By Bill Pellerin

Houston Astronomical Society

GuideStar Editor

When you think about the pioneers in astronomy,  the name Grote Reber does not generally come to mind. Yet, it is Grote Reber who was one of the early observers of the sky at radio frequencies.

When we observe the sky in visual light, we are taking advantage of the fact that our eyes see a small part of the electromagnetic spectrum; we call this part of the spectrum visual light. The electromagnetic spectrum includes radiation at many other wavelengths, though, and observing the sky at these other wavelengths can tell us things about the sky that we can’t learn from what we observe at visual wavelengths.

Radio astronomer Grote Reber was born in 1911 and died in 2002, just two days shy of his 91^st birthday. He was an electrical engineering graduate of what is now known as the Illinois Institute of Technology and an amateur radio operator with the call sign W9GFZ. That amateur radio call sign is now owned by the National Radio Astronomy Observatory Amateur Radio Club in Socorro, NM.

A personal note – on August 28, 2000 I made contact with W9GFZ via ham radio on the event of the dedication of the Green Bank (WV) radio telescope and I have a confirming postcard from that day as a souvenir.

Mr. Reber’s work in radio astronomy is only preceded by Karl Jansky’s work. Jansky was working for Bell Telephone Labs on a project to determine sources of interference in transcontinental cable systems. In completing this work, Jansky discovered a radio signal that was associated with the Milky Way, and was, as might be expected, strongest in the Sagittarius constellation – the center of the Milky Way galaxy. Jansky was not authorized by his employer to continue the investigation of the radio signals from space so his work on the subject was completed once radio sources that would interfere with cable communications were identified. The radio signals from space were too weak to affect cable communications.

Image credit: work by the U.S. government

Grote Reber, hearing of Jansky’s work, applied to work at Bell Labs in 1933, but this was during the depression and no job was available. Undaunted, Mr. Reber personally funded and built his own radio telescope, a 31 foot dish, at his home in Wheaton, Illinois. He had contacted a construction company about building the dish for him, but the cost would have been $7000. This was in 1936; adjusted for inflation the cost would have been over $110,000 today. This was out of the question, so he built the antenna himself, at his own expense, in four months. He spent $1300 (over $23,000 today) of his own money on the project. The finished antenna was considered to be the first radio telescope – designed and built to examine radio signals from space.

With the electronics built and the observing program designed, and after a couple of false starts (he initially chose the wrong frequencies to monitor), Grote Reber began his observing program in 1939. Every evening, after work, he would monitor the output of the system and record the results on paper charts. He produced a map of the sky showing the parts of the sky that were ‘bright’ at radio frequencies and confirmed Jansky’s results. These results were ultimately published as radio ‘brightness’ contour diagrams in the Astrophysical Journal and in Sky and Telescope magazine, April 1949. The Sky and Telescope article is interesting. In this article, Reber calls radio astronomy a “borderline science” but then goes on to discuss the meaning of the relative intensity of radio signals in various parts of the Milky Way. He comments that the radio profile in Sagittarius is “quite complex” and he concludes the article by suggesting that more surveys are needed at other radio frequencies and that a dedicated radio telescope near the equator could make a significant contribution to the science.

Reber determined that the radio signals were stronger at lower frequencies (longer wavelengths). This finding ruled out thermal radiation (radiation that occurs due to the motion of charged particles) as the source of the radio signals; thermal radiation would be stronger at higher frequencies. Only a few years later, the source of the radio signals was found to be what is called synchrotron radiation. This radiation occurs when electrons, moving near the speed of light, undergo a change in velocity as the result of a magnetic field.

The interesting thing is that for 10 years, Reber was the only one looking at the sky at radio wavelengths. Following the publication of his results, he began to get noticed, and was hired at the University of Virginia. His telescope was moved to Green Bank, WV in the 1960’s and it is there today.

Reber then went to Hawaii to continue his work in a less noisy radio environment. From there, for the last 50 years of his life, he lived in Tasmania (off the southeast coast of Australia). Tasmania provided a even quieter radio environment, especially on long winter nights.

He never accepted the idea of an expanding universe and the concept of the Big Bang and published a paper about the ‘Stable Universe’.

If you find yourself in Cambridge, Tasmania, drop by the Grote Reber Museum.

By Bill Pellerin Houston Astronomical Society GuideStar Editor Those of us who are astronomy enthusiasts are often asked by family and friends to identify an inexpensive item that we’d enjoy receiving as a gift. The purpose of this article is to identify several items that you may enjoy and provide you the information you need to hand off to your gift-giver. The range of prices for these items is about $10 to about $200. You should be able to find something you need that fits the budget of the giver (even if you’re giving to yourself). I have no financial interest in any company or product mentioned here… just so you know. Lunawheel Moon Phase Calculator—$17.50 (includes shipping) from http://www.lunawheel.com . This gadget calculates the moon phase for any date 2000 years in the past or 2000 years in the future. Figure out if any day is good for observing (lunar or deep sky). There are other interesting gadgets at the web site, too. Casio PAS400B-5 Wristwatch — about $30 from http://www.amazon.com . I’ve had one of these for years. In addition to telling you the mundane things like the time and date, it also tells you the moon phase, and sunrise and sunset times. (It doesn’t tell you moonrise and moonset times, though.) It’s marketed as a fishing watch, and there are other similar models in the Casio line. You have to enter your latitude and longitude manually. Fishing vest — ~ $30 – $40 from various sources. Do an Internet search for ‘fishing vest’ and you’ll find plenty of these to buy. These are valuable to amateur astronomers because they have lots of pockets. You can use these pockets for eyepieces, filters, notepads, snacks, pens, flashlights, (small) sky maps, hand warmers, etc. I have one of these that I use on the observing field and it’s great. Small tool kit – Lots of these are available at computer stores and other general stores. When you go for an observing run it’s always a good idea to take a few tools along, so a small tool kit could save the day (night, actually). You don’t need the best possible tools, because these won’t get a lot of use. I have one that has small pliers, a screwdriver (with interchangeable bits), hex wrenches, wire cutters, and so on. It’s good to know all that stuff is available if I need it. The Observer’s Handbook 2012 – $26.95, published by the Royal Astronomical Society of Canada, http://rasc.ca/handbook. This is a great publication showing you what is going on in the sky in 2012. It’s not a substitute for a good set of sky charts, or the electronic equivalent, but absolutely worth having. Darkness — $1.99 from the iTunes app store. This little app tells you when the sunrise and sunset will happen for your location, the moon phase, the moonrise and moonset times, and the time of astronomical twilight. Astronomical twilight is the time at which the sun is about 15 degrees below the horizon. The sky is not as dark as it will be, but it is dark enough to begin observing of brighter objects. Astronomical dusk, when the sun is at least 18 degrees below the horizon is not reported by this software. There is another app, called ‘Phases’ which provides similar information, but it is more focused on the moon. Sky and Telescope’s Pocket Sky Atlas – If you’re still use paper maps, this is a great set to have. This atlas is small and easy to carry (although you’d need a big pocket to put it in), and it includes stars down to 7th magnitude (which you’d be hard-pressed to see from most sites), and 1500 deep sky objects. The book is spiral bound, so it lays flat on your observing table. This atlas does not include observing lists or descriptions of the objects on the charts. You’ll need to bring an observing list with you when you use this atlas. I have two of these – one at home, and one at my observing site. While I use my computer as my sky map, it’s good to have these maps in case my computer fails. Green Laser Pointer – Available from all the astronomy equipment sellers; at least one of them is available for about $70. (Doing an Internet search, I found some that are $10 or less – maybe these work, and maybe not. Buyer beware.) Although these are not welcomed on a field full of serious observers, they are indispensable when you’re doing a public star party. You’ve probably seen these. They shoot a green beam of laser light through the sky which reflects off the dust and moisture in the air. I’ve used mine to point to, say, Albireo in the sky when I’m showing the public Albireo in the telescope. Kids are amazed by these, but I never let them use the pointer. The problem is that sometimes they become more interested in the laser than in the sky. Wonders of the Universe / Wonders of the Solar System – These are two DVD / Blu-Ray sets that are visually arresting and fascinating. They were produced by Brian Cox for the BBC and the content has the power to make you see the solar system and the universe differently. Each set is about $20 in either DVD or Blu-Ray format. If you have a HD TV and a Blu-Ray player the visuals will be all the more beautiful. There are also books with the same titles by Brian Cox. You won’t be disappointed with these. The Great Courses – There are several astronomy and many science related video (and some audio) presentations from this company (www.thegreatcourses.com), including a new course by Alex Filippenko from UC Berkeley. It’s called Skywatching: Seeing and Understanding Cosmic Wonders. There’s a course by Neil DeGrasse Tyson, called My Favorite Universe. There are more courses on black holes, on the contribution of the Hubble Space Telescope, and much more. Prices vary depending on the length of the course, and you always want to wait for a course to be on sale to get the best value. I own several of these courses and they’re all excellent. Be aware, that while these courses are often accompanied by graphics and images, much of the course consists of lecturing from a desk or a lectern. Don’t expect a visually dazzling presentation. Observer’s Chair – If you don’t have one of these, you’ve probably seen one. The idea of these chairs is that the height of the seat is adjustable and so, for many telescopes, you can adjust the seat height so that you can look through the eyepiece while sitting down. You should not underestimate the value of being able to hold your body (and head) still while observing. It makes a huge difference. These are not cheap, at from $150 to $200, but they’re worth the money. I have only bought one of these and it has lasted me many years. Look for one that is robust and will last a while. As an example, go to http://www.telescope.com (Orion telescope), and search for item 05939. Two-way radios – If you are out with a friend or a spouse and you’re not in cell-phone territory (the dreaded ‘no service’ area), you can solve the we-got-separated problem with a pair of FRS Radios. FRS stands for Family Radio Service, and it was created to provide a capability for family members to keep in touch, over short distances, by radio. The Federal Communications Commission authorized FRS radio service in 1996. These use UHF FM and are not subject to interference by other radio services. When these radios initially became available, they were quite expensive; now they’re not. For under $50 you should be able to get a set that you can use for many years. No license is required. The next step up is called General Mobile Radio Service (GMRS) and uses higher powered radios, which means they can operate over longer distances. You have to apply to the FCC to operate these radios, however. Moon filter – If you’ve ever looked at the moon through your telescope, and who hasn’t, you know that the brightness of the moon can be dazzling. To solve this problem, there are neutral density filters that fit your eyepiece and reduce the glare substantially. The word ‘neutral’ means that they reduce the brightness of all colors at the same time and don’t leave you looking at a green or pink moon. These cost from $20 (1.25”) to $25 (2”). If you want to be a bit more in control, you can get a filter with two polarized filters. You can then adjust the filters to change the brightness reduction. If you are an avid lunar observer, this is what you may want. Happy holidays to you, and clear skies!

Image of YU55 by Gary Garzone.

Image of asteroid 2005YU55 by Brian Kimball

By Bill Pellerin

Houston Astronomical Society

GuideStar Editor

At our annual Astronomy Day event, I’ll often point to Vega and say, “That star is 25 light-years away and this means that the light takes 25 years to reach us.” But, how do we know that Vega is 25 light years away? How did we determine this?

This is an interesting subject. Even the distance to the Sun wasn’t well determined until the 1960’s when radar ranging was used to measure the distance. The process is easy, send a radio pulse to an object, and see how long it takes to get there and bounce back. If you know the speed of the radio pulse, and we do, it’s easy to calculate the distance using the formula we learned in high school — d=r*t. That is, the distance is equal to the rate (speed) multiplied by the time. Since the radio pulse has to travel to the object and back the calculation for this is d=r*t/2.

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By Bill Pellerin

Houston Astronomical Society

GuideStar Editor

Last month, I wrote an article about the way we categorize nebulae (clouds in the sky). There are emission, reflection, and nebulae, which tells you how they are visible to us. The other way to categorize nebulae is as pre-stellar (star forming) and post-stellar (a remnant of a burned out star). I recently viewed the Wonders of the Universe video series by Brian Cox (highly recommended) and one of his subjects is the lifecycle of the universe and how objects in space fit into that story. That is, if we look at how the universe began, how it got to where it is today, and the future of the universe we get another perspective on nebulae.

So, let’s go all the way back to the beginning of the universe, the Big Bang. Various light elements came into being as the result of the Big Bang, but the heavier elements did not. The Big Bang, while extremely hot was also of short duration. In other words, there was not enough time for heavier elements to form as a result of the Big Bang. This formation of elements as a result of the Big Bang is called ‘Big Bang nucleosynthesis’.

What the universe began with, and what were the building blocks of the future universe, were (75%) hydrogen, (25%) helium, and small amounts of lithium and beryllium. That’s it. No carbon, oxygen, or anything else existed yet existed. The universe had to wait for these elements to be formed.

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By Bill Pellerin

Houston Astronomical Society

GuideStar Editor

When you look at the sky, what do you see? On a clear night, you’ll see stars, perhaps the moon, perhaps one or more planets. Do you ever see clouds in space? They’re a bit harder to see than many of the bright objects, but they are often the most interesting objects in the sky. These objects are generally called nebulae (the plural of nebula) and the word ‘nebula’ is from a Latin word meaning ‘cloud’. They don’t look like small points of light; they look hazy and, well, cloudy. For a long time, we didn’t know what these objects were, but now we do. If you listen, you’ll often hear observers say that an object is ‘non-stellar’ – meaning that it is not a star – meaning that it is nebulous.

Let’s begin with a bit of history.

One of the kinds of nebulae seen by early observers was a spiral nebula. One of the first observers to see these spiral nebulae was a British fellow named William Parsons, the 3^rd Earl of Rosse. In 1845, he built a very large telescope – called the Leviathian. With this telescope, he saw the spiral structure of M51, the object we now know as the Whirlpool Galaxy. In 1889, Vincent Van Gogh painted the famous ‘Starry Night’ which includes a spiral shape in the sky thought to be inspired by the drawing of Lord Rosse.

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By Bill Pellerin

Houston Astronomical Society

GuideStar Editor

As observing equipment and imaging systems become more complex the likelihood that something will happen contrary to your expectations increases. I touched on this issue in a previous article about how it is necessary to really learn how our equipment works, in excruciating detail. Many times the problem is not the equipment, it’s our expectations or it’s our lack of knowledge.

The telescope mount that I use requires that several alignment stars be located (by me) as part of the setup process. While the process makes sense, now that I understand it, for a long time it didn’t. It didn’t make sense at first because it was different from other telescope mounts that I had used in the past. I was executing the process in the wrong order – expecting to first tell the mount that I was going to point it to an alignment star instead of moving the mount to the star and then telling the mount that I did.

If you’ve even been to a dog training class, you know that the class is more about training the owner and less about training Fido. That’s often the case with the equipment we use, using it is more about training the owner than making the equipment bend to the will of the owner. You have to get into the head of the equipment designer and understand his or her thinking when the equipment was created.

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Houston Astronomical Society

GuideStar Editor

There is a lot written and said about amateur astronomy, but one thing I hear often is that someone is a 'serious observer' (not to be confused with a Sirius observer, which would be easy). Are you a serious observer? Am I?

I've heard it said that it's a requirement to be called a 'serious observer' that you own a large telescope.

Astronomy magazine's podcast (by Michael Bakich) offers observing objects for various sized telescopes. Early on, Michael referred to large telescope owners as serious observers. After receiving feedback from listeners with smaller telescopes, he doesn't make this association any more.

Phil Harrington, whose latest book is Cosmic Challenge said in an interview in our Houston Astronomical Society's GuideStar newsletter (in an interview written by Reflector contributor Clayton Jeter)  "I believe in 'go big or go home'".  By this, Phil means that you should have big goals, and you should try big things, but doing so doesn't necessarily require big telescopes. In fact, you can take a deep a dive into many observing programs with a good pair of binoculars. Phil responded to an email with, "In my mind, veteran observers should put themselves and their equipment to the test by trying to see targets that are at the edge of visibility for their instrumentation." Objects may be on the edge of visibility because they are dim, because they are small, because they are close to bright objects, or because they are difficult to identify in a crowded star field.

Barnard's Star is an example. It's a magnitude 9.5 star in Ophiuchus, but it is a bit of a challenge to find in a crowded star field. The star moves over 10 arc-seconds per year, so you have to know exactly where to look for it.

So, what are the characteristics of a serious observer? I exclude the requirement that a 'serious observer' only observes very dim objects with very large telescopes. So, if the quality of seriousness is not associated with equipment inventory, what is it?

Someone who is a solar observer and regularly (every clear day, for example) observes the Sun and records those observations with the intention of developing an in-depth understanding of solar phenomena is a serious observer. The Sun is the brightest object in the sky, so if someone can be a serious solar observer, then clearly any object, or set of objects observed in a serious manner can make an amateur astronomer serious.

There are plenty of observers of the Moon. While the moon has been observed, mapped by satellites, and visited by humans, not everything there is to know is now known. The work on lunar observing is not complete. My fellow Houstonian, Brian Cudnik has written a book, Lunar Meteoroid Impacts and How to Observe Them. Brian observed a meteor impact on the Moon visually in 1999 and discusses in his book opportunities for amateurs to participate in serious lunar observation.

Various observing organizations such as ALPO (Association of Lunar & Planetary Observers) coordinate efforts of observers of solar system objects, IOTA (International Occultation and Timing Association) works on lunar and other occultations, the AAVSO (American Association of Variable Star Observers) collects data from amateurs on variable star brightness over time to provide data to professional astronomers who are trying to understand stellar evolution.

Another friend of mine concentrated on seeing the earliest possible new moons (and latest possible old moons). He'd travel hundreds of miles to be in the best place to make the observations. Sounds serious to me.

The common characteristic of these organizations, and these observers, is the depth of effort and the depth of knowledge required to make the observation. These observers are not content to casually observe objects in the sky, they want to study the objects, they want to understand what they are observing and how the object fits into the universe.

How do you get to be a serious observer? You get there the same way you get to Carnegie Hall… practice, practice, practice (and effort). I read an article in the Scientific American ("The Expert Mind" July, 2006), and it said that the way you become proficient at something is by purposeful effort. Half-hearted effort won't get you there; your observing program must have a goal and a purpose and effort in the pursuit of that goal is required.

My observing purpose is to provide data on a regular basis to the AAVSO on variable stars with a goal of providing information that advances the understanding stellar evolution. I'm working on improving my data gathering and analysis processes and being able to provide more and better results.

The Astronomical League observing programs have introduced many an observer to object categories he or she would not have otherwise observed. These programs can lead to a passion for any of these objects and represent a valuable service to the astronomical community. Check out the observing clubs on this web site and see if any look interesting to you. Years ago, I completed the double-star club, and I've been a double star observer ever since.

If you can't decide on one, do the Universe Sampler club by Amelia Goldberg. You'll get introduced to many objects in the sky in the process of completing this one program.

You will be able to tell when you have become a serious observer; you'll be observing with a purpose and having more fun, too.

Nominations for the American Astronomical Society's Chambliss Amateur Achievement Award are being accepted, with a deadline of June 30, 2011.
 
The award is made for an achievement in astronomical research made by an amateur astronomer; that is a person not employed in the field of astronomy in a professional capacity, and who is resident in North America. The key factor is that the work contributes to the advancement of the science of astronomy.
 
 The nominator should send basic information about the nominee (including contact information), a description of the achievement being singled out for recognition (including any scientific paper references), and a statement as to why this amateur and this work are worthy of the award.
 
 Nominations are welcome either electronically (aassec@aas.org) or by mail
 
 G.F. Benedict
 McDonald Observatory
 1 University Station
  Austin, TX 78712
 
 The nomination form is at http://aas.org/files/Chambliss_Award_Nomination_Form.pdf