Optical reference

Celestron AstroMaster 130EQ: aperture, focal length and eyepiece fit

What the Celestron AstroMaster 130EQ measures, the magnification and true field each eyepiece produces in it, and the barrel, mount payload and camera adapter that fit.

Published specifications

Aperture
130 mm (5.12 in)
Focal length
650 mm
Focal ratio
f/5
Optical design
Newtonian reflector (spherical primary)
Focuser / eyepiece barrel
1.25 in rack-and-pinion focuser
Mount
CG-3 German equatorial
Highest useful magnification (published)
307x

Eyepiece ladder

2 pairings

The 130EQ is a fast 130 mm f/5 Newtonian on a light equatorial mount. The short 650 mm focal length gives wide, bright fields at low power but demands short eyepieces for high magnification, and its spherical mirror softens the very highest powers.

Because magnification is the telescope's 650 mm focal length divided by the eyepiece focal length, a 25 mm eyepiece gives 26x here and a 10 mm eyepiece gives 65x. The highest useful magnification is the published 307x, beyond which the image dims and softens without showing more detail.

The focuser takes 1.25 in eyepieces, so use 1.25 in eyepieces; a long low-power 2 in eyepiece will not fit this focuser.

Match an eyepiece, mount or camera