When is the best time to observe HIP 100325?

HIP 100325 is best observed from June through August, with peak visibility during July when it transits around midnight in the Northern Hemisphere.

Where is HIP 100325 located in the sky?

HIP 100325 lies in the constellation Capricornus at right ascension 20h 21m and declination -14° 47′.

What telescope do I need to split HIP 100325?

Splitting HIP 100325 requires an aperture of roughly 60 mm or larger — the components are separated by about 396.5″ at magnitudes near 6.1. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 100325 — Double Star in Capricornus

Magnitude 6.1^m DoubleStar Capricornus (Cap) Visible

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Observe

1Physical Properties

Magnitude 6.10

Spectral Type A0III giant

Star Color Blue-white (B-V -0.02)

Distance 326 ly

2Position & Identifiers

RA 20h 20m 46.6s

Dec -14° 47' 06.0"

Constellation Capricornus (Cap)

HR 7775

HIP 100325

HD 193452

SAO 163471

Double Cat 13717

SIMBAD

3How easy to split?

Primary 6.1 mag Companion 8.8 mag Separation 396.5″

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Telescope	Bortle 3	Bortle 4	Bortle 5
80 mm refractor 80mm refr.	Easy	Easy	Medium+
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 Jun – Aug (peak: Jul)

5Multiple Star System 8 components D: optical

Components 8

Component IDs *

Separation 396.5″

Companion Mag 8.8

Position Angle 111°

Star Colors A: Blue-white B: Yellow

Discoverer STFA 52

Notes

Complex system with HR 7776, CPM at 205". ADS 13717A is occultation double, 6.2 - 8.3v, sep. 0.8"; also 7.2, 7.2v, | sep. 0.05". Component B, 10.2v, A1, binary with A at 0.9". A is astrometric binary. The close occultation pair is | questioned; it has not been confirmed by speckle interferometry.

Separation over time

Measured 1895 → 2015 (120 y)

Separation drift 397.4" → 396.5" (-0.90")

Rate -0.0075" / y

PA drift 112° → 111° (-1°, -0.008°/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.

Eyepiece View

Telescope Eyepiece

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15x Dawes: 1.9″ TFOV: 3.3°

Seeing

Scale Realistic = true angular size

A: 6.1 · B: 8.8 · Sep: 396.5″ · PA: 111° · N up, E right

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

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Size Comparison

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Spectral Classification

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Hertzsprung-Russell Diagram

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Stellar Lifecycle

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Blackbody Spectrum

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Stellar Absorption Spectrum

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

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Stellar Fusion

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14Stellar Notes

Spectroscopic Binary

ADS 13717A = component B of multiple star of which HR 7776 is component A. 8.6780d, K 37.9k/s, asini 4.22. These are | components BC of triple spectroscopic system with HR 7776. BC sep. 0.0225", mag. diff 1.1. BC could be eclipsing. | Component C of the spectroscopic triple system is not the same as any of the visual components of ADS 13717 listed by | Worley; nor is it component C of the components Worley lists for HR 7776 = STF 52.

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