What kind of detail can I expect to see on Jupiter with the Omni 6mm eyepiece?
In a telescope like an 8" SCT (2032mm focal length), the Omni 6mm will provide 338x magnification. On a night with good atmospheric stability, this is enough power to clearly resolve Jupiter's main equatorial belts, the Great Red Spot, and even smaller ovals and festoons within the cloud tops. You may also be able to see shadow transits of the Galilean moons as tiny, sharp black dots crossing the planet's disk.
Is the 5mm eye relief on the Omni 6mm usable with eyeglasses?
The 5mm eye relief is very short and generally not sufficient for observers who need to wear eyeglasses to see the full 50° field of view. To use this eyepiece, eyeglass wearers would need to remove their glasses, which is only feasible if they are correcting for simple near- or farsightedness that can be adjusted with the telescope's focuser. It is not recommended for those with significant astigmatism.
How does the Omni 6mm compare to a more expensive planetary eyepiece?
The Omni 6mm Plössl offers excellent sharpness and contrast for its price, making it a great value. More expensive designs, such as a Celestron X-Cel LX or Tele Vue Delos, will typically offer a wider apparent field of view (60° or more) and much longer eye relief, which provides a more comfortable and immersive viewing experience, especially for eyeglass wearers. However, for on-axis planetary detail, a quality Plössl like the Omni holds up very well.
Is the Omni 6mm a good choice for splitting close double stars like Albireo?
The Omni 6mm is an excellent choice for double stars. While Albireo (Beta Cygni) is easily split at low power, this eyepiece has the magnification needed for more challenging pairs. Its sharp, high-contrast optics will help resolve tight doubles right up to the diffraction limit of your telescope, revealing clean, distinct points of light.
Should I use a Barlow lens with the Omni 6mm eyepiece?
Using a 2x Barlow with the Omni 6mm would double its magnification, effectively making it a 3mm eyepiece. This level of power is often too high for most telescopes and typical seeing conditions, resulting in a dim, blurry image. A Barlow is generally better paired with longer focal length eyepieces (e.g., a 12mm or 15mm) to achieve the magnification the 6mm already provides on its own.
Will I need to re-focus when switching to the Omni 6mm from other Omni eyepieces?
Yes. The Celestron Omni eyepieces are not parfocal, meaning each eyepiece in the series has a slightly different focal point. When you switch to the 6mm from another Omni eyepiece, you will need to make a noticeable adjustment with your telescope's focuser to bring the image back into sharp focus.
