The AsterNym star registry
Sadr
Sadr: the yellow-white star of Cygnus
yellow-white · Cygnus · γ Cyg
Sadr is a yellow-white star, a near cousin of our own Sun's colour in the constellation Cygnus, one of the stars with a proper name recognised in the IAU Catalog of Star Names. At magnitude 2.23 it is visible to the naked eye under a dark sky.
Most stars in the sky are anonymous points of light. Sadr is not. Some IAU-recognised names are ancient; others were adopted by the IAU only recently. Either way, the star already has a scientific identity, and a dedication attaches a human story to it.
Real star · Personal dedication · Recorded in the AsterNym registry
See what a dedicated page looks like: preview
Sadr at a glance
- Constellation
- Cygnus
- Other name
- γ Cyg
- Catalogue number
- HIP 100453
- Distance
- ≈ 1,800 light-years
- Brightness
- Magnitude 2.23 naked-eye
- Star type
- F8 Ib
- Colour
- yellow-white
- Best seen from
- The Northern Hemisphere and lower southern latitudes
- Right ascension
- 20h 22m 14s
- Declination
- +40° 15′ 24″
J2000 catalogue coordinates that can be independently cross-checked against astronomical databases. A planetarium app showing coordinates of date will differ slightly, because proper motion and precession move a star’s apparent position over time.
What kind of star is Sadr?
Sadr is a yellow-white supergiant. Its surface runs about 6,000 to 7,500°C, a shade hotter than the Sun. Colour in a star is a temperature reading rather than a decoration: the hot ones are blue and the cool ones red, the opposite way round to a kitchen tap.
Its colour is not the whole story. A yellow-white star still in the steady part of its life would burn for two to four thousand million years. This one is past that stage, and it is cool at the surface because it has swollen outward, not because it was born this way.
It is a supergiant, which means it has left the stable part of its life and swollen enormously. Put it where the Sun is and its surface would swallow the inner planets. Stars this size do not fade quietly; this one will end as a supernova, and on a human timescale that could be tonight or in a million years.
The light you are looking at is old
Sadr is about 1,800 light years away, so the light reaching you now set out around 226. You are not looking at the star as it is. You are looking at the star as it was, and there is no way to see it any other way.
That delay is the part people find hardest and like most. A star is the one thing you can give someone that was already old before either of you was born and will outlast anything else you could have chosen.
It is comfortably visible without equipment on a decent night.
What could a Sadr dedication represent?
Sadr is especially meaningful for someone who:
- · Deserves something older than any gift shop
- · Marks a beginning, an anniversary or a promise
- · Is remembered every time you look up
- · Has a light you want recorded somewhere permanent
Dedication idea
“For the one I think of when I find Cygnus in the sky.”
Where can you see Sadr?
It is easy to see from most of the Northern Hemisphere. It can also appear from lower southern latitudes, but it never rises for observers south of about latitude 50°S. It passes directly overhead at latitude 40°N. It stands highest at midnight in July, so July and August evenings are the best time to look. At magnitude 2.23 it is an easy naked-eye star from any reasonably dark spot.
Sadr belongs to Cygnus.
What does Sadr mean in astrology?
The classical fixed-star tradition: Ptolemy, the medieval Behenian lists, Robson’s 1923 compilation. Is silent on Sadr, and we don’t invent lore where none exists. What astrology can still read is the star’s real position, below.
Projected onto the zodiac the way fixed-star astrology reads any star, Sadr stands at 24° Aquarius at the J2000 epoch, and the Sun passes that degree around 13 February in the years around 2000. Fixed-star longitude shifts slowly against the tropical zodiac because of precession, about one degree every seventy-two years, so a natal conjunction must be calculated for the birth year rather than read off this J2000 value or a calendar date.
Traditional interpretations, not facts or predictions. The position and dates are computed.
Dedicate Sadr to someone who matters
A flower fades. A card is eventually put away. A star gives your message a place in the sky.
from$29.95a year
Dedicate Sadr →Real star · your message · a page to share
Your Sadr dedication includes
- Your chosen dedication name
- Your personal message
- Sadr's real astronomical coordinates
- A shareable dedication page
- Its location on the AsterNym Galaxy Map
- An optional printable certificate and gift presentation
Sadr keeps its established astronomical name. Your dedication is a personal commemorative record within the AsterNym registry.
Frequently asked questions about Sadr
- What does Sadr mean in astrology?
- The classical fixed-star tradition has no documented meaning for Sadr. Projected onto the zodiac, Sadr stands at 24° Aquarius, and the Sun passes that degree each year around 13 February.
- Is Sadr the brightest star?
- Sadr shines at magnitude 2.23 · visible to the naked eye on a clear night, one of the few thousand stars with an officially recognised name.
- How far away is Sadr?
- Sadr is approximately 1,800 light-years from Earth. The light reaching us tonight began its journey around 1,800 years ago.
- Which constellation contains Sadr?
- Sadr is part of Cygnus.
- Can everyone see Sadr?
- It is easy to see from most of the Northern Hemisphere. It can also appear from lower southern latitudes, but it never rises for observers south of about latitude 50°S. It passes directly overhead at latitude 40°N. It stands highest at midnight in July, so July and August evenings are the best time to look. At magnitude 2.23 it is an easy naked-eye star from any reasonably dark spot.
- Is dedicating Sadr an official astronomical renaming?
- No. Sadr keeps its internationally recognised astronomical name. An AsterNym dedication records your personal name and message in the AsterNym registry without changing the star's scientific identity.
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