All posts by Justin Avery

Justin spends most of his time creating notebooks about space, and far too little time maintaining this site.

Comet Heart and Soul

The greenish coma of comet 21P/Giacobini-Zinner stands out at the left of this telephoto skyscape spanning over 10 degrees toward the northern constellations Cassiopeia and Perseus. Captured on August 17, the periodic comet is the known parent body of the...

/ August 28, 2018

The Pencil Nebula in Red and Blue

Having children that are 4 and 2 I know the look of these remnants very well, and I’m sure my daughter has drawn it on a piece of paper once or twice before. While the colours that they use are...

/ August 13, 2018

Stickney Crater

Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline Stickney Hall, mathematician and wife of astronomer Asaph Hall. Asaph Hall discovered both the Red Planet’s moons in 1877. Over 9 kilometers across, Stickney is...

/ August 8, 2018

Eclipsed Moon and Mars over Mountains

There is something unusual about this astronomically-oriented photograph. It’s not obvious — it was discovered only during post-processing. It is not the Moon, although capturing the Moon rising during a total lunar eclipse is quite an unusually interesting sight. (Other...

/ August 7, 2018

NGC 1360: The Robin’s Egg Nebula

Usually when you see large pockets of nebula cloud it is associated with the birth of a new star. In this case the cloud in the image takes up around 3 light-years and is the remnants of the final stages...

/ August 6, 2018

Total Solar Eclipse Corona in HDF

For anyone that is fortunate to be at the right place during a solar eclipse they state it as one of the most amazing experiences in their entire life. Many resolve to say they will travel anywhere in the world...

/ August 2, 2018

The Observable Universe

How far can you see? Everything you can see, and everything you could possibly see, right now, assuming your eyes could detect all types of radiations around you — is the observable universe. In visible light, the farthest we can...

/ July 31, 2018

Saturns Hyperion in Natural Color

Like a giant pummel stone for cleaning dead skin from the from the feet of the Gods, Hyperion is an amazing moon that is orbiting around Saturn. The Cassini spacecraft swooped past for a look in 2005 and 2010 and...

/ July 31, 2018
Hubble Telescope Image Westerlund

The Massive Stars in Westerlund 1

Our Sun is pretty damn big — so big in fact that it has a volume of 1.3 million Earths — but our Sun has nothing on the largest Star inside the star cluster Westerlund 1. The biggest star inside...

/ June 20, 2017

How do you date objects?

How do you date objects?   How do you date Meteorites   Decay Constant We’ve done half-life as a way of understanding radioactive decay Another way is the use of the term, Gamma It’s done in the units of yr-1...

/ February 21, 2017