July Sky Guide

Hi all,

July's Sky guide is below. Enjoy.

OBSERVING GUIDE
(Please note all times are BST and are based on an observing location of Belfast)

The Sun

At the start of the month the Sun rises at 04:50 and sets at 22:00. By the end of the month, it rises at 05:35 and sets at 21:25.

The Planets

Mars and Saturn lie close to each other for part of the month. On the evening of the 10th, Mars passes within less than a degree of Saturn and the two remain close for several days before and after this event.

Mercury is at greatest western elongation on the 1st; but even then only rises an hour before the Sun at 03:50. It then moves back towards the Sun for the rest of the month and is at superior conjunction on the 29th. It becomes an evening object by month’s end, but is not well placed for observation this month.

Venus is an evening object this month. However at the start of the month it sets only thirty minutes after the Sun at 22:30 and by month’s end it sets thirty-five minutes after the Sun at 22:00. As a result it will be a hard object to spot low in the West after sunset this month.

Mars is slowly slipping into the evening twilight. It rises during daylight hours and can be found in Leo. It fades from mag +1.6 to mag +1.7 during the month. By month’s end it sets at 22:35.

Jupiter is at opposition on the 9th and can be found in Sagittarius. At the start of the month, it rises at 22:20 and by month’s end, it rises at 20:05. It maintains its brightness at mag -2.7 during the month.

Saturn is lost to the evening twilight this month. It can be found in Leo and sets at 00:25 at the start of the month. It is lost to the glare of the sun by the second half of the month and sets only fifteen minutes after the sun by month’s end at 20:30. It maintains its brightness at mag +0.8 during the month.

Uranus can be found in Aquarius. At the start of the month, it rises at 00:35 and by month’s end it rises at 22:30. It maintains its brightness at mag +5.8 during the month. It is just within naked eye visibility and can be located roughly five degrees South of the Circlet asterism in Pisces.

Neptune can be found in Capricornus. At the start of the month, it rises at 23:45 and by month’s end it rises at 21:40. It can be located by using Gamma and Delta Capricorni. The planet lies to the North of these two stars close to stars 42, 44 and 45 Capricorni (all mag +5 stars). It brightens from mag +7.9 to mag +7.8 during the month.

The Moon

The new moon is on the 3rd with the first quarter moon on the 10th. The full moon this month is on the 18th. The last quarter moon is on the 25th.

On the evening of the 5th and the 6th, Saturn, Mars, Regulus (Alpha Leonis) form a line low in the West after sunset. On the 5th, a 10% illuminated waxing crescent moon lies close by to the South-East of the three objects and on the 6th, a 18% illuminated waxing crescent moon lies to the South of the three objects.

On the evening of the 16th/ morning of the 17th, a 99% illuminated waxing gibbous moon lies close to Jupiter, to the South-West of the planet.

On the morning of the 28th, a 24% illuminated waning crescent moon lies to the East of M45 – The Pleiades.

On the morning of the 31st, a 2% illuminated waning crescent moon can be observed in the pre-dawn skies with moonrise at 03:40.

Meteors

There are four showers this month. The first one is the Southern Delta Aquarids. They peak on the 27th with a ZHR of 20. There may be some lunar interference with a 26% illuminated waning crescent rising at 00:10 on the morning of the 28th. They are noted as being faint meteors.

The second shower is the Alpha Capricornids. It has three peaks. The first is on the 8th, with a ZHR of 5. Lunar conditions are good for this peak with a 38% illuminated waxing crescent moon setting at 23:55 on the evening of the 8th. The second peak is on the 15th, with a ZHR of 15. There may be some lunar interference with a 95% illuminated waxing gibbous moon setting at 02:30 on the morning of the 16th. The final peak is on the 26th, with a ZHR of 5. There may be some lunar interference with a 37% illuminated waning crescent moon rising at 23:45 on the evening of the 26th. This shower has been noted to produce long, slow and bright meteors, with fireballs having been observed in the past.

The third shower is the Alpha Cygnids. They peak on the 21st, with a ZHR of 5. There may be some lunar interference with a 87% illuminated waning gibbous moon rising at 22:45 on the evening of the 21st. The final shower is the Perseids, although they don’t peak until next month, keep an eye out for them.

Comets

C/2007 W1 Boattini moves from Eridanus into Cetus during July. It is a morning comet and at the start of July is an predicted mag +5.5. It should be visible from the second week of the month onwards and will slowly fade. It passes by the head of Cetus between the 8th and the 18th approximately.

C/2008 J1 Boattini is a mag +11 comet which moves through Cepheus during July. It is not predicted to brighten any further but will be well placed for observation for the next six months as it moves through the Northern Polar constellations.

6P/D’Arrest moves through Aquila during July. It is predicted to brighten from mag +12 to mag +10 during the month with predictions of mag +9 in late summer/early autumn. On the 1st, it lies just North of the mid-point between Gamma and Zeta Aquilae. It moves South during the month and on the 26th, it lies less than a degree to the West of Eta Aquilae.

C/2006 OF2 Broughton moves from Triangulum into Perseus during July and is predicted to brighten to mag +11 during the month. It is predicted to peak at mag +10 later in the year. On the 1st, it lies close to Almach (Gamma Andromedae) to the South-East of the star.

Up to date information and finder charts for comets can be found at www.aerith.net and
www.skyhound.com/sh/comets.html

Deep Sky

On the deep sky front this month, galaxies M81 and M82 can be observed in Ursa Major. Check out the constellation Canes Venatici with the globular cluster - M3 and several galaxies including M51 - the Whirlpool Galaxy and M63 - the Sunflower Galaxy. In Hercules, two globular clusters – M92 and the excellent M13 can be observed and in Lyra – M57 – The Ring Nebula can be observed. In Vulpecula – M27 – The Dumbbell Nebula can be found. In Andromeda, M31 – The Andromeda galaxy can be observed along with its satellite galaxies M32 and M110. Also check out Sagittarius, low in the South which contains many messier objects including open clusters M18 and M25, to name but a few.

For further observing information, check out www.eaas.co.uk/stargazers.html

General Notes

Always keep an eye out for Aurorae. Check out www.stronge.org.uk/spaceweather.html for the most up-to-date information on the aurorae. The night sky does not get fully dark this month. Between May and the middle of August, Astronomical twilight is present at night. This is when the sun is between twelve and eighteen degrees below the horizon.

Watch out for NLCs - Noctilucent Clouds this month. They are also known as Polar Mesospheric Clouds as they are thought to be due to water ice particles up in the mesosphere. They are visible between the Northern latitudes of 50 to 65 degrees. Look to the North for a white/silvery glow. They can sometimes be faint, sometimes bright. Other interesting naked eye phenomena to look out for include the Zodiacal Light and the Gegenschein. Both are caused by sunlight reflecting off dust particles which are present in the solar system. The Zodiacal Light can be seen in the West after evening twilight has disappeared or in the East before the morning twilight. The best time of year to see the phenomenon is late-Feb to early-April in the evening sky and September/October in the morning sky -- it's then that the ecliptic, along which the cone of the zodiacal light lies, is steepest in our skies. The Gegenschein can be seen in the area of the sky opposite the sun. To view either, you must get yourself to a very dark site to cut out the light pollution. When trying to observe either of these phenomena, it is best to do so when the moon is below the horizon. If you are observing them when the moon has risen, restrict your efforts to the period 4 days either side of the new moon as otherwise the moonlight will be sufficient to drown them out.

Finally check out www.heavens-above.com for the latest passes of the International Space Station and satellites, details of Space Shuttle launches and passes and for details of Iridium Flare activity.

Clear Skies

Neill McKeown

Neill, I juist wanted to say that I think you do a wonderful job preparing the sky guide each month. I'm sure I speak for many here when I say how much appreciated your hard work is.

Hi Dave,

Cheers for the comments. The EAAS Stargazers link should now work.

Neill

He does it well, doesn't he?
A beautifully concise list of all the happenings every month.