Star Watch

STAR WATCH FOR July and August, 2017

The WCSU Planetarium and Observatory are currently closed for the summer season, but the Star Watch page will continue to be updated during  July and August. Watch this page for updates on the Fall public night schedule.

NIGHTLY SKY CALENDAR

*, !, !! – interesting to very interesting celestial event
WOW!! — ‘must-see’ event
E –  calendar or geometry- related event (such as an equinox)

SUN & PLANET INFORMATION                                                                                                

THE SUN will be eclipsed by the New Moon on Monday, August 21, for viewers all across North America, in what promises to be a spectacular event-─especially for those observers along the path of totality. For those people, about 80 minutes of ever-deepening partial eclipse will culminate in a maximum of 2 minutes 40 seconds of totality, in which the Sun’s pearly white corona, red chromosphere and red prominences will stand revealed, and bright stars and planets will be visible. Then the awesome total phase of the eclipse ends, followed by another 80 minutes of ever-diminishing partial eclipse until the end of the event.

Connecticut will NOT have a total solar eclipse, but it will have a respectable partial one in which about 67% of the Sun will be covered. In central Connecticut, the partial eclipse begins around 1:25 p.m. Eastern Daylight Time, with maximum eclipse around 2:45 p.m. and the eclipse ending around 3:59 p.m.

During the partial phases of the eclipse, DO NOT UNDER ANY CIRCUMSTANCES LOOK AT THE SUN DIRECTLY, either  with the eyes alone or through an optical instrument like a telescope or binoculars; you will cause IRREPARABLE DAMAGE to your eyes.

So: how do you safely observe a partial eclipse?

(1) Stand under a leafy tree! The overlapping leaves act like so many pinhole cameras (below), and you will see many bright solar crescents in the tree’s shade. Taking a picture of the crescent-brightened shade under the tree gives you a low-cost, or cost free, souvenir of the event.

(2) Make a pinhole camera or pinhole mirror. A pinhole camera consists of a cardboard box, or a postal mailing tube, on one end of which you have cut out a square that is then covered with a larger square of aluminum foil. In the middle of the foil square should be a tiny hole that you have made by carefully twirling a small sewing needle. Make sure the hole is small, and as round as possible. At the opposite end of the box, mount a white screen for viewing the Sun’s image. You will also want to be able to view the screen, so make an opening in the side of the box into which you can peer. The Sun is about 107 of its own diameters from Earth, and that is also the proportion of the diameter of the Sun’s image to the length of the box, so if you want a Sun image 1 centimeter (about 4/10 of an inch) in diameter use a box 107 cm (about 42 inches) long. … If your box or tube is too wobbly or too heavy, or if you want a larger image, consider making a pinhole mirror. With a hole punch, make a hole near the middle of a “sticky” note, then stick the note to a small pocket mirror. Aim the mirror toward the Sun and look for its reflected pinhole image, which you can project toward a smooth target (like a sidewalk, wall or white foam board. The advantage of a pinhole mirror is that your target can be more than 107 cm from you! Every 20 feet from the mirror will produce a Sun image more than two inches across that you can photograph. The smaller the diameter of the punched hole, the dimmer but sharper the Sun’s image will be.

(3) View the Sun through a safe solar filter. To be safe, the filter must protect your eyes from invisible ultraviolet and infrared light as well as ordinary visible light. A number of companies (for example, Thousand Oaks Optical) manufacture such filters, but there is a lot of demand anticipated for them. A resource closer to home is your local welding supply shop, which can sell you a 2-by-4 inch piece of #14 grade (dark green) welder’s glass for a few dollars. Glasses with side protection can also be purchased, locally or online. See https://safety.grainger.com/people/full-guide-safety-glasses-and-face-shields for a discussion of  safety glasses and the hazards from which they can protect you. … By the way, toaster pastry wrappers are NOT adequate protection from damaging sunlight!

If you are lucky enough to be somewhere along the path of totality, the same warning about looking directly at the partial phases (before and after totality) still apply. You will be tempted to look because of the drop in light level, but don’t do it! However, just before and just after totality, do notice some odd things happening! When only a sliver of sunlight is visible, terrestrial objects start looking unusually sharp. The temperature noticeably drops, and a wind may spring up. Birds stop singing and nest in the trees. The color of the sky may change. It may appear, for a short time, as though you are at the bottom of a swimming pool, with light and dark ripples passing you; these are shadow bands, caused by Earth’s moving atmosphere interacting with the razor-thin arc of sunlight. As totality approaches, watch the Moon’s shadow darken the western horizon and the daylight drains away to a deep “storm twilight.”

Just before totality itself (and just as totality ends), look at the Sun through a safe solar filter to see sunlight shining through craters at the Moon’s edge, producing a chain of lights called Baily’s beads. If only one bead is left (before totality) or has appeared (as totality ends), you have the spectacular diamond ring effect. (Remember, you will still need a safe filter, as the beads and the ring are still uncovered sunlight.)

Once totality starts and until it ends, you may safely look at the Sun without a filter. Get ready to marvel anew! No two eclipses are the same, in terms of the shape and size of the corona, the extent of the red chromosphere, or where on the Sun’s disk prominences (flames!) will emerge. Taking pictures is up to you; many people just choose to absorb the experience. Consult the Web or local news agencies for information on what bright stars and planets will be visible during totality.  However, whatever you choose to do, know the duration of totality at your observing site, keep careful track of the time elapsed since totality began, and be ready to look away (and/or put the solar filter in front of your eyes again) before full sunlight is uncovered. We want you to have an unforgettable experience with a happy ending!

MERCURY – is in the evening sky during July and the first few weeks of August, but the viewing geometry is more favorable for Southern Hemisphere observers. Mercury reaches greatest eastern elongation on July 30, 27 degrees from the Sun. 

VENUS – remains bright in the eastern pre-dawn to dawn sky during July and August; it reached greatest western elongation on June 3.

MARS – is too close to the Sun to be seen during July or August.

JUPITER – is near the spring star Spica,  low in the southwestern evening sky.

SATURN – is in eastern Ophiuchus. It reached opposition on June 15 and is visible most of the night, low in the southeastern to southern sky.

Star Watch is a service provided by the Earth and Planetary Sciences program at Western Connecticut State University. Thanks for connecting!