Some CCD
Images
Some CCD
Images| After
many letters to Santa I was fortunate to receive a CCD camera in Xmas '97,
and have now got to a stage where I can just about take tidy pictures with
the camera 'looking through' my 8" reflector. The three example images with
this note include two globular clusters (M3 & M13) and Hubble's Variable
Nebula (NGC 2261). The latter is a small faint nebula in the constellation
of Monoceros, and at its tip is found the variable star R Monocerotis. This
star's erratic brightness fluctuations between magnitudes 9.5 and 12 are
the cause of the nebula's varying brightness and appearance. I have seen
the nebula visually through an 8" reflector without difficulty. The distance
to the nebula is estimated to be 6500 light years. My CCD image is made
from 5 images each of 1 minute duration combined together. This interesting
object returns to our evening skies each winter time.
|
![[NGC 2261 - Hubble's Variable Nebula in Monoceros]](ngc2261.jpg) NGC 2261
- Hubble's Variable Nebula in Monoceros |
| M3
is a rich globular cluster located in the constellation of Canes Venatici.
Although 45,000 light years away, you can get a fine sight of it in a small
telescope. Through binoculars it looks like a hazy star. Looking at M3 it
is obvious why globular clusters are so named. Globular clusters contain
thousands of stars and sometimes hundreds of thousands of stars. Over a
hundred are known in our galaxy and they are distributed in a giant spherical
halo surrounding the central bulge of the galaxy. You might think looking
at the image of M3 that the stars are very close together, perhaps colliding
regularly! Despite appearances the stars are far from touching one another
- it is just that the star images are spread out on photographs. However
the density of stars in the central region of a globular cluster must still
be extremely high; perhaps 1000 times higher than in the neighbourhood of
the Sun. Here the skies must be truly spectacular, with the closest stars
outshining the planet Venus, and 1000 other stars brighter than even Sirius.
|
![[Globular Cluster M3 in Canes Venatici]](m3.jpg) Globular
Cluster M3 in Canes Venatici |
| M3
is one of the finest globular clusters in the sky but to view the finest
and brightest globular cluster in northern skies, seek out M13 in the constellation
of Hercules. M13 can be seen by the naked eye from a good dark sky site
and is obvious in binoculars. Its vital statistics include its distance
away of 22,500 light years, its diameter of at least 100 light years and
its contents of some 300,000 stars. Small telescopes resolve individual
stars throughout the cluster, giving a mottled, sparkling effect. The sight
of M13 through a moderate sized 'scope on a good dark night is quite breathtaking.
|
![[Globular Cluster M13 in Hercules]](m13.jpg) Globular
Cluster M13 in Hercules |
Modest telescopes will give a good view of these clusters in the night sky at the right time of year (weather permitting!).
If you are a newcomer to astronomy and would like help to find and view these objects do approach your local astronomical society.
Don't have a telescope? No problem, you will usually find a society member who would be delighted to let you view these and other objects through their telescope. Indeed many societies have their own telescopes for use by members.Chester AS
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Maintained by Graham Hodson
Last updated 28 May, 2003
