An Exciting Observation
A few weeks ago on Saturday February 13th my girlfriend and I experienced a “star viewing” night at the Perth Observatory. I wasn’t sure exactly what to expect and hadn’t previously been to the observatory since I was around 8 years old! I was extremely excited to go again, just seeing a night sky without the depressing light pollution around the metropolitan area would be exciting enough to satisfy me. But boy was I blown away! It truly was one of the most enjoyable nights I’ve had in a long time. Whilst quite brief (around 90 minutes) the whole thing left me drooling for more. During the viewing night I was madly scribbling notes down in my girlfriend’s diary (in pitch black) for fear of forgetting something. I’ll quickly give a run on the history of Perth Observatory and what is involved in their viewing nights.
A Little History
Perth Observatory is actually Australia’s oldest continually running Observatory. First built near to Kings Park (a large park near to the capital) in 1897 the construction of the observatory heralded a long lasting era of astronomical research and discovery. Aside from the scientific importance the completion of the observatory also meant that Perth at long last could accurately measure the time! The Observatory stayed at that location until it was moved (due to light pollution) in 1966 to its current location in the foothills at Bickley. Unfortunately even this move was not sufficient to properly shield the heavens from light pollution and there is an unfortunate loss of clarity in the Western portion of the sky.
The Viewing Night
Arranging the viewing night was a quick and painless affair. At the cost of a meal ($20) you can easily book yourself in with a single phone call. Once there you are greeted by the warm and experienced staff, all astronomers with at least a decade experience. After a brief history lesson in the observatory’s museum including a look at some real life asteroids and amazing sky photos taken locally, you are quickly whisked off up to the telescopes. It’s a quick walk up a path with strip lights to guide your way (which switch off once you’ve arrived) and very quickly you’re standing amongst the viewing scopes.
A quick introduction to the night sky ensues (with the help of a visible laser pointer) and such objects as Mars, The large and small magellanic clouds, the brightest stars (Sirius taking the cake) and of course the beautiful milky way itself! Seeing the thick arch of stars that is our arm of the milky way stretched out above you like a backbone holding up the sky is an amazing sight which is completely invisible inside the metropolitan area. I envy greatly those of you who live in areas where this is a common sight. I dare say that many Australians aren’t even aware that the milky way even forms this band across the sky.
After this we were divided into four groups and each rotated around the 4 public viewing telescopes that were set up for our convenience. Unfortunately the main telescope is not available for public viewing (for time, cost, safety and logistical reasons) but we were still treated to a cavalcade of astronomy goodness. At each station is a friendly volunteer to explain the site you’re looking at.
The Public Telescopes
40-cm computer-controlled Schmidt-Cassegrain Telescope (Meade)
35-cm Schmidt-Cassegrain (Celestron)
31-cm Calver (Newtonian) Telescope – made in 1910 – restored in 1996
30-cm computer-controlled Schmidt-Cassegrain (Meade)
Some of the Celestial Objects
The Tarantula Nebula (30 Doradus, or NGC 2070) was a beautiful sight. Situated inside the Large Magellanic Cloud it was originally thought to be a star until 1751. Considering it’s distance of 180,000 light years it is remarkably bright. Like all the objects on display the beautiful colours and resolution like in the picture here were not visible (being the result of high power or space telescopes), but the form and features were easily noticeable. The Tarantula Nebula has an estimated mass equivalent to a staggering 450,000 of our Suns. The closest supernova ever observed since the invention of the telescope also took place on the edge of the Tarantula Nebula.
Eta Carinae is an extremely close star system located a mere 7,500-8000 light years away. The system contains at least 2 stars with a combined luminosity calculated at 4,000,000 times brighter than our Sun. Before it was discovered that is was a binary system, Eta Carinae was thought to be the single brightest star ever found. The most exciting aspect of Eta Carinae however is that astronomers expect it to go supernova in the very near (astronomically speaking) future, anytime from today to some time in the next several millennia (pessimistic estimates range up to 1 million years however). When this does happen it will be astonishingly bright, visible during the day and bright enough to read by at night. There is also a slim chance that the supernova could affect Earth, though terrestrial life would be shielded from anything catastrophic. That is of course unless one of the polar gamma ray bursts are aimed in our direction, which would hit without warning and be the equivalent of 1 ton of TNT per square kilometer on Earth!
47 Tucanae is a globular cluster (cluster of stars that hang around outside galaxies) situated 16,700 light years away and is 120 light years across. 47 Tucanae holds the title of second brightest globular cluster visible to the naked eye, beaten only by Omega Centuari. Under ideal conditions 47 Tucanae can appear as large in the sky as a full moon! The clarity of this object in particular really hit home just how boring the night sky is when subject to light pollution.
We also had a good look at Mars through a telescope which was exciting (though I wish Saturn were visible that night). One top of all this we went through an enlightening tour of some constellations (non of which are completely visible in the city) including Orion, Taurus, Leo, Cancer, Gemini and the Seven Sisters. We were even treated to a brief tale of myth concerning Orion the hunter trying to force himself on all seven of the sisters and Zeus transforming into Taurus the bull to fight him off. On top of this as well (it just keeps coming) we were also taught a number of ways to determine our bearings using easily recognizable heavenly bodies.
It’s hard to pick a favourite object or constellation but the Large and Small Magellanic Clouds were likely the most interesting. Although not as clear as they would be with 0 pollution just seeing these smudges in the night sky and knowing that they are other galaxies, not just stars or gas clouds but other entire galaxies taking up this chunk of our night sky was truly awe-inspiring. I strongly urge everyone to make a trip to their local observatory (wherever you may be) and have a viewing night, or failing that just head out far away from the city and take a look at the sight our ancestors were privileged to every night for millions of years.