Summer is here and with summer the Objects of the Week move from galaxies to nebulae and star clusters.
This week's object is a nebula in the tail of the constellation of Serpens, the Snake.
Minkowski 1-88 a.k.a. Gum 85
18:17:53 -11d44m00s
Constellation: Serpens (Cauda)
15 red.gif 15 blue.gif
15' POSS2 Red & Blue
Dr. R.L.B. (Rudolph) Minkowski was a German born astronomer who headed the Palomar Observatory Sky Survey. Minkowski is best known for his planetary nebula research and discoveries. For his work, deemed distinguished services to astronomy, he was awarded the Bruce Gold Medal in 1961. Minkowski discovered almost 200 unknown planetary nebulae in a time when previously only 155 were known.
Minkowski published three papers on nebulae in 1946 (the Minkowski 1- objects), 1947 (Minkowski 2-) and 1948 (Minkowski 3-). A fourth list, the Minkowski 4- objects, was compiled by Perek & Kohoutek in 1965.
Combined, Minkowski's papers, along with the P-K additions, list 256 objects: 40 emission nebulae, 207 planetary nebulae, 1 galaxy, 1 supernova remnant and 7 stars.
Minkowski 1-88 is a small, irregular emission nebula, approximately 6'x4' in size, with dark rifts crossing its eastern part. Several faint mag. 13+ stars are involved, or superimposed. The nebula is on the northern edge of the much larger and fainter nebula Gum 84 (Sharpless 54 - Lynds 71 & 72) of which it may actually be a brighter part. The larger nebula is at an estimated distance of 6200 ly.
Minkowski 1-88-1.jpg Minkowski 1-88-2.jpg
Click here to download this observing guide.
Gum 84.jpg
2.7 degrees DSS mosaic
Gum 84 contains a small, concentrated, moderately bright open cluster: NGC6604, half a degree to the south of our OOTW.
In the vicinity
Pull out your 1 degree eyepiece and pan exactly two fields of view towards the south, to center Messier 16 (NGC6611) - the "Eagle Nebula".
A bit closer, 1.5 degrees to the southeast is the planetary nebula Sanduleak-Stephenson 156 - the "Red Square Nebula". Another planetary is 1.7 degrees to the north-northwest and it's another Minkowski object: 3-25, stellar and quite faint.
On your way to Messier 16, pause three quarters of the way there to observe the open cluster Trumpler 32: A small, regular cluster of about 50 faint stars, as Robert Trumpler described it. If a star 13' east-southeast of the cluster appears deep orange to you, it's good to know that it's the carbon star ES Serpentis (CGCS3987). It is a flanked by a mag. 11 star directly west, but the two are not cataloged as a double.
Well, you know what to do: give it a go, let us know!