When is the best time to observe 39 Serpentis?

39 Serpentis is best observed from April through June, with peak visibility during May when it transits around midnight in the Northern Hemisphere.

Where is 39 Serpentis located in the sky?

39 Serpentis lies in the constellation Serpens at right ascension 15h 53m and declination +13° 12′.

What telescope do I need to split 39 Serpentis?

Splitting 39 Serpentis requires an aperture of roughly 60 mm or larger — the components are separated by about 106.2″ at magnitudes near 6.1. The companion is about 5.7 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

39 Serpentis — Double Star in Serpens

Magnitude 6.1^m DoubleStar Serpens (Ser) Visible

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Observe

1Physical Properties

Magnitude 6.10

Spectral Type G0VFe-0.5

Star Color Yellow (B-V 0.60)

Distance 80 ly

2Position & Identifiers

RA 15h 53m 12.1s

Dec +13° 11' 48.0"

Constellation Serpens (Ser)

HR 5911

HIP 77801

HD 142267

SAO 101792

Flamsteed 39 Ser

SIMBAD

3How easy to split?

Primary 6.1 mag Companion 11.8 mag Separation 106.2″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Hard	V. hard+	V. hard
150 mm Newton 150mm Newt.	Medium	Hard+	Hard
Celestron C8 (203 mm SCT) C8 203mm	Medium+	Medium	Hard+

Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

4Visibility

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Best season Apr – Jun (peak: May)

5Multiple Star System

Separation 106.2″

Companion Mag 11.8

Position Angle 80°

Star Colors A: Yellow

Discoverer STT 583

Separation over time

Measured 1862 → 2016 (154 y)

Separation drift 106.4" → 106.2" (-0.20")

Rate -0.0013" / y

PA drift 131° → 80° (-51°, -0.331°/y)

Essentially fixed on human timescales — the same view your grandchildren will see.

Measured from the WDS observational archive. No orbital solution has been derived — most likely the period is too long to fit an orbit to the available measurement arc.