The Scruffy Astronomer

The Hubble Space Telescope has been in orbit since 1990. That's incredible for the high-radiation environment it has to work in. After a shaky start, it's been sending mind-boggling photos back to Earth for more than 30 years. Image: NASA But a few weeks ago the payload computer stopped. The computer equipment on board the HST has many levels of redundancies: there are backups for their backups. So the first problem is identifying the component that has failed. But even after they've found the problem, NASA can't just go up there and start soldering. Since the retirement of the Space Shuttle, they have to do it all remotely. What's currently up there is going to have to do. What's more, while many astronomers on Earth communicate with their equipment at a distance, remote maintenance is difficult when it might be the remote computer that's gone on the fritz! There are a few suspect parts. Initially, NASA though it may have been a bank...

About now, Mercury is close to its maximum elongation. This means that, viewed from Earth, it is as far from the glare of the Sun as it ever gets. This is our best opportunity to view the planet. My house is on a hillside facing the west. I look out over a freeway and the Yarra, and I have a good view to the horizon from south-west to north-west. Unfortunately, I can only see it through a double glazed window, so my images weren't going to be great. But the view wasn't the problem. I have to confess here that I'm not the world's keenest planetary astronomer. When I saw something, I didn't really know how I was going to be sure that it was Mercury. After all, it was going to be a dot, at best. You see, Stellarium was telling me that Venus was going to be nearby, separated by about five degrees. Venus would be brighter, lower, and to the left of Mercury. If I saw both planets, it would be easy. But what if I saw only one? How could I be sure it was Mercury, ...

Lunar eclipse, 26 May 2021 If you're reading this, the eclipse will be long in the past. Don't worry, there will be more soon - a lunar eclipse isn't a very rare event. The lunar eclipse is on Wednesday! On the evening, the Moon rises before entering the Earth's shadow. Because the shadow isn't a sharp line, the start of the eclipse is a bit vague. I'm saying that it begins at about 7:45, although you may have noticed some dimming on one side for some time. The mid-point is something we can be pretty certain of - it's at about 9:15pm. At this point, the Moon will be bathed in red. Why? If you were on the Moon, looking up, you'd see a solar eclipse, with the Sun behind the Earth. But more than that, the Earth would look like a circular sunset. Blue light is scattered by the Earth's atmosphere. Just the red light gets through. My photo here is from a few years ago. This is how I did it - have a go yourself! Shortly before the beginning of...

The Tianhe-1 is the first part of the new Chinese space station. If you like, it's an orbiting foundation, but more accurately, it's called a "core module". At 16.6 metres in length and 22.6 tonnes, it's big already, but it'll grow as the Chinese Space Agency adds modules. It's got several docking ports to allow expansion as well as providing parking space for service vehicles. It was launched on 29 April on top of a Long March 5B heavy-lift rocket. The launch went well and the upper stage of the Long March rocket reached the planned orbit. After dropping the payload, it was probably meant to restart and slow down. This way it would fall back to Earth not far from the launch point. This didn't happen, and the 21 tonne rocket remained in orbit, rising to over 240km, and then dipping to about 150km every 90 minutes. The rocket was also tumbling, indicating it wasn't under control. With each dip in altitude, the rocket brushed the upper atmosp...

Never heard of it 99942 Apophis is an asteroid whose orbit - somewhat worryingly - intersects the Earth's. It's defined as a hazardous object. Apophis orbits nine times for every eight Earth orbits, and because of where the intersection is located, the danger period is every eighth April. Wait, what? The intersection is on the ascending node, meaning Apophis approaches the Earth from "below" (assuming Earth's northern hemisphere is "up"). This means Apophis is visible from the Southern Hemisphere before the encounter, and it falls below the horizon, becoming visible from the Northern Hemisphere after the encounter. There's a super close (but safe) pass coming up in April 2029, meaning about now is the last encounter before then. So of course I want a photo In preparation for writing an article about the asteroid, I wanted to actually get a photo of it. Because it's not a very close pass, it wanders by rather than zooms, and so I had a good...

The Hubble Space Telescope has been working now for over 20 years. Some (maybe all) of the photos it's sent back have been incredible, and the science it's produced has developed our knowledge of the cosmos considerably. But it's also getting a little old. In 22 years, technology has marched quite a bit, meaning the instruments we put up there are not exactly cutting edge. But second, Hubble's spectrum is limited to UV and visual frequencies. We're starting to get curious about the infrared - that is, what's going on on the other side of the visual spectrum. The James Webb Space Telescope (JWT) is nearing completion, and is due to be launched in October this year. This telescope is intended to complement and replace Hubble. The telescope itself is large. Its mirror has a "sort-of diameter" of 6.5 metres, but it's not circular, Rather, it's an array of 18 hexagon-shaped mirrors, 1.32 metres across. To give you an idea of th...

February 2021 brought COVID lockdown 3.0 to Melbourne. For five days, we were required to stay home, only leaving for a few good reasons. So what do you do when you're confined to your house? Well, there's astronomy, but the clouds have been clearing during the day and then returning after sunset. I've set up my rig a couple of times, only to tear it all down after an hour of staring at a starless sky. What else can you do? Gardening, of course. Under lockdown 1.0 and especially 2.0, my garden came to be quite neat. Of course, Harley Rose, our new Labrador puppy hasn't really been good for the garden, unless you regard her as a very enthusiastic rotary hoe. And birding. I was out in the garden yesterday, trimming some plants, when I heard a begging call. It was coming from a thicket of Wattles. Eventually I spotted an Eastern Spinebill feeding a juvenile. By the time I'd retrieved my camera and attached the birding lens, the baby had disappeared, but a young...

Normally I don't comment on current events, but I thought I'd make a somewhat sad comment here. The Arecibo telescope, a 380m reflector dish located on the island of Puerto Rico in the Caribbean sea, has been destroyed. The dish of the telescope was built in a natural depression between hills. This not only made the construction a little easier, it also protected it from hurricanes (which were, of course, the eventual downfall - literally - of the facility). The dish itself was a spherical shape, rather than a parabola. This meant that the telescope could be aimed in a range of directions rather than being pointed at a fixed altitude and azimuth. To allow the telescope to be pointed, the array of receivers had to be above the dish and also had to be movable. After a few proposals for towers emerging from the centre of the dish, the designers settled on a receiver which hung over the dish on cables. The receiver itself moved under an inverted arch. This arch was suspende...