70 Ophiuchi is a colorful and attractive double star in the summer constellation of Ophiuchus. According to Jim Kaler, a Royal Navy officer by the name of Admiral Smythe referred to this gem as “pale topaz and violet” pair. The double star is easily viewable with a small telescope, so it’s not a surprise skygazers have studied the object for more than 200 years when famed astronomer William Herschel recorded his observation in 1779.
Beyond 70 Ophiuchi’s nice color contrast, the system has two other unique factors. First, the stars make their home only 16 light-years away, making this one of the closer double stars to earth. Second, the binary consists of two dwarf stars cooler than our sun, which makes it distinctive since most stars we see in the sky are hotter and more luminous.
My Observations
| Date | July 29, 2021 |
| Time | 11:00 p.m. |
| Location | Seattle, WA |
| Magnification | 226x |
| Scope | Meade 8″ SCT |
| Eyepiece | 9mm |
| Seeing | Average |
| Transparency | Above Average |
What a fantastic double to enjoy on this midsummer night. The primary star is a pale yellow, while the smaller secondary is a light red. Not sure why, but as I enjoy this view, I think of multicolor ice popsicles, a summertime staple sold at every ice cream truck.
Key Stats
| Constellation | Ophiuchus |
| Best Viewing | Summer |
| Visual Magnitude | +4.2 | +6.2 |
| Absolute Visual Magnitude | +5.6 |
| Distance from Earth | 16 ly |
| Separation | 6.7″ | 34 AU |
| Orbital Period | 88 Years |
| Milky Way Location | Orion Spur |
| My Viewing Grade | A |
Sources and Notes
The double star banner on this page is an artist’s impression showing the double star OGLE-LMC-CEP0227 in our neighboring galaxy the Large Magellanic Cloud. This media was created by the European Southern Observatory (ESO). This file is licensed under the Creative Commons Attribution 4.0 International license.
Sketch by Wayne McGraw
AKA: SAO 123107
The Garden Astronomer 
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