There is a lot of popular belief about the Moon, and according to most myths something eats it up during eclipse. According to the belief of some Indian tribes in America, huge dogs hunt the Moon this time, and when they get it, they tear it apart, and it is the blood from its wounds that paint our celestial companion dark red. Today, of course, we know that the phenomenon has nothing to do with the dogs, and the atmosphere of the Earth causes the shades of color that can be seen during the eclipse. The atmosphere of Earth filters the blue and green colors of sunlight, so the rest of the light is dominated by red or orange. Thus, as we examined the question with scientific precision, we can certainly declare that Puli will not eat the Moon, only bark at it at the most!

Well, speaking seriously: what is going to happen on June 15? After several years we can watch a full lunar eclipse again now. It should not be mistaken for the change of the Moon's phases (that can be observed every month)! The latter phenomenon namely takes place over 29.5 days, and the reason is that the Sun – in accordance with the orbit of the Moon around the Earth – illuminates different sizes of the side of the Moon turning towards us. When the Moon is crescent shaped – provided the weather is clear –you can beautifully detect the shadowed part of the Moon even with a small telescope.

However, during the lunar eclipse the Moon enters the shadow of the Earth, and that is why it gets dark for a couple of hours. In this case, the Sun, the Moon and the Earth are in line. This phenomenon, of course, can only occur during full Moon.

It is a valid question why there is no lunar eclipse during every full Moon. If our companion orbited in the plane of the Earth-Sun line (the orbital plane of the Earth), it would happen like that, but since it has a 5° angle, it usually passes below or above the shadow cone of our planet.

Now, let us look at what we can see on the evening of June 15:

The phenomenon starts with a penumbral coverage but this causes only minimal decrease of light (at this time the Moon would not even rise above our territory), so it is visually undetectable.

20:22 – the entry into full shade begins (this cannot be observed from Hungary yet)

20:30 – the Moon rises and you can already see the shadow at the edge

21:22 – the Moon is completely in Earth’s shadow

23:02 – the Moon starts to emerge from Earth’s shadow

0:02 (16^th) – the Moon leaves Earth’s shadow completely

The lunar eclipse officially ends at 1:00 (by this time even the penumbra leaves the Moon), but thus is not noticeable.

The chart above shows the progress of the eclipse and where it can be observed. Note that the time is given in UT  on the chart (Universal Time –  Central-European Time is UT+2 hours during the summer).

To observe the phenomenon, Team Puli and the Kecskemét Planetarium organizes a joint presentation at the Kecskemét Observatory (Kecskemét College Teacher Training Faculty – Kecskemét, Kaszap u. 6-14.) at 9 p.m. on June 15, 2011. The presentation is free, all visitors are welcome!

Do not worry if you miss it, the next lunar eclipse will take place on December 10, 2011.

László Szűcs / Translation by Éva Vándor

Image credits:

1.) © Greg L. Ruppel

2.) 3.) Wikimedia Commons

4.) © László Szűcs

5.) NASA, Eclipse Predictions by Fred Espenak, NASA/GSFC