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Delta Trianguli — Star in Triangulum

Magnitude 4.9m Star Triangulum (Tri) Visible
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Observe

1Physical Properties

Magnitude 4.87
Spectral Type G0.5V
Star Color Yellow (B-V 0.61)
Distance 35 ly

2Position & Identifiers

RA 02h 17m 03.2s
Dec +34° 13' 27.0"
Constellation Triangulum (Tri)
HR 660
HIP 10644
HD 13974
SAO 55420
Bayer Delta
Flamsteed 8 Tri
Double Cat 1739
SIMBAD

3How easy to spot?

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Equipment Bortle 3 Bortle 4 Bortle 5
Naked eye Medium+ Medium Hard+
50mm finder Easy Easy Easy
150mm scope Easy Easy Easy
Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season Sep – Nov (peak: Oct)

5Survey Image

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Explore

6

Size Comparison

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7

Compare Stars

8

Spectral Classification

9

Hertzsprung-Russell Diagram

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Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map
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

Discover

14Stellar Notes

Probably optical.
ADS 1739A, 10.0201d, K 9.4k/s, V0 -5.9k/s, asini 1.295.
Zeta Her group.
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.

NGC 890
Medium
Elliptical galaxy
Galaxy mag 12.0 1.4° Triangulum
6 Tri
Easy
Easy double, sep 3.9″
Double Star mag 4.94 4.0° Triangulum
NGC 752
Easy
Scattered bright open cluster
Open Cluster mag 5.7 5.3° Andromeda
Show on Map

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Biography
Triangulum
Mythology, bright stars, and deep-sky highlights.
Constellation
The Hertzsprung-Russell Diagram — Reading Stars Like a Map
The HR diagram turns the night sky into a physics map: every named star has a spot, every spot tells you mass, age, and fate. A guide for amateur observers.
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