From France to Buffalo in Seven Hours By Car

Several months ago I was invited by French AAVSO member, Laurent Corp, to give a talk for CAPAS 2012, a pro-am astronomy conference on double stars and variable stars in Rodez, France. I was happy to oblige and agreed to give a talk on 'Pulsating Stars in the AAVSO Program'. Neither the organizers or I could afford to fly me to France, so we agreed to do the presentation via Skype.

I sent them an advance copy of my PowerPoint which they translated into French. They would display the slides on two screens, one in English, the other in French, and on a third screen would be the live webcam shot of my cheery face, blown up to giant talking head dimensions. The early afternoon time slot I was assigned translated to 8:30AM local time on Saturday, September 29, the same day I was leaving to drive to Boston, via Buffalo, New York.

Mike Simonsen, the giant talking head

I logged into Skype around 8AM and began my talk around 8:40, as the talks before me had begun to run long and late. I essentially covered the history of observations of pulsating stars in the AAVSO, the types of pulsating stars we observe today, and some of the current questions in astrophysics related to stellar pulsation. I was able to stay on for a while after my talk to monitor some of the other speakers as they gave their talks, but eventually it was time to load my suitcase and computer bag in the car and head east towards New York. 

Buffalo is a 7 hour drive from my home in Michigan, which happens to be almost exactly half-way between home and Boston. Realizing that the Patriots were playing the Buffalo Bills on Sunday, September 30, I had decided rather last minute to see if I could get a ticket to the game. I could drive to Buffalo on Saturday, go to the game on Sunday and drive the rest of the way to AAVSO HQ Monday morning. As luck would have it, a very good single seat ticket was available in a season ticket holder section down near the 20 yard line. I snatched it up and set the plan in motion.

The drive to Buffalo was uneventful, and I was just able to score a decent hotel room west of Buffalo for the night. I drove to Ralph Wilson Stadium early Sunday morning so I could check out the tailgate partying, pick up a souvenier and shoot some pictures. Deciding not to wear my Patriots hoodie, I opted to go incognito, disguised as a Buffalo fan. I purchased a crazy, fuzzy Bills hat to complete my disguise. Peaking into a VIP tent set up in the parking lot, I got to meet a couple of the Bill's cheerleaders, who obliged me with a picture. The Patriots won the game, coming from behind in the second half so everything worked out great!

Mike, his crazy hat and two Buffalo Jills

I drove into Boston, early Monday morning and arrived shortly after noon. The next four days were filled with meetings from 8:30AM to 5:30PM and working at my desk and tallking on the phone until 11PM. We had some very productive meetings, discussing AAVSOnet, CHOICE, fundraising, grant writing, the variable star plotter, a new binocular program, and various other topics. When I left for home on Friday morning my to do list from those meetings was two pages long!

My next trip to Boston will be for the fall meeting. I'm sharing the drive with Kevin Paxson and Dan Taylor. I hope to see you there. Until next time...

Earth Sized Planet Found Orbiting Alpha Centauri B

October 17, 2012

This artist’s impression shows the planet orbiting the star Alpha Centauri B, a member of the triple star system that is the closest to Earth. Credit: ESO/L. Calçada/N. Risinger (skysurvey.org)

One of the most exciting exoplanet discoveries in decades was announced yesterday in an online ESO press conference. The discovery was to be officially announced in an article in the journal Nature today, but due to the excitement surrounding this discovery ESO and Nature agreed to lift the embargo a day early. I think they realized they weren’t going to be able to keep the lid on it for another day. The fact that an Earth sized planet had been discovered orbiting one of our nearest stellar neighbors, Alpha Centauri B, was a headline dying to be exploited by the press.

The planet was detected using the HARPS instrument on the 3.6-meter telescope at ESO's La Silla Observatory in Chile. HARPS can measure the radial velocity of a star with extraordinary precision. A planet in orbit around a star causes the star to move towards and away from an observer on Earth. Due to the Doppler effect, this radial velocity change induces a redshift of the star's spectrum towards longer wavelengths as it moves away and a blueshift as it approaches. This tiny shift of the star's spectrum can be measured with a high-precision spectrograph such as HARPS and used to infer the presence of a planet. Of course it’s not quite as simple as that.

How Do They Do That?
Alpha Cen B is a spectral type K1V star only slightly less massive than our Sun and cooler. There are a lot of competing signals combined in the light from Alpha Cen B, inducing a radial-velocity “jitter”. In the process of filtering out these additional sources of noise the team of astronomers was able to learn quite a bit more about the star itself. They determined that the star has spots like our Sun. As a star rotates, spots will appear to move from one side of the stellar disk to the other, introducing a periodic signal. This will correspond to the rotational period of the star. The radial velocities of Alpha Centauri B show a clear signal at 38.7 days, the rotational period of the star. They also learned the star has a solar-like star spot cycle with activity increasing and then decreasing over the four year period of the observations.

Additionally, the team had to filter out the effects of the radial velocity changes due to the star being a member of a binary system, as well as the fact that on some occasions of poor seeing the light from Alpha Cen B was contaminated with light from the primary, Alpha Cen A. As if that weren’t enough, they also had to remove the effect of the changing velocity of the Earth in the direction of the star as it orbits the Sun before the signal of a small rocky planet orbiting the star could be detected.

“Our observations extended over more than four years using the HARPS instrument and have revealed a tiny, but real, signal from a planet orbiting Alpha Centauri B every 3.2 days,” says lead author of the paper, Xavier Dumusque (Geneva Observatory, Switzerland and Centro de Astrofisica da Universidade do Porto, Portugal). “It’s an extraordinary discovery and it has pushed our technique to the limit!”

Why is this important?
The technical achievement alone makes this an extraordinary discovery. It is the lowest mass exoplanet ever discovered, and now the closest known. This is a major step forward in detecting Earth twins. Unfortunately, the planet orbits so close to its parent star (0.04 AU) that its surface temperature is estimated to be approximately 1500 degrees Kelvin, so the chance of the planet supporting any kind of life is doubtful. But, the precision required to obtain this result would also allow astronomers to detect a planet four times the mass of Earth in the habitable zone of a Sun-like star (habitable super-Earths) with periods in the range of 200 days.

Alpha Cen Bb and the habitable zone around the host star. Credit: Greg Laughlin from EPO press conference

The fact that this planet was discovered orbiting a star in the Alpha Centauri system sparks the imagination. How many science fiction books have speculated about the existence of planets around our nearest stellar neighbor? Now it is science fact. There is at least one planet in the Alpha Centauri system, and probably more.

"This is the first planet with a mass similar to Earth ever found around a star like the Sun. Its orbit is very close to its star and it must be much too hot for life as we know it," adds Stephane Udry (Geneva Observatory), a co-author of the paper and member of the team, "but it may well be just one planet in a system of several. Our other HARPS results, and new findings from Kepler, both show clearly that the majority of low-mass planets are found in such systems."

The Kepler mission has found 2300 candidate planets by searching for exoplanet transits among the 10,000 or more stars it monitors continuously. The majority of planet candidates detected by this transit method are very distant from us. In contrast, the planets found by HARPS are around stars close to the Sun, this new discovery being the closest yet. This makes them better targets for many kinds of additional follow-up observations such as characterizing the planet's atmosphere.

What next?
Astronomers will now continue with extensive Doppler monitoring of Alpha Centauri B to try to detect additional planets, perhaps some in the habitable zone. This will become increasingly difficult as the separation between the Alpha Cen binary is decreasing over the next several years. They may also try to observe it from space to see if they can detect the transit of the star across the face of Alpha Cen B. The eclipse will be too shallow to observe from the ground. There is about a 10% chance of success, with the odds being higher if the orbital plane is in line with the binary plane, estimated at 11% inclination with respect to Earth.

How does this fit into variable star science?
The study of variable stars is really the study of the secret lives of stars. How are they formed, how they live out their lives and what changes occur internally and externally as they evolve. We learn about the environments surrounding them, including planets and other companions, and their affect on these partners; and finally, how they end their lives slowly fading away, stripped of their atmospheres or violently exploding, seeding the universe with the materials to build more stars, planets and us.

At almost every phase in a star’s life it varies in its light output. If the variation is large enough and occurs on human timescales, we, the observers of the AAVSO, can record and study these changes, and we have now for over 100 years.

In that time we have learned about all kinds of variations in stellar output and how to interpret it. Some stars vary as they pulsate, actually changing size physically, growing and then shrinking again, sometimes with a precise period, sometimes irregularly. We’ve seen stars that appear to vary because star spots are transported across the face of the star as it rotates. We’ve witnessed stars being eclipsed by unseen companions in extremely close orbits around their center of gravity, and now we can see the incredibly small changes in the light of a star as a planet crosses in front of it from our point of view.

Alpha Centauri B exhibits all of these phenomena at the same time. It rotates, it pulsates, it has spots, it’s a member of a binary system, and now we know it has a planet, perhaps several, and there is a chance we can see them transit the face of our close stellar neighbor if we turn our satellites on them. It is becoming apparent that the more we look, the more we will find planets around stars everywhere. It has also become obvious that the closer we look, the more we will find every star is a variable star to one degree or another at one time or another in its life. Alpha Centauri B is another interesting and exciting member of the variable star zoo.

Leslie Peltier: The World's Greatest Amateur Astronomer

Leslie Peltier

"The world's greatest non-professional astronomer."

That is what Harlow Shapley called Leslie Peltier. If that is true, then why don't more people know about Peltier? I think the simple truth is he was a very private, soft-spoken man, who never sought the limelight and would have been embarrassed by all the attention he gets nowadays.

I've tried several times to write about Leslie Peltier, but every time before, I have begun thumbing through his classic book, Starlight Nights, for references and quotes and ended up reading the whole thing from cover to cover again instead of writing the piece that was my original intention. I'll never get tired of reading it. There are a lot of books that tell you how to observe the heavens and what you will find when you do, but this book always reminds me of why I love to be out under the stars at the eyepiece of a telescope, soaking in the sounds and smells of nature and admiring the majesty of the universe with my own eyes.

Born in January 1900, on a farm outside of Delphos, Ohio, Leslie grew up in a less complicated time, among the forests and farm fields of the area he lived his entire life. If he was famous for anything, it was his unwillingness to leave his home. He had everything he needed right there in Delphos- his family, his home, his gardens, and his observatories. Why would he want to leave any of that? So it was, that later in his life people made the pilgrimage to come visit him. Leslie was not likely to be making a public appearance anywhere near you. You had to go to the mountain.


As a boy Leslie was fascinated by the natural world around him. He read books from his family's home library and learned abut the flora and fauna that appeared on and around his home in nature guides, such as Wood's Natural History and Gray's Botany. He thoroughly enjoyed identifying each new butterfly, bird and flower. In 1977 he published The Place On Jennings Creek, a book relating the past 25 years of gardens and critters that shared the natural setting of his home with Leslie and his wife, Dorothy. 


It's kind of surprising that it took Leslie until he was in high school to realize that his natural world extended upwards, over the tree tops, past the clouds and out into the Universe into the night sky. He recalls in Starlight Nights the moment it dawned in him that he could name all the butterflies on his farm but didn't know the names of any of the stars in the heavens. One evening in May-

 "Something- perhaps it was a meteor- caused me to look up for a moment. Then, literally out of that clear sky, I suddenly asked myself: "Why do I not know a single one of those stars?"

Thus began an epic journey of discovery and observation that lasted the rest of his life. Peltier learned the stars on his own using only his eyes for the first year. He always felt this was the best way to learn the sky, as opposed to having someone teach the constellations or telescopic showpieces without investing the time and effort to become familiar with each one and its place in the heavens. 

"Each star had cost an effort. For each there had been planning, watching and anticipation. Each one recalled to me a place, a time, a season. Each one now has a personality. The stars, in short, had become my stars."

His first telescope was purchased with earnings from picking strawberries. He had to pick 900 quarts at two cents a piece one summer to save up the $18.00 for his mail order 2" spyglass telescope. He made his own alt-azimuth mount for the telescope out of a left over fence post, an old grind stone and discarded two by fours. This telescope served him well as he learned the sky and how to use a telescope to view the heavens. 


His fatal attraction to variable stars and the AAVSO began when he wrote a letter to AAVSO founder, William Tyler Olcott asking how he could contribute to science with his small telescope. Olcott wrote back explaining that observing variable stars was an exciting and scientifically useful way to spend ones time under the stars, and from the time Leslie was eighteen until his death in 1980 he never missed sending in a monthly report of variable star observations to AAVSO headquarters in Cambridge, MA. His description of how variable star observing changed his life forever is something I have quoted often to many people. 

"Life was never quite the same for me after that winter walk to town. The charts that I brought home with me were potent and ensnaring and I feel it my duty to warn any others who may show signs of star susceptibility that they approach the observing of variable stars with the utmost caution. It is easy to become and addict and, as usual, the longer the indulgence is continued the more difficult it becomes to go back to a normal life."

In 1919, Peltier was given the first of several telescopes that would be loaned, or given to him outright, based on his exceptional observing skills and perseverance. The AAVSO loaned him a 4-inch refractor with which to make variable star observations, and he immediately put it to good use by observing even fainter variable stars. Two years later, after enduring hundreds of nights in the dew and cold his father suggested it was time they build a proper observatory for Leslie. This observatory soon housed an even larger telescope, the 'Comet-Catcher.'


In 1925, he discovered his first comet, using the Comet-Catcher, a 6-inch refractor on loan from Henry Norris Russell of Princeton University. He would go on to discover 11 more comets in his lifetime, the last one in 1954. He also discovered four naked eye novae and made a habit of checking up on some old novae that still varied and occasionally had recurrent outbursts.  

Leslie with the 2" spyglass in front of the
dome of the 12" Clark refractor 

In 1959, life took a very unexpected turn when Miami of Ohio University offered to give Leslie their 12-inch Clark refractor, complete with observatory, dome and transit room! The entire observatory was cut into sections and delivered 125 miles to the Peltier home, where it was re-assembled and served Leslie as he strove to observe the faint minima of many of the variables he followed for decades. With this telescope he could follow stars down to 15th or 16th magnitude, far fainter than his other telescopes would allow. In total, Leslie Peltier submitted over 132,000 variable star observations to the AAVSO, making him one of the all-time leading observers in history.

Peltier's life was a long, steady, calm procession of days and nights lived to the fullest and enjoyed for their blessings, punctuated by events like the appearance of a new comet or nova, or unexpected recognitions for doing what Leslie would have done even if no one noticed. 


Overcoming his lack of formal education, Leslie dropped out of school after the 10th grade to work on his father's farm, he received an honorary doctorate from Bowling Green State University in 1947. In 1965, a mountain in California, home of the AAVSO's Ford Observatory, was named Mt. Peltier in his honor. In 1975, he received an honorary high school diploma from his home town's  Delphos Jefferson High School.

In his obituary, written by friend and fellow AAVSOer, Carolyn Hurless, she says, 

"Leslie was able to accomplish all he did because he was a private person. He lived exactly as he wanted to. He did nothing he didn't wish to do and was able to say "no" very easily. He was very uncomfortable with those who sought him out because he was famous, but to those fellow variable star observers who visited, he was a warm and welcoming individual."

Shortly after his death in 1980, the Astronomical League established The Leslie C. Peltier Award "to be presented to an amateur astronomer who contributes to astronomy observations of lasting significance," and that is where our histories finally intersect. In July 2012, I became the 30th recipient of the Leslie Peltier Award at the Astronomical League Convention in Chicago, Illinois.

Finding myself uncharacteristically speechless and unprepared, this is what I wish I would have said when asked to say a few words.

"I've known about Leslie Peltier, the great amateur astronomer and variable star observer, for years. I've  heard the reverence in people's voices when he is mentioned in conversation. I've read Starlight Nights more than any other book I can think of. And when I do, I'm always struck by the similarities in our experiences. 

I too learned the sky and the names of all the stars and constellations on my own, through books and star charts borrowed from the library. I earned the money to buy my first telescope by getting up early in the morning and delivering papers door to door for far longer than I ever dreamed I could endure. His story about seeing something in the sky he couldn't explain during the UFO crazed 1950's, and the fact that it turned out to be geese flying in formation, is exactly like the story I have told my friends and will share with my grandchildren one day, about a winter night in 1980. I too, have received a telescope on loan from the AAVSO, as well as a CCD with which to observe variable stars. Even the opening paragraphs of Starlight Nights, where he describes walking down the path towards the two stark-white structures as night falls reminds me of my walk to my observatories each clear night.  

But when he writes about his love of variable stars, and how he gets excited each night, year after year, to go spend some time with his old friends, that is when I hear my passion and my words coming out of his mouth. I am a hopeless variable star addict like Leslie, having now submitted over 80,000 observations of my own to the AAVSO.

Awards and accolades are great, but like Leslie, I would have done it all anyway. I don't think I really had a choice.  

It is because of who this award is named for that it means so very much to me. I'd like to thank my wife, Irene, for supporting me and enabling my addiction. Thank you to the Astronomical League for this very special and meaningful recognition. And thank you, Leslie Peltier, for being an inspiration and role model for amateur astronomers everywhere who want to reach for the stars and explore the Universe on their own terms, in their own time and in their own way."

The 2012 Leslie C. Peltier Award
proudly displayed on my office wall

The 12" LX200 Eyepiece Saga

If you are a visual observer, the eyepieces in your arsenal are as important as the optical tube or mount. One of my goals has always been to find the perfect combination of the fewest number of eyepieces to be able to handle all my typical observing requirements. I don't like to spend time changing eyepieces and refocusing. I want to observe, not focus and fiddle around. My search for the perfect combination of eyepieces for variable star observing has had episodes of experimentation and expense followed by long periods of satisfaction and observing action.

After learning the capabilities and limitations of my first set of standard Plossl eyepieces I turned to the TeleVue brand to get superior quality eyepieces that had longer eye relief and a wider true field of view.

Eye relief is simply the distance between your eye and the lens of the EP where you can comfortably and effectively view what you are looking at. If you've ever stuck your eyeball practically on top of the lens of a inexpensive, short focal length, short eye relief EP to see into the tiny peep hole, you know this is not how you want to spend two to four hours a night 100 times a year.

True FOV is the area of sky you can view in any particular eyepiece/telescope combination. When you are making variable star estimates, the larger the true field of view the better chance your comparison stars will fall in the FOV. Generally speaking, the brighter the variable and comparison stars, the further spread out they are on the sky. So an eyepiece that can show you a larger chunk of sky is very helpful.

You may notice I haven't talked at all about magnification yet. That's mostly because when you are looking at stars they always just look like points of light, unlike planets or the Moon, which get bigger and dimmer with more magnification. The real advantage of higher magnification for star viewing is it makes the sky background darker, so you can see fainter stars. This usually comes at the cost of FOV. Generally speaking, the higher the magnification, the smaller the FOV.

There is a practical limit to how much you can magnify celestial objects in any telescope. For short focal ratio telescopes 30x per inch of aperture is about right. For longer f ratios, like the f/10 Schmidt Cassegrains, 20-25x per inch of aperture is more realistic. It is rare for any telescope to be abe to use more than 400x ever. I've only experienced a dozen nights where I thought 350x was reasonable.

That never stopped me from buying a bunch of eyepieces that would deliver more magnification! I've had everything from 5mm (600x!!) to 10mm (300x) and eventually sold or traded them all away because they never came out of the eyepiece box. My 7mm Nagler was a great eyepiece, but I only used it a few times in ten years, mostly to view Mars, Jupiter and Saturn on those exceptionally rare nights of almost perfect seeing.

As you can imagine, sorting through all these factors has taken some time. For almost a decade my two "go to" EPs have been 12mm and 17mm Nagler Type 4's. The 12mm gave me .33 degrees of sky at 250x, which was perfect for the 12" LX200 telescope. It's about as much magnification as you can really use on an average to good night, and 1/3 of a degree is a large enough piece of sky to cover a typical chart I would use to observe faint cataclysmic variables. The 17mm Nagler had an awesomely comfortable eye relief. I could observe all night long with that eyepiece- I loved it. It delivered .46 degrees of sky at a generous magnification of 176x. I could see almost as faint in the 17mm as the 12mm on average nights, but the lower magnification delivered more pleasant star images in fair to poor seeing. It also weighs 5 pounds! Think about that before you buy one. You may need to add counter weights if you use it. 


Another thing I loved about these eyepieces was the adjustable click stop eyeguard. They are a handy light shield built right into the housing of the EP to position your eye and block any stray light from getting in to mar the view. Every EP should have this.


For observing Mira stars I still needed something with a much lower magnification and wider FOV. These stars can range from the very faintest I can see, 14th to 15th magnitude, all the way up to 7th magnitude. I needed something to cover the mid and top ranges of these stars. I eventually settled on mounting an 80mm short tube refractor on the LX200, but this was only useful down to about mag 10.5 or so. The real answer to this issue was the TeleVue 55mm Plossl. It gives me almost a full degree of sky (.92 degrees) at 55x. I can see down to 13th magnitude easily, and observe stars as bright as 9th magnitude while still having some useful comparison stars in the FOV. Anything brighter is perfect for the 80mm refractor and its generous FOV.

I probably could have gone on forever, blissfully, with this combination of EPs, but at the Texas Star Party in 2011, I was able to borrow a 13mm Ethos EP from a friend and using it in my telescope was a life altering experience. I couldn't believe how much larger the FOV was. It's ridiculous! You have to move your head around to take it all in. And the crisp, flat, pinpoint star images it produces are stunning, even compared to the near perfection of the Nagler type EPs I'd come to love. I had to own a set. 


But I really had no desire to give up my 12mm and 17mm Naglers. There really was nothing wrong with them and after trying dozens of EPs I had stuck with these for a decade. I have to admit, they were sort of like old friends. After 50,000 variable star observations we'd grown close. So I thought I would try to get a little more oomph out of my telescope by getting the 10mm Ethos. This would give me 300x and the same 1/3 degree of sky the 12mm Nagler did. Hopefully, I could use it as my new go to EP for faint CVs because the added magnification would give me a darker sky background. And for those really good nights I bought the 8mm Ethos. A whopping 375x with still a 1/4 degree FOV. What could be better? I could have the best of both worlds.


I settled in for a few months with the new set of EPs and found myself, as before, using the 10mm once in a while and the 8mm almost never. I don't know why I thought the Ethos EPs were going to make the sky conditions better. They are just eyepieces, not atmospheric stabilization devices! I was back to using the old-faithful 12mm and 17mm Naglers in no time. It finally dawned on me what an idiot I was after the final night of the Cherry Springs Star Party when I realized I'd never even taken either of the new Ethos EPs out of the case. I had $1350.00 invested in two EPs I wasn't using.

So I took the plunge. I traded in the Naglers and the Ethos EPs and came home from Cherry Springs with just three EPs in the case. A new 13mm Ethos, a new 17mm Ethos and the trusty TeleVue 55mm Plossl. It didn't take me long to get used to the idea of using these fantastic new eyepieces as my trusty companions at the telescope. They are both simply stunning performers. 

The weather has been warm and dry and unusually clear at night for summer. I have had some of the best viewing in the 12" I can recall in the last four or five years. I have been able to see as faint as 16th magnitude on several nights with the new EPs.

I've had several nights of very exceptional seeing where I thought to myself, "You know, Self, we could probably use at least one more eyepiece, maybe a 10mm to give us 300x for nights like this." I know, it's a disease. But this time I told myself I'm not going to spend $600.00 or more for an EP I will only use on special occasions. Besides, the situations I want 300x for don't generally require a large FOV. I don't need a Nagler or Ethos EP to see extremely faint cataclysmic variables, or to view Saturn or Jupiter at high power.

So I decided to try out a TeleVue Delos 10mm. It still has a generous apparent FOV of 72 degrees, which yields .24 degrees true FOV and 300x in my 3000mm focal length telescope. I've only had it long enough to use at the telescope for one night, but I think we have a winner. It still cost $370.00, but that is a little more than half what a 10mm Ethos would cost, and I just can't do that again.

The Delos has a new kind of adjustable eyeguard that slides into place and twist locks once you have determined the perfect place for it in relation to the lens. This is almost a requirement for this EP. The Delos is very sensitive to eye placement. If you position your eye pupil too far in or too far out you experience edge darkening and field loss. This is not a star party eyepiece for the general public. It takes a pretty experienced observer to get the most out of this complex combination of elements.  But it is a very good quality EP with no ghosting and it delivers great definition on those really good nights at 300x. I think I'm done buying EPs for a long time...or at least until Al Nagler comes up with a new exotic glass and lens combination.

Pennsylvania Star Party Adventure

I had been looking forward to this trip since last October. That is when we took a side trip on our way back from the AAVSO Centennial Celebration in Boston through the northwestern part of Pennsylvania known as the Pennsylvania Wilds. The landscape is dominated by state forests among some of the most picturesque mountains, valleys, rivers and streams in America. We stayed in Wellsboro, a quaint village with a boulevard main street dotted with antique shops, bed and breakfasts and restaurants on State Highway 6. We did some sightseeing and picture shooting at the rim of the Pennsylvania Grand Canyon, (that’s right, Pennsylvania has a Grand Canyon, and you should see it in the fall!), and then drove west on Highway 6 to find the Kinzua Skywalk which had opened just a months before we arrived.

The Kinzua Skywalk is what remains of an old railroad bridge that spanned a 400-foot deep gorge. About a decade ago they were refurbishing the bridge when it took a direct hit from a tornado, twisting and breaking most of the support columns and leaving them strewn on the floor of the canyon. You can still see the scar on the landscape where the tornado stripped all the trees from the sides of the mountains. On the south side of the gorge a few of the columns remained, so they’ve made a park out of the site and you can walk out to the end of what remains of the bridge and peer over the sides at the destruction or through the glass bottom floor at the valley 400 feet below.

In between the Grand Canyon and the Kinzua Skywalk, Highway 6 bisects the small town of Coudersport. Coudersport plays host to two annual star parties at the nearby Cherry Springs State Park. This was our destination on this trip, for the Cherry Springs Star Party.

We left Wednesday morning after 9am. It’s an 8-hour drive from Michigan to Coudersport, which after driving to the Texas, Nebraska and the Winter Star Party in Florida seemed like a jog across town. We checked into our hotel, unloaded our baggage and did a little exploring to check out the local eateries. We ended up having dinner that night and most other nights, at KayTee’s, the restaurant two doors down from our hotel.

Thursday morning we headed out to the Cherry Springs State Park, which is about 15 miles from town up a winding mountain road. The park sits on top of a mountain at 2300 feet. Unlike most places I’ve been to for star parties, this park is designed specifically for astronomical viewing. They have AC power pedestals throughout the observing field, concrete pads to sit telescopes on and permanent observatories you can rent year round. There are porta-potties conveniently located around the park, as well as a small building with running water and flush toilets near the gate. The field is large and the trees have been cut back all around to provide a good view almost to the horizon, yet there are plenty of them to block any stray light from the rare car passing in the night. There were already a couple hundred campers set up from the night before when we arrived Thursday morning, the first official day of the star party. We set up our tent, camping gear and the 12” LX200 in about an hour. We’re getting pretty good at this.

Across the road from the park is a public viewing area and astronomy trail for naked eye or binocular astronomers, with its own parking area and berms to block any stray light from the road. All in all, this is one of the darkest places I’ve ever been. Saturday morning at 4AM I could not see my car twenty feet away as I left the star party to head back to the hotel. The only clue I had I was heading in the right direction was the sound of the gravel parking lot under my boots. I had to hit the button on the key fob to flash the lights on the car to find it.

Thursday night was clear and cold. Irene took a peek at Saturn, tried a few astro-photos and then retreated to the tent and crawled under a blanket and shivered until dawn. The guy camped next to us had a 25-inch Obsession Dobsonian. He had a lot of visitors during the night anxious to see galaxies and nebulae that looked like something more than faint fuzzies in the eyepiece. I heard a lot of oohs and ahs coming from the top of the ladder as his guests would ogle deep sky treasures. I explained to him that I was usually the loneliest guy at a star party, because no one ever wanted to look at variable stars…too boring.

The sky was dark but the seeing wasn’t terrific. Still, I was able to log some pretty faint observations and see mid 15^th magnitude stars with direct vision. This was definitely my best star party observing session in the last year. I stuck to familiar targets, doing about 70 CVs in Com, Boo, CrB, Ser, Her, Lyr, Vul and Cyg before the waning crescent moon rose above the trees around 3:45AM. By then I was pretty tired, so Irene and I made our way to the car parked across the road and headed back to the hotel as dawn broke over the misty mountains of PA.

I slept most of the day until Irene came back from exploring to take me to the park. I was giving a talk on variable stars and the AAVSO and wanted to get there early to set up the presentation and box of handouts I had brought along. The crowd gathered for my talk wasn’t huge, but they were definitely interested. The question and answer session after went on almost as long as the talk and I gave away nearly all the ten-star tutorials, pamphlets and bookmarks I had brought. I showed them a map of where I was located on the astronomy field and announced that I would be doing a variable star workshop at the telescope all night long for anyone who was interested in actually trying to make variable star observations.

We drove back to town for dinner, I took a nap and Irene settled in for the night in our hotel suite. She wasn’t going to be caught dead in a tent, in the dark, in the cold, in PA again on this trip. I arrived back at camp around dusk and there were already people milling around waiting for the “variable star guy to get here.” As soon as the sky was dark enough I started showing people T CrB in a low power eyepiece on the 12-inch. I’d explain how the chart related to the view in the eyepiece, what the numbers next to the comparison stars represented and taught each one how to make an estimate of the brightness of T CrB. I also related the story of Leslie Peltier’s waiting for decades for T CrB to erupt, and how on the one night he decided to stay in because he thought he might be catching a cold, T CrB went into outburst while he lay sleeping in his bed.

I expected the crowd to thin out any time all night long, but they just kept coming, one or two at a time usually. I could hear them finding their way in the dark. “Hey, is this the way to the variable star guy’s telescope?” From about 1AM until 3AM there were five of us taking turns at each star. We would all look at the field and then when everyone had seen it we would reveal our estimates. I was glad to see everyone was in pretty fair agreement on all the targets, especially after doing a few. With just a little practice they were all quite comfortable making the call, and proud to see they were coming up with the same answers as “the variable star guy.”

As a reward for making their first estimate I was giving out some AAVSO buttons I had gotten from HQ. When those ran out I started giving away Centennial T-shirts. I ran out of steam about the same time as the last die-hard observers called it a night. I passed out t-shirts to the last four observers, and as I was packing up eyepieces and covering the telescope for the night I heard a voice in the dark say, “You’re not the loneliest guy at the star party anymore, are you?” I drove down the mountain in the pre-dawn glow feeling tired, but strangely satisfied. I slept like a stone until 11AM Saturday morning, which is later than I’ve slept in in years.

We decided that the weather was looking a little iffy and it would be better to break camp on Saturday and drive home Sunday early that to do it all on Sunday after a short rest from staying up all night. So we headed out to Cherry Springs, where I visited the vendors to make a deal for a couple Ethos eyepieces, Irene got some last pictures of the camp, we packed up the tent, gear and telescope and said goodbye to our new friends.

On the way back to the hotel, we stopped in a couple places to do some antique shopping and visited a remarkable, eclectic, funky little eatery and art gallery in Coudersport named Olga’s Gallery, Café and Bistro. Olga is this remarkable woman from the Ukraine who has decorated and painted the entire two story shop in her own style and color combinations. She’s packed it full of her own artwork in a dozen mediums, from paint to jewelry to yarn, and serves excellent food and drinks along with her husband who works behind the bar. If you ever find yourself driving through Coudersport, PA, you have to stop in to experience this place. It is literally the last thing you would ever expect to find in a small town in PA.

After studying some maps and pamphlets I’d picked up along the way, I suggested that we take the long way home on Sunday to take advantage of the nice weather and the scenic byways I’d read about in the travel brochures. This plan had the added bonus of letting us skip the Interstate 86 part of the route we’d taken to get there. I-86 is in terrible condition, and I had no desire to go thumping along on that old slab of rough concrete for 100 miles on the way to Erie, PA. Our alternate route would take us along rushing rivers and stone cliffs busting out of forest covered mountains, eventually spilling us onto I-80 where we could cruise home at light speed through PA and Ohio to get home in time to feed the cats dinner and watch the sunset from our own front porch in the Michigan countryside.

We made some wrong turns, got a little lost and discovered some unexpected treasures in the forests of Pennsylvania that Sunday. So it was worth the extra time and miles to go the scenic route. We’ve decided we really like Pennsylvania, and we’ll be going back again soon. They have another star party at Cherry Springs in the fall called the Black Forest Star Party. I think I can hear the fall colors and clear skies calling.

Koji Mukai on X-rays and Dwarf Novae

This is the second time Koji Mukai has granted me
an interview. The first time we discussed magnetic CVs,
intermediate polars specifically. That interview can be
read here.

Now Koji is back to discuss RU Peg and the X-ray
behavior of dwarf novae with massive white dwarfs.




CVnet: Hi, Koji. Thank you for granting us another interview. Let's start with
where are you working now and what are your primary responsibilities?
Also, what are you current areas of research?

Mukai: I work at NASA's Goddard Space Flight Center, although my employer
is University of Maryland, Baltimore County. I work at the
US Guest Observer Facility for the joint Japan-US Suzaku mission,
and also work on the education and public outreach group of the
astrophysics science division here. My research has always focused
on accreting white dwarfs - it still does, but over the last few
years it has expanded from just CVs to CVs and symbiotic stars.
I'm interested both in accretion and mass ejection during nova
outbursts.

CVnet: Are you still maintaining the Intermediate Polars pages?

Mukai: Yes, although I haven't had the time to make a substantial update
for the last year or so. There are quite a few new confirmed
and candidate IPs to add to the site!

CVnet: AAVSO Alert Notice 459 states you are requesting monitoring of the dwarf nova,
RU Peg, in anticipation of the next outburst. Let's discuss why RU Peg is so interesting,
and what you hope to learn by observing it with Swift.

Mukai: RU Peg is a bright dwarf nova that has been neglected, relatively
speaking, for X-ray observations. For dwarf novae, it is very
important to conduct X-ray monitoring campaigns through an outburst.
Now that RXTE has been decomissioned, Swift is the only observatory
for this type of campaign.

CVnet: Since your observations will be in the X-ray, where do X-rays in dwarf novae originate?

Mukai: In a dwarf nova, half the available gravitational potential energy is
radiated away in the accretion disk - that's a source of infrared,
visible, and ultraviolet light. The other half of the potential
energy has been converted into the kinetic energy of the disk material,
moving at several thousand kilometers per second. Since the white
dwarf is rotating much more slowly than this, that motion must suddenly
cease in a very small region - what we call the boundary layer. That's
where the X-rays originate in dwarf novae.


CVnet: How does the amount of X-rays emitted change between the quiescent and outburst
phases of the dwarf novae?

Mukai: That actually depends on what you mean by "X-rays." But if you mean
X-rays in the traditional band (photon energies of 2-10 keV, or
wavelengths of about 1-5 Angstroms), dwarf novae become fainter during
outburst than in quiescence.

Below are the AAVSO and RXTE light curves of WW Cet from
a recent paper I was involved in. This shows what I now think of

as "typical" behavior. X-ray bright in quiescence, X-ray faint in outburst, 

with sudden a transition and no intermediate states.

From 2011PASP..123.1054F  Fertig, D.; Mukai, K.; Nelson, T.; Cannizzo, J. K. 

The Fall and the Rise of X-Rays from Dwarf Novae in Outburst: RXTE Observations of VW Hydri and WW Ceti

CVnet: What do we think is happening as the outburst begins in the accretion disc
to cause this X-ray suppression?

Mukai: In quiescence, the boundary layer is optically thin - that is, X-ray
photons, once emitted, escape the boundary layer without interacting
with matter. In outburst, much more matter is flowing through the
boundary layer, so the density is much higher. In this case, the
boundary layer becomes optically thick - X-ray photons emitted by
the ions interact with surrounding matter several times before
they are able to escape. In this situation, the temperature of
the boundary layer drops, and only lower energy X-rays ("soft"
X-rays, as in X-rays that cannot penetrate matter that much) are
emitted - with energies below 0.5 keV. The optically thin case
is like the corona of the sun, the optically thick case is like
the photosphere of the sun. In fact, during outburst, the boundary
layer has both the photosphere-like region and the corona-like region.

If the line of sight to the dwarf nova is relatively free of
interstellar matter, then we can observe dwarf novae brighten
dramatically during outburst in soft X-rays and extreme ultraviolet.

CVnet: Isn't this the opposite of what has been observed in prior campaigns on SS Cygni?

Mukai: No, not really. During the peak of the outburst (as determined by
visible light observers), SS Cyg is fainter in hard X-rays and brighter
in soft X-rays. It's in the time of transitions that SS Cyg has
shown a behavior pattern that has not been seen in other dwarf novae.
Other systems have shown "quiescent" (hard X-ray bright) and
"outburst" (hard X-ray dim) states, and nothing else. SS Cyg,
on the other hand, initially brightens in hard X-rays (near the
time of the peak visible light) before switching to hard X-ray
faint/soft X-ray bright state. There is another hard X-ray brightening
near the end of the outburst. So, in hard X-rays, it goes from
bright-brighter-faint-brighter-bright through an outburst.

You can see this in the light curves here.

CVnet: Does this mean SS Cygni is actually the exception to the rule, and not the
prototype as most people have always assumed?

Mukai: You can still consider SS Cyg to be the prototype of the hard X-ray
bright (quiescence) - dim (outburst) behavior. It appears to be
an exception in showing the bright-brighter-faint-brighter-bright
behavior.

CVnet: How does the mass of the white dwarf come into play in the whole process?

Mukai: The accretion rate at which the boundary layer switches from the
optically thin regime to the optically thick regime is believed to
be a strong function of the white dwarf mass, according to theoretical
studies. The higher the white dwarf mass, the higher the accretion
rate at which the transition occurs. The state change of the disk,
between quiescence and outburst, is governed by the conditions in
the disk, and is far less sensitive to the white dwarf mass. When
the disk goes into outburst, the accretion rate through the boundary
layer rises, making it optically thick for an average mass white
dwarf, while making it brighter but still optically thin for a
high mass white dwarf - at least that''s a physically motivated
explanation of why SS Cyg might behave differently from the average
dwarf novae.

CVnet: Is this the main reason for selecting RU Pegasi as your target for the Swift campaign?

Mukai: Yes, we believe that the white dwarf in the RU Peg system is among the
most massive for a dwarf nova. Also, it is one of the X-ray brightest
dwarf novae for which an X-ray monitoring campaign has never been
done.

CVnet: How do you know the mass of the white dwarf in RU Peg?

Mukai: In the optical spectra of RU Peg, you can see both the mass donor and
the accretion disk, so the radial velocity motion of both stars can
be measured, with the usual caveats.

CVnet: So what if we don't see the same X-ray behavior as SS Cyg when RU Peg goes into outburst?
Will the campaign still prove useful scientifically?

Mukai: That would be a very important result, because it would have disproved
our current hypothesis. We will have to go back to square one in terms
of trying to understand why SS Cyg is different, but that's how science
is supposed to work.

CVnet: Thanks, Koji. Any final comments or advice for our observers?

Mukai: Thank you, and thanks to all the AAVSO observers out there who make
this kind of research possible!