A view of the southern sky in May
Wow, it is already cold at night lately, at least at my house. Be sure to rug up before you go out so that the cold doesn’t drive you back inside before your eyes even have time to adjust to the dark.
Speaking of the dark, after sunset (also before sunrise but in the opposite order) the sky goes through 3 commonly referenced stages of twilight before it is considered dark. They are called Civil, Nautical, and Astronomical Twilight or Dusk.
They are roughly based on how far below the horizon the Sun has moved. Their length depends on the season of the year.
You may see the bright planets like Venus and Jupiter before the end of evening Civil Twilight. Stars appear during Nautical twi- light, and, by the end of it, if you are at sea you can no longer discern the horizon as the sea and sky blend.
At the end of evening Astronomical Twilight light from the Sun is no longer interfering with light from the stars.
However, in populated areas, light polution and air polution can wipe out light from all but the brightest objects.
Of course the appearance of the Moon as it moves through its various phases has a great impact on what can be seen as well.
This month begins with the Moon waxing toward full which will occur during the morning of the 11th, resulting in an almost equally full and bright Moon on both nights, the 10th and 11th. Your darkest sky for viewing will be later in the month.
New Moon will occur around midnight on the 26th. But starting from the 17th the Moon will not rise until after 10:30pm and later each night. Astronomical Twilight will be ending around 7pm giving you reasonable viewing time from the 17th through almost to the end of the month at which point the Moon will brighten in the evening sky.
This month will present one of two good opportunities you will have this year to see Mercury in a dark sky, however you will have to be up well before the Sun.
All month Mercury will rise in the east before the beginning of dawn Astronomical Twilight, before the dim glow of the coming sunrise begins to interfere.
It will rise just after 6am on the 1st, just before 5:25 on the 15th, and around 6am again on the 31st. Mercury will be joined by a tiny sliver of waning moon on the 24th and 25th.
Venus also will be there as a brilliant Morning ‘‘Star’’, higher in the dark sky having risen by 4am.
If you prefer an evening viewing of Mercury it will be setting in a fully dark western sky in July and August. Mercury spends most of its time in the twilight of the rising or setting Sun, and because it is a relatively dim object it is usually hard to see.
Mars continues to hold in the west near the end of evening Nautical Twilight, setting about an hour after the Sun and making it difficult to see. By mid-July it will dip lower and set with the Sun.
Jupiter continues to move westward in the evening and night sky, followed in around 3 hours by Saturn. You will see Jupiter due north and high in the sky at 11pm on the first and before 9pm at the end of the month. Saturn will rise in the east at 8:08pm, on the 1st, and two hours earlier, just an hour after sunset, on the 31st.
We usually hear on the 6 o’clock news about anniversaries of major events like the Apollo 11 Moon landing. We tend to forget the people and events that paved the way.
This month is a good time to consider Apollo 10, BEFORE human beings actually landed, left their tiny spacecraft, and dared the next step, walking on a alien world.
On 18 May, 1969 three experienced astronauts left Earth for a successful 8-day ‘‘dress rehearsal’’ in preparation for the landing to come two months later.
Eugene Cernan flew the lunar lander, call sign Snoopy, while mission commander Thomas Stafford and pilot John Young remained in orbit in the command module, Charlie Brown.
The lander went as low as 15 kilometres above the lunar surface before returning to dock with the command module, a final test of critical equipment and procedures. Imagine being so close to the goal but not actually getting to land.
Cernan and Young both returned to the Moon in command of later Apollo missions.
If you have any questions, would like to receive or share information, or just share a stargazing experience or a thought about our place in space, please email me at firstname.lastname@example.org.
Clear night skies.