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APM-TMB-Design 1.8 x ED Barlow 1 1/4", reborn

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APM-TMB-Design 1.8 x ED Barlow 1 1/4"

The uncompromising APM TMB-Design 1.8 x ED Barlow element is available again.

now in stock


The most important data:
  • At 588 nm wavelength the negative focal length is - 104.20 mm
  • Cemented 2 lens element with ED glass
  • Free aperture : 22 mm
  • Broadband multicoated
  • Magnification factor 1.8x
  • Screwable into our APM adapter kit (see accessories)


Product description
APM TMB-Design  1.8 x ED Barlow 1 1/4"

The ultimate ED Barlow element from TMB is reissued.

This is an uncompromising barlow element with the absolute best optical components. Only high index glass of particularly high quality is used. The TMB ED Barlow element consists of a cemented doublet with blackened lens edges. All optical lenses are broadband multicoated.
The lens can be screwed directly into our APM adapter kit (see accessories).
The optical quality even slightly exceeds the former Zeiss Jena 1 1/4" ED Barlow lens.
 
Scope of delivery:
  • 1.8 x ED Barlow element 1 1/4" in cell. The mechanical drawing and picture of the TMB barlow show the old complete version which we do not remake yet. Again you buy here the barlow ( fully multicoated to the edge this time ) in cell

Customer Experience :
According to several tests, the TMB ED 1.8x Barlow is one of the best barlows currently available. Like the Zeiss Abbe Barlow, it is a cemented doublet with excellent coating, although the coating looks much darker than that of the Antares 1.6x Barlow. While the Abbe Barlow with -64 mm focal length is optimised for 2x and higher magnification, the TMB Barlow has only a slightly lower magnification and -105 mm focal length. Therefore, the lens of the TMB Barlow seems to me to be the best candidate for a barlow that is also used at lower magnification, e.g. 1.5x. Such a low magnification is particularly interesting for the Leica Asph zoom, it gives a 6-12 mm zoom. While the Baader VIP Barlow is used very successfully as a barlow for the Leica zoom (http://www.cloudynig...hp?item_id=2390) at 1.5x magnification, it leads to a certain astigmatism in the outer part of the image field at long focal lengths. Once the objective has been installed in a housing with a 2" outer diameter and 2" thread, it can be screwed directly into 2" eyepieces. By adding 20 mm long 2" extension tubes, the magnification can easily be increased up to 2.25x. The modified Barlow weighs only 50 g, each 20 mm extension tube adds another 20 g. Surprisingly, the modified Barlow works very well with the 17 mm Ethos, even at ~1.5x magnification. When screwed directly into the Ethos, about 11 mm focal length is achieved. Certainly a slight vignetting occurs, but I don't find it very disturbing. With a 20 mm extension, 9.5 mm focal length is achieved and the vignetting disappears. So far I have only been able to carry out initial tests with the Leica zoom and the 17 mm Ethos in daylight and under a light-polluted sky. My first impression is very positive, in daylight I could not notice any difference between the Leica Zoom and the Barlow Leica Zoom. As soon as I have tested the Barlow under better conditions, I can give a more detailed report.

shipping is US $ 50 by UPS worldwide

delivery start in february 2023, you can preorder now here

https://www.apm-telescopes.net/en/apm-tmb-design-18-x-ed-barlow-1-14

or by email to me : anfrage@apm-telescopes.de