When is the best time to observe Sador?

Sador is best observed from June through August, with peak visibility during July when it transits around midnight in the Northern Hemisphere.

Where is Sador located in the sky?

Sador lies in the constellation Cygnus at right ascension 20h 22m and declination +40° 15′.

What telescope do I need to split Sador?

Splitting Sador requires an aperture of roughly 60 mm or larger — the components are separated by about 141.2″ at magnitudes near 2.2. The companion is about 8.8 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Sador — Double Star in Cygnus

HIP 100453; Gamma Cygni; 37 Cygni

Magnitude 2.2^m DoubleStar Cygnus (Cyg) Visible

Star Map + List + Plan

About Sador

Description

Sadr is a yellow-white supergiant of spectral type F8Ib at magnitude 2.20 in Cygnus. Located about 1,800 light-years from Earth, it has a luminosity of roughly 33,000 times solar. Sadr sits at the center of the Northern Cross asterism, surrounded by some of the richest star fields and nebulae in the Milky Way.

Observing Tips

Sadr marks the intersection of the Northern Cross in Cygnus — the point where the crossbar meets the main beam. The surrounding Milky Way is spectacular in binoculars, with the Gamma Cygni Nebula (IC 1318) and the Crescent Nebula (NGC 6888) nearby. Best observed June through November when Cygnus is high overhead.

History

The name Sadr comes from the Arabic 'sadr al-dajajah,' meaning 'the breast of the hen.' Its position at the heart of the Northern Cross has made it a natural reference point for centuries. The surrounding emission nebula complex IC 1318 is sometimes called the Butterfly Nebula or Sadr Region.

Fun Facts

The region around Sadr is one of the richest areas of the Milky Way for astrophotography. The Gamma Cygni Nebula (IC 1318) forms a stunning butterfly-shaped emission complex around the star, though Sadr itself is actually in the foreground, not physically associated with the nebula.