It is a dark and elongated asteroid from the middle region of the asteroid belt, 39 kilometers in diameter. It was discovered on 5 May 1935, by Dutch astronomer Hendrik van Gent at the Leiden Southern Station, annex to the Johannesburg Observatory in South Africa
It is named after the Danish chemist and astronomer Ejnar Hertzsprung (1873–1967), known for the famous Hertzsprung–Russell diagram ( Together with American astronomer Henry Norris Russell ).

https://en.wikipedia.org/wiki/1693_Hertzsprung

p (14 September 1899 – March 29 1947) was a Dutch astronomer. He moved to South Africa in 1928 in order to observe the southern sky.
He obtained his PhD from Leiden University in 1931. He studied variable stars and also discovered three comets, C/1941 K1, C/1944 K2 and C/1943 W1 and 39 asteroids during 1929–1935.
The crater Van Gent on the far side of the Moon, and the asteroid 1666 van Gent are named after him.

https://en.wikipedia.org/wiki/Hendrik_van_Gent

Sun distance (au): 2.995 Mag. 18.9

Time: 02:41UT 2026-09-27 Exp.35 x 120sec. IR filter
Tel: C14 @ f/6.6 Camera ASI 174 MM Mini Mono @ +11°C 1"/pix Paramount GT-1100S
Odd Trondal Obs.code 238 (Uranium). Oslo Norway