Astromania · Eyepiece
Astromania Plossl 4mm
Affordable high-magnification eyepiece for tight planetary views and lunar detail on any 1.25-inch scope
Performance Scores
Overview
The Astromania Plossl 4mm is a short focal length eyepiece designed to pull out high magnification from your telescope. Paired with a 1000mm focal length scope, for example, you are looking at 250x, which puts this firmly in planetary and lunar territory. At that range, you can expect to resolve lunar craters, Saturn's rings and cloud bands, and Jupiter's major features on a steady night.
The 50-degree apparent field of view is standard for a Plossl design, and at 4mm the eye relief will be short, around 3-4mm, which means eyeglass wearers may find comfortable viewing difficult. The fully multi-coated four-element optics do a solid job for the price, keeping images reasonably bright and reducing chromatic fringing. For $16, the build quality is respectable, with an aluminum alloy barrel, blackened lens edges to control stray light, and a fold-down rubber eyeguard.
This is not a premium eyepiece, but it is a practical, budget-friendly option for observers who want to push magnification higher without spending much. Best results will come on nights of good atmospheric seeing, since high magnification is unforgiving of turbulence.
At a Glance
4mm
Focal Length
Specifications
Key Features
- Reaches high magnification on any 1.25-inch telescope, ideal for planetary and lunar detail work
- Fully multi-coated four-element optics improve light transmission and color accuracy at this price point
- 50-degree field of view is standard for the Plossl design, giving a clean, usable image
- Aluminum alloy barrel and blackened lens edges provide durability and reduce internal reflections
- Threaded barrel accepts standard 1.25-inch filters and Barlow lenses for added flexibility
- Fold-down rubber eyeguard adds comfort during extended sessions at the eyepiece
- Eye relief is short at this focal length, so eyeglass wearers should test before committing
Customer Reviews
381 reviews
I have been quite impressed with the eyepieces in this lineup. I've seen what appear to be the same eyepieces sold under several different brands, and all of them appear to be very high quality. This is the first one I've purchased through Amazon, so I thought I'd go ahead and share my impressions. ...
Really nice quality eyepiece from Astromania! I purchased the 6mm Plossl and it gives me a beautifully sharp image in my telescope. Apparent field of view (AFOV) is surprisingly good and stars are pinpoint in the entire field with no stray reflections. Only minor nitpick is because it's a high power...
Well made. In daytime with an f/4.7 apochromatic telescope this eyepiece is like a panoramic window. At night, stars are sharp, there is perhaps a barely visible distortion at the edges but truly minor. Frankly my eyeglasses cause more distortion than this eyepiece. I didn't notice reflections even ...