Zeta Coronae Borealis — Double Star in Corona Borealis

HIP 76669; Zeta1 Coronae Borealis; 7 Coronae Borealis

Observable Double Star Excellent (64/100)

Sep: 6.4", Companion: mag 5.9

Magnitude 6.0^m DoubleStar Corona Borealis (CrB) Visible

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Observe

1Physical Properties

Magnitude 6.00

Spectral Type B9V

Distance 217 ly

2Position & Identifiers

RA 15h 39m 22.2s

Dec +36° 38' 12.0"

Constellation Corona Borealis (CrB)

HR 5833

HIP 76669

HD 139891

SAO 64833

Bayer Zeta1

Flamsteed 7 CrB

Double Cat 9737

SIMBAD Wikipedia

3How easy to split?

Primary 6.0 mag Companion 5.9 mag Separation 6.4″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Easy
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

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Best season Apr – Jun (peak: May)

5Multiple Star System

Separation 6.4″

Companion Mag 5.9

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

Notes

Binary with HR 5834. Colors for combined light; combined mag., 66V.

Eyepiece View

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80x Dawes: 1.9″ TFOV: 0.6°

Seeing

Scale Realistic = true angular size

A: 6.0 · B: 5.9 · Sep: 6.4″ · PA: ? · N up, E right

Resolved · 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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14Stellar Notes

Dynamical

0.010".

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.

HIP 76669; Zeta2 Coronae Borealis; 7 Coronae Borealis

Easy double, sep 6.3″

Double Star mag 5.07 0.0° Corona Borealis

HIP 75411; Mu Bootis; 51 Bootis

Easy double, sep 109.2″

Double Star mag 4.31 3.1° Boötes

Elliptical galaxy

Galaxy mag 12.91 6.9° Boötes

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