Category Archives: Observing the sky

Twilight beauty: the Moon, Venus and Jupiter conjunction

Vénus, Jupiter and the Moon will be conjunct today at 22º Capricorn.

If the sky is clear enough the triple conjunction will be visible on the western sky right after sunset.

Besides being a wonderful sight, this triple conjunction also provides a good opportunity to observe the difference between zodiacal latitude and longitude.

Although Venus and Jupiter are at the same zodiacal degree, 22º Capricorn, and therefore at the same longitude, they don’t seem to be perfectly aligned.

Venus (the brightest one) seems to be below and a little to the left of Jupiter; this is so because the planets have different zodiacal latitudes: Venus is at 2º33’ South and Jupiter 0º33’ South.

So, there are two factors to take in account: longitude, the degree of a given planet in a sign (in this case 22º Capricorn), and latitude, the distance from the planet to the ecliptic (which is the central line of the Zodiac).

When latitude and longitude coincide exactly, the planets form a perfect alignment, called occultation. In such cases, the planet closer to us (which in this case would be Venus) passes between the Earth and the other planet (Jupiter), and occults it from our sight.

However, this will not occur today, as Venus does not align Jupiter.

Instead, we’ll have the opportunity to admire the two planets and the Moon, in a beautiful and inspiring configuration. … That is, if the clouds would go away!

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Observing the Mars-Saturn conjunction

Today, 10th of July, around 18:11 UT the Mars-Saturn conjunction will become exact at 5º26’ Virgo. The interpretation of this conjunction was dealt with in our previous post, so today we are giving some info regarding its observation in the sky.

5º Virgo corresponds to the “centre” of the constellation of Leo on the Sidereal Zodiac. The two planets will be close to fixed star Regulus, to which the Arabs called “al-qalb[u] al-’asad” (the heart of the Lion).
The conjunction can be easily observed as soon as the Sun sets and the twilight grows dimmer:

Even if at your location this occurs a couple of hours after the conjunction, the distance between the planets will not be noticeable to the naked eye.
To the observer the planets will appear to be slightly of line and not exactly conjunct. This is due to the difference of latitudes, in this case about half a degree. The current latitude of Mars is currently 1ºN02’ while Saturn’s is 1ºN41’.

Such a close proximity of the planets allows us to evaluate the difference of colour between the two planets. Mars has a reddish tone to which the ancients referred to as rust colour, while Saturn presents a yellowish tone.

You can also take the time to observe the Moon which will be in the end of the sign of Libra, very close to Spica, a bluish coloured 1st magnitude star located at 23º57’ Libra. (Note that in the Sidereal Zodiac they are both in the constellation of Virgo.)
Spica will be easy to locate. It will be the bright star just above and to the right of the Moon.

This combined observation allows us to understand the true distance between 5º Virgo, where the Mars-Saturn conjunction occurs, and 23º Libra where Spica is located. It is a much larger distance than the one we are used to see on paper and screen astrological charts.

We wish to all a clean sky, with no clouds and light pollution, and an excellent observation.

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