Most Distant Naked-Eye Visible Star
The most distant star visible to the unaided eye has often been claimed to be the red variable star V762 Cas in the constellation of
Cassiopeia. Its magnitude varies from 5.9 to 6.0 (the limit of naked eye star magnitude visibiliity on
a clear night). To provide a simple distance benchmark, the distances in light lears (l.y.) and visual magnitudes of
6 well known bright stars are listed here:
- α Centauri 4 l.y. Mag -0.3
- Sirius 9 l.y. Mag -1.4
- Vega 25 l.y. Mag -0.0
- Aldebaran 65 l.y. Mag 0.9
- Betelgeuse 650 l.y. Mag 0.5
- Rigel 800 l.y. Mag 0.2
- Deneb 3260 l.y. Mag 1.3
This distance range is roughly 3% of the width of our Milky Way galaxy (100,000 l.y.).
The distance to V762 Cas has commonly been quoted to be ~ 16,000 l.y. from our sun, but due to uncertainties in parallax measurement
used to determine its distance, a more reasonable estimate (reference below) is only 4,000 l.y., 5 times the distance of Rigel.
A likely more distant "visible" star is AH Sco at a distance of ~ 7000 l.y. with good certainty, but its magnitude is between 6.5 - 9 which
is just beyond the normal 6.0 magnitude limit. Deneb a member of the winter triangle at a distance of 3260 l.y. is one of the
brightest visible stars due to its very high luminosity with an absolute mag of -7.5!
The images below show the location of V762 Cas:
S23 Ultra photos: Mar 28, 2024 Carleton Place
L: 8:21 pm EDT Pro Mode ISO 400 4"
C: 9:57 pm EDT Pro Mode ISO 800 8"
R: 10:08 pm EDT Astro Mode ISO 1600 2min/15sec
Furthest-Away Star Visible to the Naked Eye
AH Scorpii (Wikipedia)