Celestron StarSense Explorer DX 102AZ: 102 mm aperture, 660 mm focal length, f/6.5, Achromatic refractor. The magnification, true field and exit pupil each eyepiece gives, and the barrel, mount and camera adapter that fit.

Updated 05 September 2026.

Optical reference

Celestron StarSense Explorer DX 102AZ: aperture, focal length and eyepiece fit

What the Celestron StarSense Explorer DX 102AZ measures, the magnification and true field each eyepiece produces in it, and the barrel, mount payload and camera adapter that fit.

Published specifications

Aperture
102 mm (4.02 in)
Focal length
660 mm
Focal ratio
f/6.5
Optical design
Achromatic refractor
Focuser / eyepiece barrel
1.25 in focuser with a 90-degree star diagonal
Mount
Altazimuth with slow-motion control (StarSense phone dock)
Highest useful magnification (published)
241x

Eyepiece ladder

2 pairings

The DX 102AZ is a 102 mm f/6.5 achromatic refractor with phone-guided star finding. The 660 mm focal length is short for a refractor, so it frames wide fields at low power and needs short eyepieces for planetary magnification.

Because magnification is the telescope's 660 mm focal length divided by the eyepiece focal length, a 25 mm eyepiece gives 26x here and a 10 mm eyepiece gives 66x. The highest useful magnification is the published 241x, 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

Questions and answers

What is the aperture of the Celestron StarSense Explorer DX 102AZ?

102 mm (4.02 in)

What is the focal length of the Celestron StarSense Explorer DX 102AZ?

660 mm

What is the focal ratio of the Celestron StarSense Explorer DX 102AZ?

f/6.5

What is the optical design of the Celestron StarSense Explorer DX 102AZ?

Achromatic refractor