Collinder 135

{{Short description|Open cluster in Puppis}}

{{Infobox open cluster

| name = Collinder 135

| image = File:Cr 135 DSS.png

| epoch = 2000.0

| constellation = Puppis

| ra = {{RA|07|08}}{{Cite simbad|title=Cl Collinder 135|accessdate=2011-08-15}}

| dec = {{DEC|-37|10}}

| appmag_v = 2.1

| size_v = 50'

| dist_ly = 1,040.5 ly

| dist_pc = 319 pc

| notes =

| names = Pi Puppis Cluster, Cr 135, C 0715-367

}}

Collinder 135, known sometimes as the Pi Puppis Cluster, is an open cluster in Puppis constellation.

It consists of six stars brighter than 6th magnitude, and a widespread population of fainter stars.{{cite journal|author=H. Baumgardt|title=The Nature of some doubtful Open Clusters as revealed by Hipparcos|year=1998|journal=Astronomy and Astrophysics|volume=340 |page=402 |bibcode=1998A&A...340..402B}} It lies in the southern celestial hemisphere near a rich star field. The main component is the star Pi Puppis, which gives to the cluster its common name; it is an orange supergiant with a visual magnitude of 2.71. Two of the 5th magnitude stars are all variables: NV Puppis is a Gamma Cassiopeiae variable, while NW Puppis is a Beta Cephei variable.