Aperture
72 mm
Small aperture, chosen on purpose. It shows the Moon, the brighter planets as small sharp discs, and rich wide star fields, and it collects enough light for real deep-sky imaging on long exposures. For visual hunting of faint galaxies, a Dobsonian several times its price will show far more.
Focal length
430 mm
Short and wide. On an APS-C camera this frames the whole Andromeda Galaxy, the North America Nebula or the Pleiades in one shot, which is the classic beginner astrophotography field. Visually it is a low-power rich-field scope rather than a planetary one.
Focal ratio
f/6
Fast enough that deep-sky exposures build signal quickly and short enough that small tracking errors stay hidden. That combination is why a 72 mm f/6 is the standard first imaging telescope. Add the matching flattener to keep stars round in the corners.
Optical design
ED doublet
Two elements, one of them ED glass, which controls the violet fringing that plagues cheap achromats. At f/6 a doublet leaves a trace of colour on the brightest stars where a triplet would not. In exchange it cools fast, holds collimation, and costs a fraction of a triplet.
Weight
2.4 kg tube
Around 5 lb. It fits in a backpack with a camera and rides comfortably on a star tracker, so this is the scope that actually travels to dark skies instead of staying in the garage.
Mount
OTA only
You supply the mount. Its light weight means a star tracker or a small equatorial is enough, which keeps the total cost of an imaging setup unusually low for this class.