You can see Venus with any type of telescope or astronomical binoculars. The optical design is not that important for this specific planet, however, Dobsonian telescopes are known to be great tools for observing the planets. If you own any other type of reflecting or refracting telescope, that’s fine too as long as they have an aperture of at least 2,5 inch (62mm) and a long focal length (800mm or more). You will enjoy a much better view if you have a larger aperture, but this is to say that you can see Venus even with a telescope for beginners.
A telescope magnification of 40x per inch of aperture is generally considered sufficient to see Venus satisfyingly. You can try to use a Barlow lens if the atmosphere is stable.
Truth to be told, Venus is a notoriously difficult planet to observe because of its high luminosity. Due to its proximity to our star, combined with the planet’s thick and highly reflective atmosphere, Venus reflects a lot of light from the sun.
This can cause a glare so intense that Venus may appear as a blob of light through the lens of your telescope. You can, however, reduce the glare by mounting a moon filter onto the eyepiece of your telescope.
The other problem is that Venus will always be positioned quite low on the horizon, whether you observe it at dusk or dawn. This means that the light coming from the planet and entering your telescope will travel through lots of gases, particles and atmospheric turbulence. This can negatively affect the quality of the image seen through the eyepiece. Pay attention to the weekly weathercast in your area and choose your observing time carefully.
Related: Check out our guide on how to choose your first telescope.