April 18 – April 25
When people see a telescope that doesn’t look like it came from a department store, they often ask how far you can see with it. The answer is difficult to explain and even more difficult to comprehend. Sometimes I just say “way far” and hope they don’t press for details.
This weekend the brightest object in the evening sky is the Moon, near its closest at about 362,000 kilometres (km). The next brightest object is Venus, currently at 224 million km, while Uranus, possibly within a binocular view lower left of the Pleiades, is 3 billion km away. Light travels at 300,000 km per second, so at 150 million km the Sun is a distance of 500 light seconds away. The Moon is a tad more than one light second away, Venus is 12.4 light minutes, and Uranus nearly 3 light hours.
The brightest star we see in the evening now is still Sirius, the closest star we can see from New Brunswick at 8.6 light years (ly). The next brightest is Arcturus and it is 37 ly or 350 trillion kilometres. The Pleiades are about 440 ly away and Alnilam, the middle star of Orion’s belt, is 2000 light years. If you are under a dark sky well before morning twilight you might get a naked eye glimpse of the Andromeda Galaxy at a distance of 2.5 million light years. Binoculars will reveal galaxies even more distant, but at what point do these distances become incomprehensible and “way far” is a reasonable answer?
This Week in the Solar System
Saturday’s sunrise in Fredericton is at 6:35 and sunset will occur at 8:17, giving 13 hours, 42 minutes of daylight. Next Saturday the Sun will rise at 6:23 and set at 8:26, giving 14 hours, 3 minutes of daylight.
The slim crescent Moon is to the right of Venus this Saturday, above the Pleiades on Sunday, near Jupiter Wednesday, and it reaches first quarter on Thursday. With next Saturday being the closest to the first quarter Moon after Easter it becomes International Astronomy Day, and Astronomy Week runs April 20-26. If you want to start the week with a tough binocular challenge, on Monday try to see Mars, Saturn and Mercury rising due east in a span of eight minutes about half an hour before sunrise. They form a line with dimmest Mars upper left and brightest Mercury lower right. Early Wednesday morning is the best time to catch some shooting stars of the Lyrid meteor shower emanating from a point overhead.
Tune in to the Sunday Night Astronomy Show at 8 pm on the YouTube channel and Facebook page of Astronomy by the Bay.
Questions? Contact Curt Nason at [email protected].
April 11 – April 18
For stargazers, early spring means it is time for a Messier Marathon. In 1758 a French comet hunter, Charles Messier, started compiling a catalogue of nebulous objects in the sky that resembled comets but weren’t. His completed catalogue was issued 13 years later with 103 objects. In the mid-20th century the catalogue was expanded to 110 based on Messier’s notes. Under a clear, dark sky all of the Messier objects can be seen in a small telescope, and it is a rite of passage for amateur astronomers to locate and observe them all.
The Messier catalogue includes 57 star clusters, 40 galaxies, 12 nebulae of new or dying stars, and an enigmatic pair of stars. The first on the list, called M1, is the Crab Nebula, the gaseous remnant of a supernova that was seen in daylight in 1054. M110 is a galaxy seen near M31, the Andromeda galaxy. The easiest to see is M45, the star cluster also known as the Pleiades or Seven Sisters. The Orion Nebula, a stellar nursery in Orion’s sword, is M42, with the much less spectacular M43 nearby. Many of the galaxies are within the area bordered by Leo, Virgo and Ursa Major.
For a few weeks in March and April, around the time of a new Moon, it is possible to see all the Messier objects in one night, hence the Messier Marathon. However, from New Brunswick the globular cluster M30 in Capricornus rises in bright twilight and is pretty much impossible to see in late March. This week it might cut through morning twilight but we could lose one or more to evening twilight.
This Week in the Solar System
Saturday’s sunrise in Fredericton is at 6:47 and sunset will occur at 8:08, giving 13 hours, 21 minutes of daylight. Next Saturday the Sun will rise at 6:35 and set at 8:17, giving 13 hours, 42 minutes of daylight.
The slim crescent Moon is a binocular field above Mercury on Wednesday morning, a challenging observation, and it is new on Friday. Venus sets around 10:15 pm midweek and it is starting to catch the eye as it climbs higher each evening. With Jupiter high in the southwest on Wednesday, telescope users might see its moon Io disappear behind the planet at 9:43 pm and Europa reappear from Jupiter’s shadow 15 minutes later on the opposite side. Early in the week rural observers might see the subtle glow of zodiacal light in the west 60 to 90 minutes after sunset. Comet C/2025 R3 Panstarrs is a binocular object low in the east around 4:30 am this week, reaching perihelion next weekend.
Tune in to the Sunday Night Astronomy Show at 8 pm on the YouTube channel and Facebook page of Astronomy by the Bay. The Fredericton Astronomy Club meets in the UNB Forestry-Earth Sciences building at 7 pm on this Tuesday.
Questions? Contact Curt Nason at [email protected].