Messier 23

Date: 2 May 2025

Altitude: 39 - 42 degrees

Angular Size: 1° 00' x 0° 45'

Orientation: North up; East left

Pixel scale: 0.86" per pixel

Total exposure time: 92 minutes

B filter: 50 x 47 seconds

V filter: 50 x 37 seconds

R filter: 44 x 30 seconds

Messier 23 is also known as NGC 6494

Open cluster: ~250 stars

Constellation: Sagittarius

Diameter: 16 light years

Distance: 2,100 light years

Age: 330 million years

Notes

Discovered by Charles Messier in 1764.

The brightest component is magnitude 9.3.

The bright star to the north-west is magnitude 6.5 HIP 87782, at a distance of approximately

330 light years.