Summer Triangle Of Stars (click for larger)

The “Summer Triangle” is a startling asterism of three bright stars. Even non-astronomers notice this prominent triangle pattern, during the Northern hemisphere summer.

The star pattern is made more noticeable by the generally light sky at this time of year (it doesn’t get properly “nautical” dark, if you are more than about 52 degrees of latitude North.

I have enhanced the image below, by drawing the “triangle sides”. Hopefully, this will help you to spot the Summer Triangle, when you look up at this time of year. (Ignore the aeroplane trail!)

Enjoy the summer!

Summer Triangle of Deneb, Vega, Altair (click for larger)

The stars are Deneb in the constellation of Cygnus, Vega in Lyra and Altair in Aquila.

Q. What are the Orionid meteors?

A. Each year in October as the Earth orbits about the Sun, it passes through an area of Space containing dust and rock fragments left behind by Halley’s comet. As these particles hit the Earth’s atmosphere they burn up, producing streaks of light we can see in the Night Sky. Occasionally, larger particles may burn up producing very bright “Fireballs” that can sometimes even be seen in daylight

Q. Why is this October meteor shower called the “Orionids”?

A. Because of the location of the Halley’s Comet debris in space, the meteors APPEAR to us on the Earth’s surface to originate from the constellation of Orion. This is nothing more than a “line of sight” effect however. The rock fragments which cause the meteors are actually very close to Earth – they have nothing to do with the distant star pattern we call Orion.

Here’s a graphic showing the apparent origin of Orionid meteor trails (the Radiant), located between the constellations of Orion and Gemini.

Orionids Meteor Shower Radiant, East Horizon, 21 Oct 2009 (Click For Larger Image)

Q. So will the meteors be seen only in the area of Orion?

A. No. The streaks of light may appear anywhere in our sky… But if you extend the traces backwards and continue the path, they will seem to have started in the area of Orion.

Q. When is the best time to look for the Orionid meteors?

A. The range of dates is expected as 16th – 27th October, with the peak meteor activity expected on 21st October 2009. In recent years, good numbers of meteors have been seen 1-2 days before and after the peak date, so it should be well worth observing over the period 18th-23rd October.

In some previous years, a double-peak of activity has been reported and this is an unusual feature of the Orionid shower. This may be because the orbit of Halley’s Comet brings it back to the Sun every 76 years, giving plenty of opportunity for depositing dust and debris.

Q. Will 2009 be a good year to observe the Orionid meteors?

A. It should be. Sometimes a bright Moon spoils the observing of meteor showers, but this time it’s very favorable. At the expected Orionid peak, the Moon will be just 2 days old. Therefore, it won’t be bright and it will set below the horizon, soon after sunset.

Q. How many meteors can I expect to see?

A. At the shower peak, something like 25 meteors per hour is predicted (this is called the ZHR – Zenithal Hourly Rate). Obviously, you will need dark, clear sky conditions to see the most meteors, and the number is just a prediction.. this makes it more fun to get outside and see for yourself, how many meteors appear!

Q. What equipment do I need to observe the meteors?

A. Good news… no equipment is really needed – just use your eyes (it will help if you allow 10-15 minutes for your eyes to become accustomed to the dark). If you like, you can try using binoculars too, but they may limit your view to a small area of the sky.

Q. Any other suggestions?

A. It’s getting cold in October, so make sure you wear warm clothing if you’re planning to spend an extended period outside, watching for meteors. Your observing session will also be more comfortable with a reclining garden chair, allowing you to lay back and look upwards. Some people like to put blankets or cushions on the ground, so they can lay flat and feel closer to the Universe, as they hopefully experience a memorable meteor display in the Night Sky.

Conclusion

Here’s wishing you the best of luck with your Orionids 2009 experience!

If you have questions or comments, please leave a reply below. I’ll do my best to answer each one personally (although I have to admit, the hundreds of questions on the Perseid meteor post, rather overwhelmed me!).

Comet Lulin (2007 N3) is speeding towards the Earth, at present.  It will get closest to us on February 24th and be  less than half the Earth-Sun distance away.  Then it heads away again, out into our Solar System and by early April, Lulin will have already crossed the orbit of Mars.

Comet Lulin, before dawn 6th February, in Libra

The comet is called Lulin, after the observatory in Taiwan where the image of its approach was captured.  It was actually discovered in 2007, by a Chinese meteorology student Quanzhi Ye.

The good news for amateur astronomers is, Comet Lulin should be easily observable with binoculars or a small telescope.  

Here are some sky maps I’ve made using Stellarium software, for three particular dates in February (click each image, for a larger version).

They show where to look for Lulin, in the skies before dawn.  

Between these specific dates, the comet will move between the positions marked, following a smooth path.

The first map shows Lulin before dawn on 6 Feb, next to the double star Zubenelgenubi in the constellation of Libra.  This will be low in the South East.

Comet Lulin, before dawn 16th February, near Spica in Virgo

By 16 February, the comet will be observable in the constellation of Virgo, near the bright star Spica.

The comet should appear noticably green.  

The colour comes from gases gushing out from the nucleus of the comet, as it is heated by the Sun’s rays.

Because of the chemical composition of the gases, they will appear green, under the intense radiation from the Sun.  

However, this is the first time Comet Lulin has come into the Solar System, so it’s not certain actually how it will behave.  To find out how big and bright it gets in our skies, we shall have to wait and see!

Here is the third map.

Lulin near to Saturn, on 24 February

By 24 February, Lulin should appear close to the planet Saturn.

This might make a particularly good astro imaging opportunity, although the rings of Saturn appear rather “edge-on” to us at present, so the great planet will not be arrayed in its full glory.

Nevertheless, I shall be trying for a nice image with the Canon/Skywatcher combination.

I hope these maps help you find Lulin in the sky,  during February.

If you do manage to get a good view of Lulin on any day, please let me know by leaving a comment on this post.

It produced a lovely astro image of the Orion nebula, earlier this week. But I was told, (quite rightly), the focus was not there.

So I had another go last night, as it was the first clear night since.

Here’s the focussing tip that was pointed-out to me, this week.

If you are imaging a faint object like a nebula, set the Canon into “live view mode” so you can see on the lcd screen what the camera is seeing, then slew to a nearby star (there should be one, not too far away).

Then use the + button on the Canon 1000D to zoom into the star and adjust the focus so it’s sharp. When you are confident about the focus, slew back to the target object.

It’s a good tip. When I had another try at the Orion nebula, l produced this image..

I think it’s a lot better, although produced in close to identical conditions, apart from the camera focus technique I have explained.

Encouraging!

My new telescope was delivered two days ago, so here are the first impressions.

It’s a Skywatcher 80ED refractor from the Evostar Pro series. This means it has an 80mm diameter, high quality objective lens, made from fluorite glass.

This special glass material is used to eliminate false color as much as possible from observations and keep them sharp.

ED1 OTA Version (optical tube assembly only)

It’s the first high-quality (apochromatic) refractor I’ve owned. Before purchase, I asked experienced astronomers and this telescope was well-recommended for it’s image quality and value for money.

Skywatcher 80ED showing necessary extension tube

I bought the ED1 version – this is the bare optical tube (OTA) only. You can also get the ED2 version. It’s exactly the same optical tube, but comes also with 2 eyepieces, finderscope, diagonal and case.

I already had eyepieces so I decided to save money and just get the OTA, which cost £235 (about $420) delivered.

Attaching To A Mount

First impressions were good.

The tube assembly is a handy size and weight. And with a focal length of 600mm (f7.5), it’s fairly short.

It was easy to attach to the equatorial mount, I already had.

You can see from the photo, I have used the white Skywatcher tube rings it was supplied with, but have attached them to the existing bar on the mount.

Because of this, the rings are rather too close together.

I have retained the Skywatcher supplied (longer) dovetail bar and will use it on the next mount. (I intend to get a much better quality, motorised polar mount for this telescope, in the next few weeks)

First Light Through The Scope

Observing Chair and Skywatcher 80ED

Amazingly, the sky was very clear on the first night, so I did some observing.

First thing to point out, is the focus tube is too short to allow use of an eyepiece, ‘as is’.

You need either an extension tube or a star diagonal, to lengthen the optical path and bring the image to focus.

Remember I mentioned above, the ED2 version comes with a 90 degree diagonal attachement.

I used an extension tube I already had. I have annotated the photo above, to highlight this extension.

Observation

Jupiter is bright, but rather low in the South at present. It made a good first target for the new refractor.

I was very pleased to get a good sharp image of Jupiter, using a 9mm eyepiece. I could clearly see the darker bands on the planet.

The crayford focuser of the scope is very smooth and nice to use.

I really needed higher magnification, but the 9mm eyepiece is the shortest focal length I have at present. With the 600mm focal length of the telescope, it gives only 66 times magnification. (600 divided by 9)

I’m confident I will see clear views at much higher power, so I am well pleased with the new refractor.

I will report progress over the next few weeks.

In mythology, Orion is said to be a hunter. The shape of the stars in the sky can be interpreted as a man, with a belt and sword, who is holding out a shield against the neighbouring constellation of Taurus, the Bull.

Constellation of Orion

However, from northerly latitudes in Summer, Orion is below the horizon at night and cannot be seen.

The main and easily recognised star pattern within Orion, is four stars in a rectangle which is bisected by the slanted “belt” of three stars.

In one direction, the belt points to Sirius, which is the brighest star in the sky and in the constellation of Canis Major. In the other direction, the belt points to the orange-red star Aldebaran in Taurus.

Orion is therefore a very useful “signpost” in the sky.

The “sword” of Orion, which appears to hang down from the belt, is actually a huge nebula (M42/M43), where stars are being created.

Each of the four main stars are bright and interesting.

Betelgeuse

The top left star (for an observer in the northern hemisphere) is the brightest. It is alpha-Orionis, called Betelgeuse.

Betelgeuse is noticably red-coloured to the unaided eye and is a red super-giant, variable star.

Its magnitude fluctuates between O and 1.3 every 6 years and it also pulsates in diameter from 300-400 times the size of the Sun. It is a true giant and it is 430 light years away.

Rigel

The bottom right star is Rigel and it is usually the brightest in Orion at magnitude 0.2. However, because of Betelgeuse’s variability, Rigel is designated beta-Orionis (not alpha-Orionis).

Rigel is a blue-white supergiant that is 800 light years away so it is nearly twice as far from Earth as Betelgeuse.

Bellatrix

The star at the top right (for Northern hemisphere observers) is a gamma-Orionis, called Bellatrix. It is a blue giant of magnitude 1.6

Saiph

The bottom-left star is Saiph, kappa-Orionis, at magnitude 2

The “Belt” of Orion

In some ways, the three stars which form the “belt” are the most interesting.

From left to right, they are zeta-Orionis called Alnitak (”the girdle”), then epsilon-Orionis called Alnilam (”string of pearls”), and lastly delta-Orionis called Mintaka (”belt”).

Alnilam is a blue super-giant, magnitude 1.7. It is 1600 light years away.

Both Mintaka and Alnitak are multiple stars.

Mintaka is an eclipsing binary with a period of 6 days. The pair is a magnitude 2.2-2.35 blue-white star with a magnitude 6 companion you can see in binoculars and small telescopes.

Alnitak is a tight pair of stars with magnitude 1.8 and 4. You need a good telescope to split them.

Sigma-Orionis

Just below Alnitak, is another multiple star, sigma-Orionis. It looks like a double star in binoculars, but a decent small telescope will actually show it to be four stars.

The “Sword”

As mentioned above, the Sword can be seen just under the belt.

It is a swirling mass of gas called the Orion Nebula, where stars are being born and it is excellent to observe through binoculars or telescope.

When Messier compiled his famous catalogue, he recorded this gas cloud as two separate objects, M42 and M43. Astronomers now believe them both to be part of the same cloud, although there is a dark area which makes them look separate, through a small telescope.

The “Trapezium”

In the centre of the Orion Nebula is the multiple star, theta-Orionis. Through a telescope, you can see a trapezium pattern of four stars.

It is believed that these stars have actually been created from the cloud of gas that is the Orion Nebula and that it is their light, that makes the Nebula glow.

Summary

As you can hopefully appreciate and see, the constellation of Orion is fascinating and well-worth some of your observing time, with binoculars or telescope.

It is known as “the Swan” because of its distinctive cross-shape in the sky. You can imagine it as a flying swan, with wings outstretched.

Cygnus has a declination of 29 degrees so it can be seen high in the sky to the south during the summer, from northerly latitudes. It is also visible to southern hemisphere observers.

Deneb

The brightest star, alpha-Cygni, is called Deneb (”the tail” from the Arabic).

Deneb is one of the brightest stars in our sky, having a magnitude of 1.2, in spite of it being 2000 light years away. Its absolute (or actual) magnitude is -7, which means it is 30,000 times brighter than our Sun.

Deneb is the most distant, first magnitude star.

Albireo

The double star Albireo (beta-Cygni), marks the head of the swan and it is a showpiece of the sky.

Look at it through a small telescope and you will see a pair of stars in contrasting colours. There is an amber star of magnitude 3, together with a blue-green star of magnitude 5. Beautiful!

The Milky Way

Cygnus lies in a particularly rich area of the sky for stars and clusters because we are looking here, into our own galaxy, the Milky Way.

On a dark and clear night, you can see with the unaided eye a “gap” in the Milky Way, to the side of Cygnus, called the “Cygnus Rift” or “Northern Coalsack”. It is not in fact a gap in the stars, but actually a dark area of dust produced by stellar explosions, that obscures our view of stars in this area.

Veil Nebula

Below the left arm (for northern observers) is an area of gas called the Veil Nebula. This is the remains of a supernova, or exploding star, from 30,000 years ago.

It is tricky to see without imaging the area, although you can see it under good conditions using a low-power telescope.

61-Cygni

This is a pair of orange dwarf stars, that are some of the closest stars to us (just 11 light years away). A good target for a small telescope.

The Coathanger

Below Albireo, towards the constellation of Aquila, is another good target for binoculars and small telescopes. It is not technically in Cygnus, but in the constellation of Vulpecula.

The Coathanger is a cluster of stars and the brightest ones, look just like an inverted coathanger.

Summary

For observers in the Northern hemisphere, the constellation of Cygnus make an interesting observation area. It is high in the sky, so you can see nice sights, even if the sky is not particularly dark.