this telescope as the ideal travel scope, it is also the perfect choice for fast observations and for astrophotography. The excellent 2,5" HEXAFOC focuser with 10:1 reduction is perfect for this - the large inner diameter of 65mm prevents vignetting by the focuser when the telescope is used for astrophotography with large sensors.These very popular EXPLORE SCIENTIFIC Triplet ED APO Refractors we do offer in 3 different product lines:Essential Line: HOYA FCD-1 Glass lens, AL-Tube, 2.0" Rack&Pinion Focusser with 1:10, 2.0" Star Diagonal 99% Reflectivity (see Part No. 0112084(AL), 0112106(AL), 0112132(AL)), 0112155(CF + 3"FT)) Professional Line: HOYA FCD-100 Glas lens, AL/CF-Tube, 2.5" HEXAFOC Focusser with 1:10, 2.0" Star Diagonal 99% Reflectivity (see Part No. 0112086(AL), 0112108(AL), 0112109(CF), 0112134(AL), 0112135(CF))High-End Line: OHARA FPL-53 Glass lens, Carbon(CF) Tube, 3.0" Feather-Touch Focusser with 1:10, 2.0" Star Diagonal 99% Reflectivity (see Part No. 0112165(CF))SPECIFICATIONSAperture: 80mmFocal Length: 480mmFocal ratio: f/6Weigth: 2,6kgBackfocus: 150mm above 2" adaptorDesign: Apochromat with three lenses, two air spaces and FCD-100 glassSCOPE OF DELIVERY Optical tube with retractable dew-shield 2.5" HEX focuser with 1:10 gear reduction 2" Star Diagonal 99% reflectivity Universal dovetail - GP levelDust caps for front-lens and focuser Universal finder slot

Five extension tubes from 30 to 5mm length with thread connection M48x0,75mm in a set. For adjusting different distances of the camera to the focal plane of the telescope or the corrector/field flattener. There is an M48.0,75 internal and external thread in each individual tube. The M48x0.75 thread is also called large T2 photo thread or 2.0 inch filter thread. Camera specific bayonet adapters or color and nebula filters can be used. Included are 5 different tubes with the steps 30, 20, 15, 10 and 5 mm. The larger free inner diameter of 45.0 mm effectively prevents undesired vignetting of the camera sensor. The outer diameter of the sleeves is exactly 50.65 mm and can therefore be mounted directly in any 2 inch diameter eyepiece adapter. FEATURES Extension sleeves M48x0,75 in set Five extension sleeves: 30, 20, 15, 10, 5 mm Use with correctors and field flatteners Distance adjustment from camera to focal plane Suitable for camera-specific bayonet adapters Also suitable for 2.0 inch colour and nebular filters Internal and external thread M48x0.75 mm (large T2 thread) Large inner diameter of 45.0 mm Outer diameter is 50.65 mm (2 inches) Black matt anodized aluminium Total weight 85 grams SCOPE OF DELIVERY Extension sleeves M48x0.75 (5 pieces)

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