Seeing Venus with a telescope is not at all tricky.
It is the brightest object in the night sky, after the moon, so finding it – when it’s visible – is not hard. In this article, we’re going to show you when and where to look for it, and what you can see of Venus when you point your scope at it.
Venus is said to be Earth’s sister planet because of its similar size and proximity to the Sun.
However, while our home planet sits lush, fertile, and brimming with oceans and various forms of life, Venus is a barren wasteland of rock and lava flows with atmospheric temperatures that can melt lead.
The carbon dioxide surrounding the planet has caused a runaway greenhouse effect as it traps the heat from our sun within the planet’s atmosphere. The resulting temperatures can hover around 900°F on its dry, rocky surface.
Why is Venus So Bright?
While Venus is a sight to behold in the night sky, it is perpetually covered in the thick clouds of its atmosphere. These clouds reflect over two thirds of the sunlight hitting their surface.
Combine that reflectivity with the short distance from Earth to Venus, just 24 million miles at its closest and 162 million miles at its furthest, and you see why the planet appears so bright.
The positive side of this brightness, which can reach an apparent magnitude of -4.9, and never dimmer that -3.0, is that you can’t fail to find the planet when it’s out.
The downside of all that thick cloud is that it’s impossible to see any surface features on Venus. What we can observe is the waxing and waning disc, which we’ll come back to in more detail, shortly.
When Is Venus Visible?
Venus is almost exclusively seen as either a morning or evening ‘star’. It is closer to the sun than we are and so, on its journey around our star, we can only see it when it is off to side of the sun from our perspective.
The effect of that is to place Venus always quite close to the sun – but not as markedly as little Mercury. Venus is either seen low over the horizon towards the east before sunrise, or towards the west after sunset.
2019 is a year of two such halves for Venus. It began the year at greatest elongation and stayed as a morning object until late spring, when it got too close to the sun to be seen.
After a summer break, the brightest planet makes a welcome reappearance in October evenings, where she remains as an evening ‘star’ for the rest of the year.
The screen grab below, from Sky Safari, shows where to look for Venus on the last day of 2019, 1 hour after sunset.
We’ve picked the last day of the year because the planet rises higher in the evening sky with each passing day this fall and winter. Note from the line on the picture how much the planet will move against the background of Capricornus over the end of December 2019 and start of January 2020.
Let’s now turn to to the steps for finding and observing Venus with a telescope.
How to Find Venus in the Night Sky
Step 1 – Is Venus in the Sky Tonight?
The simple answer to this is, if you are reading this in the summer: no. Sorry, but Venus is not visible because it is too close to the sun. (See our full guide where all the planets are tonight, here).
However, if fall is underway and you’re reading this in October – December, then you have chance to point your telescope towards it.
In October, you might just glimpse her low towards the western horizon half an hour after sunset. The later in the month, the better your view will be.
By mid November, Venus is 10° over the southwest horizon (at latitudes around 40°N) half an hour after sunset. In December 2019, we have much better viewing opportunity because that angle has increased to 15°.
If you are new to measuring angles, take a look at our article on how to make measuring degrees simple by using your hands.
Step 2 – Finding Venus Without A Telescope
For Venus, this step is easy.
Look low on the southwest horizon at least half an hour after sunset in late Oct-Dec and the brightest ‘star’ you see will be Venus. It is significantly brighter than any other object except the moon.
We’ll confirm it for definite in the next step, which doesn’t even need a telescope, a decent pair of astro binoculars will do the trick.
Step 3 – Finding Venus With A Small Telescope
Center the bright ‘star’ you located in step 2 in the middle of your finderscope and take a look at it through your main telescope.
Now, if you’ve found a regular star, it will still look like a point of light through your eyepiece. However, if you’ve got Venus in view, it will appear as a definite disc.
In fact, it will appear as a crescent, much like the moon. We only ever see phases of Venus and that’s because we always see it off to one side of the sun. When it is directly in front or behind the sun, we can’t see it because the sun outshines it.
Congratulations on seeing Venus with your telescope! Experiment with different magnifications to see what you can see.
Targets to Look For When Observing Venus With a Small Telescope
We’d love this section to be full and exciting but, sadly, that’s not the case with Venus.
The planet has no moons and, although it is bright and nearby, there are no features to see in its cloud cover and no surface features to glimpse through the clouds.
The one thing we do have is the crescent phasing.
It can be fun and interesting to catalog and view it between its various phases in relation to the sun from Earth’s perspective.
If you take the time to do that, the one thing that becomes evident is that the closer the planet gets to us, and so brighter, its crescent gets thinner, and thinner, creating a spectacular sight in a magnified eyepiece.
The picture below gives a sense of what Venus looks like through a telescope.
Venus is our sister planet in size and proximity, but she is hot, cloudy, featureless body.
This makes for easy identification, because the planet is large and bright, but it reveals little to us in the telescope.
The one thing we can observe and track is the changing phases as this morning/evening star orbits around the sun inside our own path.