Venus Through a Telescope
As the second-brightest natural object in the Earth’s night sky, Venus is a great target to view or photograph through a telescope. Venus is the second closest planet to the Sun.
Even with its thick atmosphere, there are still interesting features that can be observed. Tom Williams captured this sensational image of the planet Venus through his reflector telescope.
A distant view of #Venus this morning in Ultra-Violet false colour using the 16″ scope. Decent conditions for the ~15° elevation – probably thanks to a hard frost.
The southern polar region appears quite extended today, reaching mid-latitudes near the terminator. #telescope pic.twitter.com/Uge62TxmNk
— Tom Williams (@tw__astro) March 3, 2024
Below are a few quick tips for viewing Venus through a telescope.
- A telescope with a moderate to high magnification is best. A refractor or reflector telescope with a 3-inch (75 mm) or larger aperture is ideal.
- A Barlow lens can be used to increase the magnification of your telescope to provide a closer view of Venus.
- Using color filters (i.e. blue or violet) can help improve the contrast and visibility of the planet’s surface features.
- Use a stable mount for your telescope to get a clear and steady view and make it easier to focus.
- Make sure your telescope is properly collimated and aligned correctly.
- Wait for Venus to climb higher in the sky to avoid atmospheric turbulence.
- Use proper solar filters if you want to view Venus in the daytime sky.
Stick around below for more information on when and how to view this planet.
The planet Venus often appears appears as a ‘small crescent moon’ through the eyepiece of a telescope.
The Planet Venus
Venus is similar to Earth in size and mass and is known as Earth’s sister or twin planet.
Unlike most other planets that rotate west to east, Venus rotates very slowly in the opposite direction. A day on Venus (i.e. a full rotation) lasts 241 Earth days which is longer than its year (i.e. orbital period) at 225 Earth days.
Venus is the hottest planet in the solar system due to its extreme atmospheric conditions. Its thick, toxic atmosphere traps its heat resulting in temperatures upwards of 880 degrees Fahrenheit (471 degrees Celsius).
These harsh surface conditions make it challenging to explore this planet. However, the European Space Agency’s Venus Express spacecraft studied Venus’s atmosphere and geology from 2006 to 2014, providing valuable data about the planet.
Venus also experiences extremely high winds in its upper atmosphere and is home to some of the largest volcanoes in the solar system.
- Order from the Sun: Second planet
- Distance from Sun: 0.7 AU
- Diameter: 7,521 miles or 12,104 km
- Day: 241 Earth days
- Orbit: 225 Earth days
- Number of Moons: None
Phases of Venus
Similar to the Moon, Venus goes through observational phases as it orbits the Sun. These phases are a result of the varying angle between Venus, the Earth, and the Sun and can make for interesting observations or images.
The phases of Venus are as follows:
- New Venus: When Venus is positioned between the Earth and the Sun. At this point, the side of Venus illuminated by the Sun faces away from Earth, so it appears as a dark disk.
- Waxing Crescent: Often called “evening crescent”, Venus is visible in the western sky just after sunset or “morning crescent” when it’s visible in the eastern sky just before sunrise.
- First Quarter: Venus is a half-moon shape, during this phase, you can see some of its surface features.
- Waxing Gibbous: More than half of Venus is illuminated, and it appears as a larger crescent.
- Full Venus: Venus is on the opposite side of the Earth from the Sun and appears fully illuminated, similar to a full Moon.
- Waning Gibbous: Venus enters the waning gibbous phase, with a decreasing illuminated portion.
- Last Quarter: Half-moon shape (similar to the first quarter) but the opposite side is illuminated.
- Waning Crescent: Venus is a thin crescent, and it appears low in the sky either just before sunrise or just after sunset.
Best Phase for Viewing Venus
Many amateur astronomers enjoy observing Venus during the crescent phases (both evening and morning), and are perhaps considered the most visually appealing for observing through a telescope. During these phases, you can see a thin crescent shape, similar to the Moon with low illumination. This means you can observe surface details and changing features.
The first and last quarters, where Venus appears as a half-moon shape, are great phases for seeing surface details.
During the gibbous phase (both waxing and waning) you can observe a larger portion of the disk, with less illumination to study some of the characteristics and cloud patterns.
Ultimately, the choice of the best phase for viewing Venus depends on your personal preferences and the specific observations you want to make.
The planet Venus through an astronomical telescope. Tom Williams via X/Twitter.
When to See Venus
Venus alternates between being an “evening star” and a “morning star.” It’s typically visible in the western sky just after sunset for several months, and then it shifts to the eastern sky just before sunrise. The transition between these phases can be a great time to observe it.
As an inner planet, Venus is visible shortly after sunset or before sunrise. Look for it in the western sky after sunset or the eastern sky before sunrise, depending on its current position.
The best time to view Venus is during dusk when the sky is still bright and the planet is higher in the sky.
The planets Venus and Jupiter in the early morning sky.
Venus Through a Telescope
Here is a great representation of what you can expect to see with an 8-inch telescope when pointed at the planet Venus. The crescent shape (during its partial phases) is evident, but it is also very bright and starlike.
The following picture was taken using my Sky-Watcher 350P SynScan Dobsonian telescope at a focal length of 1650mm. I did not use any filters for this image, but a polarizing filter or blue/violet filter may have helped.
A picture of Venus taken through my telescope.
Some say the best way to help increase the contrast of subtle features of Venus, is to observe the planet in a daytime sky. If you are using your telescope while the Sun is still up, you must be very careful to not point your telescope at it.
Which Telescope to use?
Choosing the right telescope is important for good views. Planets are very small, and to see them up close you will need a telescope with a high magnification.
I recommend getting a Dobsonian Telescope with at least 8 inches of aperture. This is considered by many to be the best telescope for beginners (myself included) because it balances practicality, cost, and performance.
An 8-inch Dobsonian Reflector Telescope is a great choice to observe the planet Venus.
Additional Accessories
If you are looking to view Venus through a telescope, there are additional accessories that may help you get a better view of the planet Venus.
Barlow Lens
If you have a telescope with a lower magnification than what was recommended above, a Barlow lens can be used to increase the magnification of your telescope to provide a closer view of Venus.
These optical devices can double the magnification of your current telescope eyepiece, allowing you to get a closer look at Venus.
Filters
Using color filters can help improve the contrast and visibility of the planet’s surface features. Venus is extremely bright, many amateur astronomers agree that a blue/violet filter can help you see cloud detail on Venus.
Celestial Events
Some celestial events happen throughout the year that might offer unique views of Venus through a telescope.
- Venus at Greatest Eastern Elongation: Venus reaches the greatest eastern elongation from the Sun. This is the best time to view Venus since it will be at its highest point above the horizon in the evening sky. Look for Venus in the western sky after sunset.
- Venus at Greatest Western Elongation: The planet Venus reaches the greatest eastern elongation from the Sun. Venus will be at its highest point above the horizon in the morning sky. Look for Venus in the eastern sky before sunrise but be sure to use appropriate, solar-safe, equipment.
- Conjunction of Venus: At times, Venus will pass close by other planets in the solar system, such as Mars or Saturn. For example, during the next Venus – Mars conjunction on February 22, 2024, the two planets will be less than one degree apart. Also be on the look out for the Venus – Saturn conjunction on March 21, 2024.
- Transit of Venus: during this rare event, Venus passes in front of the Sun becoming visible against the solar disk as a small black dot. This particular event repeats every 200+ years with the next transit not happening until December 2117.
The Transit of Venus on June 5th, 2012. Trevor Jones.