Here are the Moon phases in the Northern hemisphere for September 2011 and other interesting things of note in the sky.
4th September: First Quarter
12th September: Full Moon
20th September: Last Quarter
27th September: New Moon
The ‘Harvest Moon’ is the name given to the Full Moon nearest the autumnal equinox which is either in September or October (in the Northern hemisphere – for Moon watchers in the Southern hemisphere the Harvest Moon comes in March or April). In 2011, the Harvest Moon is the Full Moon in the Northern hemisphere on 12th September, though on the days either side of this it seems as though there are Full Moons rising in the East just after sunset and setting just before sunrise. In times gone by, this yearly phenomenon allowed farmers to continue harvesting their crops after daylight as the bright Full Moon shortly after sunset illuminated their fields, giving rise to the name: Harvest Moon.
The Harvest Moon is said to be steeped in mystery by some who say the Moon gets bigger at this time and glows orange or red. However, this is easily explained by the ‘Moon Illusion’ and the scattering of light in our atmosphere.
The ‘Moon Illusion’ occurs when the Moon is close to the horizon (as it’s rising). As we recognise the Moon is large compared to the things we typically see on the horizon (such as trees, buildings, birds) our brains tend to exaggerate the size of the Moon when it’s behind these on the horizon, tricking us into thinking the Moon has grown in size.
When you see an orange or red coloured Moon low on the horizon you are seeing it through a greater thickness of atmosphere than if it was higher in our sky. Our atmosphere scatters blue light, and on passing through more of it, light is scattered more effectively meaning that we see more red light from the direction of the Moon.
The autumnal equinox occurs in 2011 on 23rd September. During an ‘equinox’ the Earth is neither tilted towards or away from the Sun such that center of the Sun lies along the same plane as that of the Earth’s equator.
Here’s a view of the sky looking South around midnight on 12th September 2011 from Glasgow.
Here’s a view of the sky looking South around midnight on 27th September 2011 from Glasgow.
*Update* Took a snap of the Moon and Jupiter around midnight on Thursday 16th Spetmeber looking roughly eastwards. It’s not a great pic, but you can see the Moon and just to the lower left of it, Jupiter. Awesome!
*Update* And here’s another snap of the Moon and Jupiter around midnight on Saturday 17th (into Sunday 18th) September looking roughly eastwards. Again, the pic is not that great but it’s brilliant to see the Moon (on the left) and Jupiter (just to the right).
My recent post, Stunning Space Missions in Late 2011 highlights 3 NASA missions, one of which is called ‘GRAIL’. GRAIL is due to launch on 8th September 2011 and will give us a clearer picture of the Moon’s interior composition than ever before.
*Update* GRAIL successfully launched on 10th September. Yay!