Struve 2276 (STF 2276) is a delightful double star, nearly equal in brightness, located in the constellation Ophiuchus. Resolving this pair offers a rewarding challenge that immerses you in the heart of the summer Milky Way. Observing Struve 2276 also connects you to the pioneering work of William Herschel, who first cataloged it on June 16, 1782, as well as to 19th-century astronomer Friedrich Georg Wilhelm von Struve, who referenced it in his own work years later.
The primary star, with a magnitude of approximately 7.0, shines with a soft, yellowish-white light. Its companion is a slightly dimmer magnitude 7.4 star. The two stars are separated by a comfortable 7 arcseconds, making them a relatively easy target to split with a small to medium-sized telescope under good sky conditions.
For Struve 2276, the answer remains somewhat ambiguous, as it’s unclear whether it’s a true binary system or just an optical double. Regardless of their physical relationship, the visual spectacle of this celestial pairing remains undiminished.
My Observations
| Date | July 15, 2023 |
| Time | 10:41 p.m. |
| Location | Seattle, WA |
| Magnification | 169x |
| Scope | Meade 8″ SCT |
| Eyepiece | 12mm |
| Seeing | Average |
| Transparency | Above Average |
What a fantastic double star to enjoy on this midsummer night! The primary star is a pale yellow, while the smaller secondary star appears white. Even from my suburban location, under less-than-ideal skies, this double shines brightly amidst a rich field of stars, making the view particularly captivating.
Key Stats
| Constellation | Ophiuchus |
| Best Viewing | Summer |
| Visual Magnitude | +7.0 | +7.4 |
| Absolute Visual Magnitude | +1.33 |
| Distance from Earth | 450.5 ly |
| Separation | 7.07″ |
| Milky Way Location | Orion Spur |
| My Viewing Grade | A |
| Designations | SAO 103373, HIP 88627, HR 6758, HD 165474, Σ2276 |
Sources and Notes
Sketch by Wayne McGraw
The Garden Astronomer 