When is the best time to observe 17 Cygni?

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

Where is 17 Cygni located in the sky?

17 Cygni lies in the constellation Cygnus at right ascension 19h 46m and declination +33° 44′.

What telescope do I need to split 17 Cygni?

Splitting 17 Cygni requires an aperture of roughly 60 mm or larger — the components are separated by about 26.1″ at magnitudes near 5.0. The companion is about 4.3 magnitudes fainter, so glare from the primary — not separation — sets the minimum aperture. Larger apertures and steady seeing help resolve the pair cleanly.

17 Cygni — Double Star in Cygnus

Magnitude 5.0^m DoubleStar Cygnus (Cyg) Visible

Star Map + List + Plan

Observe

1Physical Properties

Magnitude 4.99

Spectral Type F7V

Star Color Yellow (B-V 0.47)

Distance 67 ly

2Position & Identifiers

RA 19h 46m 25.6s

Dec +33° 43' 40.0"

Constellation Cygnus (Cyg)

HR 7534

HIP 97295

HD 187013

SAO 68827

Flamsteed 17 Cyg

Double Cat 12913

SIMBAD

3How easy to split?

Primary 5.0 mag Companion 9.3 mag Separation 26.1″

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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 Jun – Aug (peak: Jul)

5Multiple Star System Triple C,E,F: optical

Components 3 (triple)

Component IDs AB

Separation 26.1″

Companion Mag 9.2

Companion Sp K0

Position Angle 68°

Star Colors A: Yellow B: Orange

Discoverer STF2580

Notes

AB binary. B is dK6. Component C, optical. ADS 12913AB and ADS 12889 (9.2, 9.4 dK5 sep. 3") at 792" are CPM and have | same RV and parallax. ADS 12889, 259y, a = 2.27", mean mass 0.6 solar.

Separation over time

Measured 1822 → 2024 (202 y)

Separation drift 25.5" → 26.1" (+0.60")

Rate +0.0030" / y

PA drift 73° → 68° (-5°, -0.025°/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.