Friday 27 September 2013

Meteorites

With the nights drawing in it is a great time to be out looking for meteorites. At certain times of year you may be lucky to see some , especially after midnight when they are at the largest fall rate.

The Draconids should be visible best on the 8/9 October 2013 , with a possible 100 meteorites visible throughout the night. The moon will be 16% illuminated in the region of Scorpius on the evening of the 8 October.

The Taurdis offers a good chance of seeing some , with the new moon on the 3 November it should be ideal viewing conditions with the highest rate again around mid night. often these meteorites are very slow moving compared to the rest of the year.

The Leonids will not be very good this year, as it coincides with the full moon, on the 17-18 November.These are fast bright meteorites with fine tails, associated with comet Temple- Tuttle

One of the best and highest rates of meteorites comes in December is the Geminids on the 7 - 14 December with over 100 per hour reduced to 70 per hour a few days either side. Although it can be very cold, often the skies can be clear giving a good chance to see and photograph this event. Unfortunately this year the moon will be a big problem being 89% illuminated.These are fast and bright with small trails

The Ursid shower will occur between the 22-23 December and with no Moon to talk about ,it may give the best chance for the later end of the year, again the best activity will be after mid night. Much will depend on cloud cover as ever.

Meteorites are caused by streams of debris entering the earth's atmosphere at great speed . Because meteorites travel in parallel paths they will seem to radiate away from a single point in the sky. Most are very, no bigger than a gain of sand, so cause no problems. A meteorite shower is the interaction from a planet such as earth and the debris from a comet. The debris from the comet is caused by water vapor drag, so each time a comet orbits the sun it will shed debris as ice vaporizes .

Meteorite showers are named after the constellations from which they occur. Good hunting!

Sunday 22 September 2013

Software - astrophotography

Adobe have just announced that Photoshop CS6 is the last one where you will be able to buy the software, currently around £650. They intend to have a monthly subscription of $20. Photoshop is used by many to get the best out of their astrophotography photos.

Registax 6 is a FREE software to merge and alignment of your photos

Avistacks similar to above and includes movie and image stacking. - Freeware

Stellarium is another FREE piece of software and a must have, it is regularly updated. download link here
http://www.stellarium.org/ This is an open source planetarium showing realistic sky in 3D at real time, set from your home location

If you have a tablet why not download one of the following

1. Google astronomy sky pro free version
2. Mobile observatory (update due soon)
3. SKYORB runs on widows 8 Free version

Saturday 7 September 2013

Sunset

Everyone loves a sunset and Shetland sunsets can rival any in the world but do they get the appreciation they deserve? In some areas of America and in Ibiza people often gather on a pier to watch the sun going down and then give a round of applause. This should happen in Shetland !

http://www.youtube.com/watch?v=7XUPyXYtFjg  (Ibiza applause for a sunset)

People capture superb sunsets and then share them on places like face book and its great to see them and for many see what they have missed. It may be that you cannot spare the time or it may be cloudy in your part of Shetland but the weather can change suddenly and give you a window of opportunity.

Every sunset is different, it is simply the sun going down in the western sky. In astronomy it is when the sun disc finally disappears below the horizon . North of the Artic circle and south of the Antarctic circle at least one day a year has no sunsets or sunrises.

Regarding the colour of each sunset, its all about the rays of light from the sun which are scattered by airborn particles / molecules , changing the colour that the observer sees. Greens and blues,  having a shorter wavelength, are scattered more widely and are therefore not seen in the beam of light. At Sunrise and sunset when the sun is lower it has to travel further through the atmosphere which removes the blues and greens, leaving the longer wavelength colours , Orange and Red hues the more prominent. The remaining reddened light is then scattered by cloud droplets to lighten the horizon Orange and Red. Sunsets are generally more brilliant than sunrises as more air particles develop throughout the day than first thing in a morning.

Ash from volcanoes tend to mute the sunset and sunrise colours , while volcanic ejecta that instead are thrown high up into the stratosphere can enhance any sunset or sunrise, these are called afterglows.The high altitude clouds tend to reflect the reddened sunlight down to the surface of the earth.

Some people believe in the sayings ` Red sky at night sailors delight, red sky in the morning sailors warning'. There is no doubting that people stand in awe when watching a sunset, the colour, the expectation, we feel something - What does a sunset mean to you ?

With ever changing colours it is set to inspire not just me with my camera but many more, along with artists, poets, writers, and those that just want to watch.

One of my favourite poems about sunsets

I wonder why when you say goodbye
beautiful colours paint the sky.
Shades of orange, yellow and pink too.
all come out because of you.
And though i hate to see you go,
i really do enjoy the show.
I've seen you leave so many times
and still it's a favourite sight of mine.
There'll be no sadness, be no sorrow
because my sun, you'll come out tomorrow.
I won't feel hurt, i'll feel no pain
because on your way down, your colors will reign.


and just two verses from this great poem:

Twenty-nine thousand four hundred seven sunsets
With one same sun on the one same sea.

At last, in these final days, each sunset is anticipated, craved
Regardless the mood of the sea, it will receive the sun.
No matter the face of the sky, it will let go the same.
The sun itself, always churning, always burning,
Swells with new brilliance, new radiance and splendor
Each time it approaches the sea,
Then morphs into a molten pool on the sea's surface
Before plunging from view-
Never more a sunset lost
Twenty- nine thousand four hundred seven sunsets
With one same sun on the one same sea
Then on glorious day, 
The day of my twenty-nine thousand four hundred and sixth sunset,
And I sat at my usual place along the shore,
Saw the sun rise out of the sea from where it had just set !
The sun rose back up into the sky, and
In the very next moment on the very same day, it set again.
I experienced my twenty-nine thousand four hundred and seventh sunset,
The second one in one day,
Oh glorious day !
A sunset gained.

So we don't need to join together to give applause to a Shetland sunset, but if you are the one stood on the west coast and then start to clap another Shetland sunset, then you are joining with many others that rejoice at this beautiful sight. So for now share these photos of Shetland sunsets, but make an effort to get out and find your own spot to admire the sun going down