Alcor — Double Star in Ursa Major
HIP 65477; 80 Ursae Majoris
Observe
1Physical Properties
Magnitude
4.01
Range
4.00 - 4.01
Period
0.9 hours
Variable Type
Delta Scuti (Pulsating)
Spectral Type
A5V
Star Color
Yellow-white
(B-V 0.16)
Distance
72 ly
2Position & Identifiers
RA
13h 25m 13.5s
Dec
+54° 59' 17.0"
Constellation
Ursa Major
(UMa)
HR
5062
HIP
65477
HD
116842
SAO
28751
Flamsteed
80 UMa
Querying VizieR catalog...
3How easy to split?
Primary
4.0 mag
Companion
6.9 mag
Separation
1.0″
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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. | V. hard+ | V. hard+ | V. hard+ |
| Celestron C8 (203 mm SCT) C8 203mm | Hard | Hard | Hard |
Easy
Medium
Hard
Very hard
Impossible
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
To reach "Medium" at Bortle 3, you'd need at least a 320 mm reflector.
4Visibility
Set a location in User Settings to see visibility data.
Best season
Mar – May
(peak: Apr)
5Light Curve
6Multiple Star System D: optical
Separation
1.0″
Companion Mag
6.9
Companion Sp
G1Va
Position Angle
317°
Star Colors
A: Yellow-white
B: Yellow
Discoverer
SHY 248
CPM with HR 5054-5.
Eyepiece View
80x
Dawes: 1.9″
TFOV: 0.6°
Realistic = true angular size
A: 4.0 · B: 6.9 · Sep: 1.0″ · PA: 317° · N up, E right
Unresolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
8
Size Comparison
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9
Compare Stars
10
Spectral Classification
11
Hertzsprung-Russell Diagram
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12
Stellar Lifecycle
13
Blackbody Spectrum
14
Stellar Absorption Spectrum
Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.
15
Stellar Fusion
Discover
16Stellar Notes
Delta Sct.
"Dipper Stars;" Sirius group; UMa stream; UMa moving cluster.
ALCOR; Saidak.
17
Light Travel Time Machine
18
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.
Mizar
Zeta UMa (BS5054)
Colorful double, sep 14.4″
Double Star
mag 2.27
0.2°
Ursa Major
NGC 5204
Bright spiral galaxy
Galaxy
mag 11.3
3.5°
Ursa Major
Kappa Boo
HIP 69483; Kappa2 Bootis; 17 Bootis
Easy double, sep 13.7″
Double Star
mag 4.54
7.9°
Boötes
Iota Boo
Colorful double, sep 38.8″
Double Star
mag 4.75
8.4°
Boötes
TU CVn
Semi-regular variable, range 5.5–6.6
Variable Star
mag 5.84
9.1°
Canes Venatici
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