Science education through astronomy.
31/10/2022
Find out more about Family Stargazing at
Family Stargazing – Science Education through Astronomy www.starwaders.com – Updated 26 October 2022 Starwaders presents an evening of stargazing for one or two families at a time at a residence in Faerie Glen. Neville will not only show you interesting objects that are visible on the evening of your visit, but will also explain to you WHY you are able...
31/10/2022
What about some Stargazing with the family?
Starwaders has opened its premises and observatory for an evening of learning how the night sky works. See this link for further information.
Two weeks ago the moon Io cast a shadow onto Europa. This morning it was Ganymede's turn to block the Sun from Io.
This is the last Galilean moon eclipse event that will be visible for me this time around. I have to wait 6 years for the next series of eclipses.
This morning's video shows a different configuration of the moons as compared to the position on the 29th of April. Note that the angle from which we see Jupiter is not the same as the view from the Sun, allowing us to see the Ganymede darkening Io.
I love capturing unusual events.
Jupiter has many moons, four of them easily visible through telescope and sometimes binoculars. Every 6 years, these four Galilean moons can occasionally pass in front of each other or throw shadows onto another moon. Such an eclipse happened on Thursday 29th April at 03h15. The moon Io (eye-oh) blotted out the sunlight on Europa for a few minutes.
I was able to video the dimming of Europa. Here is a video which shows the dimming and explains what we are seeing. (The first minute of the video is sped up 4x in case you don't have the time to watch the eclipse in real time in the last 4 minutes of the video.)
23/12/2020
So that I never forget how close it was and so that the circumstances are recorded here in case my memory will want to exaggerate the tight timing in future:
17h30 - clouds moved in. 19h06 - not much chance (pic 1). 19h36 - a slim chance moving in from the west (pic2) . 20h03 - the first photograph taken hurriedly only minutes before the pair dropped below the observatory horizon (pic3) . 20h24 - last touch taken with smartphone (pic4).
A build-up to this event that I will always remember!
23/12/2020
I was so lucky to see and photograph the Closest Approach on Monday evening. Cloud moved in at 17h45. I knew I could only start taking photos at 19h15 and that by 20h00 Jupiter and Saturn would dip below my horizon. Well - they slowly emerged from behind the drifting cloud at 20h01, leaving me only minutes to aim, focus and expose correctly. The tension and excitement made the view all the more enthralling.
Here is my updated composite of photographs taken in the days running up to the 21st. I have arranged the planets so that they are orientated correctly to the western horizon. The Moon in the background shows how far Jupiter moved to catch up to Saturn.
A higher resolution image can be seen here http://www.starwaders.com/SMUBlog/2020/12/22/the-great-conjunction-of-jupiter-and-saturn-december-2020/
21/12/2020
Clear skies yester-evening so here is the progression towards the closest approach this evening of - purely coincidentally - our summer solstice. The clouds have to be kind this evening.
20/12/2020
Have added last night's Jupiter position to the composite image. Also added other Galilean Moon detail.
Skies forecast to be clear on Monday evening!
19/12/2020
It is important to know WHY you are seeing this conjunction.
This diagram shows the view of the solar system from the southern side of its disk. From this side, planets orbit CLOCKWISE. We live on Earth’s southern hemisphere, so it is better to ignore the northern hemisphere ANTI-CLOCKWISE convention and to look from the southern side.
Looking at Earth from its south pole side, it is rotating clockwise. Standing on Africa at sunset, you have just rotated away from daylight into dusk. Look along your western horizon and then up into the sky where you see Jupiter and Saturn. Notice that Saturn orbits more slowly than Jupiter does, which means that Jupiter has been catching up to Saturn, and from our Earthly point-of-view, it will be directly between us and Saturn on the 21st of December. Jupiter has been the planet closer to the horizon, but after the 21st, it Saturn will be the one closest to the horizon.
19/12/2020
I continue capturing the closing of the gap between Jupiter and Saturn. Thursday night 17th was clouded out. So was last night 18th, but I had my telescope aimed closely at where the planets were behind the clouds, and when I caught a glimpse of them through binoculars, quickly nudged the telescope onto them and started looping through a programmed sequence of various exposure lengths and ISOs, hoping that when the pair did peep through gaps in the heavy cloud, I would capture the narrowing gap as well as the current Galilean Moon configuration. Over the next half hour a few exposures captured were good enough to include in my composite image.
So here is the progression of the conjunction in the past 4 days. Both planets and all the Moons are photographed through my telescope, but are superimposed on the underlying image. I have taken great care to ensure that the relative distances, planet sizes and positions are correct.
16/12/2020
I set the camera going and found a few images that were taken in quick clearings between the clouds. This composite shows todays pairing, with yesterdays Jupiter top left.
16/12/2020
A gap in the clouds yesterday evening meant that I could have a go at the conjunction of Jupiter and Saturn with my 6" f/5 Newtonian, which gives a field 1.5º wide. This cropped image is a composite of the best exposures for Jupiter, and then for Saturn and finally for the Galilean moons.
I will use this technique to add Jupiter and its moons to this image on any further opportunity the sky gives me, so that the closing separation and the changing moon positions can be seen in a single image.
The previous time they were this close was 800 years ago. You will have to wait 60 years for when they will be as close as this again.