Mars ho!

Early this morning EDT, NASA landed the largest rover yet onto the planet Mars, the fourth rock from the Sun. The Mars Science Laboratory, containing a car-sized rover named Curiosity, landed in Gale Crater via a sophisticated "sky-crane" technique involving a hovering component that gradually and gently lowered the rover to the surface.

Once it had landed, it beamed back a signal of its success and its first images of the crater surface in black and white:

Color images will come later when the main cameras have been activated. At this point, mission scientists are no doubt chomping at the bit to get the rover moving and exploring. Its primary mission is to determine whether Mars was ever capable of supporting life. While this may seem like an ambitious goal, NASA scientists have tried this type of thing before with the Viking landers so they know what sorts of tests don't work as expected. The Curiosity rover, outfitted with a huge array of instruments, should be able to perform far more complex measurements and analyses to measure the mineralogical composition of the Martian surface and to search for any potential chemical building blocks for life. Orbiting spacecraft had previously identified certain minerals within the crater that may have formed in a watery environment, so Curiosity will study these minerals further. If water did indeed exist to facilitate this mineral formation, then it may have also allowed microbial life to exist within the environment as well. Within the Gale Crater there also exists a mountain roughly 3 miles high named Aeolis Mons that Curiosity intends to investigate.

Mars has drawn the attention and inspired the imagination of humanity for well over 100 years. Since Percival Lowell's time spent at the telescope observing what he believed to be canals made by an intelligent but dying civilization, mankind has wondered about the existence of life on our red neighbor. While the existence of such canals was later dismissed, observations of changing dark features on the Martian surface and a spectrum that mimicked that of chlorophyll seemed to suggest that Mars may be covered with some form of vegetation that changed with the seasons. These observations led to the development of many great science-fiction thrillers, from "The War of the Worlds", written in 1898 by H.G. Wells and adapted into both a terrifying radio program and two movies, to "Invaders from Mars" and "Mars Attacks", people have wondered about the possibility of

hostile life on this mysterious world. Other speculative movies linking life on Mars to life on Earth include "Mission to Mars" and "Red Planet". And let's not forget "John Carter" and "Total Recall." While these movies vary in quality, they all address the idea of sending humans to Mars or being visited by beings from Mars.

While the Mariner missions revealed to us that Mars appears to be a dead planet, it does retain some characteristics that make it somewhat Earth-like. A wispy thin carbon dioxide atmosphere, canyons, mountains, and polar ice caps all bring to mind thoughts of Earth. However, its vast lifeless deserts and cratered surface more closely resemble the Moon. Mineralogical evidence that liquid water may have at one time existed on Mars have motivated mission after mission to explore its surface and look for fossilized evidence of life. Now that we have landed the most sophisticated instrument lab yet, we may be able to finally answer this question once and for all.

You can keep up with the Curiosity rover's progress and scientific findings via the Jet Propulsion Laboratory's website at http://mars.jpl.nasa.gov/msl/.

July - a great time to use that new telescope!

 With the Venus transit behind us now, it seems that the astronomical skies are "calming down" - at least for now.  But that doesn't mean there is nothing to hunt down on any given night.  The sky is full of potential targets, whether using binoculars or a telescope, so let's take a look at what is coming up in July.

Unfortunately for you naked-eye viewers, there are no meteor showers scheduled for July.  The next one isn't until mid-August (the Perseids). However, with the full moon occurring on July 3, this leaves many of the early and mid-month evenings available for reasonably dark-sky constellation viewing.  Mars is currently making the transition into the constellation of Virgo right now, gradually drawing closer to Saturn in the sky.  At the same time, these two bright planets are beginning to appear lower and lower in the west as the weeks go on, so be sure to spot them before they are gone.

If you got a new set of nice binoculars or a telescope for Christmas and have been anxiously awaiting those warm summer nights to learn how to use it, this would be a great time to get it out. While you may not yet know what exactly to look at - particularly if your telescope isn't motorized - you can still learn the fine art of star-hopping. Find a star map online (free all-sky maps can be found here) or you could download one of any number of astronomy apps if you have a smartphone and you're ready to go. While your binocs or telescope will show more stars than may appear on your star map, you'll gradually get the hang of locating the next star by comparing relative positions and brightnesses. Nothing in astronomy comes easily, but learning is part of the fun. Once you are a master star-hopper, download maps of the Messier objects and push your equipment to the limit. If you are using binoculars for this, you may wish to purchase a tripod and mount for them to hold them steady.

 Star clusters are fantastic objects to point your viewing instrument at because they're generally bright enough to see even with small binoculars.  The globular cluster M13, for example, is high in the sky all night this month in the constellation of Hercules - hence its unofficial title "The Hercules Cluster."  The image below (courtesy of SEDS) will give you an idea of what to expect.

Of course, this is an image taken with a camera so your view through the eyepiece won't be so rich or saturated, but you may find that you prefer the eyepiece view even better!  As you examine its stellar population, think about the fact that this cluster is believed to be at least twice as old as our solar system and contains several hundred thousand stars all packed into an area roughly 150 light-years across.  Try to count the stars yourself to see how many you can see with your equipment.  Imagine what the night sky would look like if you lived on a planet orbiting one of these stars.  Then go exploring to see what else you can find!

Happy viewing!

Venus Transit, Conquered

Oneonta weather gave us some challenges when it came time to observe the last Venus transit for 105 years, but it was worth it!  This entry is a description of the evening's event as I described it to the folks who write for the College news.

The evening began with a solid cloud deck and rain, but by 6:00 the rain had stopped and the clouds had slightly thinned. By that point, Shawn Grove (a 2012 SUNY Oneonta graduate) and I were joined by 5 or 6 people from the community in the observatory waiting for the weather to clear. The transit technically began at 6:03 p.m. here in Oneonta, and around 6:10 we were suddenly greeted with a thin spot in the clouds where we could see the disk of the Sun. Quickly we pointed the 14-inch telescope at it and were greeted with a view showing Venus approximately halfway through its "entrance" into the solar disk. It looked like a dark dimple in the edge of the Sun. Those who were present were very excited to see this, although it only lasted a few minutes before the clouds thickened up again. From then we waited for over an hour, watching as small gaps in the clouds passed by outside the vicinity of the Sun. More people from the community arrived, and some waited while others left.

Then at about 7:20 p.m. we saw sunlight streaming through another break in the clouds. By this time the Sun had dropped low enough that it was behind trees, so we couldn't see it from the elevated 14-inch dome. However, we did have a smaller 4.5-inch telescope with a solar filter on the ground that we could move. Grabbing it, we raced across the grassy lawn to a point where the Sun was visible. Venus was well into its transit by then so we were blessed with the view that is shown in the image below.

The clouds remained thin enough to see it clearly while the group of roughly 15 people, including several children, each took turns looking through the small scope.  A handful of people had gone into the woods to check out the nearby pond and when we called out to them they came sprinting out of the woods. Everyone was able to see it, many people took pictures with camera phones (and me with my digital camera), and by 7:45 p.m. the clouds obscured the Sun again just as it dropped below the tree line for good.

Part of the excitement was that "thrill of the hunt" feeling from waiting and then pursuing with the small telescope in hand. Another part of the excitement came from being able to witness an event that won't occur for another 105 years. However, I think the greatest satisfaction for me was being able to see people from the community come up in the hopes of seeing the transit, be rewarded for their diligence, and walk away feeling like it had been worth the wait.  Everyone was thrilled to have been able to see it.  Thank you to everyone who came out to see it!

Venus Transit of the Century

With a plethora of websites dedicated to tomorrow's transit of Venus across the face of the Sun, including a page on Wikipedia about it, I don't feel the need to wax eloquent about the upcoming event in too much detail. Numerous sources can be read to learn about the orbits of Venus and Earth, the importance it once had in determining the distance scales of our solar system, and so on. However, since this blog is dedicated to the observer in the Oneonta, NY region, you're probably wondering about when it will be visible.

The most recent transit of Venus occurred in early June of 2004.  This transit occurred in the early morning in North America, with viewers in New York seeing it already in progress as the sun rose.  This made the event a bit of a challenge to see, since getting up before the sun rises isn't on most people's list of favorite things to do.  In Michigan at this time, I would have been an undergraduate at Central Michigan University.  Since I was an avid astronomer and astronomy student at the time, if it had been visible then I'm sure I would have gone to see it at our school's telescope.  The fact that I don't have any memories of it makes me think it may have been cloudy that day.

For those who don't know me...I have a terrible memory.  Case in point: I currently have 13 Post-it notes on my desk at this very moment with reminders for various things!  Not to mention the five half-page sized pieces of paper with other various notes jotted on them and an index card of notes as well.  But I digress...

The 2012 Venus is visible in North America in the early evening until sunset, making it much more accessible for the average viewer.  Expected to begin at approximately 6:00 p.m. in Oneonta, the second planet from the Sun (and our closest planetary neighbor) will continue its sojourn across our star's face until well after the sun has set, giving us only a limited opportunity to watch it for approximately an hour and a half.

The current weather forecast is for clouds and possibly rain.  If you're a sucker for "once-in-a-lifetime" opportunities, you may want to take a trip somewhere else to watch it - preferably farther west where you can watch it for a longer time period.

HOWEVER!  The Internet now offers the couch-astronomer and those of us in cloudy parts of the planet the chance to watch this event live as seen from somewhere else. You can visit the website for the SLOOH Space Camera or NASA's live webcast from Mauna Kea, Hawaii. I recommend tuning into the webcast shortly before 6:00 p.m. EDT to make sure you see it.  If you want it to feel like you're really there watching it through a telescope, get a paper towel tube and hold it up to your computer screen.  Who says you need fancy equipment?  The Internet is pretty fancy in my opinion!

If you are in the Oneonta area and the weather magically happens to be clear in the late afternoon on June 5, come see us at the SUNY Oneonta observatory at College Camp.  We will have a couple telescopes with solar filters for safe viewing set up.  Don't look directly at the sun for this event, or permanent eye damage may result.  We will have safe equipment for viewing the event.  Our viewing of the Sun and the eclipse will be open to the public starting at 5:30 p.m.

If the weather looks bad, hop online and visit one of the websites above.  This is what I did for the most recent annular solar eclipse and it wasn't bad.  Better than missing it altogether, anyway!

Happy viewing!

How to Buy a Telescope for Yourself

Throughout this blog I have made reference to viewing various celestial objects and events through binoculars or a telescope, and this works fairly well if you already own one or both such instruments. However, suppose you don't own either one - or, suppose you own a pair of binoculars but are itching to buy a telescope. It is perhaps the most common question that novice astronomers and non-astronomers ask experienced amateur and professional astronomers: "I'd like to purchase my first telescope. What telescope should I buy?" Today I will provide you with some instructions and advice that should (hopefully) be of use to you as you begin shopping around. In a future entry I will explain how to purchase a telescope for your child.

Before You Begin
If you are new to the night sky, then I would suggest buying a pair of nice binoculars first. You can drop $100 at Walmart for a cheap telescope that will quickly disappoint, or you can buy a quality pair of binoculars at the same cost that will provide better image quality. Yes, you are losing out on magnification (although don't buy the pitch from the cheap retail telescopes that claim 500X magnification!), but what you are gaining is an easily-transported, well-made optical instrument that will introduce you to the night sky before you get lost using a new telescope.

Here is a common scenario: you enthusiastically run to the store to buy a telescope, spend $150 on one that promises incredible magnification and comes in a box plastered with amazing images of planets, nebulae, and galaxies, then take it home and don't know what to look at. This occurs because the telescope didn't come with a drive motor or computerized paddle - you know you'd like to look at Saturn, but don't even know where Saturn is.  You go inside also wishing you knew what season the constellation Orion was visible, pack the telescope in its box, and it subsequently collects dust.

Is the best choice to go buy a nice computerized telescope?  Not unless you'd like to spend $500 or more on something that will likely sit in your garage or basement for the foreseeable future.  Buying a nice pair of binoculars and a star atlas allows you to fall in love with the night sky.  Go outside, lay on a blanket, and use your star atlas to guide you from star to star through a constellation.  Binoculars have sufficient magnification (the first number in the specs: for example, "7x50" binoculars have a magnifying power of 7X and an aperture of 50 mm) as to reveal rich open star clusters, the phases of Venus, the Galilean moons of Jupiter, and exquisite lunar features.  Star-hopping like this helps to familiarize yourself with the night sky.  Using star maps from an atlas or an astronomy magazine, you can become an expert in night-sky viewing.  Then go buy a telescope.

Types of Telescopes
There are several different kinds of telescopes that can be differentiated by the optical elements they utilize and the mounts on which they are built.

1. Refractors:  Refracting telescopes are long and narrow tubes with a glass lens on one end and an eyepiece on the other:
   
   These telescopes can be on equatorial mounts (shown above) or altitude-azimuth mounts (which are easier for pointing, harder for tracking).  Cheap models will have one simple lens at the aperture (the big end), while higher quality models will have a two-piece (achromatic) or three-piece (apochromatic) compound lens.  The more lenses, the better the image quality because these additional lenses are correcting for an effect called "chromatic aberration" where different colors are focused at different distances by the glass lens.  Of course, the more compound the lens, the higher the cost as well.  Many refractors are not motorized, although some of the high-end ones can be.
2. Reflectors:  Reflecting telescopes utilize mirrors to focus the light rather than an aperture lens:
   
   These can be long or short, and most often have an open aperture with a mirror on the lower end.  The light is reflected off this mirror to a smaller, flat mirror up near the opening and then directed out the side of the telescope through the eyepiece.  Reflectors do not have chromatic aberration and typically offer more bang for your buck as far as aperture size goes.  The larger the aperture, the more light is collected - producing a brighter image with better resolution.  Equatorial mount reflectors can come in both motorized and non-motorized forms.
3. Dobsonians:  Dobsonian telescopes are simply reflecting telescopes that sit on the ground in an altitude-azimuth mount:
   
   Other than this mount difference, they have the same characteristics as other reflectors while also providing much longer focal lengths - giving you higher magnification capabilities (provided you have the right eyepieces).  Dobsonians are almost never motorized, but many do come with a computer paddle that tells you which direction to move the telescope by hand.  This is a reasonable compromise between paying less for a non-motorized telescope while also having the advantage of a built-in object library.
4. Schmidt-Cassegrains: The final "general" category is the Schmidt-Cassegrain Telescope (SCT) that uses both a lens and mirrors to focus light:
   
   These provide great image quality, high magnification potential, and are usually computerized...but they are also expensive. 

Choosing a Telescope
When you are ready to purchase your first telescope, there are a number of factors that you should consider.  These factors are (in no particular order):

1. Budget
2. Optical quality / aperture size
3. Portability
4. Time available for use
5. Ease of use

Budget:  Most people consider budget the primary factor, and this is reasonable.  When buying a telescope, you can find them ranging in price from $100 to $10,000!  My first tip: don't run to a department store and buy that $100 one I mentioned earlier.  While affordable, these telescopes are mass-produced with low-quality optical elements and a wobbly mount.  Why does the mount matter?  If your telescope is constantly shaking and vibrating when you touch it and doesn't stay aimed at anything without drifting, your experience will be extremely disappointing.  Having a stable, sturdy mount is almost as important as having quality optics.  For your first telescope, plan on spending around $300-$400.  This will ensure that you have struck a good balance in quality and size for your first telescope.  Which brings me to the second factor...

Optical quality:  If the quality of the lens or mirrors in your telescope is poor, your viewing experience will be poor as well.  Department store telescopes are made with cheap glass lenses that offer more aberration than acclamation. A telescope retailer (either a store or online) will provide better quality options.  You want a telescope that uses quality lenses or mirrors!  This ties in with aperture size too.  In general, bigger is better.  However, bigger is also more expensive.  You'll need to strike a balance.  You can use a diagram like this to determine your optimal aperture size:

"Limiting stellar magnitude" in this diagram simply refers to the faintest object you can see through the telescope.  Larger numbers correspond to fainter objects.  Between 6-10 inches in aperture diameter typically provides a reasonable performance for its cost.  Refractors have smaller apertures than most reflectors, but can provide better images if you pay for it.  For reference, planets are bright, galaxies are faint.  Planets are easily visible in nearly all telescopes, while galaxies are only visible with larger apertures - typically greater than 10 inches.

Portability:  Will you be taking your telescope on trips, or will it always be used outside?  Will you be the one using it, or will your child?  Portability is an important thing to consider depending on your plans for the telescope.  Larger telescopes and sturdier mounts are heavier to move around and sometimes require a bit of dis-assembly to transport.  Additionally, if your telescope has a drive motor and/or computer it may require a source of electricity.

Time available for use:  How often do you envision the telescope being used?  Once a week?  Once a month?  Only once?  If you will use it a lot, you may wish to spend more on one that will provide a lifetime of viewing options - this generally means purchasing a larger telescope with a broad range of eyepieces.  If it will be used only on occasion, then don't spend more than $500.  If this might be used once or twice before interest in it wanes, don't spend more than $300.

Ease of use:  How good are you at learning to use new equipment?  Is this for a child or an adult?  Simple telescopes may look "too basic" but they are much easier to use than computerized telescopes.  They act as "point-and-shoot" telescopes, and all you really need to learn is how to point them using the axis knobs.  However, you also need to be familiar with the night sky.  Motorized, computerized telescopes make it very easy to find things...provided that you have it plugged in and set up properly and have done a correct alignment using several stars in the sky.  Motorized telescopes have thicker user manuals.

The Final Choice
After you have considered all these factors, it comes down to making a choice.  Many amateur astronomers will go with a 6- or 8-inch Dobsonian reflector and be very happy with it.  Others prefer to buy a nice 3- or 4-inch refractor and get superb views of solar system objects.  Motorized SCTs are extremely hard to find under $700 unless you buy one secondhand.  All things considered, I prefer to recommend getting as much aperture as you can afford.  A great 4-inch refractor is nice, but at the cost of something like that you can get a 12-inch reflecting telescope with a drive motor that will allow you to see many more types of objects than the smaller refractor.  Consider the factors I have mentioned above carefully, then talk to a telescope retailer to find one that will best fit your desires.

Resources
Check out some of these manufacturer websites to see your options and their costs:

• Meade
• Orion
• Celestron
• Galileo

Eclipse Update

After reviewing an interactive and animated web tool called Shadow & Substance, it appears that Oneonta may not get to experience even a partial solar eclipse on May 20 after all. It seems we are just a bit too far east. I had hoped that our altitude might help to override this, but it looks like that may not be the case. At any rate, this will not stop me, and should not stop YOU, from keeping an eye on the Sun as it approaches the horizon. Right at the point of sunset it may be possible to see the slightest piece of the Sun become obscured by the Moon. Try to find a place up in the hills that has a clear view of the western horizon (no trees). If you miss it, then wait until August 2017! There will be a partial solar eclipse visible from Oneonta for sure. Venus is beginning to set earlier and earlier in the evening now. It has passed its greatest elongation and is not heading down into the glare of the Sun. On June 5th it will transit in front of the Sun, with first contact occurring at about 6:10 p.m. EDT. I will write about this in more detail as the date gets closer. In the meantime, pray for clear skies!

Saturn is continuing to be a stunning sight through most telescopes. With its rings tilted at a 13-degree angle to our light of sight, they are easily spotted. During our most recent public observing night at College Camp, the air was still enough that even the Cassini division was visible in the 16-inch telescope, along with 4 moons (Titan, Tethys, Rhea, and Dione).

What a beautiful vision! Every person who views Saturn through a telescope when the seeing is good remarks how it looks just as if it were a picture held up at the other end of the telescope. Watch Saturn's moons from night to night to see how their positions change. The semester is coming to a conclusion this week, so I'm busy preparing reports and final grades. Once this has died down, I will be back with another post. Happy viewing!

Transits, eclipses, and meteors...oh my!

Ever since Venus and Jupiter made a wonderful pass by each other last month, Venus has been dominating the evening sky after sunset. Shining brilliantly in the western sky, Venus has passed its greatest eastern elongation (the point where it is farthest east of the Sun - visible in the evening) and is now on its way back into the sunset glow for the upcoming transit in front of the Sun on June 5th. This will be something nobody alive wants to miss, as the next one won't happen for another 105 years! Until then, we Oneonta residents will hope and pray for clear skies that day. For now, there are still some exciting things to come.

The United States is not often blessed with the opportunity to view a solar eclipse, but this month we will be...in part, anyway. An annular solar eclipse will be visible in the southwestern portion of our country on May 20.

If you live in New Mexico, Arizona, Utah, Nevada, or California (or will be there on vacation) you will get the chance to see the Moon almost block out the Sun completely. Annular eclipses happen when the Moon lines up perfectly with the Sun in our sky, but is at a point farther away in its orbit around the Earth than average. This results in the Moon having a slightly smaller angular size than the Sun, producing a ring of sunlight around the New Moon instead of being completely blocked out. While not quite as spectacular as seeing a total solar eclipse, annular eclipses are also amazing to watch and certainly, beggars can't be choosers!
Here in Oneonta, we will see a partial solar eclipse beginning around 5:15 p.m. on May 20 and continuing on until sunset. Even though we won't be able to see totality from our location on the Earth, I still plan on viewing this event if our skies are clear. If you plan on viewing the eclipse, be sure to use appropriate eye protection. I will probably use a telescope fitted with a solar filter. More on the eclipse as the date gets closer.

More immediately, we have another meteor shower coming up. On the night/morning of May 4th/5th, the Eta Aquarid meteor shower will be visible. This meteor shower is one of two that derive from the dusty trail of Halley's Comet (the other being the Orionids) and, while not a particularly active meteor shower, can produce 10-20 meteors per hour at its peak. While its radiant won't rise until the early hours before dawn on May 5th, it is usually better to look about 90 degrees away from the radiant anyway to see those dust particles that give us a glancing blow. Viewing after midnight is recommended, but unfortunately this year the Full Moon's overwhelming brightness may hinder attempts to see all but the brightest streaks across the sky. It's still worth a look, however. Additionally, since the maximum technically occurs during the Oneonta afternoon, if you are clouded out on the night of May 4th you can try again on the night of May 5th. Here is a chart showing the radiant of this meteor shower as it is rising in the early hours before dawn in early May:

Happy viewing!