- Open Clusters (Tri) -

And (3) CMa (3) Gem (10) Oph (3) Ser (2) Vul (8)
Aql (11) CMi (1) Her (1) Ori (12) Sge (3)
Aur (12) Cnc (3) Hya (1) Per (15) Sgr (6)
Cam (4) Com (1) Lac (6) Pup (6) Tau (6)
Cas (50) CVn (1) Lyr (2) Sco (2) Tri (1)
Cep (27) Cyg (34) Mon (7) Sct (3) UMa (1)

Collinder 21 (OC)

../dss/dss2blue_015007.00_+270500.00_12_web.jpg
Image source: DSS II (blue) - 12×12'
Name: Collinder 21
Type: OC
Constellation: Tri
Coordinates: 01h50m07.00s / +27°05'00.00"
Brightness / Size: 8m2 / 6.0x6.0'
Robert Zebahl
8" f/6, 37x, Bortle 4
Apparent group of brighter stars forming a semicircle.
EASY