36 Andromedae — Double Star in Andromeda

Observable Double Star Fair (31/100)

Sep: 1.1", Companion: mag 6.5

Magnitude 5.5^m DoubleStar Andromeda (And) Visible

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Observe

1Physical Properties

Magnitude 5.47

Spectral Type K1IV subgiant

Star Color Orange (B-V 1.00)

Distance 148 ly

2Position & Identifiers

RA 00h 54m 58.0s

Dec +23° 37' 42.0"

Constellation Andromeda (And)

HR 258

HIP 4288

HD 5286

SAO 74359

Flamsteed 36 And

Double Cat 755

3How easy to split?

Primary 5.5 mag Companion 6.5 mag Separation 1.1″

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

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 Triple D: optical

Components 3 (triple)

Component IDs AB

Separation 1.1″

Companion Mag 6.5

Position Angle 338°

Star Colors A: Orange

Discoverer STF 73

Notes

AB 6.02 G6IV, 6.41 K6IV, 164.68y, a = 1.014". Resolved by speckle interferometry 1983.94, sep. 0.68". Combined | mag., colors.

Separation over time

Period: 3.2 y Eccentricity: 0.306 Now: 1.1", PA 21° -0.31" in 5 years

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

Eyepiece View

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80x Dawes: 1.9″ TFOV: 0.6°

Seeing

Scale Realistic = true angular size

A: 5.5 · B: 6.5 · Sep: 1.1″ · PA: 338° · N up, E right

Unresolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″

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6

Size Comparison

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8

Spectral Classification

9

Hertzsprung-Russell Diagram

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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

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14

Light Travel Time Machine

15

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.

HIP 5131; Psi1 Piscium; 74 Piscium

Easy double, sep 29.8″

Double Star mag 5.34 3.3° Pisces

Colorful double, sep 6.8″

Double Star mag 5.36 4.1° Pisces

Bright spiral galaxy

Galaxy mag 12.4 4.3° Andromeda

Semi-regular variable, range 4.7–5.4

Variable Star mag 5.06 8.5° Pisces

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