The Night Sky This Month: April 2020

Image credit: Stellarium/IM

Astro-photographers of all skill levels will have an excellent opportunity on the 3rd of April to put their skills to the test. On this date, the planet Venus will be visible within Messier 45, perhaps better known as the Pleiades Cluster, as shown in the image above.

Note that since the planet may be lost in Merope’s glare through a camera, it may be necessary to experiment with various filters to show Venus, without masking Merope out of the image altogether.

On April 22/23rd  in the pre-dawn skies, the Lyrid meteor is expected to reach its peak of around 10 to 20 meteors per hour. Incidentally, Lyrid meteor shower sightings date back to 687 BC, making them the oldest of all known meteor shower.

Moon In April 2020

First Quarter Full Moon Third Quarter New Moon
April 1rd April 8st April 14th April 23th

Note that the First Quarter Moon on the 1st of the month occurs in the constellation Gemini, and is among the highest First Quarter Moons to occur during 2020. The second First Quarter Moon in April occurs on the 30th of the month, in the constellation Cancer.

Significant Earthshine can be observed from the 23rd to the 29th of the month during the waxing crescent Moon, and again during the waning crescent Moon from the 16th to the 22nd of the month.

The Planets in April 2020

Mercury is still too close to the Sun to be observed, and will therefore not be visible during the month.

Venus reached its greatest eastern elongation from the Sun on the 24th of last month, and therefore still dominates the south-western sky during twilight. The planet is still near the highest elevation it can reach, and as a result, April is the best month to observe the planet during its 8-year cycle primarily because it is now at a height of about 39 degrees above the horizon. Note that even though the planet’s phase reduces from 47% to only 26%, its angular diameter will increase from 25.5 seconds of arc to 38.2 seconds of arc – this means that the planet’s brightness will remain fairly constant at about magnitude -4.7, which is about as bright as it can get.

Mars is still visible as a pre-dawn object in the southeast as the month starts, but note that it will remain at, or below about 8 degrees above the horizon throughout the month. Observing it through the haze will, therefore, be difficult, but with some luck, it might be found just inside the constellation Capricornus at the beginning of the month, and just below the planet Saturn.

Jupiter will start April rising about 3.5 hours before the Sun just after Mars, and just before Saturn. Although the King of the planets will shine at magnitude -2.1 for much, if not all of April, it will remain at about 10 degrees above the horizon (or somewhat less at month’s end), which could make it difficult to spot through the atmospheric haze.

Saturn starts the month rising about 20 minutes or so after Jupiter, which increases to about 2 hours or so by month’s end. Saturn reaches “quadrature” on the 21st of the month; which is defined as a point of “90 degrees in angle from the Sun”. This then enhances the three-dimensional structure of the planet and its ring system. However, since the planet remains below 15 degrees above the horizon throughout the month, much of the enhanced appearance of the planet will be lost in the murk of the atmosphere.

Meteor Showers in April 2020

The month of April sees the arrival of the Lyrids meteor shower, which is expected to peak in the pre-dawn skies of both the 22nd and 23rd of the month. Since there will not be any bright moonlight on these dates, most of the 15 or so meteors that are expected per hour will be relatively bright. Note that the radiant of the Lyrids is a point close to the bright star Vega, but since this point will reach its highest elevation at about 04:00 (BST), the pre-dawn sky on the 22nd will produce the highest hourly rate.

Deep Sky Objects to Look For In April 2020

Constellations that are prominent in the south at this time of the year include Boötes, Corvus, Virgo, the eastern reaches of Hydra, Leo, Canis Minor, and Coma Berenices, which contains a relatively large number of easy targets for binoculars and small telescopes. Below are some details of three such objects in Coma Berenices

The Black Eye Galaxy – Messier 64 (M64, NGC 4826)

Black Eye Galaxy
Image credit: NASA and The Hubble Heritage Team (AURA, STScI)

Also known as the Evil Eye Galaxy, or sometimes as the Sleeping Beauty Galaxy, M64 is located about 24 million light-years away and has an apparent magnitude of 9.36.

Although the galaxy is structured like all other spiral galaxies, this particular example of a spiral galaxy is strange in the sense that its outer regions rotate in one direction, while the stars in the inner regions rotate in the opposite direction.

The exact reasons for this anomalous behavior are not known with any certainty, but many investigators believe that the black patch of dust seen in this view is the remains of a smaller, less massive galaxy that was destroyed in an encounter with the large spiral. This encounter is the most likely mechanism that imparted the contrary rotation to the larger galaxy’s outer regions. However, there is yet no direct evidence of this – apart from the fact that the region that separates the two contra-rotating regions is a hugely active star-forming region. Look for the galaxy about one degree to the east- north-eastward of the star 35 Comae Berenices.

The Needle Galaxy (NGC 4565)

The Needle Galaxy
Image credit: ESO

Given the name needle because of it edge-on orientation to our line of sight, this galaxy is located about 43 million light-years away. Despite having an apparent magnitude of 10.42, it is an easy target for small telescopes. Based on the large central bulge, most investigators believe the galaxy is a barred spiral galaxy. It is also believed by most investigators to be largest edge-on galaxy discovered to date, an assumption that is based on the 16-minutes-of-arc length of the “needle”. Look for the Needle Galaxy precisely over the North Galactic Pole, and about one degree to the eastward of the star 17 Comae.

Messier 53 (M53, NGC 5024)

Messier 53
Image credit: NASA

Located about 58,000 light-years from Earth and about 60,000 light-years away from the galactic center, M53 is not only among the most distant globular clusters, but it is also among the brightest, having an apparent magnitude of 8.33.

This cluster is also remarkable for other reasons. For one, it is predominantly populated by ancient first-generation stars. Also, it is seemingly gravitationally bound to both a nearby, but diffuse neighboring cluster, and a sort of halo of stars that envelops both clusters. This is unique in the Milky Way, and although the halo and neighboring cluster are not readily visible, M53 can be found easily with binoculars about one degree to the northeastward of the star Alpha Comae Berenices.

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