Vulpecula

Coathanger

Brocchi's Cluster, Collinder 399

modern informal / binocular asterism · high confidence

Brocchi's Cluster is the binocular asterism that really looks like its name: a straight bar with a dangling hook. It is easy to sweep up between Altair and Albireo.

Central RA: 19^h 46^m 56.3^s
Central Dec: +22° 36′ 17″
Brightest member: V 4.58
Best months from 50°N: June–September evenings
Suggested instrument: 7x50
Approx. span: 11.4°

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: 11.4°; use at least 15.9° field for context.

Observing and imaging

Naked eye

Possible as a haze or partial pattern only from darker skies; use naked-eye stars nearby for the hop.

Binoculars

Best treated as a binocular field; start with 7×50 or similar and allow roughly 11.4° of pattern spread.

Small scope

Use low power only; higher magnification breaks the pattern into separate stars.

Imaging

Frame as a wide-field scene in/near Vulpecula; a field of view around 16° keeps context without claiming exact constellation boundaries.

Observability from your latitude

Uses this asterism’s centroid RA/Dec: transit altitude, hours above 20°, and a month-scale evening window. Default is Edmonton-ish 50°N.

Latitude 50°NMonth 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: 10/10 stars — fully visibleBortle 5: 7/10 stars — partialBortle 7: 1/10 stars — washed out

Member stars

Name	Bayer / Flamsteed	HR	RA J2000	Dec J2000	V mag
13 Vul	13 Vul	HR 7592	19^h 53^m 27.7^s	+24° 04′ 47″	4.58
15 Vul	15 Vul	HR 7653	20^h 01^m 06.1^s	+27° 45′ 13″	4.64
12 Vul	12 Vul	HR 7565	19^h 51^m 04.1^s	+22° 36′ 36″	4.95
9 Vul	9 Vul	HR 7437	19^h 34^m 34.9^s	+19° 46′ 24″	5.00
17 Vul	17 Vul	HR 7688	20^h 06^m 53.4^s	+23° 36′ 52″	5.07
4 Vul	4 Vul	HR 7385	19^h 25^m 28.6^s	+19° 47′ 55″	5.16
16 Vul	16 Vul	HR 7657	20^h 02^m 01.4^s	+24° 56′ 17″	5.22
5 Vul	5 Vul	HR 7390	19^h 26^m 13.2^s	+20° 05′ 52″	5.63
14 Vul	14 Vul	HR 7641	19^h 59^m 10.5^s	+23° 06′ 05″	5.67
7 Vul	7 Vul	HR 7409	19^h 29^m 20.9^s	+20° 16′ 47″	6.33

Source and confidence

modern informal / binocular asterism; high confidence. Well-known binocular asterism name; the star pattern is informal even where associated with Brocchi’s Cluster / Collinder 399.

Citations

Bright Star Catalogue, 5th Revised Ed.: Hoffleit, D. & Warren, W.H. Jr. (1991). Positions, V magnitudes, Bayer/Flamsteed identifiers. source
Sky Catalogue 2000.0: Hirshfeld, A. & Sinnott, R.W. (eds.). Vol. 2: Double Stars, Variable Stars and Nonstellar Objects. Used for cluster/asterism cross-checks.
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.