What’s in the sky for April 2021 – Ian Bradley

Astronomy weather forecast sites

They are customizable to your location – the links below are set to Kendal.

This satellite view I find quite useful as it shows the cloud cover for the previous 2 1⁄2 hours or so. This lets you have an idea as to what cloud is coming … switch to infra-red to view the clouds at night.

Nice resources

Sky Notes for April – Ian Bradley

Noctilucent Clouds (NLC) –Ian Bradley

We may see NLC’s from around mid-May to early August during the darkest part of a summer’s night. They will occupy the northern horizon, along the twilight arch, extending to an altitude of 10 – 15 degrees. They form at very high altitudes – around 82 km above sea level – and are, thus, a quite separate phenomena from normal weather or tropospheric cloud. Normal clouds always look dark whereas NLC’s appear as thin ghostly streaks of “cloud”, often a pearly-blue colour.

The bright star Capella, in Auriga, on the northern horizon is a good marker. The clouds, if they form, tend to appear sometime between 2300 BST and 0200 BST. Unlike aurora, there is no warning [or app] indicating whether they will form any particular night – you just have to go out and look as they are completely unpredictable. Sometimes we get stunning displays, other times nothing all season.

[Image: NLC’s from the Brigsteer Road, May 2013. Capella is the obvious bright star]

The Moon

Phase May June July
3rd Quarter 3rd 1st 1st
New Moon 11th 9th 9th
1st Quarter 19th 17th 17th
Full Moon 26th 24th 23th

The Planets

Mercury Visible at dusk setting about 90 minutes after the Sun at the start of the month. By mid-month this has increased to 2 hours with maximum elongation of 22° on the 17th. By the end of the month, it’ll set only 1 hour after the Sun and it will be very hard to see. It will appear in the morning sky in June and July.

Venus is rather close to the Sun throughout May but becoming visible in at dusk in June and July.

Mars Still an evening object nestling in Gemini setting about 1am mid-month. Still quite obvious at magnitude 1.7 but quite small at 4”.

Jupiter/Saturn Both early morning objects rising about 3am mid-month. By the middle of June, Jupiter is rising about 1am and Saturn midnight. Both are roughly due south around 5am in mid-June.

Uranus Visible in the early morning sky throughout May and June.

Neptune early morning.

ISS visible passes

Many visible passes throughout May – nearly 60! They tend to be either round about 10/11pm or 2/3am. Far too many to list here.

Have a look at Heavens Above for a Kendal location website for the specific times

There are no passes in June but plenty again in July.

Meteor showers

There are two meteor showers over the summer.

eta-Aquarids – Peak: May 5th. Active: April 19th to May 28th. Activity: 60 per hour.

A difficult early morning shower for the UK with at best 10-15 meteors per hour. Aquarius rises around 4am but unfortunately the Moon is only 17° away from the radiant. Before moonrise, 04:12 on May 5th, would be the best chance of seeing anything as the Moon is a third quarter. The peak is quite broad so a day or so later might give a better chance.

Perseids – Peak: August 12th. Active: July 17th to August 24th. Activity: 120-160 per hour.

The best shower of the year? It’s a rich meteor shower, and it’s steady. The meteors are swift and bright. They radiate from a point in the constellation Perseus but appear in all parts of the sky, frequently leaving persistent trails. Activity increases as late night deepens into midnight, with typically most meteors in the wee hours before dawn. The waxing crescent moon will have set early evening, providing dark skies. Predicted peak: the night of August 11- 12, but try the nights before and after, too, from late night until dawn.

The weather forecast? I predict clouds!

Here, here, here

Sky Charts – May 15th at 10:30pm BST

Looking up, south is at the bottom.

Click for a larger version.

Now is the ideal time for imaging or detecting the faint fuzzies in Ursa Major, The Great Bear, as the constellation is almost directly overhead. As mentioned last month, Lambda λ and Mu μ, forming one of the rear legs of the Bear, are 1¾ degrees apart and make a fine binocular pairing [or very low power telescopic object] as they are of distinctly different colours; λ is white (spectral type A2) whilst μ is very red (M0). Mizar (magnitude 2.1), in the tail, is an easy naked eye double with Alcor (4.0), separation 12’ of arc. Between the two, forming a nice triangle, lies in the eighth magnitude star named Sidus Ludovicianum just visible in x8 binoculars. Mizar is itself double but requires a telescope to separate the two stars.

Using a 4” telescope at x48, a whole host of galaxies are visible: there are many fine galaxies, the best being M81 and M82. You will require a telescope for M106, 107, 108 and 109. Close to M108 is the slightly brighter Owl Nebula, M97, with its two ‘eyes’.

In nearby Canes Venatici, there are another two magnitude 8 spiral galaxies; The Sunflower Galaxy M63 and M94 in addition to the splendid Whirlpool Galaxy M51 at the end of the tail of the Great Bear.

Looking south

Click for a larger version.

No longer dominated by the constellation of Leo with Virgo in centre place. However, Leo is still the most obvious constellation. With the massive Virgo Cluster and the two groupings in Leo, the area is full of galaxies. There is the Leo Triplet of galaxies M65, M66 and NGC3628 which are visible in small telescopes below the tail of Leo. Beneath the belly of the lion are another three galaxies; M95, M96 & M105. Virgo itself is not a very exciting constellation. Its brightest star, Spica, is a blue giant star 2000 times as luminous as the Sun. It is actually a very close binary but too close for amateur telescopes to separate. Slightly west straddling the border with Leo, lies the extensive Virgo Cluster of galaxies. There are too many galaxies to mention here but M86, M87 and M84 are notable. These are very well placed in May at a reasonable time of the evening. M84 and M86 are part of Markarian’s Chain, a smoothly curved line of galaxies in the Virgo Cluster.

In addition, in Canes Venatici there is M3, a stunning globular cluster which is nice in binoculars.

In Cancer is the spectacular naked eye M44, Praesepe or the Beehive Cluster, which makes a fine binocular or low power telescope object. Nearby lies M67 is nice in binoculars although it is sometimes said to be naked eye visible.

As mentioned last month, the three stars forming Coma Berenices are in an area rich in stars and worth sweeping with binoculars. The globular cluster M53 lies just east of the most southern and brightest of this trio of stars, Cor Caroli. Just north is M64 , The Black-Eye Galaxy and just within binocular range.

Looking east

Click for a larger version.

Hercules prominent with the large globular of M13 being an easy binocular object and lovely photographic target. In Virgo, there are loads of galaxies, the Virgo Cluster, as previously mentioned. A second globular cluster M92 is almost as good as M13.

In Bootes, Arcturus is a lovely light orange and ε similarly. Very close to ε and on the same binocular field of view is W-Bootis, another orange-red hued star.

Cygnus and Lyra are now becoming better to see with the usual interesting objects there. But these will be much better placed later in the year.

Ophiuchus, a large constellation which spans the celestial equator, contains several globular clusters, the brightest pair being M10 and M12. In addition, there is M14, and just below the horizon at the time of the map are M19 and M4.

Looking west

Click for a larger version.

The constellation of Orion is now gone but Gemini is prominent above and Auriga further north. There are a trio of Messier objects, M36, M37 and M38, in Auriga which are fine binocular targets, with M35 further south in Gemini. Most interesting objects have been discussed over the past couple of months.

Looking north

Click for a larger version.

Again, most objects of interest have been discussed over the past couple of months.


Next Observing Evening

Given the current situation regarding coronavirus, observing evenings can not occur.