A Day in My Life of The Solar System
This is one day in the life of Andrew Wood, Sydney City Skywatcher's Member and avid observer. All the photographs are his and all were taken on that one day..
The weather app I use predicted that at my location on planet Earth, Saturday October 10, 2020 was going to be cloudless the whole 24 hours. With many objects of our home solar system currently visible, I set out to observe as many Solar System objects as I could that day. I had at my disposal my telescope; but even if I caught a glimpse of an object using binoculars or even naked eye it would serve the purpose of the project. In addition I have a camera with to take rudimentary images where possible.
THE DAY BEGINS WITH MOON
Waking to my alarm at 4am, I got ready and headed outside. The October morning was not too cold, and I was comfortable in jeans and short-sleeved shirt with a sloppy-joe. Looking west, Mars, currently at opposition, was shining brightly. If the weather prediction held true, however, observing that planet was on the agenda much later in the day. My first target, the Last Quarter Moon (also called 3rd Quarter), was prominent to the north.
Rising around mid-night, this phase of the Moon, and subsequent crescent phases leading to New Moon, is probably rarely seen. (For myself, its appearance has often been the signal to pack up at dark sky sites after deep-sky observing.) Using a camera with a telephoto lens on a tripod, I took an image.
By now Orion and Taurus were prominent. At this time of year both these constellations are known for meteor showers. Going inside to make a coffee then making myself comfortable in a garden chair, I watched the area. No meteors were seen but it wasn’t long until the next star of the show, Venus, made an appearance.
First seen shining very brightly through trees on the eastern horizon, once Venus had risen into clear sky I took a short time exposure of the area it occupied. Then I retrieved my 250mm Dobsonian scope out of its storage space. Still low in the sky, the image of Venus through the scope was of course shimmering strongly through the Earth’s atmosphere. For an extended period of time, at one point going inside to get a bowl of cereal and taking it back to the scope, I kept nudging the scope keeping the planet in the field of view. As it rose higher, the image became more stable so that the current gibbous phase of the planet became apparent. Right through dawn until after sunrise I kept observing. Even by the time the sky was blue I was able to see Venus for a short period of time.
When it finally disappeared to my eye alone it remained clear in the scope, and in fact looked very pretty, its gibbous white disk against the blue of the sky. With the observing area bathed in sunshine about 7:30am, it was still visible through the scope.
It was nearly time to get on with other things this Saturday, but first, using a 120mm refractor fitted with a full aperture solar filter, I took a photo of the Sun. Solar activity has been very weak for some time; and so it proved. No sunspots were visible on the surface.
MERCURY IN THE WEST
It was not until 7pm that the quest continued. The weather prediction had proved correct and the darkening dusk sky was still clear. Using binoculars, the target was Mercury. With the western horizon blocked by houses and the planet only ever appearing in a not completely dark dawn or dusk sky, I was relying on a quick view before it became too low. With Jupiter and Saturn – more on them later - becoming visible overhead, and the star Antares already visible high in the west, I still hadn’t caught of Mercury. It wasn’t until it was almost too late that I saw it just above some roofs, about to become invisible to me. I quickly took a poor photo with it just visible.
As mentioned, in the early night sky, Jupiter and Saturn were prominent overhead, and Mars was now rising in the east. There was plenty of time to observe them later. Another target in the constellation Ophiuchus in the west was, if I were to see it, the earliest priority.
Comet 88/P Howell was, on Oct 10, predicted to be 0.6 degrees south of the globular cluster NGC 6355. Predicted to be magnitude 9, it should be visible using the 250mm scope, even in the light polluted sky. Setting up the scope and aligning the Argo Navis unit I use to find faint objects, I found the globular cluster; also magnitude 9, and small at 5 arcminutes in diameter. Nudging the scope south, a much larger fuzzy object became visible. There wasn’t much detail visible but there was no doubt that I was looking at the comet. An extra sighting of a solar system object making a guest appearance along with all the main players.
JUPITER AND SATURN
Turning now to Jupiter and Saturn, I took a short time exposure of the area of sky they are currently occupying then turned the 250mm scope on them. Jupiter’s Great Red Spot was visible, as well as the system of light and dark parallel bands that make the planet such a great site through the telescope. Also visible, to one side of Jupiter, were the moons Calisto, Ganymede and Io. (When a I took another look about two hours later, the fourth Galilean satellite, Europa, had become visible on the other side of Jupiter, previously having been behind the planet on the line of sight from Earth).
Saturn, showing much less surface detail than Jupiter, makes up for this with those wonderful rings. The very bright satellite Titan was also of course visible. Many of Saturn’s other satellites, although not as bright as Jupiter’s four bright moons, can often be seen in a telescope with sufficient aperture. Tonight I was able to detect two faint satellites closer to the planet than Titan. Making a quick sketch of their positions and later using a planetarium computer program, I determined that these objects were Rhea and Tethys.
Before turning to Mars, rising ever higher, I aimed the scope to the position of Neptune, which was due to transit about 9:30pm. Consulting a detailed star atlas, I identified the pattern of stars that were visible in the eyepiece. In the same field was an object not shown on the atlas, which took on a small disc-like appearance when magnification was increased. The magnitude 8 planet was confirmed.
Now for Mars, currently at a favourable opposition, with an apparent size of 22 arcseconds.
What is exciting about observing Mars when it is close enough to Earth to show an appreciable disk, is that you can see features on the solid surface of another planet. Mercury is too small and never visible in a dark sky; Venus shows phases but is always covered in a thick atmosphere of cloud; the other planets are gas giants. On Mars, if there’s no dust storm occurring, features are visible on its solid surface. Tonight the south polar cap was visible, and also blotchy light and dark areas, so that the surface was not uniform and devoid of features. Well worth more detailed observation but there was still one more object to locate to complete this exercise.
Uranus, at magnitude 6 and definitely not visible naked eye at this location, had risen but was still fairly low in the east. Setting the scope to the correct position, I found I was looking through the upper part of my back patio. It was still well before midnight, so it would rise high enough in time for me to see it in the 24hr period. When it was finally high enough, in a field the atlas showed contained only faint stars, there was a much brighter object that became disc-like with higher magnification.
THE SOLAR SYSTEM ACHIEVED
Done. All eight planets (including Earth), the Sun, Moon, a comet and a smattering of planetary satellites all within a solar day, seen from naked eye to telescopic views, with some photographic records. (As well as the camera-on-tripod time exposures, I also took images of Venus, Mars, Jupiter and Saturn through the telescope with the camera using the afocal technique. These are not good images but do provide some record of the observations.)
The only disappointment was a total lack of meteors. Even without meteor showers, it’s unusual not to see at least a couple of sporadic meteors after spending so much time outside. Still, this was a small project I’d had in mind for some time; and well worth spending part of one day of my life doing.
Produced by: Planet Earth
Starring: The Sun
Also including: Mercury, Uranus and Neptune
Bit parts: Io, Europa, Ganymede, Calisto, Titan, Rhea and Tethys
Extra: Comet 88P/Howell