Forecast for July 2013


 

 


 

The Moon                             
 
New                           8th   07:27  --  16:24
First Quarter             16th 14:24  --  --:-- 
Full                            22nd 20:36  --  04:52
Last Quarter              29th 23:37  --  13:57                
 

High summer, but we’re past the longest day so the nights are beginning to shorten, slowly. I’m heartily sick of those short light skies of summer, get us back to the long dark nights of winter, but without the cold please.
 

Planets
 
Mercury, Venus, Mars, Jupiter, Uranus and Neptune  are all morning objects this month with only Saturn visible in the evenings

Mercury can be seen an hour before the Sun rises on the 20th, and it will rise earlier as the rest of the month progresses, so that by the end it will be up 90 mins before the Sun. It can be seen earlier in the month, by a few days, but closer to the Sun so more dangerous with optical aid. On the 20th it will be mag 2.2 with a 12% illuminated disc of 10 arcsec. A nice little crescent you’ll not see with the naked eye. By the end of the month it will mag 0.1 with a 42% illuminated disc of 7 arcsec. Worth following if you have a clear eastern horizon.

 

Venus will set 80 mins after the Sun in the WNW on the 1st, so will be easy to see. It will keep the same position all month too, gradually moving further westwards from the Sun from 25° to 32° away, but maintaining it’s -3.9mag and 12 arcsec presence. Its phase will change from 90% to 84% during the month.

Mars is also to be seen in the east, at 3:35am, well before the Sun, but still in dawn twilight. It will show a tiny 4 arcsec disc of mag 1.5. It will change little in size or mag. But will be up half an hour earlier. On the morning of the 22nd, it will rise next to big brother Jupiter, just ¾ of a degree away. On the 27th it will have Jupiter 2°20’ away to the south  and Mercury 7°30’ away on the other side. And 12° further north from Mercury will be comet ISON, the supposed “Big One” for this year. But it will be at mag 13, so will not be visible. Mars will rise at 3am on the 31st but with little change to its size or brightness.

Jupiter will rise at 4:15am on the 1st, a mag -1.9 and 32 arcsec disc, but spoiled by the morning twilight, so don’t expect much. By the end of the month it won’t have changed it’s presence but will be up by 2:45am and before twilight starts, so just beginning to be worth seeking, not that you’ll have to seek it, at mag -1.9 it will be difficult to miss.

Saturn will be alone among the planets visible in the evenings this month, and not very well at that, as it will be setting in evening twilight and be visible on the 1st, from about 11pm till it sets at 1:30am, an 18 arcsec disc of mag 0.5. On the 15th it will set at 12:45am and at the end of the month at 11:30pm.

Uranus will rise on the 1st, in Pisces, just before 1am, a tiny 3 arcsec disc of mag 5.8. The sky would be dark enough to find it but for the half Moon 6° away to its left, brightening the sky. But this will only intrude on the first couple of days, thereafter it will be marginally easier to find with binoculars as a small blue dot. A well set up goto telescope would make it easier still. For the rest of the month it will be as easy, or difficult, until the 28th when the Moon gets too close again, 3° away. On the 31st it will rise at 11pm, but unchanged in size or brightness, or ease of finding with little in the way of guiding stars to help.

Neptune, in Aquarius, will be even tinier at mag 7.9 and 2 arcsec  on the 1st, and without a guiding star, much more difficult to find without a goto system. It will also be available all the short night, all month as is Uranus. On the 24th it will have the the almost full Moon on its shoulder so will be more difficult to find as though it wasn’t difficult enough.

Meteor Showers. There isn’t much in the way of showers to be seen this month, several showers but all of faint and minimal ZHR.  

 

Comets. Comet C/2011 L4 PANSTARRS is still visible at mag 10.9, in the bottom end of Ursa Minor, 8° south of Kochab, and C/2012 S1 (ISON) is available in the morning sky with the planets, but is very faint so is better to wait till October.

 

You can look for yourselves on the Minor Planets site. http://minorplanetcenter.org/iau/Ephemerides/Comets/index.html

The latest from a few years ago, are listed there. Click on one for the ephemeris. If you like it, download it as a KML file by clicking on the KML file link. Then click on it on your desktop, which is where it’ll land when it gets to your machine. Click on it there and it will ask you to run google earth then to change it to google sky and the path of the comet will be drawn across the google sky for you. Don’t bother with any that show a mag number larger than 7 or 8. Most on the list are more than 15, which is very faint indeed.