Final answer:
A radio telescope is the best option for observing when visible radiation is blocked, as radio waves can penetrate Earth's atmosphere and observations can be conducted from the ground both day and night.
Step-by-step explanation:
If visible radiation is blocked and observations need to be made, a radio telescope is the best option. Earth's atmosphere blocks most radiation at wavelengths shorter than visible light, but radio waves are among the exceptions that can penetrate the atmosphere. Unlike other telescopes that need to be placed above the atmosphere, such as ultraviolet, X-ray, and gamma-ray observatories, radio telescopes can operate from the ground. They are especially useful for day or night observations as the Sun is not very bright at many radio wavelengths. Also, advanced radio observatories can achieve incredibly fine resolutions by using arrays like the VLA and ALMA, and infrastructure such as the Arecibo observatory for radar astronomy.