Product description TS-Optics Full frame size corrector for Ritchey-Chrétien Astrographs The corrector was developed for all RC telescopes with f/8 which have a 2.5"+ focuser. It corrects the field without altering the focal length. The large clear aperture of 60 mm allows full illumination of full-frame size sensors with suitable adaption. Adaption to the focuser via the M68x1 thread The corrector has a male M68x1 thread at the telescope side. There are adaptions for many established focusers. For the adaption to the female M69x1 thread of the MONORAIL focusers of TS-Optics, AstroTec and GSO RC telescopes you need: M69a-M68a: adapter to the male M68x1 thread M68i-M68i: conversion adapter from male to female M68x1 thread Connection of the camera via the female M69x1 thread The corrector provides a generous working distance of 89.5 mm from the female M69x1 thread at the camera side. Connecting DSLR cameras For connecting DSLR and astro cameras via the M48x0.75 thread, the adapter TSO-M69A-M48A is used. You have exactly 55 mm from the M48 thread to the sensor position. That would be exactly a T-ring and a DSLR camera. Connecting the Zeiss style M68x1 adapters system Many astrophotographers like to work with this professional adapter system. The adapter TSO-M69a-M68a provides an M68x1 connection to the corrector. The working distance from the M68 thread to the sensor is 84.2 mm, so you have enough space for your adaption. Connection of the M48x0.75 adapter system Alongside the T2 system, the M48 adapter system is also very popular. Almost any off-axis guider and many filter wheels have the M48 connection at the telescope side or, at least, can be adapted to this thread. With the adapter TSO-M69-M48, you get a very short transition to M48 with only 1 mm length. Extension tubes for the female M69x1 thread For maintaining the optimal illumination, one should adapt to smaller threads as late as possible. For this purpose, 30 mm and 10 mm extension are offered. These are screwed directly into the camera side thread and reduce the remaining working distance correspondingly. Delivery contents Corrector
Glas FK61 (similar to Ohara FPL51), has blackenededges, a measured transmission von over 99% from 400 nm to 700 nm, optimized for F/4 Newtonian-Telescopes. The barlow has a negative focal length of - 62.9 mm and a working backfocuse of 105 mm from center last lens to focuse ( eyepiece field stop). You will need now a 1.25" eyepiece holer 104 mm long
The uncompromising APM TMB-Design 1.8 x ED Barlow element is available again. 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". 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.