Nu Serpentis, also known as 53 Ser, is a double star in the lesser-known constellation of Serpens, the serpent. Late spring and summer are ideal times for backyard astronomers to observe the pair.
When observed without the aid of a telescope, Nu Serpentis appears as a white-hued solitary star located in the serpent’s head. The primary star is a fairly bright A-type main sequence star shining at magnitude +4.3. At 46 arcseconds away is a dim optical companion with a magnitude of +9.4. While most observers see a white or slightly off-white color for this pair, Jim Kaler reports that the 19th-century observers “Smythe and Chambers called the brighter ‘pale sea-green,’ the fainter ‘lilac’.”1 The star lies 203 lightyears away from us.
My Observations
| Date | July 7, 2023 |
| Time | 12:05 p.m. |
| Location | Seattle, WA |
| Magnification | 169x |
| Scope | Meade 8″ SCT |
| Eyepiece | 12mm |
| Seeing | Above Average |
| Transparency | Above Average |
Nu Serpentis is not as attractive as Delta Serpentis. Perhaps of interest, Smythe and Chambers saw the star as pale sea green in color. As I gaze at this, perhaps one might see a tinge of green, but I observe a duller white. The dim secondary appears white as well.
Key Stats
| Constellation | Serpens |
| Best Viewing | Summer |
| Visual Magnitude | +4.3 | +9.4 |
| Absolute Visual Magnitude | +.37 |
| Distance from Earth | 203 ly |
| Separation | 45.6″ |
| Position Angle | 25° |
| Milky Way Location | Orion Spur |
| My Viewing Grade | B |
| Designations | ν Serpentis, 53 Ser, HD 156928, SAO 160479, HR 6446, HIP 84880 |
Sources and Notes
Banner adapted from an illustration created by Pablo Budassi. The illustration is licensed under the Creative Commons Attribution-Share Alike 4.0 International license. Full details here.
1 Kaler, J. (2013, July 19). Nu serpentis. http://stars.astro.illinois.edu/sow/nuser.html
Sketch by Wayne McGraw
The Garden Astronomer 