Forecast for September 2013:

 

The Moon

New                     5th 06:25 - 10:21

First Quarter       12th 14:43 - 23:10

Full                     19th 18:50 - 06:44
Last Quarter       27th 23:50 - 15:03

 

 

Planets

 

Mercury sets 10 mins after the Sun on the 1st of September, and should be avoided. It

is moving away from the Sun as the days go by, but in an horizontal fashion rather than

in time so will set in very bright twilight, but further away, not really a great help. By the

end of the month Mercury will set 23° further south than the Sun, but only 20mins later.

Not Mercury’s month.

On the 1st, Venus will set 39° further south than the Sun and 50 mins later, so its mag

-4.0 disc of 15 arc sec should be easily seen. Try to see the 74° phase. A week later, it

will be mag -4.1 and 16 arc sec with a 71° phase and a bit further from the Sun. It will

also have a thin crescent Moon 2° below as it sets at about 7:50pm. On the 18th it will

lead Saturn (3° above) down to the horizon. Venus will set at 7:20pm, still about 50 mins

after the Sun. On the 30th it will set at 6:50pm in darkening twilight, but easily seen as a

mag -4.2 and 18 arc sec disc of 63° phase.

Mars will rise on the 1st at 3:30am, as a mag 1.6/4 arc sec disc with comet ISON 5° to

the north and the crescent Moon 12° to the south. The Moon will be 7° away the next

night and will, of course, follow it through the rest of the night. On the 21st it will be

within 2° of the comet, but the comet at mag 11 won’t be visible, partly because of its

faintness and also because of the murky air it will be in so near the horizon. On the 30th

it will rise at 3:15am but with all its other parameters unchanged. It will again have the

Moon for company. As the nights are lengthening you’ll be able to study it for two hours

at the end of the month instead of the one at the beginning, though it is still too small

to see much detail.

Jupiter will rise on the 1st at 1:15am as a mag -2.1/35 arc sec disc and it will be 4 hours

before dawn twilight cancels observing, but a good start to this apparition. By midmonth

it will rise at 12:30am with the same parameters, with 5 hours of observing time,

though mostly close to the horizon. By the end of the month it’ll rise at 11:30pm, giving

us 6 hours of observation, of its now mag -2.2/37 arc sec disc. More to come in the

coming months as it takes over from Saturn as lead planet of the night.

Saturn sets on the 1st, at 9pm, an hour and a half after the Sun, and it will be difficult to

see much detail so close to the horizon, other than to be able to say that you’ve seen it.

On the 15th it’ll set at 8pm in darkening twilight again with little detail to be seen. By the

end of the month it will have set by 7pm, just over an hour after the Sun. Time to

transfer your affections to Jupiter. It ends this appearance as a mag 0.7/16 arc sec disc,

but with rings held wide almost in defiance.

Uranus will rise at 9pm on the 1st, as a mag 5.7/4 arc sec blue disc, and will be available

all night, or at least till 5am when dawn starts to show herself. Try to see the moons

during the next few months. Remember that it rotates almost at right angles to the

Ecliptic so the moons will be up and down rather than from side to side as with Jupiter.

On the 30th it will rise at 7pm in evening twilight and set at 7:15am, giving you all the

hours of darkness to observe.

Neptune is ahead of Uranus and rises at 8:15pm on the 1st, in darkening twilight, a tiny

mag 7.8/2 arc sec disc. You’ll need all your wits about you to find it as it rises, so better

to wait a couple of hours when the sky is darker. You’ll have more difficulty on the 17th

when the almost full Moon travels within 4° of it across the sky. It rises at 6:30pm, in

bright daylight, so is visible from dusk to 3am when it sets. Much harder work to see

anything of its moons but maybe worth a try, they orbit side to side as do all the rest of

the planets other than Uranus.

 

Meteor Showers. September is almost free of meteor showers, with just one peaking in

the month but with only 5/hour at best, and those counted as faint.

 

Comets. None at naked eye visibility, but for the photographer the same comets as

listed in last month’s will still be available, as will be many others if you’re really intent

on photographing one. But doing that isn’t easy if it’s faint and you have to guide.

Photographing comets is quite different to photographing other objects in the sky and

in processing too.

 

To find a comet yourself go to http://minorplanetcenter.org/iau/Ephemerides/

Comets/index.html .

The latest comets 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.