When is the best time to observe Theta Serpentis?

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

Where is Theta Serpentis located in the sky?

Theta Serpentis lies in the constellation Serpens at right ascension 18h 56m and declination +04° 12′.

What telescope do I need to split Theta Serpentis?

Splitting Theta Serpentis requires an aperture of roughly 60 mm or larger — the components are separated by about 405.6″ at magnitudes near 5.0. Larger apertures and steady seeing help resolve the pair cleanly.

Theta Serpentis — Double Star in Serpens

HIP 92951; Theta2 Serpentis; 63 Serpentis

Observable Double Star Good (43/100)

Sep: 405.6", Companion: mag 6.8

Magnitude 5.0^m DoubleStar Serpens (Ser) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.98

Spectral Type A5Vn

Star Color Yellow-white (B-V 0.20)

Distance 109 ly

2Position & Identifiers

RA 18h 56m 14.6s

Dec +04° 12' 07.0"

Constellation Serpens (Ser)

HR 7142

HIP 92951

HD 175639

SAO 124070

Bayer Theta2

Flamsteed 63 Ser

Double Cat 11853

SIMBAD Wikipedia

3How easy to split?

Primary 5.0 mag Companion 6.8 mag Separation 405.6″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Easy
150 mm Newton 150mm Newt.	Easy	Easy	Easy
Celestron C8 (203 mm SCT) C8 203mm	Easy	Easy	Easy

Easy Medium Hard Very hard Impossible

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

4Visibility

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Best season May – Jul (peak: Jun)

5Multiple Star System Triple C: optical

Components 3 (triple)

Component IDs AB

Separation 405.6″

Companion Mag 6.8

Position Angle 56°

Star Colors A: Yellow-white B: Yellow-white

Discoverer STF2417

Notes

Binary with HR 7141.

Separation over time

Measured 1908 → 2007 (99 y)

Separation drift 414.8" → 405.6" (-9.20")

Rate -0.0929" / y

PA drift 56° → 56° (+0°, +0.000°/y)

Apparent motion is significant on a human timescale — worth revisiting in a decade.

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.