in Southwestern Virginia The Dark SideRVAS NL – April 2011 – Pg. 2 of 17 Contined next page The Australian Aboriginals saw many of these dark constellations. The most famous is

Volume 28 – Number 4 April 2011

Roanoke ValleyAstronomical

SocietyAmateur Astronomy News and Views

in Southwestern Virginia

RVAS NL – April 2011 – Pg. 1 of 17 Contined next page

The Dark Sideby Jack Gross

We are most familiar with recognizing patterns in light illuminated shapes. However, like in the Star Wars’ force, constellations can have their own dark side.

Since ancient times “dark constellations” have been recognized by cultures in both hemispheres. Our eyes have grown accustomed to seeing patterns in light areas, but there are pictures to be seen in darkness as well. Do you see white chess pieces, or five men the photo below?

Dark patches in the Milky Way stand out vividly when viewed far from light-polluted night skies. You can make out shapes in these dark patches and lots of folks have given names to these “dark constellations.”

Linus – That group of clouds over there reminds me of St. Steven being stoned, and there’s British Honduras, and Thomas Ekins. Charlie Brown – I was going to say I saw a duck and a horsie, but I changed my mind.


The Australian Aboriginals saw many of these dark constellations. The most famous is the Emu, seem below, whose head is formed by the Southern Coal Sack, which itself is another dark constellation.

The Inca civilization also identified dark areas in the Milky Way as animals, and associated their appearance with the seasonal rains. Just like their bright star pattern counterparts, these dark shapes have their own myths and stories.

The reason for these dark areas in the Milky Way is the molecular dust and gas which obscures the stars behind. As we look toward the center of our galaxy, this stuff doesn’t allow light in the visual spectrum to shine through. But viewing in infrrared allowes us to see into these clouds and the vast regions of star-forming activity they hide.

While not as famous as its counterpart in the Southerh Hemisphere, we have a coal sack of our own nestled in the wings of Cygnus, the Swan. It’s close to Deneb and easily visible with binoculars or even the unaided eye. And, in an interesting coincidence, the Southern Coal Sack is located near the Southern Cross while the Northern Coal Sack is in Cygnus, also known as the Northern Cross. The Northern Coal Sack is pretty large and extends over six degrees in the band of our Milky Way.

E. E. Barnard, known for his discovery of Barnard’s Star in 1916, liked to explore the dark regions of the Milky Way. He cataloged his findings, giving them numerical designations, just like the Messier catalog. His first list was published in 1919 in the Astrophysical Journal. It was titled “On the Dark Markings of the Sky with a Catalogue of 182 such Objects”. His final catalog begins with Barnard 1 and ends with Barnard 370. Many other dark nebulae like The Pipe, Snake, Prancing Horse and William Herschel’s Hole in the Heavens have also been cataloged.

There are many dark nebulae in sections of the Milky Way seen from our hemisphere. The Northern Coal Sack marks the beginning of the Great Rift which divides the Milky Way into two branches. This huge dark lane of gas and dust, is buffeted by supersonic winds, and stretches from Cygnus into Sagittarius. Just like the curtain which hid the Wizard of OZ, it conceals the stellar nurseries it contains. This irregular black cleft gives our northern Milky Way its blotchy appearance. The Great Rift contains some one million solar masses of cloaking gas and dust which is thinly spread through many light years of space. About one percent of the mass of this interstellar dark cloud is due to dust, and the other 99 percent is mostly to hydrogen gas. The dust consists of microscopic grains of carbon and silicates. The stars behind the dark cloud are hidden by the more than one million particles per cubic centimeter. While this density is low, compared with the 1019 molecules per cubic centimeter in the air we breathe, dark nebular clouds are opaque because of the enormous distances starlight must travel through them.

The Mayans called The Dark Rift “Xibalba Be” - The Road to the Underworld. They saw it as a place of birth and death. The 2012 Doomsday myth is closely tied to this dark pattern in the night sky. They recorded their history with the Long Count calendar, which tracked for 5,125 years. But, this calendar ends on December 21, 2012! Also on this date an alignment occurs as the winter solstice sun crosses the Milky Way in Sagittarius. This crossing point is in The Great Rift. Does all this sound ominous? Not to worry; the Mayan concept of time is cyclical, and this calendar resets.

Not dark constellation stories depend upon ancient fancy. Some are quite new. The Great

Rift is an area deep in Star Trek’s Alpha Quadrant, far beyond Federation space. It was largely unexplored until the late 2360s when The USS Marignano was assigned to survey it in 2369.

Check out these Dark Constellations for yourself. While it may seem odd for a stargazer to look at absence of stars, you may acquire a fondness for observing dark nebulae. As astronomy

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The Roanoke Valley Astronomical Society is a membership organization of amateur astronomers dedicated to the pursuit of astronomical observational and photographic activities. Meetings are held at 7:30 p.m. on the third Monday of each month, at the Center in the Square in downtown Roanoke, Virginia. Meetings are open to the public. Observing sessions are held one or two weekends a month at a dark-sky site. Yearly individual dues are $20.00. Family dues are $25.00. Student dues are $10.00. Articles, quotes, etc. published in the newsletter do not necessarily reflect the views of the RVAS or its editor.

RVAS web page: http://rvasclub.orgOfficers/Executive Committee/Editor

Paul Caffrey, President ([email protected])Michael Good, Vice President ([email protected])

Mark Poore, Secretary ([email protected])Jeff Suhr, Treasurer ([email protected])

Randy Sowden, Immediate Past President ([email protected])Mark Hodges, Past President ([email protected])

Carol Mesimer, Member at Large ([email protected])Clark M. Thomas, RVAS Newsletter Editor ([email protected])

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John Goss has prepared a fascinating side-by-side visual comparison between an ordinary sized full perigee Moon, and the so-called full Super Moon that was celebrated in the March 2011 popular press.

On the day after the “Super Moon” people chattered at their workplaces about how large the Moon appeared. However, the real difference was just one arc minute, or about 1/30th the ordinary width of a full Moon. Such a small diameter difference cannot alone be easily perceived by the naked eye.

People who marveled at the rising full Moon early on that night were simply experiencing the well known optical illusion of the Moon appearing larger when close to the horizon.


What our “Quiet” Sun is Really Doingby Dave Thomas

Here is a chart of a solar event that occurred between the hours of 1957 and 2009 UTC on March 7 ICW, a M class solar flare and coronal mass ejection

associated with active sunspot region 1164. This chart shows a type II radio burst and continuum bursting during the period.

This is me standing in front of my Radio Jove radio telescope antenna. I wonder what Galileo would have thought of a telescope with this design.


Roanoke Valley Astronomical Society March 2011 Meeting Minutes

March 21, 2011 - 7:30 p.m.

Attendance - 29

Treasurer’s Report• Checking Account Balance - $3,810.95• Certificate of Deposit Value - $8,642.19

Observing Reports - various members shared observing reports

TriStar Report - by John Goss [see article]

Future Meeting Location - Discussion on options for a RVAS meeting location during Center in the Square renovations. RVAS can continue to meet at its current location in April, and possibly May.

Astronomy Day 2011- Genevieve Goss presented several outreach ideas for RVAS to consider for Astronomy Day this year (May 7th). Further details will be e-mailed to the club once they are finalized.

Keynote Presentation - by David & Michael Fleming • Stratospheric balloon launch & recovery• For more information, refer to the following links

+ Roanoke Times story http://www.roanoke.com/extra/wb/273812 + YouTube video http://www.youtube.com/watch?v=otx7b0iuPvk

Balloons and Astronomy - Presented by Michael Good

• Michael gave a short presentation on how balloons are used in astronomy research.

Star Trek Star Birthday Celebration• RVAS Celebrated the 80th Birthdays of Star Trek co-stars William Shatner and Leonard

Nemoy with cake, soft drinks and toasts of “Live long and prosper!”• Mark Hodges presented a YouTube video of a behind-the-scenes look at various Star Trek

filming sets.

Geegaws Galore • Thanks to Mark Hodges for allowing RVAS members to rummage through astronomy-related

items from the Science Museum’s impending move clean-out efforts.

Respectfully submitted,

Mark Poore, RVAS Secretary

Frank Baratta’s Astro-QuizWhen did a transit or occultation of one planet by another last occur and what were the planets involved?

Answer to Last Month’s Astro-Quiz: In the early 1900s, Harvard College Observatory was the locus of some of the most noted women in the history of astronomy. Cecilia Payne-Gaposhkin was in the top rank. Studying under Harlow Shapley, in 1925 she produced her doctoral dissertation entitled “Stellar Atmospheres.” Otto Struve called her brilliant, yet Henry Norris Russell rejected her 1925 doctoral thesis’ conclusion that hydrogen is the dominant constituent of stars. Dissuaded from her own results, she failed to publish. Ironically, years later Russell reached and published the same conclusion, with no credit given to Payne-Gaposhkin.


Let’s Make Plans for Astronomy Day 2011by Genevieve Goss

This year, the main observance of Astronomy Day is scheduled for Saturday, May 7.

The Astronomical League also offers a fall date (October 1st) as an alternative.

Since RVAS has traditionally chosen the spring date, plans are underway for a series of public observing events clustered around the date of May 7.

Two years ago, in conjunction with the 2009 International Year of Astronomy’s “100 Hours of Astronomy”, RVAS scheduled a series of four observing sessions.

Since clear observing conditions are always a challenge, planning more than one activity improves our chances of actually

delivering an event to the public!

RVAS members will soon receive notification of the exact schedule, and will have the opportunity to choose the location and time slot that best suits their needs. A signup sheet will be available at the next club meeting on April 18. You don’t need to bring a telescope, just yourself, to help out. You don’t need to be an “expert” either, as we are all astronomy experts in the eyes of the general public.


Space Shuttle Obituaryby Clark Thomas

After the March 9th landing of Discovery there will be only one more flight of these rocket planes. When Atlantis lifts off on its last scheduled flight around April 19th, that will be The End for this storied program.

What did it all cost, and what did America get for our money? A bit of history is in order:

This program began in 1972 under President Nixon. Discovery alone flew nearly 150 million total miles during its 39 missions. But now it is off to a museum.

There were a few scientific highs, notably the Hubble lift and subsequent servicing – but there also was a lot of make work involving the ISS. Just what has the ISS accomplished, beyond being a grand hotel for Americans and Russians? If you stretch your brain, you can find something good to say about the ISS, but how good is that short-lived Leggo contraption relative to the billions spent?

The Space Shuttle program has cost American taxpayers nearly $170 billion – just to go into low Earth orbit to mostly build a floating hotel. That’s about $1.3 billion per launch. Factor in the obliteration of heroic Challenger (1986) and Columbia (2003) crews in gruesomely spectacular fashion. Our Shuttle crews experienced a two percent death rate per astronaut-flight, and an average failure rate of one in every 65 missions. [Would you ever drive your car if the odds of you and your passengers’

violent death on that occasion were one in 65?]

In 1972, when these shuttles were hatched, computers were primitive. Compare computers then to IBM’s Watson in 2011. Computer power

in the Apollo Moon capsules was less than today’s smart phones. Of course, using fleshy humans in jeopardy to justify space adventure encourages projection of taxpayer dreams.

We officially conquered the western frontier

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in 1890, so what’s left? Space, “to infinity and beyond,” as Buzz Lightyear would say. Now we have gone to the Moon, and there are multiple robots in space and on Mars – all much more affordable than packaging delicate protoplasm on suicide missions.

In 2010 the U.S. Air Force launched an experimental space plane, the X37b. It stayed in Earth orbit for over two hundred days. Another one has recently been launched on a second secret research mission. Most notably, they were launched by a conventional rocket, and they can return to Earth after a long stay aloft. These spacecraft are entirely controlled by robots and Earth guidance. No protoplasm packaging required.

The X37b is a prototype for the real future of space travel. The future will not showcase

fearless astronauts, but will feature advanced cybernetic intelligence (which I have previously described in this newsletter).

We will safely view in time delay their actions. This type of “you are there” science will be just as real as watching humans in time delay on Mars. Honestly, nearly all of us will never go there under any scenario.

Unlike low-Earth orbiting, distant journeys – even within the Solar System – will require a high level of artificial intelligence with independent feedback. Advances in computer capabilities from 1972 to 2011 will be greatly exceeded by startling advances in cybernetic consciousness from 2011 to 2050. And the clock doesn’t stop there.

Was that $174 billion invested in the Space Shuttle program the wisest way to

go? My guess is yes, considering all factors. Starting into space with Buck Rogers fanfare enabled all the real astronomical science to piggy-back on the glory rides of brave humans in space.

Now is the time to plan for science that is safer and more cost effective. Five hundred years from now the 21st century will be known as a great century for astronomy, and an even greater one for computer consciousness.

We amateur astronomers are very lucky to enjoy the technology shows and scientific discoveries in our era. After all, the more we Earthlings learn about the cosmos, the more we appreciate ourselves. Hopefully, this new knowledge will help inspire the wisdom to preserve our rare and precious home planet.


In Roanoke there is a group of women called “The Athenian Society” who promote the arts and sciences.

On March 17, 2011 they listened to club member John Goss lecture on “Letting the Moon Be Your Guide to the Stars and Planets.” I was there too. After the lecture John was bombarded by questions from fascinated listeners who made this lecture one of the most successful in recent Athenian memory.

• Where does ‘outer space’ begin? John held a globe of the Earth in one hand. With the other hand he put a layer of bubble wrap around the globe to illustrate the Earth’s atmosphere. All artificial Earth satellites (except those in geo-synchronous orbit) orbit on the outer surface of that bubble wrap. You could “drive” a car at 60MPH and reach those satellites in just six hours.

• If you kept driving another 40 days you would reach the Moon.

• The Apollo photo of “Earth

Rising” is misleading. It is impossible for an observer on the Moon to see the Earth rise because the same side of the Moon always faces the Earth. The Earth appears almost stationary when standing on the Moon’s surface. However, that Apollo capsule was going

around the Moon, creating an “Earth rise.”

• John then explained ‘libration,’ or the apparent back and forth rocking of the Moon. He explained that part of libration is because the Moon’s orbit is not a perfect circle. (There are also other reasons).

John projected a time lapse video of the Moon that showed libration. (You can find the video by searching for “libration” on Wikipedia.)

He also showed two photos he took of the Moon two weeks apart, showing, when placed side-by-side, obvious differences in diameter caused by different distances from Earth (or apogee and perigee).

Astronomy outreach lecture...

John Goss Addresses Roanoke Athenian Society

By Roger Pommerenke

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Are Those Colors Real?by Neal Sumerlin

[This essay was originally published at http://www.lynchburg.edu/astronomynews, on October 26, 2010. This, and older posts, are archived there. Republished by permission of the author. – Editor]

Today’s Astronomy News is more technical than lyrical, but if you have ever wondered about the colors shown in astronomical images, dive right in!

Introduction

One of my very favorite web sites is NASA’s Astronomy Picture of the Day (www.apod.nasa.gov), showcasing gorgeous images ranging from the Earth at night (http://apod.nasa.gov/apod/ap040822.html) to a “baby picture” of the universe at 380,000 years of age (http://apod.nasa.gov/apod/ap050925.html). Each week, viewers are given the opportunity to vote for the APOW-astronomy picture of the week-and if the candidates include an emission nebula, that is very often the winner in a landslide. These are glowing clouds of gas powered by hot and energetic stars in their midst, and the brightest and most familiar of these is the Great Orion Nebula.

After the Big Dipper, Orion is probably the most familiar grouping of stars in the sky to Northern Hemisphere observers. At this time of year, it is not fully above the eastern horizon until after midnight, but it rises a little earlier each night and is a familiar sight shortly after dark during the winter months. In a dark sky, one can easily spot the soft glow of the nebula in Orion’s sword, hanging from the three stars of his belt.

Telescopes give us a more detailed and close-up view, and digital cameras allow those of us without access to world-class instrumen-tation to share the full glory of the object.

But if you do a Google Image Search for “Orion Nebula”, you get not only a variety of orientations and angles of view-the equivalent of zooming in or zooming out on the same object-you also get a bewildering variety of colors. Are any of these “real”? Forgive me if I remind you of a former president, but it depends on what the meaning of the word “real” is.

I am sometimes asked whether the images returned by the Hubble are what we would see if we were actually “there”: hanging in space at the appropriate location, observing with our own two human eyes. For several reasons, the answer is no.

The Limitations of the Human Eye

First of all, our eyes just aren’t that sensitive. We require more light that is generally available in deep interstellar space, and while very bright nebulae such as Orion would certainly be visible (it is after all visible from over 1300 light years away), many of the objects familiar from Hubble images would not be. Our eyes are very good at detecting motion (good for avoiding predators), which means they are not so good at building up an image of a single dim stationary object over time, collecting enough photons to reveal the otherwise invisible.

But the main difference between that Hubble image and what your eyes would see is in the color.

Here is a quick reminder of something you may not have visited since middle school. Our eyes are sensitive only to a narrow band of the entire electromagnetic spectrum. What we call

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visible light ranges from violet at one end of our range of sensitivity to red at the other.

And it’s even more complicated than that. The color detectors in our retinas are of three types, sensitive to wavelengths centered roughly on blue, green and red. They do not respond with equal sensitivity to

all wavelengths of light, and their areas of sensitivity are not equally spaced from each other. All of this means that while our eyes are remarkably versatile detection devices, they have some limitations as scientific instruments!

Enter the digital camera, or more precisely, the CCD (charge-coupled device) camera. A CCD is simply a light-sensitive silicon chip that can turn light into electricity, and create an image in the form of digital information. It is at the heart of everything from your point-and-shoot digital camera to your cell phone camera to the webcam you use to visit with your distant friends over the internet. The CCD actually has a grid of tiny picture elements (pixels), and the more of these there are, the finer the detail in the final image.

How CCD Cameras Take Color Images

A CCD is not color sensitive. Although it responds to some colors more strongly than others, essentially it is similar to black-and-white film, just recording the intensity of visible light falling on it. Your digital camera creates color by putting a tiny color filter on each pixel so that it preferentially detects one of three colors. The camera adds the resulting three images together to create color. The disadvantage is that your resolution (the fineness of detail which depends on the number of pixels) is only one-third of what it would be otherwise. But, given the ever-lowering cost of CCD chips, this is much cheaper than the alternatives.

How Astronomical CCDs Take Color Images

The objects imaged by telescopes are not changing! Or at least they don’t appear to change from our perspective in any short period of time. So we can take an image now, and then another image a few minutes later, and be confident that the object will not have changed in between.

This lets us create color images in a way that takes full advantage of the pixel count of our detector. If we wished to create something close to what our eyes would see if they were sensitive enough, we would take one image each through red, green and blue filters, then combine these to create a color image. Four-color magazine printing (which adds black) works in much the same way.

Do the Hubble Images Show “Real” Color?

Let me rephrase the question: Do the Hubble images show visual color-what we would see with our own eyes? No. Do they show real color? Well, they aren’t making up any information that isn’t there to start with! It’s how the information is processed that makes the difference.

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The filters that the Hubble uses are not just colored pieces of glass. Rather than passing a wide range of wavelengths centered around red, for example, they pass only a very narrow band centered on very specific wavelengths. This allows us to reject a great deal of stray light from a variety of objects (sunlight reflecting off the moon or the Earth) and create much crisper images.

Most of what is in the universe is hydrogen, and so most of what glows is glowing hydrogen. Hydrogen emits light of several different and very specific wavelengths, but what is called hydrogen-alpha emission dominates. This is a deep red color, and many images of nebulae are taken solely through this filter, then rendered as red images. Here above, for example, is an image of the Eagle Nebula taken only through a clear filter and a hydrogen-alpha filter.

And here below is an image of the same Eagle Nebula taken with what is called the “Hubble Palette”. This image uses three filters. A hydrogen-alpha filter passes red light emitted by hydrogen atoms, but it is rendered green here. An SII filter passes light that is even more deeply red than hydrogen-alpha, and here it is the red part of the image. It is emitted by ionized sulfur atoms. Finally, doubly ionized oxygen atoms are passed by an OIII filter. This light is green, but here it is rendered as blue.

It makes for a beautiful image, doesn’t it? But the reason for using these specific filters is both practical and scientific. Emission from

different atoms gives us information about different parts of the nebula, and rendering them as very distinct colors emphasizes those differences. And these emission lines are fairly bright. Hydrogen is by far the most abundant

element present in these clouds, but even elements present in far lower abundances can shine relatively brightly.

Are there other palettes? Sure there are.You could make up your own! One of the more popular is the so-called CFHT (Canada-France-Hawaii Telescope) because it more closely resembles old images created on photographic film. CFHT uses hydrogen-alpha for red, OIII for green, and SII for blue. Here below is the Eagle Nebula rendered via the CFHT palette.

All of these are simply different ways of depicting the same object. All of them are “real”. All of them convey information, albeit in different forms. And to my mind at least, they are all beautiful!


March is a relatively quiet time of year, not having as many weekend activities to keep oneself busy as a few weeks later. Michael Good and John Goss took advantage of this lull in weekend scheduling to visit the Tri-Star conference in Greensboro, NC on March 5. The two hour trip

was well worth the time. It was bound to be, since this was Tri-Star’s tenth anniversary.

The first talk was given by Mike Malaska, a volunteer professional researcher on the Saturn-Titan system. In his “Titan’s Earth-like Landscape,” he emphasized the large moon’s many similarities to our Earth. Primarily because of the Cassini mission, Titan, of all places, is recognized as being the most Earth-like body in the solar system. Internally, both Earth and Titan have a differentiated structure with several materials playing crucial roles. On their surfaces, they both have many of the same types of features including craters, dunes, mountains, volcanoes, clouds and storms, lakes and rivers. Their respective surfaces exist in a dynamic state. In other words, tomorrow will be somewhat different than today.

Titan was again featured in the second talk, “Outside In: IMAX Film about Space.” Greensboro film producer Steven van Vuuren described his efforts to bring Saturn and its moon’s, including Titan, to the big high resolution

screen of IMAX. This project, taking several years to complete by their limited staff and funding, is resulting in incredible fly-by scenes of the Saturn system. Mr. van Vuuren’s film project can be found at www.outsideinthemovie.com, and www.facebook.com/outsideinthemovie.

North Carolina State astrophysicist Dr Steven Reynolds presented the first afternoon talk. He described supernova processes and X-ray astronomy, before focusing on Kepler’s supernova and other more recent supernova

explosions in nearby galaxies. Dr. Reynolds definitely held the audience’s attention when he demonstrated how the internal bounce of an imploding star can thrust its materials into space, thereby blowing the star to smithereens.

Tri-Star’s concluding talk, “Galaxy Life Stories: Growing Up in a Violent Universe,” presented a big picture

view of galaxy evolution. Dr. Sheila Kannappan of the Department of Physics and Astronomy at UNC-Chapel Hill engaged the crowd with video simulations of galaxy formation. She covered the topics of galaxy collisions, hierarchical galaxy evolution and the puzzle of disk re-growth to show how large galaxies, such as the Milky Way, have grown and changed, and what the future has in store for them. This is definitely an evolving topic.

For next year’s Tri-Star, here is what you need to know: It is always held on the first Saturday in March. It is always educational. It is always fun. It is always free.

Tri-Star Conference Ten Years Runningby Michael Good and John Goss

Telescope review...

Burgess Optical 91mm CaF2 PlanetHunterby Michael Good

John Goss and I went to the annual *Tri*Star (The Triad Starfest) this year in North Carolina (http://www.gtcc.edu/services/observatory/triStar/index.html).

In addition to a thoroughly enjoyable day of talks, I had the pleasure of meeting optical designer and small businessman Bill Burgess and his wife Tammy and son, who travelled from their home in Knoxville TN to partake as vendors for Tri-Star.

As I had been in the market for a small (read: wide field) refractor for astro-photographic use, my eye immediately went to the Burgess Optical 91mm, FL700mm, f/7 that Bill has designed. Bill is always on the look-out for ways to offer good quality at affordable prices.

All astro-photographers know the value of a good APO... the three lens design allows colors to come to a sharp focus. The drawback is cost. For a well constructed 91mm you can certainly expect to pay in the $2000-2500 range foran APO.

A way around this is the use of Fluoride. This is an expensive lens to manufacture, yet Bill has found a supplier in China who can make these lenses in a new, affordable fashion, and since they are doublets (two lenses) they don’t break your bank. I ordered the scope.

I received my refractor March 29, 2011. It is a 90mm, f/7, 700mm (Bill) Burgess Optical - CaF2 (Calcium

Fluoride) PlanetHunter. I believe it is also coated in Lanthanum. The lens is actually 92mm, and at *Tri*Star Bill referred to 91mm due to the lens cell, but to be even more conservative he has now labeled the scope as a 90mm.

God smiled on me last night by allowing me to have two hours of clear weather before this week’s rains set in. I performed star tests with a 6.4mm Meade Ploessl on our friendly brightest star-in-the-sky Sirius, with the telescope attached via the 1/4 threaded socket Bill designed into the base, attaching this scope to a cheap and light Velbon tripod (read: this is a grab and go setup).

I was not disappointed. No major color fringing. Concentric rings inside and out. I did spot what appeared to be the slightest reddish hue at the bottom of stars and slight blue at tops, but Bill warned that the color correction of this scope only comes with critical focus.

One photo shows the padded bag this scope comes with. Another image shows the scope in the stowed position with the lens shade retracted and the rack and pinion racked most of the way in. This photo also shows the excellent 2” diagonal that Bill includes with the scope. The third photo shows the dew shield fully extended and the 2” tube fully racked out showing the incredible 13+ inches of back focus that Bill has designed the focus to allow. Many other scopes require purchasing extensions.


In the next photo I look down the barrel, reflecting light from a white basement fluorescent light fixture. You can see the multiple light baffles inside the scope, the thick 2mm telescope walls with a rubber bumper on the front edge of the extended dew shield. One small difference with this scope is you will notice no aperture or f-ratio are printed on the lens collar as is found in many scopes. This only shows how custom these scopes really are. Clearly not mass-produced. It should be pointed out that Photoshop was used to stretch this photo looking down the barrel, since with the baffling it is actually quite dark, even with light pouring straight down the tube, and required manipulating the image to easily see the baffles.

The next feature is very clever: the lens cap for this telescope also serves as a solar filter, with a second inner cap covering the solar filter material. As always, check the integrity of such filters by holding up to the sun to look for damage before using.

The final image shows the optional finder mount, the single-speed yet very smooth focuser, and the markings on the barrel. I inquired as to why Bill

chose a single speed over the now very popular double speed focusers (course/fine). Despite what I assume is a cost difference, he stated that he found the single speed focus holds more weight without losing focus. There are two screws under the Crayford style focuser: the focus lock and a second to disengage the Crayford assembly completely

while locked (the wheel turns with no friction). The entire focus assembly rotates for framing a camera or CCD on your object.

After my initial star tests, I proceeded to use almost all the eyepieces in my Meade Ploessl eyepiece “kit”. I then tried my 32mm Televue, and finally spent most of the evening using my 2” 35mm Panoptic that I won at Laurel Highlands Star Cruise. As many of you know, the Panoptic is a beast of an eyepiece, and extremely heavy. The views of M42, the Orion “cluster,” the Pleiades, open clusters in Auriga and the winter Milky Way, all were sharp.

Next month I hope to have mounted this telescope piggy-back on my C14 and can report on the optical quality while imaging (and hopefully that the focus holds the weight of the heavy ST10xme+CFW8+AO7 CCD camera assembly without losing focus).



Calendar of Eventsby Frank Baratta

Monthly meeting: Monday, April 18th, 7:30 p.m.,

Center in the Square, Roanoke.

The featured program for the evening will be a celebration of our last meeting in the Science Museum until renovations are complete.

Several surprises await those who attend.

RVAS WEEKEND OBSERVING SESSIONS: Unless otherwise indicated, observing sessions are held at Cahas Mountain Overlook, milepost 139 on the Blue Ridge Parkway.

◆ Friday and Saturday, 1st and 2nd. Sunset is at 7:43 p.m. As-tronomical twilight ends at 9:12 p.m. The Moon sets at 5:14 and 6:10 p.m., respectively.

◆ Friday and Saturday, 22nd and 23rd. Sunset is at 8:02 p.m. As-tronomical twilight ends at 9:37 p.m. The Moon rises at 1:12 and 1:53 a.m., respectively.

◆ Friday and Saturday, 29th and 30th. Sunset is at 8:08 p.m. As-tronomical twilight ends at 9:46 p.m. The Moon sets at 5:04 and 6:00 p.m., respectively.

◆ May Sessions: 27th and 28th.

ROANOKE CITY PARKS and RECREATION PUBLIC STARGAZE: Saturday, April 30th, 8:45 p.m., Cahas Overlook, Milepost 139 Blue Ridge Parkway. Nonmembers must register with Parks & Rec. at 540-853-2236. Members can call 540-774-5651 for information. (Next session: May 21st, 9:15 p.m., Cahas Overlook.)

FRANKLIN COUNTY PARKS DEPT. PUBLIC STARGAZE: We regret to inform our members that Franklin County sessions have been discontinued.

Documents

in Southwestern Virginia The Dark SideRVAS NL – April 2011 – Pg. 2 of 17 Contined next page The Australian Aboriginals saw many of these dark constellations. The most famous is