Eye on the Night Sky over Whitby: April

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The Day the Sun Smiled

All things considered, I think we were quite fortunate to catch more than a fleeting glimpse of the partial eclipse last month.

Certainly the forecast was pessimistic for the area, but the change in wind direction cleared out all the murk, with cloud fragmenting and thinning enough, and at the right time, for the greatest show ‘off earth’ to be viewed by the masses.

From the Whitby pier band stand (our location for the event), people were thrilled that the Sun (with moon) could be seen at all, and far from being stood idle the filtered scopes soon had queues forming up behind them. Around the time of maximum eclipse, (9:36am) the ‘smiling sun’ was visible to the naked eye through the thin layer of cloud without any filter employed.

Light levels diminished, the temperature dropped, and the ambience of the morning looked and felt ‘different’ for a while. Eclipses have the capacity to do this.

I hope that from wherever you managed to catch the event from, it had the same effect to some degree.

Another 11 years will pass before the next solar eclipse of similar magnitude will be visible from our shores, although a couple of lesser events will occur before then.

However a total lunar eclipse will be visible from the UK in September, yet another opportunity to marvel

at the beautiful outcome of the chance alignment of Sun, Earth and Moon.

Over the course of the month Venus passes between the two open star clusters in Taurus, the Pleiades or seven sisters on the 11th and the Hyades from the 13-16th.

Aldeberan, the fiery eye of the bull, will lie to the left of Venus. Telescopically Venus is best observed in bright twilight, reducing the glare of the planet somewhat.

You should then be able to detect the gibbous phase of the planet.

The young crescent moon is nearby on the 21st. Mars continues to slide down toward the W horizon lower right of Venus and is passed by elusive Mercury travelling the other way on the 22nd.

By the end of the month Mars will finally be lost in twilight. Mercury pops into the sky after mid month reaching almost 10 degrees altitude above the west horizon before falling back in early May. After passing Mars on the 22nd Mercury then pays the Pleiades a visit at the end of April and start of May residing to the lower left of the ‘sisters’

You will need to look around 8.45pm to 9.15pm less than a binocular field above the west horizon.

The moon passes through this part of the sky from the 19th to the 21st. Jupiter is well placed to the south as twilight falls and should be on everyone’s observing list.

The dance of the Galiean moons is of particular interest, especially as they are strung out in a line like individual pearls this year.

The moon passes by on the 25/26th,Saturn is steadily improving in the dawn sky and by mid month begins to rise before midnight. The ringed wonder lies above ruddy Antares, chief star in Scorpius.

The moon passes close by on the 8th.

The Virginids peak on April 7/8th but will be hampered by a waning gibbous moon. The Scorpiids peak on the 27th, but you will have to up before dawn to spot any.

The month’s most prolific shower, the Lyrids, peak in the early morning hours of the 23rd this year.

Zenith Hourly Rates are around the 25 mark and as it will be a ‘no moon’ period actual observed rates could reach 15 from 2am to 4am, with perhaps 7-10 beforehand.

Lyra; the constellation radiant, will be located low in the NE during the evening, and high to south before dawn. The observer would therefore concentrate on other areas of the sky, not the radiant area itself.

The lighter evenings of April offer up an interesting stellar challenge, testing the observing dexterity of astronomers; casual or otherwise in a race against time.

No, this is not a ‘faint fuzzy blob’ hunt, like the Messier marathon, the exact opposite in fact, more of a sprint really. This is all about spotting first magnitude stars; those ranked brightest in the sky at the same time.

Piercing the spring twilight dotted around the sky, no less than 13 are currently visible (we will count Castor), more than at any other time of year.

However the window of opportunity in which to identify these stellar jewels rapidly diminishes as we head deeper into April, from little over an hour at the start, to just 15 minutes by mid-month. You will require clear views right around the horizon and complicating matters further, a number of bright planets may confuse the unwary. Let us assume it is April 8, at which time twilight deepens around 9pm. Our first port of call lies over in the west, where the mighty hunter Orion is about to lose his right toe, marked by bright Rigel, (1) below the horizon. But, you also need to spot Spica (2) low in the south east when Rigel is above the horizon, so you will need to be quite sharp in doing this.

Got both? Good. Now look above Orion’s three belt stars which are aligned parallel to the west horizon, to locate the conspicuous orange hue of Betelgeuse (3). A hand span to the right of Betelgeuse and slightly closer to the horizon another orange star, Aldebaran (4) chief star in Taurus is visible in the ‘V’ of the Hyades cluster.

A word of caution here, the brilliant ‘star’ visible in the W is in fact the planet Venus, and both Mars and Mercury will also be visible to the lower right towards the end of the month. Low in the WSW the brightest proper star in the sky - sparkling Sirius (5) is quite unmistakable. Having picked out this first clutch of stars, there is no time to waste, so raise your gaze somewhat higher, to pick out the next wave of luminaries.

Starting in the SW again seek out the bright solitary white hue of Procyon (6) in Canis Minor located above Sirius and to the left of Orion. Due west and higher still, Castor (7) and Pollux (8) denote the twins of Gemini, which is descending feet first down toward the horizon.

At a similar altitude to Gemini further across in the WNW and above Venus, shines brilliant Capella (9) in Auriga, the only one of our bright seasonal winter stars not to set, being circumpolar from our latitude. Capella will spend the summer months arcing low above the north horizon. Turn and face due south, where midway up you will encounter bright Regulus (10) in the ‘sickle’ asterism of Leo. The prominent ‘star’ to the right of Regulus is Jupiter. Our next star is located due east, where brilliant Arcturus (11) in the constellation of Bootes is very noticeable, its soft orange hue contrasting markedly with Sirius, the only star of the baker’s dozen brighter.

Now for a test within a challenge, see how far into April you can spot both Sirius and Arcturus above the horizon at the same time.

We still have a couple of stars to indentify, so direct your gaze toward the north, where low in the NE brilliant steely blue Vega (12) resides in the constellation of Lyra.

Vega almost rivals Arcturus in apparent magnitude, but unlike the ‘guardian of the bear” it is circumpolar from Whitby’s latitude. Our final star, Deneb (13) is located just above the NNE horizon and appears much less brilliant than Vega but is by far the most distant of the stars visited.

It too is circumpolar and along with Vega constitutes two of the three stars forming the ‘summer triangle’. In less than three months, only Arcturus, Capella, Deneb and Vega will remain of our original stellar baker’s dozen, the rest having set. So, are you up for a fun observing challenge, it should only require 5 minutes (at most) to complete.

Here’s a date for your diary, popular astronomer and top astro-lecturer Paul Money will be giving a presentation in Whitby’s Pannett Park Museum on Tuesday April 21.

Paul will be presenting Images of the Earth, - our planet from space.

Doors are open from 7pm for a 7.30pm start. Admission is £3 adults and £1.50 under 14s. Home-made refreshments will be available.

Anyone who has seen Paul before will know a great evening is in store.

For more information go to www.whitby-astronomers.com