Observing Exercise – Spring 2012Open Cluster Observing

Date and Time are set for 9 pm April 20 but we can

use this for 10 pm Mid-March so

you can do this exercise earlier.

Looking due South:Meridian shows the great

divide between galaxies (pink

ellipses) on the East side of the

meridianand Open (Galactic) clusters

on the West

First: Clusters towards the West Open Clusters in Auriga

Date and Time are set for 9pm April 20

We will focus on the Western part of the sky to observe someOpen Clusters– gems of the early evening spring sky

First stop: Open Clusters in Auriga:

M37, M38, M36:Locate the Bright Star Capella in the pentagon of Auriga.Point your telescope or binoculars to the East of the flanking side to pick up M37.Continue sweeping westward to pickup up M36 and M37Compare and contrast…Which is the richest star field?Are they all at the same distance?Do they contain the same kinds of stars?

Capella

Canis Major, Minor and MonocerosM41, M46 and M47

Locate brightest star Sirius (the dog star)

Locate brightest star Sirius (Canis Major - underneath Orion) Note: reason for its brightness is both its intrinsic luminosity and closeness to the Sun

Slide your scope or binoculars parallel to the dog’s back and then move west of that line.

You will pick up a large rich field of stars – Open Cluster M41

Procyon (Canis Minor)

Locate next large and (also close) Procyon This points the way to 2 very different open clusters in Monocerous,

M47 (bright!) and M46 dim

Compare and contrast…

The Beehive!Open Cluster M44 (and neighbour M67)

Open Cluster M44 is observable with the eye in an unpolluted sky.

In this view it Is due south, leading constellation Leo.

To find it point your telescope or binoculars midway between the heads of Leo and the Gemini twins You will see the swarm of ‘bees’ (many suns) underneath.

Then drop down parallel to Regulus and look for the very dimmer M67. You need optical aid here! If you have problems finding it, locate the “head” of Hydra, you can see the pair naked eye and go up from the right one.

Compare and contrast…

u1. Locate Constellation Cassiopeia . It’s the W in the NorthEast

2. Locate the wish-bone (y-shape) of Constellation Perseus

3. The Double Cluster NGC 869/864 is in-betwwen the top of the wish-bone and the top star of Cassiopeia

Observe the Double Cluster NGC 869/864