When is the best time to observe Psi Serpentis?

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

Where is Psi Serpentis located in the sky?

Psi Serpentis lies in the constellation Serpens at right ascension 15h 44m and declination +02° 31′.

What telescope do I need to split Psi Serpentis?

Splitting Psi Serpentis requires an aperture of roughly 260 mm or larger — the components are separated by about 4.5″ at magnitudes near 5.9. The companion is about 6.1 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

Psi Serpentis — Double Star in Serpens

Magnitude 5.9^m DoubleStar Serpens (Ser) Visible

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Observe

1Physical Properties

Magnitude 5.88

Spectral Type G2.5V

Star Color Yellow (B-V 0.68)

Distance 71 ly

2Position & Identifiers

RA 15h 44m 01.8s

Dec +02° 30' 54.0"

Constellation Serpens (Ser)

HR 5853

HIP 77052

HD 140538

SAO 121152

Bayer Psi

Flamsteed 23 Ser

Double Cat 9763

SIMBAD

3How easy to split?

Primary 5.9 mag Companion 12.0 mag Separation 4.5″

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

Easy Medium Hard Very hard Impossible

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

To reach "Medium" at Bortle 3, you'd need at least a 260 mm reflector.

4Visibility

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Best season Apr – Jun (peak: May)

5Multiple Star System Quintuple C,D: optical

Components 5 (quintuple)

Component IDs AE

Separation 4.5″

Companion Mag 12.0

Companion Sp M

Position Angle 15°

Star Colors A: Yellow E: Red

Discoverer A 2230

Notes

Quintuple system of which E is brightest companion; B, 12.0V at 4"; others at 172" and 208".

Separation over time

Measured 1910 → 2018 (108 y)

Separation drift 3.6" → 4.5" (+0.90")

Rate +0.0083" / y

PA drift 103° → 15° (-88°, -0.815°/y)

Slow change over generations — observable in lifetime comparisons.

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.