More astronomy

This isn't the most exciting photo I've ever taken but last night was the first sight of Venus this winter. I knew it was going to be an evening star and had been looking out for it after getting home from work. The other dot is Jupiter. I realised that they would get closer together as Jupiter moves nearer to the Sun and so I thought I'd get my Starry Night software out to see when they get close.

Back in February this year these three were close just before sunrise and I set up my then new camera to try and get photos. Unfortunately on that morning it was cloudy. Starry Night said that Jupiter and Venus will get close on December 1st, but even better is that a 3 day old crescent Moon will also be there in the evening. In fact the Moon will occult Venus, that is Venus will disappear behind the Moon. It's rare for a bright star to be occulted, never mind a planet and something I've never seen.

According my Starry Night Venus disappears at around 3:47 PM - just after sunset. It reappears at about 5:14 PM - about the time I usually get home from work. You can't miss Venus - it's the very bright object in the southwest. I hope to have some good photos in December.

International Space Station

The International Space Station (ISS) can often be seen in our skies. It orbits the Earth roughly every hour and a half, but the Earth is spinning underneath it so it will only be above the horizon about 4 times per day. But to be visible it also has to be out of the Earth's shadow that is caused by the Sun and this usually means one viewing per day, sometimes two, for a few days and then a week or so without any sightings.

The Heavens Above website gives details of when you can see the ISS - I'm pretty sure it is always after sunset or before sunrise. All you need is your location - and Google Maps can give that very accurately, especially as you can centre the map on your garden. As I type (11th September) the ISS will be visible tomorrow (twice) and the next two days early in the morning and then on the 20th around 8:54. The length of time is very variable; on the 14th it's just 12 seconds, this morning it was nearly 4 minutes.

It looks like a very bright star moving about the speed of an aircraft. On 10th February it was due to appear, and being a Sunday I was at my mum's, so I tookmy telescope mount and camera and took a 30 second exposure of the area I knew the ISS would pass through. I took the telescope mount as that is motor driven so the stars wouldn't streak. Unfortunately I didn't get a good focus on the stars - but they haven't streaked. The bright line is the ISS as it passed across the field of view from right to left.

The brightest star is Aldeberan, an orange star (this was taken black and white) and one of the brightest in the sky. The V of stars to the right and above is the Hyades open cluster, which is also easy to see in winter. Many of the stars you can see in the photo wouldn't be visible to the naked eye.

Also on 10th February was an Iridium Flare. These are caused by sunlight reflecting off the antannae of these small telecommunication satellites. There are 66 Iridium satellites in orbit and the short, roughly 2 seconds, flares are easy to predict - and these are also on the Heavens Above website. Some can even be seen in daylight. As an example there are two tomorrow evening, one at 20:57 and as bright as Venus (3rd brightest natural object in out sky after the Sum and Moon) and another as 22:23 almost as bright as Sirius (brightest star). However if I was to drive 10 km to the west for the first or 50 km for the second then these would be over 4 times as bright as Venus.

Moon shots

My T-mount (connects the Nikon to the telescope) arrived in February and on the 9th there was a nice young Moon. Its age is measured from when it is New, with a Full Moon being at nearly 15 days. This day it was less than 3 days old so a nice crescent.

It wasn't dark like the photo suggests. That was taken at 1/160th of a second to avoid overexposure. Here's a couple of close-ups.



What I was really after though was a photo of Earthshine. The Full Moon can create shadows here on Earth. Because the Earth is bigger and reflects more sunlight it will light up the night side of the Moon even more. When there's a crescent Moon it's possible to see the whole.

The crescent is over-exposed because it's a 1 second shot. That star is called HP115945 and would just be visible to the naked eye if you had no street lights, perfect eyesight and a very dark moonless sky.

I also took a photo of the Moon with my 200mm lens three weeks before. Here the Moon is 9.5 days old. It was taken in colour but I had left it set to tungsten light balance by accident so I've just grey-scaled it. The above photos were all taken black-and-white.

I have cheated a little on all these using sharpen.

Eclipses

I expect all of us remember the total solar eclipse of 1999. If only I had my Nikon DSLR then! However on March 3rd 2007 there was a total eclipse of the Moon and I took my telescope and Sony Cybershot over to my sister's so that my nephew and mum could also look. My sister was at work that night. As with the photos further below, the camera was just held at the eyepiece of the telescope and I had to hope that everything settled down shaking when the timer ran out.

Taken at 10:27 PM showing the Earth's shadow across the Moon.

This is the same picture but I've messed with the brightness so you can see the Moon in the shadow.

Total. Taken at 10:45 PM only a few minutes after totality started. The bright edge never disappeared, only moving to different positions.

On August 1st 2008 there was a partial solar eclipse visible from the UK. It's maximum was at 10:15 AM and unfortunately I don't have a break until 10:30. It was a cloudy day and very difficult to get a decent photo. Sometimes I held a welding shield lens over the camera, sometimes I did without and hoped I had the exposure right. Automatic exposure never works well with astronomy.

Astronomy

Back in 2005 I bought a decentish telescope. I used to have one before a fire at the house and decided to replace it. To be honest I haven't done all that much with it, partly because it's a bit of a pain to set up every time. It's an equatorial mount, with motor drive, 150mm reflector. To use the motor drive you have to set it up pretty accurately and I couldn't use it on the garden as it was. Using it on the front was pointless with all the street lights.

At work I made a contraption that could hold my Sony Cybershot digital camera at the eyepiece and on April 14th 2005 I took these shots. My first attempt at astro-photography.

From left to right, Callisto, Jupiter, Io, Europa, Ganymede (and no I didn't know without running my Starry Night software). The image has been rotated 180 degrees because through the telescope Callisto would have been on the right. It's a 2 second exposure, which has over exposed Jupiter but it's hardly a professional setup. Jupiter is the bright "star" low in the south that you might have seen recently.

The photo of the Moon has also been rotated 180 degrees and I was chuffed to bits with it. Magnification is x30. I have no idea what the exposure was because I lost all that data with the software I used. What I do remember is moving the spot meter to get different settings.