Lambda Cassiopeiae — Double Star in Cassiopeia

Magnitude 4.7^m DoubleStar Cassiopeia (Cas) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.73

Spectral Type B8Vn

Star Color Blue-white (B-V -0.10)

Distance 109 ly

2Position & Identifiers

RA 00h 31m 46.4s

Dec +54° 31' 20.0"

Constellation Cassiopeia (Cas)

HR 123

HIP 2505

HD 2772

SAO 21489

Bayer Lambda

Flamsteed 14 Cas

Double Cat 434

3How easy to spot?

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Equipment	Bortle 3	Bortle 4	Bortle 5
Naked eye Naked eye	Medium+	Medium	Hard+
50 mm finder 50mm finder	Easy	Easy	Easy
150 mm telescope 150mm scope	Easy	Easy	Easy

Easy Medium Hard Very hard Impossible

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

4Visibility

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Best season Aug – Oct (peak: Sep)

5Multiple Star System

Separation 0.1″

Companion Mag 5.6

Companion Sp B9V

Position Angle 239°

Star Colors A: Blue-white B: Blue-white

Discoverer STT 12

Notes

5.5 B7.5V, 5.8 B8.5V, 640y, a = 0.586". Combined mag. and colors. Components 14 and 13 solar masses.

Separation over time

Period: 245.7 y Eccentricity: 0.689 Now: 0.11", PA 343° + 0.06" in 5 years

Apparent separation over time, computed from ORB6 orbital elements. Steep curves indicate fast-changing pairs — catch them while they're splittable.

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6

Size Comparison

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Compare Stars

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8

Spectral Classification

9

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map

10

Stellar Lifecycle

11

Blackbody Spectrum

12

Stellar Absorption Spectrum

Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.

13

Stellar Fusion

Discover

14Stellar Notes

Dynamical

0.004".

15

Light Travel Time Machine

16

Relativistic Travel

Nearby in the Sky

Other targets within a few degrees — pan your scope a little and keep exploring.

Visibility scores assume a 150 mm Newton at Bortle 4.

Emission nebula — try an OIII filter

Emission Nebula mag 7.0 3.7° Cassiopeia

HIP 3821; Eta Cassiopeiae; 24 Cassiopeiae

Colorful double, sep 13.6″

Double Star mag 3.44 4.1° Cassiopeia

Easy double, sep 3.1″

Double Star mag 4.88 4.8° Cassiopeia

Galaxy mag 10.3 5.0° Cassiopeia

Tight double — a rewarding split at 1.5″

Double Star mag 5.96 5.3° Cassiopeia

Caroline's Rose

Rich open cluster

Open Cluster mag 6.7 5.3° Cassiopeia

Semi-regular variable, range 6.8–7.7

Double Star mag 6.90 7.1° Cassiopeia

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