Orion Sirius Plossl 17mm (Pre-owned)

The Orion Sirius Plossl 17mm eyepiece is a popular choice among amateur astronomers for observing celestial objects through telescopes. Plossl eyepieces are known for their good optical performance and comfortable viewing experience. Here are some key features and considerations for the Orion Sirius Plossl 17mm:

1. Magnification: The 17mm focal length of the eyepiece determines the magnification when used with a telescope. Magnification can be calculated by dividing the focal length of the telescope's objective lens or primary mirror by the focal length of the eyepiece.

2. Apparent Field of View: Plossl eyepieces typically have a narrower apparent field of view (around 50-52 degrees) compared to wide-field designs like Erfle or Nagler eyepieces. This narrower field can provide higher contrast views of celestial objects.

3. Eye Relief: The Orion Sirius Plossl 17mm provides a comfortable eye relief, making it easier to use for extended periods without straining your eyes.

4. Build Quality: Orion is known for producing eyepieces with good build quality. The Sirius Plossl series typically includes multi-coated optics to enhance light transmission and reduce reflections.

5. Versatility: A 17mm focal length is versatile for a variety of observing targets, including lunar observations, planetary viewing, and deep-sky objects such as star clusters and nebulae.

6. Compatibility: It should be compatible with telescopes that accept standard 1.25-inch eyepieces, which is the most common size for many telescopes.