APM 2 inch coma-correcting telecentric 1.5x Barlow
by the well known physicist and optic designer Philipp Keller
About 2 years ago APM Telescopes introduced the coma-correcting 2.7 times Barlow designed by Gerd Düring, which enjoys great popularity.
When our customers asked for a 2 inch version with a smaller magnification factor APM Teleslescopes let the well known physicist and optical designer Philipp Keller calculate a new 1.6x Barlow.
All of today's knowledge was incorporated to optimize the optical design. The telecentric design prevents that the distance has to be individually adjusted for each eyepice. Just insert the eyepiece into the optional 2-inch adapter sleeve and automatically have the optimum distance.
As already for the Barlow by G. Düring the design was calculated to yield a large back focus, in order that it can be used as an optical glass path corrector with coma-correcting effect combined with binocular viewers.
The large back focus allows the use of an off-axis guider + filter + CCD to take photographs with full format chips.
- Magnification 1.5 x
- Coma correction
- M54 x 0.75 male thread and M48 x 0.75 female thread (eyepiece/CCD side)
- Telecentric design with 4 lenses
- Works as optical path corrector 1.6 x for bino-viewers
- Large imaging field for full format chips
- 100 % illuminated Image Circle : 30 mm diameter
- Outward focus shift: 96 mm
- Distanz end M54 Thread to Focus 95 mm
- Telecentric Barlow include 2" eyepiece adapter
- Coating: Fully multicoated
- Filterthread: 2"
- Magnification: 1.5
- Optical design: 2 achromatic lenses
- Backfocus: 105 mm (from centre last lense)
- Fully corrected field: 44 mm
- Fully illuminated field: 44 mm