Baader Alan Gee Mark II Telecompressor (Flattener / Reducer) for Maxbright II Binoviewer
Stock count is accurate & shown in real time.
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
Contiguous US / Lower 48:
Free shipping applies to orders over $50 using our chosen carrier/method. Faster paid options are available at checkout.
Alaska, Hawaii & US Territories:
Free shipping applies to many—but not all—products. Enter your ZIP code in cart or upon checkout to confirm options and costs.
International:
International orders do not qualify for free shipping. Shipping, duties, brokerage, tariffs, and taxes are the customer’s responsibility. Some items may be restricted due to export, size, or manufacturer limitations.
- Schmidt-Cassegrain telecompressor/reducer and flatfield-corrector
- For Schmidt-Cassegrain-telescopes with 2" eyepiece clamp or for direct connection to SC-thread through Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / 2408160) or Baader SC / HD Ultra Short T-Adaptor, 7mm optical length (#2958500B)
- Variable reducing factor 5.9 to 3.5
- Preconfigured for use with T-2 thread of the Maxbright II binocular and for Mark V Großfeld (Giant)-Binocular (#2456410) with T-2 quick changer
- Can be used with T-2 eyepiece clamps
- Baader T-2 / 7.5 mm Extension Tube (T-2 part #25C / #1508155) is included
The Universal Alan Gee II is the only telecompressor/reducer on the market which works well with a binoviewer.
The standard Alan Gee Telecompressor Mark II was designed by Roland Christen (the producer of AstroPhysics apochromatic telescopes) as a reducer for Schmidt-Cassegrains which also delivers a flat field. The Universal Alan Gee II (UAG II) puts the optical elements of the Alan Gee in a regular 2" nose piece with an additional T-2-thread on the telescope side. The UAG II can be used for visual observations with Celestron EdgeHD telescopes. too.
The combination: Mark V Giant Bino / Baader 35mm ED-eyepieces / Universal Alan Gee II (UAG II) / Baader T2 Prism delivers a field of view of ca. 1.2° when used with a C8 – that's 72 minutes of arc, as much as a 2" 40mm eyepiece will show you! So, instead of waiting for an (unaffordable) 2" binoviewer, you can achieve the same effect on most SC-telescopes with the UAG II – be it monocular with a star diagonal or binocular with a binoviewer!
Please note that the reducing factor of the UAG II only depends on the distance between UAG II and eyepiece. It is designed for a working distance of 121mm then you get a reduction factor of 0.59. But if you focus to a focus plane farther away than the designed back focus of a Schmidt-Cassegrains or EdgeHD telescope, the focal length of the telescope itself becomes longer, and you get a different reducing factor than that which is calculated only from the distance between reducer ad eyepiece. The result depends on the individual adaptation and the telescope, we can't give a universal value for the reducing factor – but you will clearly notice the much larger field of view.
Use with a binoviewer
The UAG II can be attached directly to all Baader T-2 star diagonals with the included Baader T-2 / 7.5 mm Extension Tube (T-2 part #25C / #1508155) . Although a binoviewer could mechanically also be attached to a 2" star diagonal, we recommend for a Schmidt-Cassegrain the short adaptation with a T-2-prism and the Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / #2408160), so that the ideal focus point (and the focal length of the telescope in front of the UAG II) don't change too much from the original design. A binoviewer with T-2 thread like the MaxBright II or the Mark V Großfeld (Giant)-Binocular (#2456410) can be attached directly to the UAG II. The distance to the eyepieces is then about 120 mm.
Monocular use with a star diagonal
The UAG II can also be installed in front of a T-2 star diagonal. In addition, you need a T-2 eyepiece clamp and – depending on the desired distance/reduction factor – a T-2 extension. The UAG should be as close to the telescope as possible, so we recommend the optional Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / #2408160) to attach it to the telescope's SC-thread. If your telescope is equipped with a 2" ClickLock eyepiece clamp (#2956220 for C8/C925 or #2956233 for C11 and C14), you can also use this with the 2" nose piece of the UAG.
Baader 2" star diagonals with removable 2" nosepiece, you can also use the Baader Expansion Ring 2"a/T-2i with 1mm optical path length (T-2 part #28 / #2958242) to install the UAG in front of the star diagonal. It replaces the 2" nose piece. The distance between eyepiece and reducer is then equal to the optical length of the star diagonal. To place the UAG closer to the telescope, you can use the optional Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / #2408160).
Photographic Use
The UAG II may also be used with a camera (up to APS-C sensor size); the distance between UAG II and camera should be 121mm. The Alan Gee II was originally designed to be placed inside of the baffle of a Schmidt-Cassegrain, so for photography we still recommend the classic Alan Gee Telecompressor Mark II (T-2 part #20 / #2454400) in a configuration as described in its manual.
Baader part numbers: # AGII and # 2454400
Other Information
- Country of Manufacture: Germany
- Baader Planetarium Warranty: Baader products are warranted for two years for flawless optical function (not necessarily cosmetic optical appearance).
The Universal Alan Gee II is the only telecompressor/reducer on the market which works well with a binoviewer.
The standard Alan Gee Telecompressor Mark II was designed by Roland Christen (the producer of AstroPhysics apochromatic telescopes) as a reducer for Schmidt-Cassegrains which also delivers a flat field. The Universal Alan Gee II (UAG II) puts the optical elements of the Alan Gee in a regular 2" nose piece with an additional T-2-thread on the telescope side. The UAG II can be used for visual observations with Celestron EdgeHD telescopes. too.
The combination: Mark V Giant Bino / Baader 35mm ED-eyepieces / Universal Alan Gee II (UAG II) / Baader T2 Prism delivers a field of view of ca. 1.2° when used with a C8 – that's 72 minutes of arc, as much as a 2" 40mm eyepiece will show you! So, instead of waiting for an (unaffordable) 2" binoviewer, you can achieve the same effect on most SC-telescopes with the UAG II – be it monocular with a star diagonal or binocular with a binoviewer!
Please note that the reducing factor of the UAG II only depends on the distance between UAG II and eyepiece. It is designed for a working distance of 121mm then you get a reduction factor of 0.59. But if you focus to a focus plane farther away than the designed back focus of a Schmidt-Cassegrains or EdgeHD telescope, the focal length of the telescope itself becomes longer, and you get a different reducing factor than that which is calculated only from the distance between reducer ad eyepiece. The result depends on the individual adaptation and the telescope, we can't give a universal value for the reducing factor – but you will clearly notice the much larger field of view.
Use with a binoviewer
The UAG II can be attached directly to all Baader T-2 star diagonals with the included Baader T-2 / 7.5 mm Extension Tube (T-2 part #25C / #1508155) . Although a binoviewer could mechanically also be attached to a 2" star diagonal, we recommend for a Schmidt-Cassegrain the short adaptation with a T-2-prism and the Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / #2408160), so that the ideal focus point (and the focal length of the telescope in front of the UAG II) don't change too much from the original design. A binoviewer with T-2 thread like the MaxBright II or the Mark V Großfeld (Giant)-Binocular (#2456410) can be attached directly to the UAG II. The distance to the eyepieces is then about 120 mm.
Monocular use with a star diagonal
The UAG II can also be installed in front of a T-2 star diagonal. In addition, you need a T-2 eyepiece clamp and – depending on the desired distance/reduction factor – a T-2 extension. The UAG should be as close to the telescope as possible, so we recommend the optional Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / #2408160) to attach it to the telescope's SC-thread. If your telescope is equipped with a 2" ClickLock eyepiece clamp (#2956220 for C8/C925 or #2956233 for C11 and C14), you can also use this with the 2" nose piece of the UAG.
Baader 2" star diagonals with removable 2" nosepiece, you can also use the Baader Expansion Ring 2"a/T-2i with 1mm optical path length (T-2 part #28 / #2958242) to install the UAG in front of the star diagonal. It replaces the 2" nose piece. The distance between eyepiece and reducer is then equal to the optical length of the star diagonal. To place the UAG closer to the telescope, you can use the optional Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / #2408160).
Photographic Use
The UAG II may also be used with a camera (up to APS-C sensor size); the distance between UAG II and camera should be 121mm. The Alan Gee II was originally designed to be placed inside of the baffle of a Schmidt-Cassegrain, so for photography we still recommend the classic Alan Gee Telecompressor Mark II (T-2 part #20 / #2454400) in a configuration as described in its manual.
Baader part numbers: # AGII and # 2454400
- Schmidt-Cassegrain telecompressor/reducer and flatfield-corrector
- For Schmidt-Cassegrain-telescopes with 2" eyepiece clamp or for direct connection to SC-thread through Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / 2408160) or Baader SC / HD Ultra Short T-Adaptor, 7mm optical length (#2958500B)
- Variable reducing factor 5.9 to 3.5
- Preconfigured for use with T-2 thread of the Maxbright II binocular and for Mark V Großfeld (Giant)-Binocular (#2456410) with T-2 quick changer
- Can be used with T-2 eyepiece clamps
- Baader T-2 / 7.5 mm Extension Tube (T-2 part #25C / #1508155) is included
The Universal Alan Gee II is the only telecompressor/reducer on the market which works well with a binoviewer.
The standard Alan Gee Telecompressor Mark II was designed by Roland Christen (the producer of AstroPhysics apochromatic telescopes) as a reducer for Schmidt-Cassegrains which also delivers a flat field. The Universal Alan Gee II (UAG II) puts the optical elements of the Alan Gee in a regular 2" nose piece with an additional T-2-thread on the telescope side. The UAG II can be used for visual observations with Celestron EdgeHD telescopes. too.
The combination: Mark V Giant Bino / Baader 35mm ED-eyepieces / Universal Alan Gee II (UAG II) / Baader T2 Prism delivers a field of view of ca. 1.2° when used with a C8 – that's 72 minutes of arc, as much as a 2" 40mm eyepiece will show you! So, instead of waiting for an (unaffordable) 2" binoviewer, you can achieve the same effect on most SC-telescopes with the UAG II – be it monocular with a star diagonal or binocular with a binoviewer!
Please note that the reducing factor of the UAG II only depends on the distance between UAG II and eyepiece. It is designed for a working distance of 121mm then you get a reduction factor of 0.59. But if you focus to a focus plane farther away than the designed back focus of a Schmidt-Cassegrains or EdgeHD telescope, the focal length of the telescope itself becomes longer, and you get a different reducing factor than that which is calculated only from the distance between reducer ad eyepiece. The result depends on the individual adaptation and the telescope, we can't give a universal value for the reducing factor – but you will clearly notice the much larger field of view.
Use with a binoviewer
The UAG II can be attached directly to all Baader T-2 star diagonals with the included Baader T-2 / 7.5 mm Extension Tube (T-2 part #25C / #1508155) . Although a binoviewer could mechanically also be attached to a 2" star diagonal, we recommend for a Schmidt-Cassegrain the short adaptation with a T-2-prism and the Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / #2408160), so that the ideal focus point (and the focal length of the telescope in front of the UAG II) don't change too much from the original design. A binoviewer with T-2 thread like the MaxBright II or the Mark V Großfeld (Giant)-Binocular (#2456410) can be attached directly to the UAG II. The distance to the eyepieces is then about 120 mm.
Monocular use with a star diagonal
The UAG II can also be installed in front of a T-2 star diagonal. In addition, you need a T-2 eyepiece clamp and – depending on the desired distance/reduction factor – a T-2 extension. The UAG should be as close to the telescope as possible, so we recommend the optional Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / #2408160) to attach it to the telescope's SC-thread. If your telescope is equipped with a 2" ClickLock eyepiece clamp (#2956220 for C8/C925 or #2956233 for C11 and C14), you can also use this with the 2" nose piece of the UAG.
Baader 2" star diagonals with removable 2" nosepiece, you can also use the Baader Expansion Ring 2"a/T-2i with 1mm optical path length (T-2 part #28 / #2958242) to install the UAG in front of the star diagonal. It replaces the 2" nose piece. The distance between eyepiece and reducer is then equal to the optical length of the star diagonal. To place the UAG closer to the telescope, you can use the optional Baader T Adapter (BTA) for SC and MAK Telescopes (T-2 part #21 / #2408160).
Photographic Use
The UAG II may also be used with a camera (up to APS-C sensor size); the distance between UAG II and camera should be 121mm. The Alan Gee II was originally designed to be placed inside of the baffle of a Schmidt-Cassegrain, so for photography we still recommend the classic Alan Gee Telecompressor Mark II (T-2 part #20 / #2454400) in a configuration as described in its manual.
Baader part numbers: # AGII and # 2454400
Other Information
- Country of Manufacture: Germany
- Baader Planetarium Warranty: Baader products are warranted for two years for flawless optical function (not necessarily cosmetic optical appearance).
Baader Alan Gee Mark II Telecompressor (Flattener / Reducer) for Maxbright II Binoviewer