The Krakow Summer Astronomy Guide

Summer 2018 is great for amateur stargazers, and this week might be the best. Read on to learn how you can see the lunar eclipse, Mars, and meteor showers in and around Krakow…

Lunar Eclipse

During the 21^st century there will be a total of 230 lunar eclipses, but, among them, the closest one that falls on Friday, July 27th will be a really special one.

The lunar eclipse occurs when the Moon passes through Earth’s shadow, which can be divided into penumbra (a partial shadow) and umbra (the darkest part of the shadow). In the first case, penumbral lunar eclipse occurs, and when the Moon enters the planet’s umbra it’s called a total lunar eclipse.

This month will feature a special case of total lunar eclipse, a relatively rare central lunar eclipse which occurs when the Moon passes through the center of Earth’s umbra[1].

Another favorable circumstance on July 27^th is that the Moon will be at its apogee, the farthest point from the Earth in its orbit. Thanks to that it will stay longer in the planet’s shadow, exactly 1 hour, 42 minutes, and 57 seconds which sets a record for the longest lunar eclipse in this century[2].

The visibility of the eclipse in Poland will be fairly good, although it falls on the moonrise time, so the best spots to observe it will be those with a southeastern view on a clear horizon. The moonrise in Krakow will start at 20:21, when the Moon will be already in penumbral phase. The total eclipse will start around 21:30 and will last till 23:13[3].

There is no need of any special preparations or equipment to observe this sky event. The long-term weather forecast looks promising up till now, so astronomy lovers might be really lucky on July 27^th night.

Great Mars Opposition

Mars opposition is a moment when the planet and the Sun are exactly on the opposite sides of the Earth. It occurs every 26 months, but there is a less common scenario which recurs every 15 or 17 years. It’s when Mars is at its perihelion, the point of the orbit closest to the Sun and at the same time the closest to the Earth. But, because the shape of the orbit changes, the distance between those celestial bodies can vary too[4].

The next opposition will occur on July 27^th, when the planet will be the brightest, and the closest Martian approach to the Earth (since 2003) will take place on July, 31st. Another similar distance won’t be visible until 2035[5].

The Red Planet can be observed with bare eyes and binoculars, so it can be enjoyed easily alongside the lunar eclipse. Nevertheless, to admire the details such as rocky areas, deserts, polar icecaps, or possible dust storms, telescopes are required[6].

Meteor showers

Each year, from mid-July to mid-August, the Southern Delta Aquariids meteor shower appears in the sky. Because this year they may be outshined by the full moon during their peak activity on July 29/30th, you can try again to look for them in August.

The Delta Aquariids meteor shower is a faint one: it normally counts 16-20 ZHR (zenithal hourly rate), which means a single observer can see a maximum of 20 meteors in one hour.[7]  

The Perseid meteor shower is the most popular among observers, as its ZHR is more favorable and counts up to 100 meteors per hour. It overlaps with the Aquariids shower, but its peak falls on August 11/12/13th[8].

The best visibility of both meteor showers will be during predawn hours. The Delta Aquariids and Perseids fall from different directions, crisscrossing the sky. The most lucky and patient observers may even see a perseid earthgrazer, a really slow and bright meteor passing through the firmament.

Tips

A lot of impressive celestial events can be observed without special equipment. You will only need to:

• Find a place far from city light, with open sky and possibly clear horizon since some of the events appear closer to the skyline. In Krakow there is a glade next to the Astronomical Observatory Fort Skała at ul. Orla 171. Other good spots are Krakow’s mounds or just the outskirts of the city.
• If you plan a trip outside the city, you can check the Light Pollution Map or go directly to Mountain PTTK chalet on Kudłacze, a popular stargazer rally spot.
• Be patient – your eyes need around half an hour to fully adjust to darkness.
• Check the weather and keep yourself warm (since Polish nights can be chilly even in the summer).

Special thanks to Agnieszka Nowak, the president of Krakow’s branch of the Polish Society of Amateur Astronomers

[1] http://eclipsewise.com/lunar/LEhelp/LEglossary.html

[2] https://www.crazynauka.pl/najdluzsze-w-xxi-wieku-calkowite-zacmienie-ksiezyca-juz-27-lipca-swietnie-widoczne-z-polski/

[3] http://www.polskiastrobloger.pl/2018/04/calkowite-zacmienie-ksiezyca-w-polsce-27.07.2018-ad.html

[4] https://mars.nasa.gov/allaboutmars/nightsky/opposition/

[5] http://earthsky.org/sky-archive/close-and-far-martian-oppositions

[6] http://www.polskiastrobloger.pl/2018/05/wielka-opozycja-marsa-2018-czerwona-planeta-najblizej-ziemi-od-15-lat.html

[7] http://www.polskiastrobloger.pl/2018/06/niebo-nad-polska-w-lipcu-2018-zjawisko-roku.html

[8] http://earthsky.org/astronomy-essentials/everything-you-need-to-know-perseid-meteor-shower