Saturday, June 2, 2012

The Transit of Venus

Second contact of Ingress taken in 2004Providing the skies are cloud free, Venus Bay will be a great place to observe the Transit of Venus. Remember you must not look directly at the sun SERIOUS EYE DAMAGE MAY RESULT.
The transits of Venus, they are like an eclipses, are very rare but when they occur there are two such events 8 years apart. During the transit Venus is positioned between us and the sun and casts a shadow. Unlike an eclipse of the moon this show is small and seen as a small dark dot as it moves across the face of the sun.
This is only the fifth transit since James Cook travelled to Tahitti in 1769 to make observation there. Astronomers back in England wanted to know exactly how long the transit took and from that they predicted they would be able to compute the distance of the earth and Venus from the sun. This trip is also famous because on the way back to England he reach Australia, called it New South Wales and claimed it for England.

When?

There are four key events in the transit
First touches the sun
8:18 AM
Just inside the Sun, ingress
8:34 AM
Just inside the Sun, egress
2:27 PM
Last Touches the Sun
2:45 PM

 

Where is the best place to observe?

Well really anywhere around Venus Bay you can see the sun at the times above. Remember the sun will be relatively low in the sky during the Ingress. So I might start my own observations just near lees Road and Jupiter avenue intersection, on the bike track as it comes off the little rise. There is a very clear view of the eastern sky from here. During the Egress the car park at Beach One is a good location as it has a good view of the north western sky.


The Venus Bay, Tarwin Lower Men’s Shed are having activities around observing the transit, weather permitting, including a sausage sizzle & live music from local artists. They will have a solar telescope for safe viewing of the transit, solar flares, sunspots and active regions of the sun. Gold Coin Donation. Check the May edition of Matter of Fact Newsletter for more details.

How to Observe?

I will be using the same method used by captain cook. I will project an image of the sun onto a screen using my telescope. I took the picture below of the transit in 2004 and I’m hoping I can do better this time.
Taken in Wheelers Hill on 8 June 2004
The Sydney observatory has a great factsheet on the 6 June 2012 Transit of Venus. If you’d like more information of making observations yourself, it will even help you do the calculations of distance to the sun and Venus if you want to independently verify the astronomers work.

Wednesday, May 16, 2012

Sand in movement

Panoramic photo taken on Tuesday at Beach 1 showing some erosion occurring to the fore-dune. Notice the water pooling in the bottom right.


This next photo is facing SE at the same site and the undulating effect from the pooling water extends to the horizon.  Truly a dynamic environment!

Sunday, April 8, 2012

Bad weather for Sailors, but good for Diatoms

Beach One was the location of a mass stranding of Velella lata, more commonly known as by-the-wind-sailors. These little blue creatures are no more than 5cm long and are related to jellyfishes and anemones. Their natural habitat is on the surface of the open ocean, where the Velella feed on plankton.



They move across the ocean with their distinctive transparent "sail" catching the wind, visible in this first picture.

Every now and again a change of wind direction (like the cold blast we are currently experiencing) blows thousands of Velella helplessly towards the shore.
This second picture shows the underside of the Velella where its feeding tentacles are visible.


The same sort of weather that was responsible for the stranding of the Velella brought waters rich in nutrients that has allowed the Diatoms to bloom along the surf of Beach One.


This picture taken this morning at Beach One showing the characteristic browny-green "stain" of a Diatom bloom.


Saturday, February 4, 2012

WEEDS WEEDS EVERYWHERE!


There is no set definition of what a weed is, other than that they are always undesirable. In the context here I am referring to plants that are not endemic to an area, and that escape into our natural areas to become weeds.



This is undesirable for two main reasons;




  • It changes our natural areas from being natural, which is the reason those areas are valued in the first place.


  • It alters the balance in the ecosystem. The weeds out compete the native seedlings, so natural regeneration gets hampered. The native animals are all linked to the native vegetation and start to struggle, and pest animal species often displace them.


What can we all do?



Learn to recognise a few of the weeds, and which ones are particularly nasty. Below are a couple of useful links,



South Gippsland Weeds;



http://www.southgippslandweeds.com.au/



and the DPI's weed site;



http://www.dpi.vic.gov.au/agriculture/pests-diseases-and-weeds/weeds



The weeds pictured are from top to bottom; Ragwort Senecio jacobaea, Inkweed Phytolacca octandra & Spear Thistle Cirsium vulgare.