SKY-WATCHER ESPRIT 100 ED Super APO, Instruction Manual, Page: 12 / 13

11
Specifications
Telescope specifications
Optical Design Refractor (air-spaced triplet APO)
Field Flattener Thread-on (2 lenses)
Aperture (mm) 80 mm (3.15 in)
Focal Length 400 mm (15.75 in)
Focal Ratio 5
Finderscope 9x50, erect-image, right-angle
Diagonal 2" dielectric coatings
Dovetail EQ5(Vixen style) dovetail plate
Highest Useful Magnification 180 x
Lowest Useful Magnification 11 x
Limiting Stellar Magnitude 11.6
Resolution (Rayleigh) 1.74 arc seconds
Resolution (Dawes) 1.45 arc seconds
Light Gathering Power (Compared to Human Eye) 131 x
Optical Coatings Fully multi-coated
Fully Illuminated Field With Field Flattener 33 mm (1.3 in)
Optical Tube Length 44.6 cm (17.6 in)
Optical Tube Weight 4.05 kg (9 lbs)
Telescope Visual Backfocus
∗
> 160mm (6.3 in)
Field Flattener Backfocus
**
61mm (2.4 in)
Threads specifications
Rings/
Threads Focuser
Tube
Drawtube
Adaptor
Field
Flattener
DSLR
Ext. Tube
Enlarged
T-Ring
In
Ø
n/a M74x1 F. M65x1 F. M66x1 F. M48x0.75 F.
In screw depth n/a 7 mm 8 mm 6 mm variable
Out
Ø
M74 x1 M M65x1 M. M66x1 M. M48x0.75 M Camera
Out screw depth
6 mm 6 mm 5 mm 5.9 mm n/a
∗
The visual back focus of the telescope is the distance from the end of the focuser tube (with 2’’ adapter
installed) to the focal plane. This means, all accessories needing 160mm back focus or less can be installed.
**
The back focus of the field flattener is the distance from the back of the field flattener to the focal plane.