CDAA

Written by David Pugh

Dear Colleagues

I hope you are all keeping well. Firstly, apologies for such short notice of the monthly meeting tonight. I have had a very busy week. This evening from 7.30pm we have guest speaker Jerry Workman giving us an illustrated talk on "The Curiosity Mission to Mars". I will follow with a Stellarium planetarium software presentation on the night sky for July. Hope to see you there.

In the night sky this month the planets Saturn and Venus dominate the planetary scene, Jupiter is now emerging in the pre-dawn sky and there continues to be a chance to see noctilucent clouds.

Mercury, the inner-most planet, continues to be visible very low in the WNW after sunset for the first few days of July.. Dazzling Venus (mag -4.1) lies in the pre-dawn eastern sky in Taurus but getting higher in the sky (23 degrees). Mars, the red planet, (mag +1.6), is now fading in the west in Leo, close to the star Regulus. It is best seen early in July soon after sunset before it is engulfed in twilight..

Jupiter, king of the planets, at mag -1.9, is now emerging in the pre-dawn eastern sky. However, it is not easy to see as it is hugging the sunrise horizon. The beautiful ringed planet Saturn (mag +0.9) lies in Pisces in the eastern sky. It climbs to over 30 degrees high by the end of the night by the end of July making it suitable for telescopic observation. Uranus (mag +5.8) lies near the Pleiades cluster in Taurus, visible in binoculars around 30 degrees high by the end of the month in the pre-dawn eastern sky. Neptume (mag +7.9) lies about a degree north of Saturn all month where it will be fairly easy to discern its tiny blue disc with a telescope

As mentioned last month, June and July provide the best chance of seeing noctilucent clouds. These are beautiful high level clouds, often bright, iridescent blue, silver and white. At altitudes of 75-85 kilometres, they are visible only in twilight after sunset. Look to the northern sky between the NW and NE horizons.

Still nothing happening concerning the possible outburst of the recurrent nova T Coronae Borealis currently at mag 10 as I have been keeping an eye on this area with binoculars.. If it does outburst in the next few weeks, it lies below the handle of the Plough in Corona Borealis. It last outburst in 1946 reaching mag 3.0 and mag 2.0 in 1866 when it was discovered. It is nicknamed the "Blaze Star"

For the first three weeks of July the night sky does not get truly dark, just astronomical twilight. This means it is not worth trying for faint "fuzzies" like galaxies or faint nebulae. Rather, apart from planets and the Moon, try for bright concentrated objects. Fortunately the early summer night sky includes a number of globular star clusters that are both fairly bright and concentrated into tight balls of millions of old stars. As such, with their high surface brightness, they are a good choice to view with a telescope and take magnification well if seeing conditions are favourable. Many are also easy binocular targets.

All of the globular clusters mentioned last month, such as M13 and M5, are still on view as well as the Ring Nebula M57. Continuing our tour of globular clusters, but now in the southern sky, the large constellation of Ophiuchus the Serpent Bearer has no less than seven listed in Charles Messier's famous catalogue, more than in any other constellation. These are M9, M10, M12, M14, M19, M62 and M107. They range in brightness from mag 6.6 for M10, M12 and M62 to mag 7.9 for M9. Therefore they are all binocular objects but obviously look best through a telescope with higher magnifications resolving some outer stars in these globe shaped clusters of many thousands of stars.

If you have a good southern horizon, this month also take a look at the bright star Antares in Scorpio. It is sometimes called the rival of Mars because of its orange-red colour.

Good Hunting and I hope to see you this evening at the society's monthly meeting.

Best Regards

David