In the steps of Galileo and beyond

In 1610 the Italian scientist Galileo trained one of the new telescope devices on the skies; amongst his observations were 4 moons that orbit Jupiter. Today we know that there are over 60 moon like objects that orbit this great planet; but it’s still an experience to view the 4 Galilean moons [that is, Callisto, Ganymede, Io and Europa]. And so it is here that our continued educational adventures with a telescope have taken us.

Mid summer planet watching at our Latitude can be a seriously middle of the night activity, so whilst the rest of the family slept, I was despatched to carry out the necessary viewing and to return with the photographic & video evidence for our study. The Azores high has recently pushed in over Wales, so seeing conditions were quite acceptable but with some ground mist forming by about 4am. To capture an image of Jupiter & the moons I used a Canon G7 camera and afocal technique. That is, focus the digital camera to infinity & then take a picture of what you see through the telescope eyepiece. A problem here is that an exposure for the moons is far too bright for any detail in Jupiter to be saved. Therefore the next step is to capture some planetary detail, for this I used a CCD camera (Celestron’s Neximage) mounted via a Barlow lens onto the scope. The resulting avi file was processed with Registax and the best 70 frames stacked.

Having captured the images, they were then combined in Photoshop before being given a final tweak in Lightroom. Orientating everything correctly is a bit tricky since the different lens set-ups flip the images in different ways, so my apologies to any hardcore astronomers if I’ve slipped up on that one. The resulting image is below, it’s far from perfect and I hope to improve, but it’s good enough for some fun & education. Besides the feeling of recreating Galileo’s observations & photographing them, is a really exiting one.

Whilst waiting for the right moment to take the above shots, I was experimenting with some other techniques (prime, positive projection & wide field). One thing I was doing was taking wide field shots with my Canon 20D mounted on the scope’s equatorial mount. This set-up allows the camera to track the stars, thereby avoiding star trails in exposures over 30 seconds. Whilst taking a series of 1 minute exposures, the camera captured several shooting stars but of particular interest was a bright object that appeared in two frames, whilst crossing the sky from west to east. I processed & stacked these two frames (with Deep Sky Stacker) and then tweaked in Photoshop. Here’s the resulting image, orientated as seen from the observatory:

I then started researching to identify the object, which turned out to be the International Space Station [thanks to Heavens Above]. So the image title should be “ISS crosses beneath Milky Way”, since the original exposures were of the south eastern view of the Milky Way; a cool bonus for the night. I wonder what Galileo would have thought?


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