When is the best time to observe HIP 90804?

HIP 90804 is best observed from May through July, with peak visibility during June when it transits around midnight in the Northern Hemisphere.

Where is HIP 90804 located in the sky?

HIP 90804 lies in the constellation Scutum at right ascension 18h 31m and declination -10° 48′.

What telescope do I need to split HIP 90804?

Splitting HIP 90804 requires an aperture of roughly 60 mm or larger — the components are separated by about 12.4″ at magnitudes near 5.7. The companion is about 3.6 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

HIP 90804 — Double Star in Scutum

Magnitude 5.7^m DoubleStar Scutum (Sct) Visible

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Observe

1Physical Properties

Magnitude 5.72

Spectral Type B2V

Star Color Blue (B-V 0.24) (reddened by dust)

2Position & Identifiers

RA 18h 31m 25.7s

Dec -10° 47' 45.0"

Constellation Scutum (Sct)

HR 6946

HIP 90804

HD 170740

SAO 161569

Double Cat 11414

SIMBAD

3How easy to split?

Primary 5.7 mag Companion 9.3 mag Separation 12.4″

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

5Multiple Star System

Separation 12.4″

Companion Mag 9.3

Position Angle 257°

Star Colors A: Blue (reddened by dust) B: Orange

Discoverer STF2325

Notes

CPM companion A0V.

Separation over time

Measured 1796 → 2021 (225 y)

Separation drift 12.2" → 12.4" (+0.20")

Rate +0.0009" / y

PA drift 256° → 257° (+1°, +0.004°/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.