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Deneb

DENEB (ALPHA (α) CYGNI)
BLUE STAR

Right Ascension:
20h 41m 26s

Best Seen:
7/1-12/15

Declination:
45º 16' 49"

Magnitude:
1.25

Computer File:
deneb

Constellation:
Cygnus

Actual

Compared to Sun

Distance

3,230 l.y.

--

Actual Brightness

--

80,000

Surface Temperature

~ 18,000 ºF

~ 1.8

Diameter

~ 147 million miles

~ 170

Mass

--

--

Surface Gravity

--

--

Surface Composition (by mass)

74% hydrogen 24% helium 2% everything else

same

Spectral Type

A2 lae

G2 V

Density (gram/cubic cm)

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WHAT TO LOOK FOR THROUGH THE TELESCOPE:

  1. Recommended eyepiece: 24mm or 40 mm.

  2. When people look through the telescope a bright bluish point of light should be seen.

DENEB INFORMATION:

  1. Deneb is the 14th brightest star in the Northern Hemisphere’s night sky (19th brightest in the night sky when including Southern Hemisphere’s bright stars).

  2. Deneb radiates nearly 80,000 times as much energy as our sun does! Yet because it is so very far away, it’s not very bright in the sky.

Item
Updated Notes

Coordinates 07-15-2002
SIMBAD

Distance
07-15-2002
from 1,600 ly to 3,230 ly (Hipparcos)

Actual Brightness
10-18-2002
see the addendum to Scott’s The Flamsteed Collection

Surface Temperature 07-15-2002
with approx. temp. 10,000K for A stars

Diameter
07-15-2002
with approx. temp. 10,000K for A stars; and luminosity 244,000 times the sun

Mass
07-15-2002
previously said 25 times that of sun

Surface Gravity –

Surface Composition 01-06-2003
OK for all stars

Spectral Type
07-15-2002
from A2 Ia to A2 Iae (SIMBAD)

Other Information
07-15-2002 07-22-2002
1. added #2. why Deneb not so bright 2. with Hipparcos, brightness “rank”

Composition 7/30/13 Changed to 74% / 24% / 2%