Tag Archives: Mercury

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.”

NASA Space Place – Triple Treat

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in May, 2013.

By Dr. Ethan Siegel

2013february2_spaceplaceThe solar system is a busy place, with five wandering planets visible to the naked eye alone. When any two pass close by each other from our point of view, we see an astronomical conjunction, but on very rare occasions, three planets will find themselves grouped together: a triple conjunction. Towards the end of May, Mercury, Venus and Jupiter will treat us to the best triple conjunction in years.

On May 25th, Mercury will pass within 1.4° of Venus, then two days later Mercury comes within 2.4° of Jupiter, and finally on the 28th, Jupiter and Venus approach within 1° of one another. If it weren’t for the slight orbital tilt of our solar system’s planetary orbits, these conjunctions would all be occultations instead. During the nights of May 26th-27th, all three planets are visible immediately after sunset within the same 3° field of view, with the triple conjunction peaking in a triangular shape on the 26th. (For scale, the full Moon subtends about 1/2°.) The three planets appear close together for a few days more, making a line in the sky on the 30th/31st.

How does this happen? Mercury and Venus race around the Sun far faster than Earth, with Mercury completing more than four revolutions around the Sun for each one that Earth makes. At the same time, Jupiter is far slower, taking 12 years to orbit just once around the Sun. Jupiter’s been high in the sky during the early parts of the night, but steadily lowers throughout May as Earth continues to move away from it, approaching its maximum distance from Earth. Mercury and Venus, meanwhile, begin to move out from behind the Sun during May: Venus at the beginning of the month and Mercury in the middle.

Thus, during this triple conjunction, all three planets will be on the far side of the Sun, something that happens just 25% of the time in triple conjunctions involving Mercury and Venus! If you telescopically resolve these planets into disks, you’ll see our inner worlds in a nearly-full gibbous phase. Jupiter will appear largest in terms of angular diameter, followed by Venus and lastly by Mercury. Just a year ago, during its now-famous transit, Venus took up more than a full arc-minute in the sky; during this conjunction, it will just one-sixth that angular size and less than a third the apparent diameter of Jupiter. Nevertheless, Venus will still be more than six times as bright as Jupiter during this time, outshining all night-sky objects other than the Moon. Closer conjunctions of two naked-eye planets are frequent, but getting three or more like this happens just once or twice per decade, so don’t miss your chance to see it.

And speaking of occultations, The Space Place has a great kid-friendly explanation of the Venus transit and solar eclipses of 2012 at spaceplace.nasa.gov/venus-transit.

Dr. Ethan Siegel, a theoretical astrophysicist, is a professor at the University of Portland (OR) and Lewis & Clark College.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.


Caption: The image shows the configuration of Mercury, Venus, and Jupiter in the western sky just after sunset on May 26, 2013. Insets show the relative size appearance of the planets on that date.

About NASA Space Place

The goal of the NASA Space Place is “to inform, inspire, and involve children in the excitement of science, technology, and space exploration.” More information is available at their website: http://spaceplace.nasa.gov/