Lyra / Cygnus / Aquila

Summer Triangle

Vega-Deneb-Altair triangle

common observer pattern · high confidence

Vega, Deneb, and Altair frame the Milky Way's summer river. The triangle is huge, high, and forgiving: start with Vega overhead, then sweep east to Deneb and south to Altair.

Central RA: 19^h 43^m 08.9^s
Central Dec: +30° 58′ 39″
Brightest member: V 0.03
Best months from 50°N: June–September evenings
Suggested instrument: naked-eye
Approx. span: 38.0°

Finder context

This wider chart is deliberately schematic: it uses nearby bright-star context and boxes the asterism’s member-star footprint, but it does not draw official constellation boundaries or promise horizon/season precision.

Framing: Approximate member-star span: 38.0°; use at least 53.2° field for context.

Observing and imaging

Naked eye

Primary naked-eye pattern; suburban skies should show the main stars unless the description notes a low horizon or dark-sky need.

Binoculars

Binoculars are optional: use them to check colours, nearby doubles, or richer Milky Way background.

Small scope

A telescope is usually too narrow for the whole shape; use it after the pattern has guided you to a target.

Imaging

Frame as a wide-field scene in/near Lyra / Cygnus / Aquila; a field of view around 53° keeps context without claiming exact constellation boundaries.

Tonight from your latitude

Observability from your latitude: uses this asterism’s centroid RA/Dec with a schematic local clock from longitude, astronomical twilight (Sun below −18°), and the 2026 Moon heuristic. Month stays for the seasonal readout.

Latitude 50°NLongitude -114°Date Month Sky darkness Bortle 4 · limit V 6.1

Naked-eye visibility by sky class

Approximate limiting magnitudes: Bortle 3 ≈ V 6.6, Bortle 5 ≈ V 5.6, Bortle 7 ≈ V 4.6. The shape is counted recognisable when at least 70% of defining stars clear the limit.

Bortle 3: 3/3 stars — fully visibleBortle 5: 3/3 stars — fully visibleBortle 7: 3/3 stars — fully visible

Moon impact

Reference year 2026, Sep: 22/30 nights (73%) have a sampled ≥2 h window with Summer Triangle above 20° and the Moon below the horizon. At transit the Moon is up on about 50% of nights; the average moonlight penalty is roughly 0.40 mag of naked-eye limiting magnitude. Good nights below are the deterministic 2026 best-month mini-calendar for 50°N; green means a ≥2 h sampled dark window with the Moon down.

010203040506070809101112131415161718192021222324252627282930

Member stars

Name	Bayer / Flamsteed	HR	RA J2000	Dec J2000	V mag
Vega	3Alp Lyr	HR 7001	18^h 36^m 56.3^s	+38° 47′ 01″	0.03
Altair	53Alp Aql	HR 7557	19^h 50^m 47.0^s	+08° 52′ 06″	0.77
Deneb	50Alp Cyg	HR 7924	20^h 41^m 25.9^s	+45° 16′ 49″	1.25

Source and confidence

common observer pattern; high confidence. Widely used modern observing guide-pattern; provenance is practical observer usage rather than an official constellation figure.

Citations

Bright Star Catalogue, 5th Revised Ed.: Hoffleit, D. & Warren, W.H. Jr. (1991). Positions, V magnitudes, Bayer/Flamsteed identifiers. source
Star Tales: Ridpath, I. Constellation and asterism notes used to cross-check common sky-pattern names. source
The Hipparcos and Tycho Catalogues: ESA SP-1200 (1997). Used as the modern astrometric reference named by the atlas; the MVP pages expose BSC5 J2000 fields for the plotted bright-star members.