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Alpha Monocerotis — Star in Monoceros

Magnitude 3.9m Star Monoceros (Mon) Visible
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Observe

1Physical Properties

Magnitude 3.93
Spectral Type K0 III giant
Star Color Orange (B-V 1.02)
Distance 148 ly

2Position & Identifiers

RA 07h 41m 14.8s
Dec -09° 33' 04.0"
Constellation Monoceros (Mon)
HR 2970
HIP 37447
HD 61935
SAO 134986
Bayer Alpha
Flamsteed 26 Mon
SIMBAD

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Easy Medium+ Medium
50mm finder Easy Easy Easy
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 Dec – Feb (peak: Jan)

5Survey Image

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7

Size Comparison

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8

Compare Stars

9

Spectral Classification

10

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
11

Stellar Lifecycle

12

Blackbody Spectrum

13

Stellar Absorption Spectrum

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

14

Stellar Fusion

Discover

15Stellar Notes

In early catalogues called Gamma Mon; HR 2227 now called Gamma, was Alpha in BAC and numerous older | catalogues.
16

Light Travel Time Machine

17

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.

Melotte 72
Easy
Open cluster
Open Cluster mag 10.1 1.3° Puppis
NGC 2438
Hard+
Planetary nebula — try an OIII filter
Planetary Nebula mag 10.0 5.2° Puppis
NGC 2517
Hard+
Bright spiral galaxy
Galaxy mag 12.3 6.0° Puppis
Show on Map

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Monoceros
Mythology, bright stars, and deep-sky highlights.
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