High power eyepieces (e.g. 3mm to 10mm) are used not only for obvious observations of planets and double stars, but can be employed for bright, compact deep sky objects. Not only will the scale of an object like a planetary nebula or globular cluster be impressive as it fills the eyepiece FOV, but the background sky will be very dark as the contrast effect increases with added magnification, provided that the atmospheric seeing conditions are favorable enough to reveal a sharp image. The 4.5mm is a popular choice for a wide variety of telescopes, producing some of the highest magnification views that most astronomers will observe at.
Explore Scientific Waterproof Eyepieces - Comfort, Quality, Value. The Explore Scientific 52° Series eyepieces are excellent flat-field multi-element oculars that can transform your visual astronomy experience. With an apparent field of view of 52 degrees, these eyepieces offer incredible value in a very nice eyepiece. Expect exceptional quality and value versus a comparably priced Plossl.
Another great benefit of these eyepieces is the excellent contrast and ease with which you can gaze, not directly at an object, but slightly to either side. This skill, called using averted vision, is especially helpful when observing faint objects, because using averted vision puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.