Tag Archives: Prominences

CNYO Observers Log: MOST Climate Day And North Sportsman’s Club Practice Session, 19 April 2014

Greetings fellow astrophiles!

The Saturday after NEAF was a busy one for CNYO members, including a lecture and observing session for the MOST Climate Day during the afternoon and a nighttime “dry run” for the North Sportman’s Club Public Viewing Sessions we’re on the verge of hosting for the rest of the year.

The morning started with a hectic rearrangement of speakers for the TACNY Jr. Cafe session, with Prof. Peter Plumley (MOST, Syracuse University) and Prof. Timothy Volk (SUNY-ESF) admirably filling in for a missing speaker (and the crowd requests for future topics were heavy in astronomy!). And speaking of Jr. Cafe astronomy, we note the May 17th lecture features CNYO’s own Ryan Goodson speaking on Newtonian Telescopes (with a solar session to follow if the skies hold)!

The indoor part of CNYO’s contribution to the MOST Climate Day featured myself and a lecture about the Sun/Earth relationship. While that lecture was given to only 2.5 people (one person left half-way), a 50 minute talk extended to 90 minutes thanks to some excellent discussions and deeper probing of some of the slide content.


Larry and observers on the Creekwalk. Click for a larger view.

Outside, Larry Slosberg hit the public observing jackpot with his 12″ Baader-ized New Moon Telescope Dob and NASA Night Sky Network Solar Kit. Between the MOST crowd, Record Store Day at Sound Garden, and a Creekwalk made busy by the clear skies and comfortable temperatures, Larry counted over a few dozen new observers before I even made it outside. To Larry’s solar collection I added a Coronado PST for some excellent H-alpha views of sunspots and several prominences that changed significantly over the course of an hour (which was made all the more impressive to passers-by when you mention that these changes could be measured in units of “Earths” instead of miles).


An intrepid observer at the Coronado PST. Click for a larger view.

Larry and I packed up around 4:00 p.m. after giving nearly 40 people a unique view of our nearest star, providing a three-hour window before heading off to North Sportsman’s Club (NSC) for an evening session.


Some of the NSC crew setting up. Click for a larger view.

We also used April 19th as a reintroduction to the skies above the NSC, with this session opened up to a short-list of people with scopes interested in helping reduce the lengths of observing lines at future public sessions (and we welcome others interested in bringing their scopes to these sessions to please contact us using our online form or by emailing us at info@cnyo.org).


The Big Dipper (Ursa Major) and surroundings. Click for a larger view.

The total in attendance was between 10 and 12 over the two hours I was present (and the event continued for some time after), with about half as many scopes present (which is a great number for even large public viewing sessions). Despite it becoming a very cold evening, the combined observing list was extensive from among all parties, with New Moon Telescope’s 27″ Dob making many views extra memorable.


The view to the Southwest (featuring a bright Jupiter near center). Click for a larger view.

We are planning our first public session for 2014 in late May, perhaps to coincide with the predicted meteor super-storm on the early morning of May 24th. Keep track of cnyo.org or our Facebook group page for details!

Barlow Bob’s Corner – The Solar Spectroscopy Project

The following article has been provided by Barlow Bob, founder & organizer of the NEAF Solar Star Party and regional event host & lecturer on all things involving solar spectroscopy. You can read more about Barlow Bob and see some of his other articles at www.neafsolar.com/barlowbob.html.

Most solar amateur astronomers observe sunspots on the surface of the Sun through a white light (Baader) solar filter. Some also observe prominences and other features above the surface of the Sun through a Hydrogen-Alpha solar filter. If you are an amateur solar astronomer who shares your safe solar telescope at educational outreach events, please consider including solar spectroscopy at these events.

You do not have to make an expensive investment to purchase a solar spectroscope or spectrometer. Science First (www.sciencefirst.com) and Edmund Scientific (www.scientificsonline.com) both sell several inexpensive types of low-resolution spectroscopes and spectrometers for under $40.00.


The very affordable Quantitative Spectroscope from Science First.

A spectroscope is an instrument for producing and examining spectra, producing spectra of visual electromagnetic radiation (visible spectra). A spectrometer is an instrument for dispersing electromagnetic radiation and analyzing the location of the spectrum lines. A spectrograph is an instrument for dispersing electromagnetic radiation and recording the spectrum.

These spectroscopy products are all easy to use. Laminate an 8.5-by-11 inch sheet of white paper and place this laminated sheet on a table next to your solar telescope. Point the spectroscope down at the sheet of paper. Sunlight reflected off of the laminated sheet enters the front of the spectroscope to the grating or prism. You then can observe the dark Fraunhofer lines of the solar absorption spectrum. These are thin, vertical dark lines in the horizontal colors from red to violet.

Turn a cardboard carton on its side and put it on a table next to your solar telescope. Place a lighted camp lantern with florescent bulbs inside the carton. You can see the lighted lantern better in bright sunlight. Observe the emission spectra of the element mercury inside of the florescent bulb. You can use this demonstration to explain how astronomers discovered what the dark Fraunhofer lines were in the solar spectrum.

You can allow people to observe the dark absorption lines of the solar spectrum through a spectroscope. They can compare these dark absorption lines to the bright emission lines of the florescent light bulb.

The gas in the interior of a star like the Sun is under high pressure. The gas in the outer atmosphere of the Sun is under lower pressure. A photon (a piece of light) moves from the interior to the surface of the Sun and passes through the outer atmosphere. When it passes through the outer layer of the Sun, this outer layer absorbs the wavelengths of the specific elements in this outer layer while the remaining light passes through. The spectra of the elements in the outer layer appear as dark vertical lines in the spectroscope as those photons were absorbed by those elements in the Sun’s atmosphere.


The solar spectrum (Fraunhofer lines and all).

In 1802, William Hyde Wollaston (1766 – 1828), an English Chemist and Physicist, discovered the spectrum of sunlight is crossed by a number of dark lines. This was the birth of solar spectroscopy.

In 1814, Joseph Von Fraunhofer (1787 – 1826), a German glass maker, rediscovered the dark lines in the solar spectrum noted by William Hyde Wollaston and determined their position with improved precision. He made careful measurements of over 500 dark lines in the Sun’s spectrum. He never tried to find out what the lines were or where they came from. Today we honor his careful benchmark investigations by referring to the dark absorption lines of this type as Fraunhofer lines.

Fraunhofer needed a way to measure small differences in the composition of his glass from one melt to another. When white light comes into the prism, the different wavelengths are bent through different angles, resulting in a spread of colors. Prisms made of slightly different pieces of glass will bend the same wavelength of light through different angles. He therefore needed some sort of calibration standard. He used a series of dark bands superimposed at regular intervals over the colored spectrum of light to solve his calibration problem. However he had no idea what these lines were.


An idealized prism in action.

In 1959 Germans Gustav Robert Kirchoff (1824 – 87), a physicist, and Robert Bunsen (1811 – 99), a chemist, observed the bright emission spectrum lines of different heated elements through a prism spectrometer. They discovered that dark Fraunhofer lines appeared when they observed the light from a fire in their city through smoke. When they compared the dark absorption spectra lines to the bright emission spectra lines in their laboratory, they realized that they discovered that they now had a way to analyze the chemical elements by observing the dark Fraunhofer absorption lines. This was the start of astrophysics to analyze stars.

Kirchoff studied light spectra using the spectrometer he developed with Bunsen. He observed that individual atoms and molecules emit certain colors when heated. Kirchoff realized that each element produces a distinct spectrum of colored emission lines that can be used to identify the element.

Kirchoff and Bunsen observed the light from a distant fire through their spectrometer. They observed dark Fraunhofer absorption lines of light from the fire as its light passed through smoke. They noticed that these dark absorption lines appeared in the same location as the bright emission lines of elements they observed in their laboratory.

In 1861, Bunsen and Kirchoff performed experiments leading to the conclusion that the dark lines in the solar spectrum, observed by Wollaston and Fraunhofer, arise due to the absorption of light by gases in the solar atmosphere that are cooler than those emitting the light.

In 1872, Henry Draper, a wealthy American physician and amateur astronomer, was the first person to photograph the Fraunhofer absorption spectrum of a star using a prism spectrograph. This introduced the world to a powerful tool for probing the physical properties of stars. For the first time, the Henry Draper (HD) Catalogue of spectral data was available as an astronomy research resource.

When Henry Draper died in 1882, his widow Anna Parker Draper funded the HD catalogue. Edward C. Pickering, the Harvard College Observatory director, continued creating Henry Draper’s catalogue. Hired women, called computers back in the day at Harvard College, examined the spectra of thousands of stars in these photographic plates. They noticed that the series of dark Fraunhofer lines of red stars had a similar pattern. Other star colors each had similar dark line patterns. These women created the OBAFGKM system to organize this catalogue of star spectra. These computers worked seven-hour days for six days a week and were paid 25 cents per hour. For these women, the opportunity to contribute to science was more important than the salary. By the middle of the 20th century, Henry Draper’s namesake catalogue would contain position and spectral information for nearly a quarter of a million stars.


Pickering and the Harvard computers. From wikipedia.

Spectroscopy is still used today. Astronomers use spectroscopy today to analyze the fingerprints of stars and other celestial objects. Manufacturers of food, drug and chemical products use spectroscopy to analyze the quality of their products. Government agencies including the FBI, FDA and OSHA also use spectroscopy for analysis.

You can allow people to observe the dark absorption Fraunhofer lines of the solar spectrum through the spectroscope, then allow them to observe the bright emission lines of elements in the florescent light bulb in the camp lantern. These two observations can be used to explain how astronomers use spectroscopy to analyze starlight.

You do not have to wait until sunrise to do solar spectroscopy. You can observe the solar spectrum reflected off of the Full Moon at midnight. You can recreate how Fraunhofer, Kirchoff and Bunsen discovered absorption and emission spectra for kids of all ages – and this could be someone’s excellent science fair project.

© 2013 Barlow Bob

CNYO Brochure – A Guide For Solar Observing

Greetings fellow astrophiles!

In preparation for upcoming 2013 lecture and observing sessions, we have put together instructional brochures to help introduce the Night Sky to attendees. The third of these, entitled “A Guide For Solar Observing,” addresses our solar observing sessions and is provided below in PDF format. This brochure will be available at our combined lecture/observing sessions, but feel free to bring your own paper copy (or the PDF on a tablet – but have red acetate ready!).

Download: A Guide For Solar Observing (v6)

NOTE: These brochures are made better by your input. If you find a problem, have a question, or have a suggestion (bearing in mind these are being kept to one two-sided piece of paper), please contact CNYO at info@cnyo.org.

NOTE 2: We’d like to thank the great solar photographer Alfred Tan for the use of his solar image in this brochure. For a regular feed of his stellar (pun intended) solar views from Singapore, we encourage you to subscribe to his twitter feed at: twitter.com/yltansg.



A Guide For Solar Observing

Solar Safety: Read Me First!

“NEVER Look At The Sun Through ANY Eyepiece Without Protection!”

Pre-Observing Observing Tips

“The Sun is a blindingly bright object all by itself – and your observing session has you constantly looking in its direction!”

Sun Cross Section – 697,000 km Radius

“Radiative Zone: 348,000 km thick, energy from the core is passed through as photons (light) – thousands of years for light to pass through it from the core!”

The Solar System To Scale

“The solar diameter in “planets” is listed.”

More Information About The Sun

“The Sun is the reason why we’re here!”

And Just Why Is The Sky Blue?

“At sunrise and sunset, most of the blue light has been scattered by air molecules, so more of the Sun’s longer wavelength light (red and orange) makes it to our eyes (“R”).”

What You’ll Observe On The Sun

“The savvy (or lucky) observer may see a plane (1), a satellite, a planet (“transit” of Venus (2) or Mercury), or the International Space Station (3).”

About The Sun (History & Future)

“The Sun is a spectral type G2V star in the Orion Arm (Orion Spur) of the Milky Way, some 25,000 light years from the Milky Way’s center and, on average, 8 light minutes away from Earth.”

What You’ll See Through Solar Filters

“All other filters work by picking out a single wavelength (shade of one color) from the entire visible spectrum (ROYGBIV – red, orange, etc.), allowing only that color to pass through to your eye.”

Tenth Annual NEAF Solar Star Party (NSSP) Announcement – Direct From Barlow Bob

Greetings fellow astrophiles!

2013february24_nssp_bbdgaEast Coast amateur astronomers have been gearing up for NEAF all Winter long (see our original announcement HERE). One of the special extra NEAF events, now in its 10th year, is the NEAF Solar Star Party (NSSP), featuring several solar-safe scopes, many well-versed solar observers, and hopefully an active solar surface as we approach solarmax.

The host of the NSSP is none other than Barlow Bob (the brightly lit one pictured at right with the author at NEAF 2011), a solar-centric observer who has graced several CNY locations in the past few years both with truly remarkable views of our nearest star and his great knowledge of optics, light properties, and the Sun itself. Provided the skies are at all reasonable, you can be guaranteed of some excellent views of prominences and sunspots.

The official announcement from Barlow Bob is below:


The Rockland Astronomy Club Is Proud To Present

The 2013 Tenth Annual NEAF SOLAR STAR PARTY

APRIL 20 AND 21, 2013

At Rockland Community College – Suffern, New York

NEAF attendees are invited to observe the Sun with attitude in different
wavelengths, through a variety of solar filters and spectroscopes.

Join us, for two days of solar observing at NEAF 2013.

No star party entrance fee, or registration required.


For further information, please visit our website:

www.rocklandastronomy.com & neafsolar.com