The Pages of The Gray Wizard

Deep Skies

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Solar System
Milky Way
Deep Skies

Deep Sky Objects (DSOs)


Deep Sky Objects include Open Clusters, Globular Clusters, Nebulae, Galaxies, Double Stars and Variable Stars.


Open Clusters

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A loose group of a few dozen to a few thousand stars, usually associated with clouds of gas and dust.  All known open clusters are, like our Sun, located relatively far from the galactic center, in the galaxy's spiral arms; they consist of young stars, with ages ranging from a few million to a few hundred million years

Globular Clusters

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A densely packed sphere of several thousand to several hundred thousand stars, held together by their mutual gravitation.  Nearly all globular clusters are relatively close to the center of our galaxy.  They have also been observed in other galaxies.  In all cases their stars seem to be billions of years old.


Nebulae are objects composed primarily of dust and gas.  Classes of Nebulae include Emission Nebulae, Reflection Nebulae, Planetary Nebulae, supernova Remnants, and Dark Nebulae.


Emission Nebulae

m42.jpg (68875 bytes) Emission Nebulae shine by internally produced light.  They are often the birthplaces of Stars 

Reflection Nebulae

m78.jpg (19556 bytes) Reflection Nebulae shine by reflecting light from nearby stars.  Most are very faint.

Supernova Remnants

crab.jpg (85244 bytes) When a large star dies, the result is a cataclysmic explosion, or supernova.  The star is often completely annihiliated or leaves behind a small pulsar.  The gaseous and plasma remnants slowly diffuse into space, becoming visible as twisted filaments or nebulous blobs.

Dark Nebulae

horsehead.jpg (52881 bytes) Dark Nebulae are regions of dust which obscure stars or bright nebulae behind them. 

Planetary Nebulae

m27.jpg (11244 bytes) Planetary nebulae are layers of gas which have been shed by dying stars. They are often very small and difficult to separate from other stars.


M31.jpg (17621 bytes)

Any very large collection of stars outside of the Milky Way.  Galaxies are classified as spherical, Elliptical, Spiral, Barred Spiral, and Irregular.

Double Stars

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Any two stars whose positions (as seen from Earth) are very close.  Doubles are classified as visual doubles if the closeness is only apparent due to the stars lying in almost the same direction from Earth and true doubles or Binary Stars

Easy-Find DSOs Intermediate-Find DSOs Hard-Find DSOs
Object Type
M42/M43 Diffuse Nebula
M31 Galaxy
M13 Globular Cluster
NGC 869/884 Double Open Cluster
M81/M82 Galaxy Pair
M98, M99, M88 Trio of Galaxies
M22 Globular Cluster
M104 Galaxy
M17 Diffuse Nebula
M57 Planetary Nebula


NGC 7331


NGC 253



Supernova Remnant


Seyfert Galaxy


Planetary Nebula


Elliptical Galaxy


Spiral Galaxy

M20 & M8

Diffuse Nebulae

M30 & M75

Globular Clusters


Spiral Galaxy

Object Type

3C 273


Stephan's Quintet

Galaxy Cluster

NGC 7479




NGC 7000

Diffuse Nebula


Spiral Galaxy

NGC 891

Edge-On Spiral Galaxy


Spiral Galaxy

NGC 4567/4568

Pair of Colliding Galaxies

NGC 4038/4039

Pair of Colliding Galaxies

Messier Catalog
CM.jpg (22020 bytes)During the years from 1758 to 1782 Charles Messier, a French astronomer, compiled a list of approximately 100 diffuse objects that were difficult to distinguish from comets through the telescopes of the day. Messier's Catalog became well known as a collection of the most beautiful objects in the sky including nebulae, star clusters, and galaxies. It was one of the first  comprehensive list of Deep Sky Objects. The study of these objects by astronomers has led, and continues to lead, to important discoveries such as the life cycles of stars, the reality of galaxies as separate 'island universes,' and the possible age of the universe.