Cometron Firstscope

Optical Design

Newtonian Reflector

Aperture (mm)

76 mm (2.99 in)

Telescope Type

Manual

Focal Length

300 mm (12 in)

Focal Ratio

3.95

Focal Length of Eyepiece 2 (mm)

Kellner 10 mm (0 in)

Finderscope

5x24

Tripod

None

Highest Useful Magnification

180 x

Lowest Useful Magnification

11 x

Limiting Stellar Magnitude

11.9

Resolution (Rayleigh)

1.83 arc seconds

Resolution (Dawes)

1.53 arc seconds

Light Gathering Power (Compared to human eye)

118 x

Secondary Mirror Obstruction

1.1 in (28 mm)

Secondary Mirror Obstruction by Diameter

37%

Secondary Mirror Obstruction by Area

14%

Optical Coatings

Aluminum with SiO2

Optical Tube Length

10 in (254 mm)

Total Telescope Kit Weight

4.3 lbs (1.95 kg)

Warranty

2-year Telescope Warranty