Tag: Telescope

Categories
Science Stargazing Universe

Solar Eclipses

Solar eclipses are dramatic events
Solar eclipses are dramatic events

A solar eclipse occurs when the Moon, in it’s own movement, finds itself between the Earth and the Sun. One of the consequences of this alignment will be the blocking of a part (or all) of the Sun’s light here on Earth, in areas where the eclipse is visible. This is due to the fact that the Moon covers the Sun’s disk partially, or sometimes even totally.

Solar eclipses can thus be of two types: partial (when the Moon covers only part of the Sun’s disk) or total (when the Sun’s disk is covered completely by the Moon).

Total Solar eclipse

A total solar eclipse, which is the most dramatic – because the sky turns dark just like at night for a few minutes during mid-day – is much more rare, as the conditions needed for such an eclipse to occur, are much more strict.

For a total eclipse to occur, the Moon needs to be closer to the Earth on its elliptical orbit, so that its apparent size can be large enough to cover the Sun’s disk. In addition, the totality (the period of only a few minutes when the Sun is completely covered by the Moon) occurs only along a very narrow path along the Earth’s surface.

Annular and partial Solar eclipses

So, most of the Solar eclipses are not total!

But even if the Sun’s disk is not covered completely by the Moon, the concentricity of the two disks can create another beautiful Solar eclipse – an annular one, when the Sun is visible around the moon, just like a ring – hence its name!

However, most of the times a Solar eclipse will be partial, when the Sun’s disk will be partially covered by the Moon, and not in a concentrical manner. This is the most common type of Solar eclipse that we see.

Visibility of a Solar eclipse

One solar eclipse (be it partial, annular or total) can’t be visible from everywhere on Earth. The Sun needs already to be visible – which narrows down the visibility of an eclipse to less than half of our planet! As the relative positions of the Moon and Sun in the sky, seen from our planet, are always changing, the alignment of the two for an eclipse to occur, narrow its visibility down even more.

Sizes of the Sun and the Moon

The Sun is much bigger than the Moon, that’s for sure. So how can it be completely covered by the Moon then?

To answer this question, we need to look at the distance of the Sun and Moon, from us, from our planet. The Sun is much more far away from Earth than the Moon is! Which makes it have an apparent size more or less equal to the apparent size of the Moon! The Moon moves along an elliptical orbit around Earth, which makes it, at times, be closer to our planet. Which translates itself into a bigger apparent size of the Moon, which actually becomes slightly larger than the Sun’s apparent size. Which finally, can lead to a total Solar eclipse, if the other conditions for this event to occur, are met!

Looking at an eclipse

Warning! Never look at a solar eclipse with the naked eye. Not even sunglasses aren’t enough! In order to see a solar eclipse, you need a special solar filter, which makes it safe to look directly at the Sun. Otherwise, you risk getting extreme eye damage, and even blindness!

The Annular eclipse of 10 June 2021

On June 10 this year, an annular solar eclipse is scheduled to occur! The actual annular eclipse will be visible from a narrow band along Earth, which crosses the North Pole and a few far-North regions of Canada and Russia.

In the rest of the Northern Hemisphere, the eclipse will be a partial one and will be visible from places such as the Eastern part of the US, almost the whole of Europe and parts of Asia.

If, by any chance, you’ll find yourself in Vadsø, you will see a partial Solar eclipse, with a maximum obscuration of 51%, occuring at 13:09, Norway time.

For other location and times, check out this map from NASA to see exactly where on Earth the eclipse will be visible from, in 2 days!

And by the way, did you know that with Aurora Labs you can discover the mysteries of our own Sun by observing it through our telescope? The eclipse seen through a telescope (with a special solar filter, of course!) is a magnificent sight!

A partial solar eclipse.

Update June 10, 2021:

The beginning of the partial solar eclipse on June 10, 2021.

Categories
Nature Stargazing Universe

See the “Bethlehem Star” in the Night Sky

The Great Conjunction of Jupiter and Saturn occurs on 21 December 2020.
The Great Conjunction of Jupiter and Saturn occurs on 21 December 2020.

In astronomy, a conjunction means the “meeting” of two planets in the night sky. Jupiter and Saturn, the biggest planets in our Solar System, can meet as well, but when they do, their conjunction is a “great” one – hence the term Great Conjunction!

Jupiter and Saturn are one of the brightest objects in the night sky. They look just like two very bright stars – but don’t mistake them for stars! They are planets, so they don’t create light themselves just like the stars (like our Sun does for example). They are “lit” only because of the reflection of the sunlight. Which is the same reason why the Moon shines in the night sky!

The Great Conjunction of 2020

In their perpetual movement around the sun, it happens sometimes that planets “meet”. The word “meet” is quoted because the planets don’t actually meet in reality. It is just how we see things from here on Earth. In fact, the two planets are aligned in such a way in their orbits, that from Earth, we see them as if they came into contact with eachother. In reality though, they’re some million kilometres apart!

And why is this conjunction “great” you may ask? Well, this is because Saturn and Jupiter, due to their size, they are already bright even when they’re “apart”. When two bright lights touch each other, they are seen like only one light, even brighter! The same happens with the conjunction of Jupiter and Saturn.

When does it happen?

Jupiter and Saturn are already close in the night sky since quite some time now. But on December 21 (thus tomorrow!), the two planets will be so close (less than 0.1 degrees) that they will look like an elongated, very bright star. So, stargazers, get ready for a Christmas treat!

Why is the Great Conjunction so special this year?

The Great Conjunction occurs regularly, roughly every 20 years. But why is it so special this year?

In function on the position of the “meeting” with respect to the position of the Sun, the conjunction may be more or less bright. If this meeting place is too close to the Sun, the brightness diminishes. This year, the position is ideal for a very bright Great Conjunction!

Another thing to take into account is how close the two planets will appear to be. Not every 20 years the planets have such an apparent closeness! In fact, to get an idea of how rare this occurs, know that last time Jupiter and Saturn appeared so close, was in year 1226! It actually happened in 1623, but it was rather close to the Sun, which made it actually less visible.

Where and how to look?

You need to look in the night sky about 1 hour after sunset, almost anywhere on Earth, even in light polluted areas! In the Northern hemisphere look towards south-west. As for the Southern hemisphere, look towards the west. Needless to say that you will need a clear sky!

It will be impossible to miss such an impressive sight so, don’t worry, it will not be difficult to spot it!

“Christmas Star”

As the Great Conjunction this year happens very close to Christmas, it is also called the “Christmas Star“, or the “Bethlehem Star“. To go even further, some astronomers believe that the Star of Bethlehem which led the Three Wise Men to the place where Jesus was born, might have actually been a Great Conjunction! But there are other theories that suggest that a supernova might have occurred that time. Or, was it indeed a divine miracle?

Categories
Nature Science Stargazing Universe

“Stargazing” during the day

Is a telescope useful during the daylight?
Is a telescope useful during the daylight?

The polar day has almost arrived in Vadsø and the night sky is almost as bright as during the daytime. Therefore, the stars, planets and other sky objects will not be visible anymore during “classical” stargazing sessions, under a dark night sky! But we at Aurora Labs, did find a possibility to enjoy the sky from an astronomical point of view nevertheless – even in daylight!

The International Space Station, or ISS as it is commonly known, is today the largest man-made object that flies in space, at around 400 km altitude above Earth. And because it has the size of a football field, it is big enough to be seen even from our planet!

The International Space Station orbiting Earth
The International Space Station orbiting Earth

Things are easier at night: if you look at the sky, the ISS will appear as a very bright star (approximately the same brightness as planet Venus). Because it is so bright, it should be seen even from urban areas! The bright dot suddenly appears on the horizon, moves steadily without changing speed or direction, and disappears again below the horizon. And it doesn’t blink as a plane does. If you’ve ever seen something like this, chances are that you’ve spotted the ISS! In addition, there are online tools and phone apps which calculate for you when ISS should be visible in your exact location – such as, for example, Spot the Station, provided by NASA.

You don’t need a telescope to see this show; however, to the naked eye, the ISS looks like a bright dot, with no other features. A telescope would permit you to see some features, as solar panels for example.

During the day, things are more difficult. At night, ISS is seen because it reflects the light of the already set Sun. During the day, however, a possibility to see ISS is when it passes across (or transits) the face of the Sun. And what a great sight that is! Be careful though, in order to see this great show, you need a properly equipped telescope with solar filters when you look at the Sun, otherwise the light of our star is so bright, that it can create even blindness!

Multiple photographers around the world have taken such photos of the ISS transiting the Sun or moon. ISS travels at a speed of around 28.000 km/h, so, can you imagine how precise you need to be in order to capture such a moment that only lasts less than half a second? Because – yes – the ISS transiting the Sun or moon lasts less than 0.5 seconds!

One of the most recent photos of this kind, is the one taken by the photographer Mack Murdoc from Los Angeles, which is a composite photo showing the ISS as it passed across the Sun.

"International Space Station Solar Transit." © Mack Murdoc - see the original publication on Mack Murdoc's Instagram: https://www.instagram.com/p/B_h851mHpah/
“International Space Station Solar Transit.” © Mack Murdoc – see the original publication on Mack Murdoc’s Instagram: https://www.instagram.com/p/B_h851mHpah/

During daytime hours, besides the ISS, it is possible to see even planets, such as Venus, transiting the Sun! In the photo below, the black dot is not a sunspot, as you might believe, but it’s no other than planet Venus!

Gestrgangleri (https://commons.wikimedia.org/wiki/File:20040608_Venus_Transit.JPG), „20040608 Venus Transit“, marked as public domain, more details on Wikimedia Commons: https://commons.wikimedia.org/wiki/Template:PD-self
Gestrgangleri (https://commons.wikimedia.org/wiki/File:20040608_Venus_Transit.JPG), „20040608 Venus Transit“, marked as public domain, more details on Wikimedia Commons: https://commons.wikimedia.org/wiki/Template:PD-self

And here, meet Mercury as the small black round dot (you can also see sunspots in this picture, and how different they look compared to the perfect round shape of a planet):

Elijah Mathews (https://commons.wikimedia.org/wiki/File:Transit_Of_Mercury,_May_9th,_2016.png), „Transit Of Mercury, May 9th, 2016“, https://creativecommons.org/licenses/by-sa/4.0/legalcode

The Moon is also sometimes visible in the sky during the daylight, and with a properly equipped telescope, you can see its features really well, too!

The Moon seen during the day
The Moon seen during the day

Last but not least, our Sun is a star, just like the million others out there that you can see in the night sky! Therefore it can be observed with a telescope as well! A specially equipped telescope with solar filters, of course, to protect your eyes from the extremely bright light! If you visit me here in Vadsø, I offer this activity as part of the Cloud Spotting under the Midnight Sun activity and we’ll have a look at our star and at its sunspots!

The Sun and a few sunspots