The North America and Pelican nebulae are actually the same cloud of hydrogen gas. Their shape and separation are caused by a cloud of dark dust between us and the emission nebula.

Cratering, such as that on the Moon, is a useful indicator of relative age. Areas with more craters are generally older than areas with fewer craters. This is due to the rate of cratering slowing as the solar system aged.

NGC 3717: A Nearly Sideways Spiral Galaxy

Image Credit: ESA/Hubble & NASA, Processing: D. Rosario #APoD

Canadian Politics - Don Cherry 

A close look at the planetary nebula M57 shows its central star. This star is the remnant of the core of the original star that formed the nebula. Once the nebula dissipates the central star will become a white dwarf, the ultimate fate of stars less than about 8 solar masses.

They shall grow not old,
as we that are left grow old:
Age shall not weary them,
nor the years condemn.
At the going down of the sun
and in the morning
We will remember them.

Messier 45: The Daughters of Atlas and Pleione

Image Credit & Copyright: Adam Block, Steward Observatory, University of Arizona #APoD

The answer to last night's Astroquiz is that this is a picture of the Earth's shadow.

During the January 2019 lunar eclipse this series of images was taken. The telescope tracked at the sidereal rate so was pointed at the same point in the sky as the Moon drifted through.

With one image taken every minute, the combined image shows the Moon's path through the sky during the eclipse as well as the Earth's shadow.

Note how the Earth's shadow is round...

Spiral Galaxies Spinning Super-Fast

Image Credit: Top row: NASA, ESA, Hubble, P. Ogle & J. DePasquale (STScI);

Bottom row: SDSS, P. Ogle & J. DePasquale (STScI) #APoD

Daphnis and the Rings of Saturn

Image Credit: NASA, JPL-Caltech, Space Science Institute, Cassini #APoD

M33 is one of the three large spiral galaxies in our Local Group of 50+ galaxies. Located in the constellation Triangulum, M33 is the third largest galaxy in our Local Group after M31 (Andromeda galaxy) and our own Milky Way Galaxy.

The Horsehead nebula is an example of a dark nebula. What we see as a horse's head is actually a cloud of dust between us and an emission nebula. We can only see the head because it blocks out the light of the nebula behind it.

Three types of nebula in one! In M20 we can see the red light emitted by the emission part of the nebula. The blue light is from the reflection part of the nebula. The dark bands across the emission nebula are a dark nebula.

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