|
Ascension 80ED Triplet APO
|
Premium Quality - Triplet Apochromat Refractor
To order this item outside mainland Britain or Highlands & Islands, please contact us.
|
 |
|
Ascension 80ED Triplet with dual-speed focuser. Also included are: 2" dielectric diagonal and two wide-angle eyepieces.
|
- Lens diameter: 80mm
- Focal ratio: F/6
- Triplet Japanese FCD1 ED objective
- Strehl Ratio: 0.90 or better
- Fully (broadband) multi-coated lenses
- Precision dual-speed Crayford style focuser
- Retractable Dewshield (with aluminium cap)
|
- 2" dielectric diagonal (over 99% reflectivity) with 1.25" eyepiece adapter
- 10mm & 20mm 70° wide angle fully multicoated eyepieces
- Sturdy Aluminium case
- Dovetail
- Optional: Interferometer report
|
|
|
|
|
|
|
Ascension 80ED Triplet APO O.T.A.
|
|
|
|
Outline
|
High contrast and minimal colour aberrations are both highly desirable
features in a modern telescope. Triplet lens designs incorporating exotic
glasses present optical systems practically free of chromatic aberration
(colour fringing) and capable of pin-point star images.
The Ascension APO (apochromatic) refractors use a high quality Japanese
made triplet lens objective made of premium ED (Extremely Low Dispersion)
glass to achieve images of high contrast and virtually free of secondary
colour. Fully (broadband) multicoated lenses ensure maximum light transmission.
|
|
|
 |
The Ascension 80ED Triplet optical tube.
|
Designed with wide field observing and imaging in mind these triplet apochromatic
telescopes offer an array of features including a versatile mounting system,
precision 2-speed Crayford focuser and retractable dewshield.
|
|
|
|
Optical Performance
|
The new Ascension ED Triplet refractors guarantee an RMS of 0.052 (0.9 Strehl) or
better clearly outperforming diffraction-limited (RMS 0.071, Strehl 0.82)
apochromatic ED refractors. In addition the High Precision (HP) range guarantees
an even higher RMS of 0.36 (0.95 Strehl) or better offering unmatched value for
money and excellent performance.
In imaging terms the high quality Japanese FCD-1 objective ED triplet will bring
the image in sharp focus when imaging unlike apochromatic ED refractors that rely
on a doublet ED objective for imaging.
|
|
|
| RMS Rating |
Strehl Ratio |
Comments |
Note |
| 0.094 |
0.710 |
. |
. |
| 0.071 |
0.820 |
Rayleigh Limit (diffraction limited) |
good |
| 0.057 |
0.880 |
. |
. |
| 0.052 |
0.900 |
Ascension ED Triplet |
very good |
| 0.047 |
0.920 |
Ascension ED Triplet |
very good |
| 0.041 |
0.940 |
Ascension ED Triplet |
very good |
| 0.036 |
0.950 |
Ascension ED Triplet - High Precision |
excellent |
| 0.032 |
0.960 |
Ascension ED Triplet - High Precision |
excellent |
| 0.028 |
0.969 |
Ascension ED Triplet - High Precision |
excellent |
|
Ascension High Precision optics are subject to availability from the manufacturer.
The Strehl Ratio is calculated from the RMS rating value: Strehl ratio = 1 - (2π x RMS Rating)2
|
|
Features
|
The optical tube greatly benefits from knife-edge baffles that prevent light
which has bypassed the optical system or which is outside the field of view from
reaching the focal plane thus increasing image contrast.
The Ascension 80ED Triplet comes complete with a 2" dielectric (99% reflectivity) diagonal,
dovetail and two high quality, wide field eyepieces, all securely kept in a sturdy aluminium case.
With a minimum total length of only 38cm and an 80mm aperture the Ascension 80ED is
the perfect travel scope. The telescope comes complete and is ready to use out of the box,
all you need is a mount or photographic tripod.
At f/6 (80mm) the focal ratio of the Ascension 80ED Triplet is well suited for wide
field astrophotography.
|
|
|
 |
The Ascension 80ED Triplet's 2" focuser, dielectric diagonal and wide-angle fully multi-coated eyepieces.
|
| Ascension Specification Comparison Chart |
| Specification |
Ascension80ED Triplet |
Ascension
102ED Triplet |
Ascension
127ED Triplet |
Opticstar
AR80 |
Opticstar
AR90S |
| Optics |
ED Triplet |
ED Triplet |
ED Triplet |
Doublet-achromat |
Doublet-achromat |
| Coatings |
Fully-multicoated |
Fully-multicoated |
Fully-multicoated |
Fully-multicoated |
Fully-multicoated |
| Aperture |
80mm |
102mm |
127mm |
80mm |
90mm |
| Focal Length |
480mm |
714mm |
952.5mm |
600mm |
500mm |
| Focal Ratio |
f/6 |
f/7 |
f/7.5 |
f/7.5 |
f/5.5 |
| Focuser Type |
2-speed Crayford |
2-speed Crayford |
2-speed Crayford |
Rack & pinion |
2" Crayford |
| Focuser Drawtube |
2" with 1.25" adapter |
2" with 1.25" adapter |
2" with 1.25" adapter |
1.25" with T-thread |
2" with 1.25" adapter |
| Focuser Design |
Fixed |
Fixed |
Fixed |
Fixed |
Fixed |
| Focus Travel |
12cm |
12cm |
12cm |
14cm |
7cm |
| Baffles |
Knife-edge |
Knife-edge |
Knife-edge |
Knife-edge |
Knife-edge |
| Tube (LxWxH) |
38x9x9cm |
59x13x13cm |
85x16x16cm |
49.5x10.5x10.5cm |
40x10.5x10.5cm |
| Length with extended dew-shield |
48cm |
74cm |
106.5cm |
58cm |
49cm |
| Focuser assembly width |
15cm |
15cm |
15cm |
9.5cm |
15cm |
| Weight w/supplied rings & dovetail |
-- |
5kg |
7.5kg |
-- |
-- |
| Weight w/supplied rings |
-- |
-- |
-- |
2.1kg |
2.2kg |
| Weight w/ 1/4" tripod support |
-- |
-- |
-- |
-- |
-- |
| Weight w/ dovetail |
2.75kg |
-- |
-- |
-- |
-- |
| Finder scope and bracket |
-- |
8x50 illuminated |
8x50 illuminated |
-- |
-- |
| Dielectric 2” diagonal & 1.25” adapter |
99% reflectivity |
99% reflectivity |
99% reflectivity |
-- |
-- |
| Wide-angle 70° 1.25" eyepieces |
10mm & 20mm |
10mm & 20mm |
10mm & 20mm |
-- |
-- |
| Case |
Aluminium |
Aluminium |
Aluminium |
Nylon, padded |
Nylon, padded |
|
|
|
Notice
|
We are constantly checking the accuracy of the technical data. We are prepared
to provide more detailed information on request. Technical data is subject to
change without notice.
|
|
|
|
|
