Zodiacal Light: Oft Ignored Astronomical Phenomena?

Even though it seems to longer register in the consciousness of most amateur astronomers, are they missing out on observing one of the most interesting astronomical phenomena?

By: Ringo Bones 

Although no prominent astronomers – amateur or otherwise – had been recently talking about it, are first time amateur astronomers missing out one of the most interesting astronomical phenomena that can even be seen by the naked eye. But why does it ever seldom if ever even mentioned at all?

The zodiacal light or the zodiacal band is a faint glow of light seen along the ecliptic just after sunset or before sunrise is another manifestation of the interplanetary meteoric material. This “zodiacal light” is caused by the reflection of sunlight from the meteoric grains moving in interplanetary space. A still fainter diffuse luminous spot called the gegenschein or “counter glow”, found directly opposite the sun in the sky and the false “F corona” of the sun seen during total eclipse are the two other phenomena caused by this interplanetary material. Although such material is slowly spiraling into the sun, it is continually replenished by the destruction of comets.  

The zodiacal light appears as a large, faint pyramidal glow whose base is the horizon after the twilight glow has faded. This form is best seen on spring evenings and mornings in October. A fainter incarnation of zodiacal light stretches clear across the sky along the ecliptic – as in the orange line in our sky maps. Because urban light pollution overpower the glow, the vast majority of amateur astronomers will only get a chance to see the zodiacal band at a star party located at a rural location devoid of most urban light pollution – where the skies are usually quite dark - as in Class 1 to Class 4 - in the Bortle Dark Sky scale. Though urban regions that register as Class 5 in the Bortle Dark Sky scale will provide adequate Zodiacal Light observations for non demanding amateur astronomers. 

Observing the zodiacal band is one of those funny things. You don’t generally notice it until someone points it out, then – under a dark sky – it is fairly straightforward to see. Keep in mind that the zodiacal light is a magnitude or two fainter than the Milky Way.

One way to detect the zodiacal band is to watch for the sky background brightness to change as you slowly scan up from the horizon. Initially you’ll see a brighter horizon haze followed by darkness, then the sky will brighten a bit – this is the zodiacal band – only o fade as you look higher. You might have to block the light from Jupiter with your hand – it’s that dim.

Once you recognize this faint belt, you’ll notice that Saturn clearly lies beneath it as shown on the Path of the Planets map if you are on the northern hemisphere.

Affordable CCD Cameras: Amateur Astronomy’s Weakest Link?

Given that quite a number of amateur astronomers now use “affordable” CCD cameras to capture what their telescope sees for posting on the web, does ultimate CCD camera performance still matters?


By: Ringo Bones


Once upon a time – or at least back in the 1970s and very early 1990s from my perspective – amateur astronomers used to rely on their handy film-based cameras with selectable exposure times to capture wonderful photos of what their home-based astronomy telescope set-up had seen. Then, digital Charged-Coupled Device cameras (CCD cameras) became low enough in retail price to pose serious competition to the humble film-based camera with selectable exposure times. As of late, given that CCD cameras capture what they “see” in digital form – as in format – quite a number of amateur astronomers had been busy posting / uploading what their astronomical telescope had seen on the web and / or their respective social network accounts – i.e. Facebook. But does the ultimate quality of your “affordable” CCD camera currently connected to you backyard telescope really matters?

The plain truth is, the quality of your imaging system – i.e. your backyard astronomical telescope and affordable CCD camera set-up – is fundamental to the quality of your results. Since the proliferation of back-illuminated grade one CCD cameras on the market aimed at amateur astronomers, the issue of quantum efficiency has more than ever became the selling point in the entry-level price point of CCD cameras for astronomical telescope use. But why is quantum efficiency so important by the way?

Quantum efficiency or QE is a measure of how much light gathered – typically by the front-end optics of your astronomical telescope – actually gets converted to charge in a typical CCD chip of a CCD camera. If your CCD camera has a rated peak QE of 85%, then it means that 85 out of every 100 photons striking the CCD get counted.

In practice, typical front-illuminated CCD cameras have a much lesser quantum efficiency than back-illuminated CCD cameras. Front-illuminated CCD cameras have a typical quantum efficiency of around 25% to 45%. And front-illuminated CCD cameras are also quite inefficient in the blue end of the visible spectrum where their quantum efficiency falls to a mere 5%, while a typical back-illuminated CCD camera only falls off to 70%.

During the latter half of the 1980s, mechanical sophistication – i.e. the expensive bits of your backyard astronomical telescope set up like optics and the related support systems – can already be replaced by relatively low-cost electronics, thus bringing enormous cost savings resulting in reduced exposure times brought about by a CCD camera with much higher quantum efficiency can be a boon for the amateur astronomer on a budget.

A shorter exposure time means lesser reliance on your astronomical telescope’s rather expensive mechanical systems – i.e. low-cost telescopes usually use low-cost mechanical systems. Better sensitivity via use of CCD cameras with higher QE means a smaller aperture can now accomplish what a larger – and pricier – telescope would before. Using a CCD camera with higher quantum efficiencies also allows you to image fainter objects in a shorter time, allowing you to image more objects per night using the backyard astronomy telescope set-up that you currently have. So buy the best-performing CCD camera for your astronomical telescope that you can comfortably afford to attain amateur astronomy bliss.

Buying Your Own Starter Astronomical Telescope

From the elementary grade amateur to the tenured professional astronomer who decides to buy one, is buying your own astronomical telescope still a good investment?


By: Vanessa Uy


For the tenured professional whose significant other is understanding enough to allow him or her to own a “reasonably-sized” astronomy telescope – given that the one he or she uses on the job probably has a primary mirror taller than their two-story house. Owning a “portable” astronomy telescope surely has it’s own advantages. For the elementary grade amateur – or those in between – there’s nothing more satisfying than emulating the Golden Age of 17th Century Astronomy every time you use your telescope. But if you are looking for one, read on. Given that 2009 has been designated as the International Year of Astronomy, everyone should have the opportunity to experience first hand of using your very own astronomical telescope.

Even though there are very user-friendly astronomical telescopes that cost around 3,000 US dollars though the wisdom of shelling out with that sum of money can be questionable - especially if your funds doesn’t stretch that far. We should be looking for something more modest given that the world is currently in a recession. The second hand classifieds selling such items – like those on major astronomy magazines like Astronomy or Sky & Telescope - can be a good place to check out. But there are those brand-new priced between 150 to 500 US dollars that will do very well as starter telescopes. Even the ubiquitous 10 X 50 binocular telescope qualify as a very good starter refracting astronomical telescope. It can be used to see the major craters on the Moon and even has the magnifying power to see the planet Uranus.

There are two basic kinds of astronomical telescopes that you can choose: refractors and reflectors. A telescope’s primary function is to collect light and gather it to a focus. A refractor telescope uses a lens – called the objective lens – to refract or bend light to a focus. While a reflecting telescope uses a mirror – called the primary mirror – to reflect light to a focus. To know which type of astronomical telescope is best for you very much depends on what you will be looking at most of the time – or your specialty. Refractors are generally better for viewing small bright objects, like the Moon – if you consider the full Moon “small” – the planets, and double stars. Reflectors are generally suited for viewing large dim objects like the Milky Way, nebulae, other galaxies and star clusters.

When those in the know talk about a telescope’s “size” they are talking about its aperture. Aperture is the diameter of the telescope’s primary lens or mirror. For example, a 4-inch reflector doesn’t mean that the telescope is 4 inches long. It means that its primary mirror is 4 inches in diameter. For some weird reason, the aperture measurement of refractors or lens telescopes are usually given in millimeters, while the apertures of reflecting or mirror-type telescopes are usually given in inches. And remember an astronomical telescope’s job is to collect light. The larger the aperture, the more light it collects and the sharper the image it delivers. So chose the largest one you can afford because more than anything else, aperture determines what you will be able to see with the telescope.

Vibration can be an issue when it comes to starter astronomical telescopes. No matter which kind of telescope you choose, make sure it is attached to a good, sturdy mount. Telescopes mounted on long skinny legs that are held together with tiny screws are not worth the time and money. There is nothing worse than trying to use a telescope that makes the planet Jupiter look like that alien probe in the sci-fi TV series Threshold every time the cat walks by. Astronomical telescopes – especially the reflecting type – are prone to vibration. Even though my trusty but rusty Celestron 8-incher probably cost 1,500 US dollars when new, I can’t even play my stereo at a decent enough volume every time I use it because it vibrates wildly in time to the music. So listening to J.S. Bach’s organ cantatas or Iron Maiden’s Fear of the Dark while using a reflecting astronomical telescope is out of the question.

Speaking of astronomical telescope mounts, most beginners’ telescopes come with a simple alt-azimuth or equatorial mount. The “alt” means altitude and “azimuth” refers to horizontal movement. Which means an alt-azimuth mount allows the telescope to be moved or aimed up and down of left and right. An equatorial mount is set up so that one axis always points to the North Star. This type of mount moves in curves that match the movement of the celestial bodies in the night sky. Which can be an advantage if you want to use your telescope to capture long exposure photographs of a dim star using de rigueur 150 ASA 35mm photographic film.

There are advantages and disadvantages of each type of mount. Alt-azimuth mounts are mostly used in refractor or lens-type telescopes and are easier to use. And can be a boon if your telescope does double duty as a sniper’s spotting telescope. Especially if you are skilled enough to be a able to hit a bowling pin from 6,000 feet away using a rifle that fires the .50 caliber Browning Machine Gun cartridge. Although equatorial mounts – usually relegated to reflecting astronomical telescopes - are primarily designed to track celestial objects with ease. Plus the latitude and altitude readout on the equatorial mount can be very educational, especially if a seasoned astronomer ask you about the coordinates of the particular patch of night sky you are currently looking at. But most of all, it doesn’t matter which kind of mount you get, as long as it is sturdy enough for your telescope not to vibrate wildly every time the cat walks by.

By now, you’re probably asking how much magnification capability can I buy for my money. Sure enough, commercially manufactured astronomical telescopes’ power specification can be a contentious issue, especially since entry-level manufacturers tend to be too optimistic – even dubious - about the capabilities of their product lines. A telescope by itself doesn’t magnify anything because it doesn’t make objects look bigger it makes objects look brighter.

Making things look bigger is the job of the eyepieces you use with the telescope. Which – to the astronomical telescope’s manufacturers’ disdain – can allow you to use microscope magnification eyepieces as magnification eyepieces for your starter astronomical telescope. So it can be a boon if you also own a starter microscope. By changing eyepieces, you change the magnification. In most cases, the eyepiece will be marked with a number – usually in millimeters – that tells its focal length. The same eyepiece will deliver different magnifications in different telescopes. But in general, the lower the number on the eyepiece, the higher the magnification it delivers.

And believe it or not, you don’t even need a lot of magnification to see some interesting celestial vista. You can see Jupiter and the planet’s four biggest moons at a magnification of just 15 times (15X) – which is half that of the magnifying power of Galileo’s first astronomical telescope. While Saturn’s rings pop out at around 30X magnification. It is worth noting that most beginners’ astronomical telescopes – especially those with small apertures – can’t deliver a good image of anything at much over 150x. Either the result is an image that is too dark, since higher magnifications tend to darken the image, or is an overly distorted mush. Most entry-level astronomical telescopes – those priced between 150 to 300 US dollars – come with one or more eyepieces. You can also buy extra eyepieces separately or use ones from your microscope. Generally, it’s nice to have three sets of eyepieces: one for low power around 15X, one for medium power around 30X to 60X, and one for high power around 100X or greater.

For those beginners looking for an astronomical telescope on the cheap – which usually means second hand – avoid falling into the “long skinny trap”. I mean don’t discount a telescope just because it doesn’t looks like your typical astronomy telescope – i.e. long and skinny and mounted on a tripod. I’ve frequently encountered second-hand telescopes being offered on garage sales and swap meets that although very good, tend to look weird. Like the Astrocan, a round telescope that rotates on a short metal base. And Dobsonian reflectors – featured in the movie Roxanne – which have very stable box-shaped alt-azimuth mounts are often featured on Internet adverts being offered at prices too low to ignore. These two types are probably the most common second-hand astronomical telescopes being offered for sale. Although these types of astronomical telescopes have the disadvantage of not being so man-portable, unless of course your observation spot is accessible by car.

A good place to buy an astronomical telescope if you chose to buy one brand new are astronomy specialists shops – although some offer second-hand and “ex-dem” models at “very reasonable” prices. The clerks are more than likely to be able to help you choose a good scope within your budget, and you’ll also be able to test the telescope at the store. Also, you will be able to take the telescope back to the store if there are manufacturing defects. Or servicing within the warranty period since the shop is probably the telescope manufacturers authorized distributor / dealer. And the specialist shop carries a line of eyepieces and other accessories that you may want to buy later on. And believe it or not, specialist astronomy shops are probably the last place on the planet that sells 35mm photographic film. Given that - to my knowledge - everyday picture taking / photography has more-or-less gone completely digital since 2005.

Seeing Pluto

Debate over its planetary status aside, is it possible to actually see the planet Pluto using astronomical instruments commonly available to amateur astronomers?


By: Vanessa Uy


Mysterious Pluto managed to acquire “Page Six” supermarket tabloid-style popularity during the last few years. Mostly due to the International Astronomical Union’s somewhat hasty dethronement of its planetary status, thus inciting a populist uprising of a significant portion of planet Earth’s population. But to an amateur astronomer lucky enough to own an 8-inch reflector, chances of seeing this far-off real estate of our Solar System is now a possibility.

For some amateurs, seeing Pluto first hand via their own telescope can be a transcendental experience. Not unlike that of experiencing a live performance of "Beethoven’s Ninth” first hand. For others – like me – glimpsing it’s feeble light means creating your very own cherished memory. Especially if the most advanced digital camera you happen to own doesn’t have enough resolution to capture your “Pluto Moment” and post it on the Internet.

After the older members of our astronomy club had their “Pluto Moment” via their 8-inchers back in 1998. Using the star Zeta Ophiuchi as a guide star to find it back then. By the way, Zeta Ophiuchi is the bright middle star in the row of three at the bottom of the constellation of Ophiucus the serpent handler. Pluto’s current position on the latest Telrad Finder Charts puts it within the field of the constellation of Sagittarius, where it will remain until 2023.

As a consequence of our Earth-based vantage point, Earthbound astronomers will always see Pluto initially describes typical annual loop formations – which in this region of its orbit – averages around 2 ½ degrees across measured from Eastern to Western stationary points. The loops gradually open out into zigzag formations as Pluto approaches and then crosses the ecliptic – i.e. the apparent path of the Sun through the Zodiac as seen from our earthbound perspective. The helical nature - though it looks more like a squashed spring stretched sideways - of Pluto’s loop formations – which resembles a stretched spring – is a consequence of its steep – 17 degree - orbital inclination to the ecliptic. Coupled with the fact that Pluto is currently on the descending half of its orbit. Pluto’s opposition magnitude or brightness as seen from the Earth’s surface fades during the 16-year period – i.e. between June 2006 and July 2022 – from +13.9 to +14.3.

With Pluto’s magnitude fast approaching +14.0, you should be able to spot it with an 8-inch reflector from a dark observation spot, preferably one not plagued by urban light pollution. Once you become familiar with the Sagittarius constellation star field at medium power, crank up the magnification past 150x. An even higher power is better still, if the seeing conditions are good – i.e. the night sky is not shimmering like the air over a barbecue grill – or if your telescope’s optics is up to the task. Higher magnifications will darken the background, making Pluto more than just a faint flicker.

Even though blink comparators for amateur astronomers isn't yet widely available, the best way to confirm your very own observation of Pluto is to look for it twice – preferably a few days apart. You could decide to sketch the field with stars slightly dimmer than 14th magnitude. Use the second night’s observation to see which star has moved against the distant background stars. A broad V-shape of 8th to 9th magnitude stars can be used to anchor your sketch. Some newer telescopes are even equipped with a built-in LCD combining display with memory function. Which allows you to save your sketch into your telescope. To display their handicap prowess, some amateur astronomers who served as US Army or USMC snipers during Operation Desert Storm even masked down their 8-inchers while trying to find Pluto with less than 4 inches of available aperture.

My first hand experience – or is impression more apt - of “seeing” Pluto is that it looks like a pale blue robin egg colored star. From the eyepiece of my 8-incher with the magnification set at 150x – assuming that it’s chromatic aberration is invisible to my own eyes – Pluto does look different when compared to other stars within the Sagittarius star field. You can somewhat tell – assuming your own visual acuity is up to it – that Pluto merely reflects light from a primary source like our Sun. As opposed to the distant stars which can generate light by themselves. If an amateur astronomer has the ability to spot Pluto with his or her own 8-incher, and can do this with handicaps like masking their telescope to reduce available aperture. Then maybe they should consider becoming pros.