And then two came along at the same time

After waiting for weeks (for one reason and another, not just the weather), it was finally a clear night last night. Intending to get the telescope out later that evening, I started browsing my twitter updates and noticed one that said ‘ISS viewable from the UK from 9:45pm, approaching from the west, getting dimmer as it passes overhead’. I looked at the time – 9:45pm! Dashing outside, I started scanning the skies; true enough, it didn’t take long for a bright pin-point of light, surprisingly bright, approach from the west. I called my wife to see it and we watched as it passed almost directly overhead, getting dimmer and dimmer until it was lost amongst the night sky, directly overhead. ‘Wow’ was both our response and as there was nothing else to see, we both went back inside.

So I started looking for websites that would give me real-time updates of the ISS and its current position. The best one seems to be:-|35817

This link will give the current position of the ISS and the Japenese H-2 transfer vehicle, which are currently docked (or near as). A useful feature of the site is that it will give a 5 day prediction of where it will be, useful for planning your next observation.

Whilst I was scanning the sky, I noticed another bright star in the south-west. Seeing a good opportunity for a quick observation, I decided to get the telescope out and set it up in the back garden. I didn’t bother with getting it aligned or level, simply to get the aim and ‘scope pointed at the object and to view it as quickly as possible. Using the red dot spotting sight, the ‘scope was lined up and I fitted the 25mm lens. Once it was focused and the object was in sight, I was puzzled by three faint dots spaced around the main object. Heart sinking, thinking this was a problem with the lens, I quickly realised this wasn’t the case when I focused the main object a little more and noticed two horizontal bands – I’d found Jupiter! The three dots along the horizontal axis were some of the Galilean moons. I’d read earlier in the week that one would be out of view, either in rfont or behind of Jupiter itself.

For the next 20 minutes I swapped the 25mm lens for the 10mm and mixed the Barlow lens, looking to get the best possible view. I found that using the 10mm lens on its own offered the best level of sharpness and contrast when looking at the dark atmospheric bands on Jupiter. The Barlow lens appeared to give a slight colour distortion around the edges of Jupiter. I couldn’t also believe the speed that the object moved across the sky; I was changing the lens and within a few seconds, the view had changed and I had to re-align the ‘scope, using the red dot viewer or the 25mm lens, to centre the object.

Satisfied with my discovery, I packed the kit away for the night.

However this morning, still intriged by what moons I had seen, I searched the web for some answers. I found them at:-

…where you can enter any time/date to get the positions of Jupiters GRS (great red spot) and main moons.

Jupiters moons at 11:55pm 12/09/09

Jupiters moons at 11:55pm 12/09/09

So I’d spotted (L to R) Callisto, Ganymede and Europa. Io was transiting Jupiter at the time. Don’t forget this view is inverted, as I’m using a reflector telescope.

If I can get hold of some more lenses with a higher magnification (I have some in mind), this should enable me to achieve even better views of Jupiter and its moons. I feel the credit card getting itchy…


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