Yildun — Double Star in Ursa Minor
HIP 85822; Delta Ursae Minoris; 23 Ursae Minoris
Observe
1Physical Properties
Magnitude
4.36
Spectral Type
A1Vn
Star Color
White
(B-V 0.02)
Distance
815 ly
2Position & Identifiers
RA
17h 32m 12.9s
Dec
+86° 35' 11.0"
Constellation
Ursa Minor
(UMi)
HR
6789
HIP
85822
HD
166205
SAO
2937
Bayer
Delta
Flamsteed
23 UMi
Querying VizieR catalog...
3How easy to split?
Primary
4.4 mag
Companion
11.8 mag
Separation
4.5″
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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 | V. hard+ | V. hard+ | V. 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 450 mm reflector.
4Visibility
Set a location in User Settings to see visibility data.
Best season
May – Jul
(peak: Jun)
5Multiple Star System
Separation
4.5″
Companion Mag
11.8
Position Angle
67°
Star Colors
A: White
Discoverer
DRS 59
Eyepiece View
80x
Dawes: 1.9″
TFOV: 0.6°
Realistic = true angular size
A: 4.4 · B: 11.8 · Sep: 4.5″ · PA: 67° · N up, E right
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
7
Size Comparison
Querying VizieR for stellar data…
8
Compare Stars
9
Spectral Classification
10
Hertzsprung-Russell Diagram
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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
Yildun; Vildiur; Gildun.
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.
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