A Historical Conjunction Between Jupiter And Saturn Sets On December 21st


On Monday, the 21st of December, Earthlings will observe ones in a 20 year event known as the conjunction which will be between the last two naked eye planets, Jupiter and Saturn, of which they will appear much closer as if they are merging. But in reality, the distance between these two celestial objects  still stands at 4.32 AU or 646.3 million km. The matter is that they just got aligned in the sky from our perspective.


Meaning of Conjunction

So many meanings can be read from the sentence “Alignment of Planets”. To make it clearer, beginning with the fact that all the planets in the solar system revolve round the sun, through a common disc-like plane known as the ecliptic. For that reason, these planets align and appear to be merging, and we call that “The conjunction”. This conjunction can happen in a variety of ways: a conjunction in which a celestial object completely obscures the other is called “Occultation”. We witnessed this between our Moon and Mars at the beginning of the last quarter of 2020 in which the former completely blocked the latter in the night sky. In fact, this is some worth like an eclipse. But we specially use the word “Eclipse” to denote the alignment among any of the Moon, the Earth and the Sun.


Mars – Moon Occultation. Image credit: Slooh


On the other hand, if any celestial object partially obscures the other, we call it “Transit”. But in general, conjunction does not necessarily require alignment. There could be a conjunction between a planet and a background star or a galaxy. Simply put, conjunction is an event that involves the meeting of celestial bodies relative to our vantage point.


How much Of Them Can We See?

Both Jupiter and Saturn currently located at Capricornus constellation normally have apparent magnitudes of -2.2 and 0.46 respectively, that implies that Jupiter is 12 times brighter than Saturn in the logarithm scale. So since the beginning of December both planets have been seemingly racing alongside, but on 21st they will come much closer just merely separated by a distance smaller than the size of a full Moon. In terms of angular resolution, they will be separated at 0.1 arcminute. An angular resolution is a term used in Astrophysics to quantify the ability of an instrument or a living thing to distinguish two separate light sources, be it the two headlamps of an incoming vehicle or two stars in the sky. At this value of 0.1 arcminute, all humans with normal sight will be able to see this conjunction which will be towards the southwest at every sunset. It is also safe to use binoculars or telescopes to have a better sight of them, most especially, their moons and rings.


Credits: NASA/JPL-Caltech


Why there is Jupiter and Saturn Conjunction

As earlier said, it is worthy to note that this event between Jupiter and Saturn always occurs ones every 20 years. This is because the two target planets move pretty slow. They are very far away from the sun, and from the laws of orbital mechanics, the farther away an object is relative to the point mass, the slower its speed,  so they orbit slowly.

In addition to that, because it takes Jupiter and Saturn approximately 12 and 30 years respectively, to make a revolution, from simple mathematical analysis, the two should align at one time in their rendezvous.


Image of Jupiter and Saturn captured using the Slooh’s telescopes on December 18 Image credit: Slooh


A brief History of Jupiter and Saturn Conjunction

The conjunction of December 21st is a special one because: it will be visible in the evenings just shortly after sunset and will be pretty close to each other. But unlike it, which dominated the conjunctions of other times which includes the conjunction of 1623 BC, that is, 400 years ago (during Galileo times), had their appearances mostly in the day time where the sun’s rays made them almost impossible to be observed. One other kind of conjunction that have the same similarities with this December 21st  as mentioned earlier is the conjunction of 1226 BC, that is, 800 years ago which was widely observed, according NASA’s Astronomer, Dr Henry.


All about other designated names of the Conjunction

Since we all learned about the coming of this conjunction, many fancy names tagged to it have been going viral, some calling it, “Christmas star, “Bethlehem Star”, “The great conjunction” etc. The latter has conflicting meanings given to it, on some websites, it was explained that “Great” was used to indicate that the conjunction is between the two most massive planets in our solar system, while other sources said it is because it happens ones every 20 years. Either one of the two still sounds great though.

On the other hand, why the name “Christmas star” or “Bethlehem star”? Also according to Dr. Henry, for ages, people have been looking up and studying the stars and the planets. They do have this tendency of incorporating the knowledge which they gained in astronomy into their respective religions, cultures and beliefs. So this star of Bethlehem, we believe, was due to the events of the night sky which involved the three wise men, during when Christ was born, around 7 BC. It could be that what they observed was this kind of conjunction or it could even be a comet. But since there was no record of any professional observation, we cannot say what really went on.

For more information on how to take photographs or viewing it live, check Slooh star party.

Wishing you a clear sky

Great South America Total Solar Eclipse on Dec 14th


In this year 2020, Earth has witnessed eclipses a number of times, including both lunar and solar, about six (6) of them. The forthcoming would be the sixth and the last for this year, a total solar eclipse.

We witness solar eclipses or eclipse of the Sun not only because the New Moon gets positioned and aligned in-between Earth and the Sun. But because of the simple reason that the Sun’s diameter is approximately 400 times larger than the Moon. And Sun-Earth distance is also approximately 400 times the Earth-Moon distance. So from simple geometry, relative to the Earth, the Moon and the Sun appear to be the same size.

Now, whether it will be a total solar eclipse or annular solar eclipse will depend on the elliptical orbit of the Moon round the Earth. Apogee is the point of the orbit at which the moon is furthest away from Earth which is the one we see during annular solar eclipses. While Perigee is the case at which the moon is closest to Earth and at which point we observe a total solar eclipse, like the one which we are about to observe on December 14.

During total solar eclipses, as the Moon continues to transit, its shadow creates a path called the Path of Totality on the surface of the Earth. Regions around this path will observe Partial solar eclipse. And for any given point on the Earth which has witnessed a total solar eclipse, will see another round of it in the next 400 years.

This upcoming total solar eclipse dubbed the Great South America Total eclipse will make first appearance as a partial solar eclipse at the Southern Pacific Ocean by 1:34 p.m UTC and about one hour later, that is,  at 2:32 pm UTC, the Moon’s umbra will fully emerge. Both will then proceed due East, touching some parts of South American Continent like: Chile and Argentina.  And will come to a halt over the Southern Atlantic Ocean, of the coast of Southwest Africa at 6:53 p.m UTC.

Image Credit: https://c.tadst.com/gfx/eclipses2/20201214/anim2d-960.mp4


The event can be viewed on several astronomy channels worldwide.

You can follow NASA guidelines on observing solar eclipses.

Wishing you all a favorable weather conditions.

Annular Solar Eclipse on June 21, 2020. What Holds for Africa?

On the 21st of this month of June, our planet Earth will witness the 3rd out of six (6) rounds of eclipses scheduled for the year 2020. The first two eclipses were lunar eclipses which occurred on January 10th and June 5th. They were both observed from Africa. The forthcoming will be a solar eclipse. The remaining three (3) will be: July 5th Lunar eclipse, November 30 Lunar eclipse and December 14 Solar eclipse.


This occurs when the moon comes between the Sun and the Earth in such a way they become so aligned or almost aligned in a straight form.  This results in some parts of  the Earth to be partially of totally obscured from the rays of sunlight. Solar eclipses can as well be called “eclipse of the Sun” and it should be noted that it happens during new moon but not during all new moon.

Image showing during solar eclipse, the moon is between Earth and the Sun. Image credit: NASA

There are three (3) but four (4) types of solar eclipses:

Image credit: national eclipse. com

Partial solar eclipse is the most recurring and can  be seen alongside with each of the aforementioned three. It can occur alone. In such case there is no perfect alignment, so Earth transits along the  diffuse shadow  of the moon called the penumbra

Image showing what a partial solar eclipse typically looks like.
Image credit: Himal Bhandari from Nepal

Total solar eclipse is the most thrilling of all the solar eclipses. It occurs when the moon is in a perfect alignment and at its perigee to Earth. As a result of that, the Sun’s disk becomes completely blocked. Regions under the Umbra of the shadow of the moon experience total darkness, and as indicated earlier, regions of the world not under the umbra experiences partial solar eclipse (that is, penumbra). To have the best view of the Sun’s Corona, it is during total solar eclipse. It is not only the best but the only moment to do so. Note: Total solar eclipse occurs ones in every two years somewhere on Earth but any region of the Earth that has ever experienced it will encounter it again in the next 400 years counting from the year in occurred last there.

Portions which fall under the umbra experiences total solar eclipse while parts which fall under the penumbra experiences partial solar eclipses.
Image credit: TimeAndDate.com
What total solar eclipse really looks like. Those white in the background are the Sun Corona.
Image credit: NASA

Annular solar eclipse is the second most spectacular after the total solar eclipse and second most frequent after partial solar eclipse. Like total solar eclipse, it occurs when the moon is on a perfect alignment, but this moment at Apogee. As a result of that, the Sun’s disk is not completely submerged by the moon’s disk. So regions that fall under the Antumbra see a ring of fire called Annualus in Greek while the region which fall under the penumbra see a Partial solar eclipse.

                                                   Image credit: In-The-Sky.com
                                                                 Image credit: NASA

Hybrid Solar Eclipses for a given solar eclipse is the case where by some parts of the Earth perceives it as a total solar eclipse and other perceives it as an annular solar eclipse. This is as a result of the geometry of Earth. It is also called
Annular/Total solar eclipses. This kind of eclipse is the rarest of all. The last time such was experienced was on November 3, 2013.

                                                      Image credit: TimeAndDate.com

On June 21 of this year, we will experience Annual solar eclipse across some parts of: Africa, South – East Europe, Asia and the Pacific.

Regions of the African continent that will come under path of Annularity are: Republic of Congo
Democratic republic of Congo. Central Africa republic
South Sudan
and Into the red sea and beyond.

Nearby countries to these aforementioned ones will experience ONLY partial solar eclipse (penumbra). Every other person can stream it live from this link.

Starting from the Republic of Congo, it will kickoff as a partial solar eclipse at 4:46 a.m (GMT + 1) and then Annular by 5:47 a.m (GMT + 1) an will then move to the East according as depicted on the map below.

                                                                 Path of Annularity
Image credit: national eclipse. com

So if you are in or around these mapped locations and you do want to witness this event, you have to be on the guide from 04:46 a.m (GMT + 1), because  for a given point it will last for less than 3 minutes. the whole event from Africa to Asia, from Penumbra to Annular and back to penumbra will last for 5hrs, 38 minutes.


It is very dangerous to look at the sun with your naked eyes, binoculars or telescope. This Handbook and Posters (1, 2, 3, 4, 5, 6, 7) designed by the African Astronomical Society explains all about the eclipse and how to see it. A free android app on the eclipse has been developed by Alok Mandavgane for the Astronomical Society of India, and adapted for Africa.

Wishing you all a clear skies on June 21st

A Potentially Hazardous Asteroid To Make A Flyby On Saturday (June 6) Morning.

Following the news about the transit of Asteroid 1998 OR2 on April 29, 2020. Another Asteroid dubbed Asteroid 2002 NN4 is set to make a flyby in the early morning hours of Saturday by these times according to the six (6) time zones in Africa:

GMT – 1 =  2:20 am
GMT + 0 = 3:20 am
GMT + 1=  4:20 am
GMT + 2 = 5:20 am
GMT + 3=  6:20 am
GMT + 4 = 7:20 am


Map showing the different time zones in Africa. Image Credit: TimeTemperature.com


Just as the name implies, Asteroid 2002 NN4 was discovered on July 9, 2002.
Compared to Asteroid 1998 OR2, Asteroid 2002 NN4 is lesser in size, its diameter measured as at range of 254 meters to 568 meters according to SpaceReference.org This is roughly comparable to the size of a football stadium.

More so, according to NASA’s JPL, like Asteroid 1998 OR2, Asteroid 2002 NN4 is also classified as potentially hazardous. Potentially Hazardous Asteroids (PHA) are the ones whose orbits come closer to Earth at a distance less than or equal to 7.5 million kilometers.
Asteroid 2002 NN4 will pass at a safe distance of approximately 5.1 million kilometers, which is about more than 13 times the distance from the Earth to the moon.


              Image showing Earth’s orbit round the sun. Image credit: SpaceReference.org

Image showing the orbits of Asteroid 2020 NN4 and Earth. Image credit: SpaceReference.org

To play around with the orbit simulation, click here.

Generally, Both Asteroid 1998 OR2, Asteroid 2002 NN4 and 1,679 other Asteroids  are  grouped under a certain  category called Aten-Class or Apollo Asteroids. These are group of Asteroids whose orbital paths bring them in close proximity to Earth.

                   Image credit: Wikipedia


Lan O’Neill of NASA’s Jet Propulsion Laboratory said: “In short, 2002 NN4 is a very well-known asteroid with a known orbit that will pass Earth at a (very) safe distance.”

The Asteroid makes a complete revolution about the sun within 300 days. It spins about its axis every 14 days 30 minutes.

Since the transit of Asteroid 2002 NN4 is slated for Saturday morning, Stars gazers around Africa maybe able to spot it using their backyard telescopes. It can also be viewed via various NASA channels or agencies serving the same purpose.


Lunar Eclipse + Strawberry Full Moon. What Holds For Africa.

Every year, our planet Earth is capable of experiencing  four (4) to seven (7) eclipses.
But this year 2020, we will experience only six (6) of them: four (4) lunar and two (2) solar eclipses.
We have already witnessed a penumbra lunar eclipse earlier this year on January 10.
This June month alone, we will experience two (2) of them, each of solar and lunar.
The lunar eclipse will occur on June 5th and the solar eclipse, on 21st.

Lunar eclipse occurs when Earth comes between the sun and the moon and its shadow falls on the moon.

There are three (3) different kinds of Lunar eclipse:

The total
The partial
The Penumbra lunar eclipse.


Image showing how the different kinds of Lunar eclipses look like.  Image credit: Earthsky


Image credit: Time and Date

During the total lunar eclipse, the three: Sun, Earth (at middle) and moon are on a straight line.
Here, the moon is completely submerged into the umbral of the Earth and we observe the red moon. This kind is the most impressive of all. And can be seen by everyone. The last time we witnessed this was on January 20/21, 2019.


Images showing how the moon is wholly within the umbral of Earth during total Lunar eclipse. Image credit: Mocomi


The red Moon.Image credit: NASA

For partial lunar eclipse, with Earth still in between the Sun and the  moon but do not form a straight line, what is observed is a small part of the moon covered by the umbral of the Earth. It is the second most impressive and the last time such occurred was on July 16, 2019.


Image shows part of the moon covered by the umbral of Earth. Image credit: Mocomi


Part of the lit side of the moon is covered by the umbral of Earth. Image credit: Time and Date

Penumbra lunar eclipse is the one in which the Moon crosses the Earth’s diffuse shadow and it does not appear red. In fact, it is hardly noticed and it looks pretty much like a normal full moon. A slight dimming of the lunar disk is usually observed. This is the one that we are expecting on June 5th, 2020.


How a penumbra lunar eclipse looks like. Image credit: Earthsky


Image showing the start, maximum and end of penumbra lunar eclipse. image credit: Hong Kong Observatory

What is general for all kinds of lunar eclipses is that they do not require any aid for use to be able to observe them. So, starting from June 4th till 6th, there will be a full moon. During these periods, will lie behind the moon, is a  red supergiant star by name Antares. Which is the brightest star in the constellation Scorpius the scorpion


Image credit: nemesis maturity

But the  real event  starts on the 5th. Regions such as: Europe, Asia, Australia and Africa are the ones that will be privileged to witness it.

Image credit: Space.com

This Penumbra lunar eclipse is expected to last for three (3) hours, eighteen (18) minutes.
The time from start to end for the six (6) time zones across Africa are below:

Image showing the six time zones in Africa. Red corresponds to GMT – 1 and Black corresponds to GMT + 4. Image credit: TimeTemperature.com


Table showing the start, maximum and end of the lunar eclipse for the six time zones of Africa. image credit: AWbNigeria


Why was it called “Strawberry Full moon?”

Like every other cultures in the world has a name and meaning they call each full moon of any given month. The name “strawberry moon” dates back to the native Americans. June was that period of the year for harvesting strawberries. On the other hand, strawberries are not native to the Europeans, so they call theirs, “Rose moon”

Hence, we call it Strawberry full moon or Rose full moon.

As you go outside to observe the lunar eclipse + full moon, I wish you a clear night sky.