The Planets by Rishon Sabri

Let there be Light!

Many people  probably bought their first amateur telescope after being inspired by stunningly detailed and colourful pictures from NASA's Hubble Space Telescope of nebulae and galaxies, such as the image of the Andromeda Galaxy above. And those people who peered into their tiny little refractors at Andromeda were probably bitterly disappointed when they found that all they could see in their eyepiece was a small, barely visible fuzzy patch of grey in the sky - if they could see anything at all. Even with relatively large amateur telescopes, it would be impossible for you to visually see in your eyepiece the kind of detail you would see in those NASA pictures - Andromeda would more likely appear as a dim patch, as pictured near the centre of my image below.  

The problem is that a telescope's lens can just gather a limited amount of light - especially when the object you're looking at is 2.5 million light-years away. At those kinds of distances, every photon of light counts and using cameras and imaging devices to capture even that tiny amount of light will make you lose even more of those precious photons. One way you can help overcome this problem is to process the digital image you obtain with a graphics processing programme such as PhotoShop to manipulate gamma, brightness, contrast, midtone, highlight and shadow levels, so that you can obtain a more enhanced image, such as the one below.

 However, the most effective way to enhance such images is to do what the professional astronomers with building-sized telescopes do to their own images - mesh together multiple images of of the same region of space to allow every photon of light recorded to be used and to provide a brighter, more detailed image. With us amateurs, we would take many pictures of our target (or use the individual frames of a video taken through the telescope with a webcam or CCD imager) and then to produce a 'stack' of the images. This 'image stacking' would then produce a single image that comprises either the sum, or the average, or some value in between of the individually stacked images. Stacking images is a well-established method for increasing the signal-to-noise ratio in a series of similar images. Every photon of true "information" recorded in every frame taken is captured and used in the final image, while random noise is dropped out

For example, multiple exposures of the image above, when 'stacked' with software such as Registax or 'RotAndStack', will produce the image below, where the much more of the Andromeda Galaxy's spiral disk can be seen and even the fainter stars not evident in the previous image shine gloriously through. And with something the size of Andromeda, you don't even need a telescope to produce images such as these - the image below was taken by a modest, ancient Olympus Camedia C-4040Z digital camera (40 quid on e-Bay) without the aid of a telescope.

The first step is to take, say, 48 exposures of the target of, for example, 8-16 seconds (or long enough for a good exposure to light but short enough not to produce star trails or too many 'hot' pixels on the image). Obviously, the more exposures taken, the better - depending upon how much observing time you have and how cold out it is that night. Don't take too long, though - your lenses might mist up or even frost up if exposed to the night air too long. You then run your image stacking program, such as Registax, and load all 48 exposures into the program. You will then need to chose some prominent stars or region as common alignment points (the boxed area in the picture below) so that all 48 images can be properly aligned and stacked together, using these alignment points as the points of references.

The program will then compare the alignment points of each of the 48 images to make sure they are properly rotated and placed in each 'layer' of the final stacked image. Once aligned and optimized, you can proceed to 'stack' each of the 48 images into a single output image.

Once the 'stacked' image has been produced, most stacking programs allow you to do further processing on the image to enhance it even more. Once you're happy with your image, all you need to is then save your picture and your tiny 80mm refractor or humble digital camera has now produced an image that would put a monster telescope 10 times its size to shame!

V is for Hyades

“V” may be for Victory, but it’s also the shape of one of the closest star clusters to Earth: the Hyades. Located in the constellation Taurus, finding this star cluster is easy-peasy - the brightest stars in the cluster make a distinctive 'V' or arrowhead shape and it is located south of its more well-known half sisters, the Pleiades, or Seven Sisters. The Hyades are 'only' about 150 light years from our solar syste - the Pleiades, for example, is three times farther or about 400 light years away.

The first star to catch your eye in that V shape will be a bright orange spark to the bottom left - the 'eye' of the Taurean bull. This is the red giant pictured below, Aldebaran  - a star that is approximately 50 times the diameter of our Sun.   Aldebaran is actually not part of the Hyades star cluster at all. It’s only 65 light years from Earth (that is, almost halfway between us and the Hyades) but coincidentally happens to be in the foreground of our line of sight to the Hyades. That said, without Aldebaran, the cluster would be a little disappointing; so it does adds a little lustre to it and helps anchor the overall shape of the cluster for us astronomers. The name Aldebaran actually comes from Arabic (al-dabaran) and translates literally as "the follower", presumably because this bright star appears to follow the Seven Sisters in the night sky - in which case, perhaps 'Stalker' might have been a better word! For the Seris of northwestern Mexico, Aldebaran is said to provide light for the seven 'women' giving birth. And those Trekkers among you probably know of one of Scotty's favourites, the Aldebaran whiskey and the Aldebaran mud leeches used by the Denobulan Dr Phlox!

The Hyades contains about 20 orange and blue stars that are perhaps visible to the naked eye; If you like double and binary stars, you'll love Hyades - as you can see from the image below, the Hyades cluster has quite a few pairs in it. Even with average eyesight, you can probably make out and split with tree pairs without any difficulty - the Sigmas (just a little to the south pf Aldebaran), the Thethas (to the east) and the Kappas (way up north).

While  the cluster appears like the letter “V” from our perspective on Earth, its true shape is approximately spherical.  And while we may be able to observe about 20 stars visually, the Hyades actually contains some 300-400 stars. Below is a 'stacked' enhancement of the image above, which clearly show a lot more stars than is evident at first.

All photographs on this page  © Sabri Zain 2012.

My date with the Seven Sisters

The Pleiades is an open star cluster in the constellation Taurus and, at this time of the year, makes its entrance in the north eastern skies of the northern hemisphere round about midnight. Popularly called the Seven Sisters, it is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky.

These stars are so clearly seen in the night sky that even those who do not dabble in astronomy can easily spot them - at least 6 or 7 bright stars, gathered in a region only a bit larger than 1 degree, are clearly seen with the naked eye. See the little cluster of stars near the bottom right hand side of the picture below?

The Pleiades have been used for testing eyesight from antiquity onward. In good observing conditions, an observer with average sight can see 6 stars. What about people with excellent eyesight? Maestlin, the teacher of the astronomer Kepler, saw 14 stars; he had drawn 11 stars on charts of the Pleiades before the telescope was invented! The well-known English observer Denning also saw 14 stars in the cluster. Madame Airy (the wife of a well-known nineteenth-century English Astronomer Royal) could see 12, while the English amateur astronomer William Dawes, who was in his time known to have extraordinary eyesight, saw 13 stars in the cluster. How many can you make out in my picture below?

If the Pleiades seem charming with the naked eye, they are truly breathtaking when viewed through a small low-powered telescope  or binoculars! The six stars are suddenly joined by numerous fainter ones, making the field of the cluster literally overflowing with stars, as you can see in my image below. Investigations of the cluster have shown that it may actually contain approximately 500 stars.

If I'd always felt slightly deprived because of the relatively low magnification of my telescope set-up, when observing the Pleiades low magnification becomes an advantage. The large field of view of a small refractor offers a panoramic view of this splendid group. With larger amateur telescopes or at high magnifications, we somewhat lose the magnificent feel of this cluster. Below is an image of the centre of the Pleiades taken at high magnifications.

In Greek mythology, the Pleiades were the seven daughters of the titan Atlas and the sea-nymph Pleione - Maia (the eldest), Electra, Taygete, Alcyone, Celaeno, Asterope and Merope (the youngest). However, because most people can only see six of the Seven Sisters, this has inspired legends of the “Lost Pleiad.” The most commonly told is that Electra - she’s shocked to see her home city Troy burning and hides her face. Another story says Merope wasn’t made as bright as the others because she married a mortal - the other sisters married immortals. Yet another story says she couldn’t fit in with the other sisters anymore and left for Hades. In another story, a thunderbolt hit Celaeno and she disappeared.

Intriguingly, other cultures such as the Aborigines of Australia and Iroquois of North America had similar legends of a missing seventh star. Some modern astronomers think that means there may actually have been seven stars easily visible a long time ago. The Greeks, the Iroquois, and the Aborigines may have told stories appropriate for their own cultures to explain why one vanished. If that’s true, one of the many Pleiades we see in a magnified view could have been the one that faded from naked eye visibility.

All photographs on this page  © Sabri Zain 2012.

Twin Terrors

Sunspots look like pimples on the face of the sun. In the case of the sun, though, it's acne problem occurs every 11 years, the cycle starting with a few pimples and building up to an outburst of blotchy rashes at its peak. Fortunately for me, the sun is currently in an active phase of its 11-year solar cycle. That's why last weekend saw the sun firing off one of the year's more spectacular solar eruptions, with super-hot solar filaments erupting and arcing into space and snaking between two huge sunspots - AR 1538 and AR 1540. Below is a video I took yesterday of these two sunspots. It may look like a single dark blob at first but careful inspection of the video will reveal that the 'blob' actually consists of a pair of sunspots.

Processing the video above with an astronomical image stacking program such as Registax reveals the two sunspots in greater detail, below. The two sunspots appear quite identical, like two evil twins spitefully spewing deadly plasma a (as well as a much smaller sunspot to the south) nd radiation towards poor little Earth. Sunspots are basically magnets - well, magnets with the magnetic force perhaps 8,000 times greater than the magnetic field around our entire planet. But just like any magnet, it has opposite north and south poles of positive and negative force. Sunspots therefore tend to form in pairs, just like the ones I captured in my images above - one with negative and one with positive polarity. The twins are often side by side, parallel with the equator and they rotate with the sun from west to east.

Zooming in on the sunspot with a 2X Barlow lens, you can see more clearly below the two dark spots (the central umbrae, where the magnetic field is approximately vertical to the Sun's surface), as well as the surrounding penumbra, which is lighter, where the magnetic field is more inclined.

Astronomers expect the current solar cycle, known as Solar Cycle 24, to peak in 2013, so probably lots for me to observe and video capture for quite a while yet - stay tuned!

All photographs on this page  © Sabri Zain 2012.

Due to bad weather, the Meteor Shower has been cancelled!

The Perseids are a prolific meteor shower associated with the comet Swift-Tuttle and so-called because the point from which they appear to come, called the radiant, lies in the constellation Perseus. This weekend was supposed to be the peak period of the Perseids, where the rate of meteors reaches 60 or more per hour - a meteor a minute! But being England, the skies were of course shrouded with blankets of cloud and what was supposed to be a meteor shower turned out to be hardly a meteor drizzle - I could hardly see no more than half a dozen in three hours of gazing in between the angry rolling clouds above. Nevertheless, I did manage to capture half a dozen interesting images from last night:

You can see from some of the images above that many are framed to a gorgeous background of other bright objects such as Capella, Jupiter and the Pleiades. But you will also some of the terrible cloudy conditions - made worse by the hideous orange glare of the street lights below and the floodlights from the useless guided bus station nearby. Why anyone would spend thousands of pounds a year floodlighting an empty bus station at 2 o'clock in the morning is beyond me - with business sense like this, it probably explains why this country up to its eyeballs in debt to China.

I took the above images using the time lapse photography techniques I described in my earlier article 'How to catch falling star.', using 8-second exposures for each shot  However, I also had another camera taking much faster exposures and one result of this is a meteor suspended in mid-flight, below.

Below is a magnified and 'cleaned up' version of the bright 'star' to the far let.

And how do I know the above is a blazing meteor and not just a particularly large and bright star? Because below is a shot of exactly the same position a couple of seconds later:

I'm also pretty sure it wasn't a plane either, as the 'blip' does no appear again in subsequent frames. Neverthless, when taking time lapse photographs of meteors, you should certainly make sure that the meteors you capture aren't actually aircraft, as they would leave a similar streak of light in your frame. There are two ways telling the difference. Firstly, for an 8-second exposure, a plane would leave a 'streak' that would appear in subsequent frames, whereas a meteor would only appear in one frame. Secondly, a plane would leave a distinct dotted line streak as pictured below (since the navigation lights are usually red and white).

The picture below, on the other hand, is not a plane or green meteor hurtling its way to the top of my telescope - it's just the beam from the laser I have mounted on top of my scope that I use to aim at my target star.

Below is the set-up I used for last night night's observations. There's a camera mounted on a tripod scanning the  eastern horizon and an identical camera mounted on my telescope scanning the northern horizon (much of the time, I had to run from one camera to the other, swivelling the cameras to different directions, depending upon where there was an opening in the clouds). Two laptops are connected to the cameras to take the time lapse photographs automatically and save the images to hard disk. And, of course, there's a nice warm tent to retire to with a hot cuppa while the cameras and computers do all the work!

Rishon also joined me in my observations, as this was also the night we allowed him sleep out in the garden in the tent for the first time. However, despite the long afternoon nap he took earlier, staying up to after midnight was just too much for his poor little eyes and, thanks also to the cloudy skies, he fell asleep before he could see a single shooting star. He was quite inconsolable when he woke up the next morning, and the only thing that stopped the bawling was when I told him that he didn't really miss anything as there was announcement in the news this morning that last night's meteor shower had been cancelled due to cloudy weather!

All photographs on this page  © Sabri Zain 2012.