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Vixen SLV & NPL Series Eyepieces Reviewed: Recommended

Vixen SLV Series Eyepieces

Rating: 4.4/5 Stars

Vixen SLV 50° Eyepiece 2.5mm


  • Extremely sharp 50-degree apparent field
  • Long eye relief at all focal lengths, unlike a regular Plossl
  • Features simple twist-up eyecup
  • Lanthanum glass for maximum sharpness


  • 50-degree apparent field can be claustrophobic
  • Really expensive for what you get
  • You could just get a wide-angle eyepiece, and the central 50 degrees will be at least as sharp

Overlapping heavily with the Explore Scientific 52° series is the Vixen SLV line, now exclusively offered by Explore Scientific. These eyepieces have the same Plossl-like design as the ES52 eyepieces but use lanthanum glass for slightly better contrast and reduced scatter. They also feature a twist-up eyecup, which is a little more comfortable to use, and you get more focal length options: 25mm, 10mm, 15mm, 12mm, 10mm, 9mm, 6mm, 5mm, 4mm, and 2.5mm (all 1.25”). The views through these eyepieces are exceptionally sharp, and the consistent 20mm of eye relief combined with the twist-up eyecup makes them extremely comfortable to use, but whether that’s enough to justify the narrow 50-degree apparent field of view or the sky-high sticker price is up to you.

Vixen NPL Series Eyepieces

Rating: 4.1/5 Star

Vixen NPL Series Eyepieces


  • Sharp 50-degree apparent field
  • Twist-up eyecup for comfort
  • Fairly cheap


  • 50-degree apparent field can be claustrophobic
  • Terrible eye relief at focal lengths under 15mm
  • Similar price to acceptable quality wide-angle eyepieces

The Vixen NPL eyepieces are quite literally Plossl eyepieces, and are offered in 40mm, 30mm, 25mm, 20mm, 15mm, 10mm, 8mm, 6mm, and 4mm focal lengths, all in 1.25” barrels. Being Plossls, they are of course pretty sharp but aren’t quite as good as the Vixen SLV eyepieces and suffer from the usual caveat of very short eye relief at the shorter focal lengths, making the 15mm mildly uncomfortable, the 10mm rather difficult to use, and the 8mm and shorter oculars pretty much worthless. The 25mm and 30mm are good low-power eyepieces and are the only ones we would really recommend; if you want performance and don’t care about apparent field, you should really consider an SLV instead. The price isn’t even all that good; the ES52 line is similarly expensive, as are eyepieces like the Agena Starguiders, which offer similar performance but much greater comfort.

An amateur astronomer and telescope maker from Connecticut who has been featured on TIME Magazine, National Geographic, Sky & Telescope, La Vanguardia, and The Guardian.

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