Gamma Arietis is an icy-blue double star in the constellation Aries. The pair is best viewed in winter. At a magnitude of 3.86, urban stargazers will be able to see the star with the naked eye, while a small telescope should suffice for viewing both stars.
Between when Ptolemy of Alexandria recorded the constellation Aries in the 2nd century and when Robert Hooke discovered the binary star in 1664, Gamma Areitis’s name underwent some interesting changes before settling on its traditional name, Mesarthim. Read more on the website nineplanets.org. According to several sources, it’s one of the first binary stars to be discovered with a telescope.
My Observations
| Date | February 12, 2022 |
| Time | 7:45 p.m. |
| Location | Seattle, WA |
| Magnification | 169x |
| Scope | Meade 8″ SCT |
| Eyepiece | 12mm |
| Seeing | Above Average |
| Transparency | Above Average |
I’ve started off my evening searching for this pair, and I’m glad I did. As I focus on Gamma A, my mind rings with the words ‘icy blue.” So right away, I’m thinking of the blue pair in 8 Lacerta—the post I refer to as Crystal Blue Persuasion. These are a close double that sparkle with a blue tinge and are well worth the trip through Aries to find.
Key Stats
| Constellation | Aries |
| Best Viewing | Winter |
| Visual Magnitude | +4.6 | +8.6 |
| Absolute Visual Magnitude | +1.1 |
| Separation | 7.6″ |
| Position Angle | 1° |
| Distance from Earth | 164 ly |
| Orbital Period | 5000 yrs |
| Milky Way Location | Orion Spur |
| My Viewing Grade | A- |
| Designations | Gamma1, γ Arietis, Mesarthim, Struve 180 (STF 180), 41 Arietis, HD 11502, HIP 8903, HR 546 |
Sources and Notes
Sketch by Wayne McGraw
The Garden Astronomer 
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