Looking up into the sky for fun!
Thank you for checking into my blog, even though I haven’t posted anything for a while. I started with the goal of posting a new article every Sunday evening. I have found that it is not easy to come up with a good article on a weekly basis.
So, my new goal is to post something every Sunday, even if it is very brief.
Your Guide to the 2017 Total Solar Eclipse – by Michel Bakich – Springer International Publishing – 395 pages – $23.17
Your Guide is exhaustive. It gives good advice on every topic of viewing a solar eclipse: choosing a site, what to bring, and what to expect. It even points out the importance of taking a restroom break well before totality!
Many topics are covered in this large book, such as:
If you wanted to buy only one book about the August 21, 2017 eclipse, this one should cover all your needs. Even if you won’t be viewing the total eclipse this August, Your Guide is still very interesting and informative.
Keep looking up!
John
On Monday, August 21, 2017, residents of the continental United States will have the opportunity to view a solar eclipse. A total eclipse will be visible along a narrow path which goes through 14 states. For the rest of the 48 states, a partial eclipse will be visible.
I have already done a few things to get ready to see the total eclipse:
Since so much good material is available, I will not try to write a book. I would like, however, to list some things I have learned:
My general plan is as follows:
Here are some videos of recent eclipses:
https://www.youtube.com/watch?v=ffBYVQ7j8MI
https://www.youtube.com/watch?v=15iufFqah9E
https://www.youtube.com/watch?v=KE4nwAvoGx8
https://www.youtube.com/watch?v=gzh-nZBP0d4
The only thing missing in these videos is the enormous crowds we will have in the US!
Keep looking up!
John
Cost
To estimate the cost to travel to Mars, it is necessary to identify what needs to be shipped to Mars, what kinds of spacecraft need be built, and what kind of difficulties may arise. Since we cannot easily answer these questions, we can only make a vague guess as to the cost of the program.
Some high-expense items to consider would be:
To raise the funds for a venture this big, the governments of several countries will need to work together. Each of these participating nations well need to make a firm commitment to staying with the program for many years. Unfortunately, the politics of many countries works against long term participation.
In a democratic country, the voting public would need to be willing to pay high taxes for a long time. They would need to keep paying, even with the inevitable cost overruns. It is doubtful that this would happen.
Currently, in the USA, funding for robotic missions does not come automatically. Each mission must be justified to obtain funding. Given this difficulty, it is difficult to expect that human travel to Mars would be approved.
All of this leads to the third topic:
Value
I won’t dispute the fact that human explorers would be able to do things which robots cannot do. People have intuition, which will enable discoveries which are not anticipated. People can make repairs to equipment, which would be awkward or impossible to do otherwise. People observe on a deeper level than mere instruments. When something new or unusual is found, the human observer wants to understand it, and immediately examines it in detail.
In discussing value, we try to predict what we will accomplish, and decide if it worth the cost. Currently, robotic missions are steadily building up our understanding of Mars. No doubt, more will be launched during the next decade. Eventually, they will bring samples of Martian soil back to Earth.
For the cost of a single human mission, many robotic missions could be launched. These devices would not need to be identical, but could incorporate the lessons from previous successes and failures.
After Mars has been well examined by robots, human exploration could begin. Then human beings could begin to do what machines can’t do. Today, we don’t know what that necessarily human contribution would be.
So, the good news is that we are already exploring Mars in a logical, progressive, and affordable manner!
Next week, I will ask you how your plans for 8/21/17 are coming along!
Part 1 – Safety
Honestly, I am not having a bad day, and I love space exploration. I am very enthusiastic about exploring Mars. I am amazed at how well some of the robotic craft have performed.
I would like to see larger numbers of roving vehicles traveling the rocky red paths of Mars. I do not think, however, that we are ready to think seriously about human travel to Mars. Also, I don’t take it as a certainty that it will happen “someday in the future”. Here are my reasons: safety, cost, and value.
Safety
I have seen sketches of proposed missions for travel to Mars, and I think that they would have some chance of getting our people to Mars and back home safely. The problem is that they assume that everything will go reasonably well. We have learned a lot about building reliability into our spacecraft, but we have had the option of returning quickly to Earth if malfunctions became too great to handle.
A craft en route to Mars will need the capability of managing and recovering from a major problem. What kind of problem? Since the flight of Yuri Gagarin, we have had fires, a burst oxygen tank, rocket motors which failed to run when needed, attitude thrusters not shutting off, a loss of hull pressure from a docking mishap, failures of modules to undock, release of toxic gas into a crew compartment, and several types of space suit malfunctions.
The Mars spacecraft will need to have extensive countermeasures and backup systems. Even so, to have a high level of safety, it may be necessary to travel in tandem with a complete redundant spacecraft, with a means of getting from one to the other quickly.
Although there may be astronauts willing to take a great risk, I would not wish to put them in danger by paying for a mission which doesn’t have an excellent prospect for success.
In addition to the difficulty of building a robust spacecraft, the problem of radiation must be addressed. When a vehicle moves outside of low-Earth orbit, radiation becomes a serious concern. There is a constant stream of high-energy particles in space. During a solar flare, it becomes much more intense. We have only begun to learn how to provide effective shielding to protect the crew.
Thank you for bearing with my somber treatment of such an exciting topic as space exploration. I promise to wrap up this series with some very encouraging ideas!
Coming: Cost and Value
A Star Party in an Unexpected Place
A month ago, I visited a cousin in New Jersey, who shared about his experiences at a local star party. I was surprised to hear that there was such an event in his area. This part of New Jersey is one of the most light-polluted areas of the country. It is about 6 miles from New York City.
This observing night was held at the William D. McDowell Observatory in Lyndhurst, NJ. At their viewing nights, they select objects which are bright enough to stand out against the bright background sky.
Here is more information about the McDowell Observatory programs:
Viewing Nights at the McDowell Observatory
It may seem odd to build an observatory in an area where the sky never gets truly dark, but it provides viewing opportunities for millions of people (but not all at the same time!). Consider the opposite extreme: an observatory on top of a mountain in the New Mexico desert. There would be outstanding viewing, but very few people would be able to travel the long distance to enjoy it. So, if you are in northern New Jersey, this ought to be fun!
The Best of the Best Objects to View
When you attend your star party, the astronomers will select objects that are interesting, and are in a good portion of the sky. Here are some of the most interesting things, roughly in order of visual impact:
The Moon – A quick look at the Moon reveals craters of all sizes, mountains, and flat dark “seas”. If you take more time to study the Moon, there is an endless variety of features, too many to describe here.
Saturn – for many people, the first look at Saturn through a telescope is an emotional experience. Even though larger and more detailed views can be found in books and on line, this is not the same as looking at the planet directly. Saturn is very bright, and has a sharp contrast to the background sky.
Jupiter and its moons – Because Jupiter is larger than Saturn, and is closer to us, it makes a larger image in the telescope. There are many features on the surface of Jupiter to enjoy. The main ones are the belts (dark bands which wrap around the globe), and the Great Red Spot (which nowadays is somewhat small and orange). The four largest moons of Jupiter are very bright, and move fast enough for changes to be noticed in a few hours.
The Hercules Cluster – This object is a globular cluster, a spherical collection of hundreds of thousands of stars orbiting a central point.
The Orion Nebula – This is an immense cloud of gas which is being transformed into new stars.
The Ring Nebula – This object comes from a very old star, which has shed a layer of its surface. This expelled layer has taken a ring shape, and is expanding in size.
Mars – Mars is called “The Red Planet”, but would be better described as orange. A casual view of Mars shows only a bright orange disk. The constantly moving pockets of warm and cold air in our atmosphere prevent a good view of the details of Mars. Persistence pays off, however, because there are occasional moments when a sharp view gets through. During these split-second opportunities, polar ice caps and dark areas can be seen on the surface.
Albireo – This is a “double star”, a pair of stars which orbit each other, or appear to do so. Albireo is unique for its brightness and the colors of its two stars.
The Double Cluster of Perseus – This is a pair of star clusters somewhat close to each other. They are called “open clusters”, which have far fewer stars than globular clusters. In the Double Cluster, many bright stars are beautifully arranged against the dark background sky.
The Andromeda Galaxy – This is the closest large galaxy in our stellar neighborhood. Through a telescope, it appears as a fuzzy oval, a little bit bigger than Jupiter. Looks can be deceiving, because the Andromeda Galaxy is composed of billions of stars, and is over two million light-years away!
That’s all for now. My goal is to post something interesting every Sunday night.
lookin’ up,
John
Because of the elliptical shape of the Moon’s orbit, its distance from the Earth is constantly changing. This week – Monday, November 14, 2016 – we will have a Full Moon which will be at its closest since 1948. Since it is closer than usual, it will appear larger than usual. Hence, the name, supermoon.
The supermoon has gotten a lot of publicity, although the event will not be very exciting. The visual size difference between the Moon at its closest and the Moon at its farthest is about 14%. If we could view both the “large” Moon and the “small” Moon at the same time, a 14% difference would be obvious. Unfortunately, the Moon doesn’t present itself that way. So, we need some way to measure the Moon’s apparent diameter, so we can compare it with a future sighting. I have added some links to articles on this topic.
In my humble opinion, the easy ways of measuring the Moon’s apparent diameter are not very accurate. However, if you have a camera which can make a large, sharp image of the Moon, try taking pictures this Monday and compare them to future pictures. Of course, you would need to use the same settings for all the images. This would be fairly easy, and fairly accurate.
Another technique would be to take a good look at the supermoon, and examine the finest possible details of it’s surface. Make a sketch or make a mental note of what you could see. Repeat this exercise next month.
My plan is to simply go out and take a good look at the supermoon, and call it a night.
Here are some links to more information:
http://www.skyandtelescope.com/observing/see-the-biggest-supermoon-in-68-years/
http://www.astronomy.com/observing/news/2016/11/theres-super-hype-for-this-months-super-moon
You may not realize it, but there may be opportunities in your area to enjoy the sights of the sky with knowledgeable amateur astronomers who love to have people look through their telescopes.
In the astronomy jargon, a star party is a small or large gathering of people interested in looking at stars, planets, clusters, galaxies and other interesting objects. There are many variations on the general theme of star parties. Some are held away from cities to enjoy the darker skies. Others are held in built-up areas, so that people can see some beautiful sights without having to travel. Some are held at observatories, some in parks, some are informal gatherings at private homes.
A common element of all star parties is a chance to meet people who are excited about exploring the universe. There will be an opportunity to look through a variety of telescopes. One can go from scope to scope, see different objects, and hear explanations. Later in the event, the crowds are smaller and attention shifts to more unusual or difficult objects. This is a great time to make requests.
How to find the nearest star party? The best way is to find an astronomy club in your area. If the club doesn’t conduct star parties, they should know how to find one. Here is a link to a directory of astronomy clubs:
http://www.skyandtelescope.com/astronomy-clubs-organizations/
Having found an event, there are a few courtesies which help everyone have a good time:
After dark, use only a small flashlight with a red filter when walking. This preserves everyone’s night vision.
Ask the owner before using a telescope, and be careful not to push the telescope while looking through it.
Bring your children, but don’t let them run around.
In the Northern half of the world, we are experiencing cooler weather as winter approaches. Compared to summer, fall is a great time for star-gazing, because sunset is earlier, and the skies tend to have less haze. So, why not find some people who can help you to enjoy the night sky?
Whenever one reads about solar eclipse-watching, many warnings about eye damage are found. They tend to be repetitious, but they are very important. Rather than trying to “reinvent the wheel”, I would like to summarize them as two different types of mistakes that can be made:
First type of mistake: Looking directly at the Sun. Normally, we find it very painful to look directly at the Sun. Almost as a reflex, we turn our gaze away from the fiery disk. However, during the partial phase of a solar eclipse, the sensation of pain is not so strong, because the overall brightness of the Sun isn’t so great. Unfortunately, the light from the visible portion of the Sun is still very destructive.
“Eclipse glasses” from a reputable source are inexpensive, and allow one to view the sun safely.
Second type of mistake: Looking at the Sun through improperly filtered optics. This mistake is far more serious than looking directly at the Sun. A telescope or binocular is designed to concentrate the light from a dim object to make it easier to see. When it is aimed at the Sun, an enormous amount of energy is delivered to the eyepiece. Complete, permanent loss of vision can occur quickly.
Telescopes can be safely filtered for looking at the Sun, but mistakes can happen. I am apprehensive that in some unruly, crowded observing field, a filter will get knocked off of a telescope. This would expose the viewer to serious injury. So, in addition to setting up a safe telescope, steps have to be taken to keep it safe.
There are several ways to use a telescope as a projector, and view the image of the Sun indirectly. These work well, but someone needs to be on the lookout for any misuse of the equipment.
Finally, there is one time when eye protection is not needed: during the total phase of the eclipse. If you are wearing eclipse glasses, you will see uncovered portion of the Sun getting smaller and smaller. When you can’t see anything through the eclipse glasses, totality has begun, and you should take the glasses off (otherwise you will miss the reason you went through all of this trouble!). Enjoy watching the corona, until you notice that the Sun is no longer completely covered. At this point, put your eclipse glasses back on.
Having said all of this, you shouldn’t be afraid to enjoy solar eclipses. Like many other things, the extremes are to be avoided. There is no need to stay indoors and close the curtains. Likewise, watching the Sun without protection is unwise. The rules are fairly simple, and will help you have an unforgettable day!
Here is a link to good information on viewing the eclipse safely:
http://eclipse2017.nasa.gov/safety
On August 21, 2017, a total eclipse of the sun will be visible in 14 states. More precisely, it will be visible in portions of these 14 states. Furthermore, some places will be better than others. Let’s try a few locations, using an interactive map from the NASA website:
http://eclipse.gsfc.nasa.gov/SEgoogle/SEgoogle2001/SE2017Aug21Tgoogle.html
By clicking on any place on the map, a table of statistics pops up. Right now, the important figure is: “Duration of Totality”. Click on Murfreesboro, Tennessee, which is close to Nashville, Tennessee. Note that the duration of totality will be approximately one minute. Next, try a location near the red line above Nashville. You will find that totality is much longer here, over 2-1/2 minutes. For the place with the longest possible totality, click on the purple balloon marked “GD” (greatest duration). For this location, the total portion of the eclipse will be 2 minutes, 40.2 seconds. For the longest look at the total eclipse, this is the “best” place to be. All other places will have shorter times of totality.
In summary, one must be between the purple lines to view a total eclipse, and the closer to the red line, the longer it will be visible. Finally, click on a location outside the purple lines, like Cincinnati or Louisville. The pop-up indicates that the eclipse will be partial, not total.
The word “best” can be misleading. For this eclipse, the location with the “Greatest Duration” is a wooded area, so viewing the eclipse may be difficult, if not impossible! Fortunately, there are many locations which have a very long duration of totality. To find them, click on places on the red line.
In addition to duration of totality, your “best” location will depend on many things, like how far you can travel, weather, and lodging. Above all, traffic jams must be avoided. Millions of people will be interested in this event, but the roads can’t handle all of them at once!
I have booked a motel room in Western Missouri, close to the “red line”. This location is reasonably close to our home in Michigan, and has a good history of clear skies in August. As I plan, I may find a better place, but I have a good “fallback” location.
Enjoy your planning!
John
Real Simple Astronomy 