The binary star Struve 742, also known as HD 37013, lies near the famous Crab Nebula in the constellation Taurus. The pair shines down from 220 light years away and is best viewed on winter nights.
This binary was first observed and recorded in 1826 by astronomer Friedrich Georg Wilhelm Struve. It consists of two tiny white stars that are separated by a distance of only 4.2 arcseconds. When viewed through a telescope with a low-power eyepiece, the binary appears as a single star. Employing a higher power will help separate the two stars nicely—see my observation below.
The two stars are fairly close in magnitude; the primary shines at 6.9 magnitude and the secondary at 7.5. The Stelle Doppie page on Struve 742 provides a good graphic on the orbit characteristics of this binary.
My Observations
| Date | November 24, 2023 |
| Time | 10:20 p.m. |
| Location | Seattle, WA |
| Magnification | 169x |
| Scope | Meade 8″ SCT |
| Eyepiece | 12mm+2x Bar |
| Seeing | Above Average |
| Transparency | Above Average |
I’ve been in a comatose state following Thanksgiving dinner earlier, so much so that I’ve lacked the energy to set up my scope for stargazing. However, I am grateful that I made the effort. I am currently enjoying the clearest skies I have ever experienced in the Seattle area. The sky is illuminated by the near-full moon, which is the only imperfection on an otherwise near-perfect night.
I first landed upon Struve 742 with my 12mm eyepiece. The single elongated point of light indicated a hidden pair, so I connected my 2x Barlow to the 12mm, which gave me a great visual of this binary. Both stars are close in magnitude, and both appear white. I did navigate around the area to see any faint glow of the Crab Nebula, but the nearly full moon had washed the sky with too much light for such a sighting.
Key Stats
| Constellation | Taurus |
| Best Viewing | Winter |
| Visual Magnitude | +6.9 | +7.5 |
| Separation | 4.2″ | 299 AU |
| Position Angle | 276° |
| Distance | 220 ly |
| My Viewing Grade | B |
| Designations | SAO 77313, HIP 26328, STF 742 |
Sources and Notes
The banner illustration was created by the European Southern Observatory (ESO) and is under the Creative Commons Attribution 4.0 International License. Per ESO agreement: Here is the original image on the ESO website.
Star Information: 05364+2200 STF 742 (HD 37013). WDS 05364+2200 STF 742 (HD 37013). (n.d.). https://www.stelledoppie.it/index2.php?iddoppia=20745.
The Garden Astronomer 
2 thoughts on “Struve 742 (HD 37013): A Tight Binary Star Nestled Up to the Crab Nebula”