Apertura 20mm SWA vs Celestron 23mm Luminos: Which Wide-Field?
By TelescopesPlus - The #1 Online Store for Telescopes and Accessories | Published: 2026-10-30
Category: Comparativas
Compare the Apertura 20mm SWA and Celestron 23mm Luminos eyepieces: field of view, build, and price to find your best wide-field match.
Quick answer
For most observers, the Apertura 20mm SWA offers the best balance of wide field and value, while the Celestron 23mm Luminos justifies its higher price with a broader apparent field and parfocal convenience.
Field of view: 70° vs 82°
The most obvious difference is the apparent field of view. The Apertura 20mm SWA provides a 70° apparent field, while the Celestron 23mm Luminos steps up to 82°. That extra 12° makes a noticeable difference in how immersive the view feels, especially when panning across star fields or framing large deep-sky objects.
Remember that true field also depends on your telescope's focal length. A wider apparent field doesn't always mean a wider true field if the focal lengths differ. Here, the 3mm focal length difference shifts magnification slightly, so check the true field for your specific scope.
Parfocal convenience vs. budget
The Celestron Luminos is parfocal, meaning you can switch between eyepieces with little or no refocusing. This is a genuine convenience during a busy observing session, especially if you frequently swap magnifications.
The Apertura 20mm SWA is not specified as parfocal, so you'll likely need to refocus each time you swap. That's a minor trade-off, but one that matters if you value efficiency at the eyepiece.
Which wide-field eyepiece should you choose?
- Choose the Apertura 20mm SWA if: you want a wide 70° field and solid multi-coated optics without spending a lot. It's ideal for beginners or anyone adding their first wide-field eyepiece.
- Choose the Celestron 23mm Luminos if: you want the widest apparent field (82°) and parfocal convenience for quick eyepiece swaps. The higher price buys a more immersive view and smoother sessions.
- Check your telescope's focal ratio: Both are 1.25" eyepieces, but they perform differently on fast scopes. The Luminos's wider field may show edge distortion on very fast telescopes (f/5 or lower). The Apertura is more forgiving on a budget. Before buying, calculate the true field in your scope to ensure you get the view you expect.
Product facts
- Celestron 23mm Luminos Telescope Eyepiece - 93434: The 23mm Celestron Luminos Eyepiece offers a wide 82º field of view and is parfocal, meaning you can switch out eyepieces with little or no additional focusing. This gives you a more immersive view and smoother observing sessions, especially when changing magnifications frequently.
Celestron 23mm Luminos Telescope Eyepiece - 93434 - Apertura 20mm 70º Super Wide Angle Eyepiece - 1.25" - SWA20: The Apertura 20mm Super Wide Angle Eyepiece features a 70 degree apparent field of view and fully multi-coated optics. It delivers a wide, bright view at a budget-friendly price, making it a great entry into wide-field observing.
Apertura 20mm 70º Super Wide Angle Eyepiece - 1.25" - SWA20
Who should buy which?
Best for
- Beginners or budget-conscious observers wanting a wide, bright view without a big investment.
- Observers who don't mind refocusing between eyepieces and prioritize value.
Not for
- Observers who want the widest possible apparent field and parfocal convenience—consider the Celestron 23mm Luminos instead.
