PCW Memorial Observatory – Erika Rix

2012 08 23, 0925 UT – 1024 UT NGC2169/H 8.24/Cr83/Lund 206/OCL481/GC1361/h379

AT6RC f/9 1370mm, LXD75, Baader Planetarium Hyperion 8-24mm Mark III
(FOV 50 deg at 57x and 68 degrees at 171x)
73.4F, 83% H, 3.5 mph winds, lightly scattered, Pickering 6, T 3/6
Alt 17deg 30´, Az 83deg 59´ – Alt 30deg 0´, Az 91deg 20´

Open cluster in the constellation Orion, 30*, Tr Type I 3 p n, 6h 08.24m, -13deg 57´53´´, 6´, m5.9v

There are several references that state NGC 2169 was first discovered by Giovanni Batista Hodierna before 1654. William Herschel independently discovered and cataloged this open cluster in 1784 using an 18.7 inch reflector.

NGC 2169 was easy to locate in a 6” scope at 57x magnification by the condensed bright double pair of stars that run nearly north to south, forming a bright trapezium NW to SE ~3´ x 4.3´ in size. A more thorough look revealed two sub-groupings within this cluster. Both groups had 5 stars each in them with only 3.18´ separating the brightest northern star in each sub-group to the respective brightest southern star. Two pairs of stars were located 7-10´ to the north and northwest in the FOV. A chain of stars ran northwest to southeast just inside the FOV to the west with a second long chain of stars running north to south about 8´ to the east of the cluster.

At 171x magnification, 14 stars were observed in the eastern sub-group, forming the number “3”. There were 6 stars in the western sub-group that formed the number “7”. Close to 26 stars were observed within this grouping at 171x using a 6” RC, assuming my measurements were correct.

The brightest northern star in the number “3” looked slightly elongated and is actually Struve 848 (7.5/8.0 at 2.5″). Struve 844 (8.8/9.9 at 24″) makes up the two northwestern stars of the number “7”.

Sketches created with AL templates, #2 graphite pencil, super-fine Faber-Castell Pitt artist pen “S”, 0.5mm mechanical pencil.

Location of NGC2169:

~ by Erika Rix on August 26, 2012.

Posted in Collinder Catalog, Cr 83, Deep Sky Objects, H 8.24, Herschel Catalog, Lund 206, Lund Catalog, New General Catalog, NGC 2169
Tags: 37 cluster, Cr83, double stars, GC1361, H 8.24, h379, Lund 206, NGC2169, OCL481, open clusters