When is the best time to observe HIP 81702?

HIP 81702 is best observed from April through June, with peak visibility during May when it transits around midnight in the Northern Hemisphere.

Where is HIP 81702 located in the sky?

HIP 81702 lies in the constellation Ara at right ascension 16h 41m and declination -48° 46′.

What telescope do I need to split HIP 81702?

Splitting HIP 81702 requires an aperture of roughly 60 mm or larger — the components are separated by about 10.2″ at magnitudes near 5.7. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 81702 — Double Star in Ara

Observable Double Star Excellent (72/100)

Sep: 10.2", Companion: mag 6.8

Magnitude 5.7^m DoubleStar Ara Visible

Star Map + List + Plan Star Hop

Observe

1Physical Properties

Magnitude 5.65

Spectral Type O5III(f) giant

Star Color White (B-V 0.13)

Distance 466 ly

2Position & Identifiers

RA 16h 41m 20.3s

Dec -48° 45' 47.0"

Constellation Ara

HR 6187

HIP 81702

HD 150136

SAO 227049

SIMBAD

3How easy to split?

Primary 5.7 mag Companion 6.8 mag Separation 10.2″

Sign in and configure your equipment and default location to see a personalized row.

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

Set a location in User Settings to see visibility data.

Best season Apr – Jun (peak: May)

5Multiple Star System Sextuple

Components 6 (sextuple)

Component IDs AC

Separation 10.2″

Companion Mag 6.8

Position Angle 265°

Star Colors A: White C: Yellow

Discoverer DUN 206

Notes

AB binary, 5.6, 9.0v sep. 1.6". C = HD 150135, O7:, CPM.

Separation over time

Measured 1836 → 2016 (180 y)

Separation drift 10.0" → 10.2" (+0.20")

Rate +0.0011" / y

PA drift 266° → 265° (-1°, -0.006°/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.

Eyepiece View

Telescope Eyepiece

Log in to set your own equipment

80x Dawes: 1.9″ TFOV: 0.6°

Seeing

Scale Realistic = true angular size

A: 5.7 · B: 6.8 · Sep: 10.2″ · PA: 265° · N up, E right

Resolved · Rayleigh: 2.3″ · Dawes: 1.9″ · Eff: 2.3″

Explore

6

Size Comparison

Querying VizieR for stellar data…

7

Compare Stars

Compare with another star

8

Spectral Classification

9

Hertzsprung-Russell Diagram

Loading HR diagram…

Read: The Hertzsprung-Russell Diagram — Reading Stars Like a Map

10

Stellar Lifecycle

11

Blackbody Spectrum

12

Stellar Absorption Spectrum

Simulated absorption spectrum based on spectral type. Hover over lines to identify elements.

13

Stellar Fusion

Discover

14Stellar Notes

Spectroscopic Binary

Component A of visual system.

Group/Cluster

In cluster NGC 6193 #1. Neutral hydrogen shell around the cluster probably at greater distance and not associated with | the cluster. High luminosity member of Ara OB1a complex.

Spectral

Also classified O5III:n(f).

15