When is the best time to observe HIP 17797?

HIP 17797 is best observed from October through December, with peak visibility during November when it transits around midnight in the Northern Hemisphere.

Where is HIP 17797 located in the sky?

HIP 17797 lies in the constellation Eridanus at right ascension 03h 49m and declination -37° 37′.

What telescope do I need to split HIP 17797?

Splitting HIP 17797 requires an aperture of roughly 80 mm or larger — the components are separated by about 8.2″ at magnitudes near 4.7. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 17797 — Double Star in Eridanus

Observable Double Star Excellent (68/100)

Sep: 8.2", Companion: mag 5.2

Magnitude 4.7^m DoubleStar Eridanus (Eri) Visible

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Observe

1Physical Properties

Magnitude 4.73

Spectral Type B9V

Star Color Blue-white (B-V -0.03)

Distance 136 ly

2Position & Identifiers

RA 03h 48m 35.9s

Dec -37° 37' 14.0"

Constellation Eridanus (Eri)

HR 1190

HIP 17797

HD 24071

SAO 194550

SIMBAD

3How easy to split?

Primary 4.7 mag Companion 5.3 mag Separation 8.2″

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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 Oct – Dec (peak: Nov)

5Multiple Star System

Separation 8.2″

Companion Mag 5.2

Companion Sp A1V

Position Angle 216°

Star Colors A: Blue-white B: White

Discoverer DUN 16

Notes

Binary with HR 1189.

Separation over time

Measured 1826 → 2020 (194 y)

Separation drift 7.0" → 8.2" (+1.20")

Rate +0.0062" / y

PA drift 202° → 216° (+14°, +0.072°/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.