Archive for the ‘Focus On’ Category

Focus On: Tadpole Galaxy

Monday, February 5th, 2018


The Tadpole Galaxy, aka ARP 188 / UGC 10214, is a barred spiral galaxy that has been stretched and distorted by a long-ago interaction with a smaller galaxy. The resulting “tail” – an elongated region of dismantled stars, gas, and dust – spans a length of about 250,000 light years. The collision, itself, effected new starbirth, including some clusters hosting hundreds-of-thousands of new stars, two of which – seen as blue clumps in the tail – that will likely to form new dwarf galaxies.

This fascinating galaxy is located some 400-million-light years distant in the constellation Draco. The intruder galaxy is located another 300-thousand-light-years away and is visible through the Tadpole’s spiral arms!

FUN CHALLENGE: How many other galaxies can you see in this Hubble image?

Take a Hubble Image Tour of the Tadpole Galaxy!


Focus On: Wishing Well Cluster

Friday, December 29th, 2017


The Wishing Well is an open cluster of about 400 stars, located 1300-light-years away, in the southern constellation, Carina. Formerly known as NGC 3532 and Caldwell 91, it was originally catalogued in 1755, by Nicolas Louis de Lacaille, a French astronomer who catalogued nearly 10,000 stars, introduced 14 new constellations, and determined the solar and lunar parallaxes, from his observatory at the Cape of Good Hope.

Targeted as the Hubble Telescope’s first light image in 1990, the Wishing Well is about 300-million-years old and includes several red-giants, white dwarfs, and binary stars. Southern hemisphere observers can easily spot this colorful cluster, spanning a visual region about twice the size of the Full Moon, next to the famous Eta Carinae nebula – NGC 3372 – and just a few degrees from the famous “Southern Pleiades” cluster – IC 2602.

FUN FACT: NGC 3532 is known as the Wishing Well because, to some observers, it appears as colorful coins scattered across the bottom of a fountain. It is also nicknamed the Football Cluster, for its oval shape resembling a rugby ball.

BONUS: Click on the Wishing Well image for a fun ESO full dome video of the cluster!



Focus On: Messier 80

Monday, October 9th, 2017


Messier 80, aka M80, is a globular cluster located nearly 33,000-light-years away, towards the constellation Scorpius. While most of the stars in this cluster are of similar age – about 13-billion years – scientists have noted a large number of younger “blue stragglers” within the cluster’s core. M80 also contains many bright red-giants, which you can see in greater detail by clicking on the Hubble image at left.


Globular clusters are dense collections of tens-of-thousands to hundreds-of-thousands of gravitationally-bound stars. They include the oldest stars in a galaxy and orbit the galactic core as a halo system. Our Milky Way has about 150 known globular clusters; larger galaxies can contain hundreds and even thousands of globular clusters. With upwards of 200,000 stars, our subject cluster, M80, is one of the most densely populated globulars in our galaxy. A few globulars, like M13 and Omega Centauri, contain even more stars.

Blue stragglers, like those found in M80, are younger main-sequence stars that are more massive and luminous than the general population of a cluster. The prevailing theory for their existence centers around the interactions between two or more cluster stars, resulting in the consequential transference of materials from one star to another.

Red-giants are older main-sequence stars with vastly inflated, thus cooler but brighter, atmospheres and lower masses. Our own Sun will someday expand into a red-giant star, engulfing the inner planets as it undergoes the hydrogen shell fusion stage.

The entire collection of M80’s stars spans some 96-light-years across. It has an apparent diameter of 10′, an apparent magnitude of 7.8, and appears as a distinctly fuzzy ball of light through a telescope or higher-powered binoculars. You can find this celestial gem about 4-degrees NW of bright red Antares (or between the scorpion’s bright red eye and its famous claw,) anytime that Scorpius is visible in your local sky. While you’re looking for M80, check-out another globular beauty, Messier 4, closer to Antares.

** ESO and HST offer some stunning images of globular (and open) clusters, here and here. **