When is the best time to observe Miram?

Miram is best observed from September through November, with peak visibility during October when it transits around midnight in the Northern Hemisphere.

Where is Miram located in the sky?

Miram lies in the constellation Perseus at right ascension 02h 51m and declination +55° 54′.

What telescope do I need to split Miram?

Splitting Miram requires an aperture of roughly 60 mm or larger — the components are separated by about 28.7″ at magnitudes near 3.8. The companion is about 4.7 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Miram — Double Star in Perseus

Eta Per

Observable Double Star Excellent (72/100)

Sep: 28.7", Companion: mag 8.5

Magnitude 3.8^m DoubleStar Perseus (Per) Visible

Star Map + List + Plan

About Miram

Description

Miram, Eta Persei, is a K-type supergiant of spectral class K1 III about 876 light-years away. With a mass around 6 Suns and a luminosity of about 1,100 Suns, Miram is a rich amber-colored naked-eye star at magnitude 3.76. It has a visual companion, Eta Per B, at 28 arcseconds separation — a physically associated G-type dwarf.

Observing Tips

Miram forms the sword-hand of Perseus and is an ideal binocular target: the companion star is well-separated from the bright primary, showing a striking color contrast with the orange giant. A small telescope at 50x reveals both stars distinctly. Miram is a few degrees northwest of the Double Cluster (NGC 869/884) — the two targets pair well in a single observing session. Best observed September through February.

History

The name Miram is a later Latin name with uncertain origin, possibly from Arabic via medieval European manuscripts. The Double Cluster region has been an important celestial landmark since antiquity.

Fun Facts

Miram's proximity to the Double Cluster in Perseus makes it a natural signpost for amateur astronomers sweeping the Persian section of the Milky Way. The companion at 28 arcseconds is a genuine physical pair, sharing a common proper motion — one of the few wide visual binaries in this region of the sky.

Observe

1Physical Properties

Magnitude 3.76

Spectral Type K1III giant

Star Color Red (B-V 1.68)

Distance 876 ly

2Position & Identifiers

RA 02h 50m 41.8s

Dec +55° 53' 44.0"

Constellation Perseus (Per)

HR 834

HIP 13268

HD 17506

SAO 23655

Bayer Eta

Flamsteed 15 Per

Double Cat 2157

SIMBAD Wikipedia

3How easy to split?

Primary 3.8 mag Companion 8.5 mag Separation 28.7″

Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Medium+
150 mm Newton 150mm Newt.	Easy	Easy	Easy
Celestron C8 (203 mm SCT) C8 203mm	Easy	Easy	Easy

Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

Set a location in User Settings to see visibility data.

Best season Sep – Nov (peak: Oct)

5Multiple Star System Sextuple C,E,F: optical

Components 6 (sextuple)

Component IDs AB

Separation 28.7″

Companion Mag 8.5

Companion Sp B9V

Position Angle 301°

Star Colors A: Red B: Blue-white

Discoverer STF 307

Notes

Component B, B9V, CPM, vsini 149k/s.

Separation over time

Measured 1779 → 2018 (239 y)

Separation drift 26.0" → 28.7" (+2.70")

Rate +0.0113" / y

PA drift 290° → 301° (+11°, +0.046°/y)

Slow change over generations — observable in lifetime comparisons.

Measured from the WDS observational archive. No orbital solution has been derived — most likely the period is too long to fit an orbit to the available measurement arc.