Sarin — Double Star in Hercules
HIP 84379; Delta Herculis; 65 Herculis
About Sarin
Description
Sarin is a white subgiant of spectral type A3IV at magnitude 3.14 in Hercules. Located about 75 light-years from Earth, it has a luminosity of roughly 26 times solar. It is a spectroscopic binary with a period of about 10 years. Sarin forms the southwestern corner of the Keystone asterism.
Observing Tips
Sarin marks one of the four corners of the Keystone in Hercules — the trapezoidal asterism used to find the great globular cluster M13. M13 lies along the western side of the Keystone, between Sarin and Eta Her. Best observed May through September.
History
The name Sarin is of uncertain origin. The Keystone asterism is the most important feature of Hercules for amateur astronomers, as it serves as the guide to finding both M13 and M92, two magnificent globular clusters.
Fun Facts
M13, the Great Hercules Cluster, lies about one-third of the way from Eta Her to Sarin along the Keystone's western edge. This makes Sarin one of the most useful guide stars in all of amateur astronomy.
Observe
1Physical Properties
2Position & Identifiers
3How easy to split?
| Telescope | Bortle 3 | Bortle 4 | Bortle 5 |
|---|---|---|---|
| 80 mm refractor 80mm refr. | Medium+ | Medium+ | Medium+ |
| 150 mm Newton 150mm Newt. | Easy | Easy | Easy |
| Celestron C8 (203 mm SCT) C8 203mm | Easy | Easy | Easy |
Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs
4Visibility
Set a location in User Settings to see visibility data.
5Light Curve
6Multiple Star System Quadruple optical
Separation over time
Apparent motion is significant on a human timescale — worth revisiting in a decade.
Measured from the WDS observational archive. No orbital solution has been derived — most likely the period is too long to fit an orbit to the available measurement arc.
Eyepiece View
A: 3.1 · B: 8.3 · Sep: 14.0″ · PA: 293° · N up, E right
Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″
Explore
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Size Comparison
9
Compare Stars
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Spectral Classification
11
Hertzsprung-Russell Diagram
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
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.
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