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Astronomy Know How
Helping you See the Night Sky - Newsletter No. 12 October 2007
In this issue:
  1. October's Highlights
  2. The Humboldt Crater
  3. Venus and Saturn
  4. Tip of the Month
  5. News Links
  6. Become a confident Astronomer
  7. Contact Us
October's Highlights

We are now well and truly in the Fall of the year and with this comes longer nights and darker skies. Also, the weather can potentially be clear and steady without being too cold!

The Summer Triangle of the stars Deneb in Cygnus the Swan, Altair in Aquila the Eagle and Vega' the bright star in Lyra the Harp, is now sinking low into the west. Instead we have the 'watery' constellations of Aquarius the Water Bearer, and Piscis Austrinus the Southern Fish and Cetus the Whale, as well as Capricornus the Sea Goat (whatever a Sea Goat is?)dominating the southern horizon if you live in mid northern latitudes.

Also this month we have the Square of Pegasus the Winged Horse riding high in the south. By counting the number of stars that you can see inside the square is a good indication of sky conditions, such as light-pollution and transparency. In other words how clear and dark the sky is from your viewpoint. If you see less than 3 or 4 stars it would suggest that you are not going to see much in the way of faint deep sky objects. So your observing is likely to be restricted to the Moon and planets.

If you do have reasonably dark skies from which to observe, then keep an eye out for the Orionid meteor shower, that has a broad peak between the 20th and 22nd of the month. It is best to go looking for these meteors after midnight when the rotation of the Earth means that we are moving towards the source of the stream. Although this is not one of the largest showers of meteors of the year, you may see rates of 10-12 per hour.

October will also give us a conjunction of Venus and Saturn in the early morning sky. The Moon at the end of the month will also give us a view that we don't often see due to the effect of it wobbling on its axis, a phenomena know as libation, that allows us to see up to 52% of the lunar surface rather than just 50%.

Finally, you can have a go at seeing a new comet that has recently been discovered low in the western sky, shortly after sunset towards the end of the month. CometC/2007/F1 LONEOS was discovered by the Lowell Observatory Near Earth Object Search (LONEOS) last March and it may reach magnitude 5.5 by the end of October, which will bring it well within the grasp of binoculars and on the edge of naked eye visibility. Look for it low in the constellation of Bootes the Herdsman from around mid month.
The Humboldt Crater

The Humboldt Crater is in fact an enormous walled plain very close to the eastern rim of the Moon. To see this feature we need both the libation, that is the rock and roll so to speak, of the Moon and its phase to be favourable for us. So we need a certain amount of luck as well as a little careful planning to see the elusive area of the Moon well.

The most favourable date in October is the 25th.

The wall of Humboldt contain a fascinating array of lunar features, among which is a central mountain range and a somewhat less prominent range of hills to be found between the main peak of the mountains and the crater Humboldt North, which is 14km (8.6 miles across). The range can be seen to continue towards the north eastern rim of the plain where there seems to be a break in the wall.

The floor of the plain itself is covered and criss-crossed with small craters and rilles or cracks. If you can't get a good view of this region then don't worry, Apollo 15 took an amazing image of this region as it flew of the lunar surface, which to can see if you go to

So make a note in your diary to have a look at a remarkable region of the Moon on the night of October 25th
Venus and Saturn

The planets Venus and Saturn are in conjunction (close together) in the sky on the morning of 13th this month and can be seen gracing the sky with the bright star Regulus in the constellation of Leo the Lion.

Venus is very bright (magnitude -4.4) so your unlikely to miss it, but Saturn will be much fainter at magnitude +0.6. Very bright objects are given minus magnitude values and the fainter the object is, its magnitude will increase positively!

Venus appears to move past Saturn quite quickly over the few days either side of the 13th, but when it is at its closest, it will be approximately 3-degrees or the equivalent of 6 full Moon diameters away. The star Regulus will be found north west, or above and to the right of the planets forming an attractive triangle.
Tip of the Month

Searching for comets...

Tip: If you are looking for comets, either to view ones that are well known or even to try and discover one yourself(!), then you'll need an instrument that can give you a large field of view. binoculars work well for this as do larger short focal length telescopes and low power eyepieces. Comets are usually quite faint and you need to gather as much light and have as large a field as you can practically get. On top of that, a good knowledge of the positions of the stars is also helpful if you are comet hunting as they can often appear as faint nebulae for which they can easily be mistaken. Good hunting!
  Here are some links to some other recent news stories that I thought you would find interesting...

Earth camera outdoes itís stellar rival with sharpest pictures

Largest terrestrial solar telescope to be commissioned in five years more...

USING broadband 10 times as fast as the average home connection, scientists in Australia, China and Europe have joined forces to create a telescope almost as big as the earth more...

Scientists model possible planets more...

  Do you want to learn more about the night sky and how to use telescopes and binoculars to see it better?..

My online course gives you all the essential information to be a good astronomer, without lots of jargon or difficult maths. You'll get loads of free bonuses and it also has videos and animations to help make the explanations clear and concise. So if you want to know what Sir Patrick wished for...

...please take a look at my eCourse called
'Basic Astronomy with a Telescope'. It's what Sir Patrick wished he'd had when he started out in astronomy!

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