ASTR1010L &
ASTR1020L
DEEP SKY HUNT
LAB #3
The purpose of this exercise is to locate and observe three deep sky objects. Deep sky
objects is the general term used to describe nebulous (non-stellar)
objects. They cover a wide range
of astronomical phenomena from galaxies to loose aggregations of stars called
open or galactic clusters. I
realize that two sentences ago I characterized nebulous objects as non-stellar
and that last sentence I said that galactic clusters were a type of deep sky
object composed of dozens or hundreds of stars. The reason galactic clusters can be considered deep sky
objects is because to the naked eye or in binoculars they look fuzzy
(nebulous). With our telescopes you see a galactic cluster as it really is: a
bunch of young stars that are still in the same general region (they will
eventually disperse and be individual stars – the Sun most likely started
out in a galactic or open cluster).
The really faint deep sky objects (at least as far as this class is
concerned) are galaxies and planetary nebulae. They are virtually impossible to see with our small telescopes from the roof of the Physics Building. Realize that if we took our telescopes to the north Georgia mountains, on a clear, moonless night we could see dozens of galaxies and other faint objects - but not from the roof of the Physics Building because of the ambient light pollution. And let's hope the Stadium lights aren't on, otherwise you'll have trouble even with the items below. In this lab, you will look for relatively easy-to-find deep sky objects: primarily open clusters and a more compact type of cluster called a globular
cluster (globular clusters are better visible in the fall semester. Also, there's an object called M42, a hot gas cloud called an HII region, M31, the nearest large spiral galaxy – they're both really easy to find, and a planetary nebula (the expanding outer atmosphere of a dead star) called M57 or the Ring Nebula, but this one is harder to find). Globular clusters are very different from open
cluster: Globulars are composed of
hundreds of thousand or millions of stars versus hundreds for open
clusters. The stars in globulars
are old, the stars in open clusters are young. Globular clusters are tightly grouped in a spherical ball,
while open clusters are spread out and misshapen. More differences are discussed in ASTR 1020. In this lab, you will be asked to find three examples of deep sky objects from the list below. You will find the first object, point
the telescope to it and then show the instructor that you have indeed found
it. After the instructor has seen
it, you will move to the next object and repeat the process. When you are practicing finding these objects, you will have to use your star atlas to locate stars near them and then find the deep sky object by offsetting the telescope, because virtually all of the deep sky objects are impossible to see with the naked eye from our location. Practice is the only way to find these faint nebulae. Choose and find 3 objects from the following list to get full credit; if you find only two, you will get 15 out of 20 points, and if you find only 1, you will get 10 out of 20 points.
|
Name |
RA |
Dec |
Magnitude |
Size |
Object Type |
|
|
|
|
|
|
|
|
M42 |
05h 35m 24s |
-05o 27¢ 00"
|
4.0 |
65'
|
Hot Gas Cloud |
|
M31 |
00 42 42 |
+41 16 00 |
3.5 |
185'
|
Spiral Galaxy |
| M34 | 02 42 06 | +42 45 | 5.2 | 40' | Open Cluster |
|
M41 |
06 47 00 |
-20 44 00 |
4.6 |
38'
|
Open Cluster |
|
M45 |
03 47 00 |
+24 07 00 |
1.6 |
110'
|
Open Cluster |
|
M44 |
08 40 06 |
+19 59 00 |
3.7 |
95'
|
Open Cluster |
|
M37 |
05 52 24 |
+32 33 00 |
5.6 |
20'
|
Open Cluster |
|
M35 |
06 08 54 |
+24 20 00 |
5.1 |
28'
|
Open Cluster |
|
M38 |
05 28 42 |
+35 50 00 |
6.4 |
21'
|
Open Cluster |
|
M67 |
08 50 24 |
+11 49 00 |
6.9 |
29'
|
Open Cluster |
| M13 | 16 42 00
|
+36 28 00
|
5.8
|
20'
|
Globular Cluster
|
| M92 | 17 17 06
|
+43 08 00
|
6.4 | 14' | Globular Cluster |
| IC 4665 | 17 46 18
|
+05 43 00
|
4.2 | 70' | Open Cluster |
| M57 | 18 53 36 | 33 02 00 | 8.3 | 8.8' | Planetary Nebula |
| Cr 399 | 19 25 24
|
+20 11 00
|
3.6 | 60' | Open Cluster |
| M15 | 21 30 00
|
+12 10 00
|
6.2 | 18' | Globular Cluster |
| NGC 869 & 884 | 02 15 36
|
+56 55 00
|
4.3 | 30' | Double Open Cluster |