A good month to see the planets in our night sky
In spite of, or perhaps because of, the crazy stormy weather earlier in April, I had a couple of nights of unusually crisp and clear sky. On the 6th I was lucky and got to see Mars and Saturn while they were still close together. I hope you were able to spot them during the conjunction of the pair.
Then the power to the streetlights in my neighbourhood was out for several days (strangely but happily only the streetlights were affected). This additional level of darkness made for excellent viewing of the Large and Small Magellanic Clouds as well our own Milky Way. The socalled ‘Clouds’ of Magellan are actually small and nearby galaxies that appear to be two faint white smudges of ordinary cloud adrift in the night sky. Closer examination, however, will reveal that they don’t change shape, or grow, or dissipate and float away as clouds usually do.
But they do move. They advance ever so slowly around the South Celestial Pole (SCP), completing a full circle once every 23 hours and 56 minutes. The SCP is the point in the sky directly above the south pole of Earth. This is different from the magnetic South Pole. Visualise the axis on which Earth spins as a real pole that extends north and south into the sky. The pole points true north and true south. Celestial objects near the poles appear to revolve around the poles as Earth rotates daily on its axis.
If you want to check this out, go outside and find the Southern Cross. Note its position and orientation relative to a fixed object - a chimney or corner of the house or a tree, etc. Then wait a couple of hours and go out again. Stand in the same spot and, if the sky is still clear, you will see that the Cross has moved higher and a little right of its previous position. It moves clockwise around the SCP.
If the sky is very dark at your location then while you were observing the motion of the Cross, you may have noticed the Clouds of Magellan below and to the right, or at least the large one, since they lie inside the circle the Cross makes around the SCP. The Southern Cross and the Large and Small Clouds of Magellan are visible all year round at Timaru’s latitude, which is close to midway between the Equator and the South Pole.
New Moon in May will be on the 15th. Haratua, the 12th month of the Maori lunar calendar, will begin at sunset the following day. The Moon will be full around 2am on the 30th so be sure to look for it on Tuesday night, the 29th.
The large but waning Moon will not rise until after 8:30pm on the 4th, and later each night after, so the darkest nights for evening stargazing will be the two weeks following.
Through mid-month Mercury will still be visible as a ‘morning star’ in the east before sunrise. Venus will be visible above the western horizon during the end of twilight this month. I saw it last evening around 6:30, bright in the fading sunset. It was my first sighting of the Evening ‘Star’ this year, which is always special as I rarely see it in the morning sky. It will appear more brilliant as the year progresses and it sets later in a darker night sky.
Jupiter has been rising earlier and earlier and will be up in the east before sunset this month, starting its evening westward journey across the sky. You may find it shining brightly in the opposite side of the darkening sky from Venus. On the 9th we will pass Jupiter in our faster inner orbit around the Sun. Earth will be between the Sun and Jupiter, and Jupiter will be said to be ‘‘in opposition’’.
Meanwhile Saturn will rise in the east around 9pm on the 1st, followed an hour later by orange-tinged Mars. By the end of the month Saturn will be up by 7pm and Mars will follow two hours later. When our upper atmosphere is not unduly perturbed, the two planets may catch your eye and stand out from the stars around them because they will shine with a more constant light. Stars will tend to twinkle.
Venus is brighter than Jupiter, and Jupiter is brighter than the brightest star. Mid-month at around 8pm, if you stand facing north and look to your left (west) you will see Jupiter midway above the horizon. Look to your right (east) and Sirius, the brightest star in our night sky, will be midway above the horizon. Sirius is 8.6 light years (8.6 times 9,500,000,000,000 kilometres) away from us and is around 25 times brighter than the Sun.
If you have any questions, would like to receive or share information, or just share a stargazing experience or thought, please email me at firstname.lastname@example.org. Clear night skies, Freidl Hale