U Delphini — Variable Star in Delphinus
Excellent (60/100)
Observe
1Physical Properties
Magnitude
6.38
Range
6.14 - 7.61
Period
120 days
Variable Type
Semi-Regular Variable (Late-type Giant)
Spectral Type
M5II-III
bright giant
Star Color
Red
(B-V 1.68)
2Position & Identifiers
RA
20h 45m 28.2s
Dec
+18° 05' 25.0"
Constellation
Delphinus
(Del)
HR
7941
HIP
102440
HD
197812
SAO
106458
Variable ID
U Del
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3How easy to follow?
Magnitude
6.1 – 7.6 mag
Amplitude
1.5 mag
Period
120 d
Type
SRB
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| Equipment | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| Naked eye Naked eye | V. hard | Imp. | Imp. |
| 50 mm finder 50mm finder | Easy | Medium+ | Medium+ |
| 150 mm telescope 150mm scope | Easy | Easy | Easy |
Easy
Medium
Hard
Very hard
Impossible
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
Best season
Jun – Aug
(peak: Jul)
5Survey Image
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6Light Curve
7Comparison Stars for U Del (6.1–7.6)
Nearby stable stars for estimating brightness (AAVSO)
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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
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16Stellar Notes
SRb 7.6 - 8.9p, 110d or 160 - 180d. Mean mag. varies in period 1100d. Amp. 0.26V, 0.04(B-V), 0.19(U-B).
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.
EU Del
Semi-regular variable, range 5.8–6.9
Variable Star
mag 6.25
1.8°
Delphinus
Gamma Del
HIP 102531; Gamma1 Delphini; 12 Delphini
Colorful double, sep 9.8″
Double Star
mag 5.14
2.0°
Delphinus
C42
NGC 7006
Globular cluster — dense ball of ancient stars
Globular Cluster
mag 10.6
4.3°
Delphinus
22 Vul
Observable variable star
Variable Star
mag 5.15
8.9°
Vulpecula
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Article
Delphinus
Mythology, bright stars, and deep-sky highlights.
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