Astronomical twilight will still last for much of the night, but the skies are darker for noticeable longer as we approach the equinox next month.
Planets:
Mercury
Mercury begins the month as a morning object and is well placed for observation before sunrise. It reaches greatest western elongation on 2nd August and will be 19o from the Sun. It will be observable for much of the month, reaching a magnitude of -1.1 by the middle of the month.
Venus
Venus reaches greatest eastern elongation on the 14th and will be 46o from the Sun. It is a very prominent evening object. The disc diameter rapidly increases to about 30 arcsec and, while the phase decreases to 41% by the end of the month.
Mars
Mars remains a morning object and is not well placed, but does rise around 2 am (BST) in Taurus. With a diameter of 5.0 arcsec and magnitude 1.3, it is not an easy object. Best to wait until late in the year.
Jupiter
Jupiter reached conjunction with the Sun on 29th July and is therefore not really observable this month
Saturn
Saturn is still a morning object but rises around 10pm. It is magnitude increases to 0.5 and lies below the square of Pegasus. The rings are open to about 9o, and therefore more noticeable.
Uranus
Uranus remains a morning object in Taurus, but rises around midnight. Its coordinates are RA: 4h 14m, Dec: +21o. It is magnitude 5.6 with a diameter of 3.8” (arcsec). It should appear as a tiny bluish disc.
Neptune
Neptune is now visible in the late evening and is not far from Saturn.
Magnitude 7.8 and diameter 2.”. RA: 0h 14m, Dec: 0o 00’
Moon Phases:
| 6th August: Last Quarter | 12th August: New Moon |
| 20th August: First Quarter | 28th August: Full Moon |
Meteor Showers
The Perseid meteor shower reaches its peak this month, around the 13th and lasts until the 24th. The Perseids are associated with debris from the comet Swift-Tuttle. Moonlight will not be a problem until late in the month. They reach a maximum next month of up to 140 per hour. They are fast moving and often contain some bright ones. Very favourable!
Sun
We remain near solar maximum, so watch out for major sunspots and sunspot groups. Remember to never look at the Sun directly without a proper solar filter.
Total Eclipse of the Sun: 12th August
The track of totality crosses the north pole, sweeps down over eastern Greenland and the western tip of Iceland. It then passes down the north Atlantic and crosses the north coast of Spain. Passing across north central Spain it then enters the Mediterranean Sea, over the Balearic Islands and finishing at sunset just beyond. Best weather prospects are in central northern Spain, although the Sun will be only 8o above the horizon near sunset. Totality in central Spain is about 1m 45s. At Palma, it is 1m 36s, but the Sun is only 2o high.
In the UK there will be a Partial Eclipse. At maximum, the Sun will be 93% covered in the Cheltenham/Gloucester area. Times are given below:
Please note the times are UT. For BST, add one hour.
| Start (first Contact): | 17h 16m 24s | Altitude: +20.4o |
| Maximum eclipse: | 18h 12m 57s | Altitude: +11.7o |
| End of eclipse: | 19h 06m 27s | Altitude: +03.7o |
| Sunset: | 19h 39m |
If anyone wants times for other places, contact Neil at: coordassist@cotswoldas.org.uk
Alternatively, use the interactive website: xjubier.free.fr
Aurora
The Sun remains active, so keep a watch out for aurorae now. I recommend one of the many Apps that can warn you of aurorae.
Deep Sky Objects
The evenings are getting much shorter making deep sky observing much easier now. The Milky Way will be more visible late in the night. Cygnus is well placed as well.
The Whirlpool Galaxy (M51), below Ursa Major, as well as the Pinwheel galaxy (M101) just above the handle of the Plough are now very well placed high in the sky. The M13 globular cluster in Hercules is also now well placed and a good object for binoculars, small telescopes or astrophotography. The Perseus Double Cluster is another very rewarding sight, both in binoculars and for astrophotography.
Neil Havard.
Any questions or for more information, contact Neil at coordassist@cotswoldas.org.uk