Brightwell Dayspring 30 mm wide-field eyepiece

Specifications

Description

The Dayspring 30 mm is a five-element wide-field eyepiece with a 60-degree apparent field and a 1.25 in barrel. A 30 mm eyepiece gives low magnification in most telescopes: 23x in a 700 mm refractor, 40x in a 1,200 mm Dobsonian, and 68x in a 2,032 mm Schmidt-Cassegrain. Low power combined with a wide apparent field shows large objects such as the Pleiades, the Double Cluster, and the broader arms of the Milky Way with a sense of depth that narrower eyepieces do not give.

The 26 mm field stop sets the true field. In a 700 mm telescope, that gives a true field of about 2.1 degrees, and in a 1,200 mm telescope about 1.2 degrees. Either is wide enough to frame the full Moon, which spans about half a degree, with room around it. A large field stop also keeps the image bright toward the edge when the eyepiece is used at low power.

The five-element design places a cemented doublet near the eye and a field lens near the focal plane. It keeps stars round across most of the field in telescopes slower than about f/5. In faster Newtonians, expect some edge distortion, which is typical of wide-field designs at this focal length. The lenses are multi-coated, and the inside of the barrel is blackened to reduce internal reflections.

With 15 mm of eye relief, the eyepiece suits observers who keep the eye close to the lens. Glasses wearers can fold down the rubber eyecup, but they may see less of the field. The barrel is 1.25 in and the filter threads accept standard 1.25 in filters, so the eyepiece fits any standard focuser, diagonal, or Barlow lens. At about 190 g, it is manageable on most mounts.

About this configuration

All configurations of the Brightwell Dayspring 30 mm wide-field eyepiece share the same optical design; the options change the eyecup, the case, and the finish. This configuration comes without a case, which suits observers who keep their eyepieces in a shared foam box. No case is included, so the eyepiece ships in a simple box with its two dust caps fitted. The fold-down rubber eyecup blocks stray light, and you can fold it back if you observe with glasses.

Black anodizing is the standard finish of the Dayspring line and matches most focusers. The 2025 edition keeps the same optical figures as the earlier years of the Dayspring line. To find the magnification, divide the focal length of your telescope by the eyepiece focal length in the specifications.

What's in the box

• Eyepiece with fold-down rubber eyecup
• Top and bottom dust caps
• Padded storage pouch

Compatibility notes

• Fits any 1.25 in focuser, diagonal, or Barlow lens.
• The barrel accepts standard 1.25 in filters (M28.5 x 0.6 thread).
• Sharp across most of the field at f/5 and slower; softer at the edge in faster Newtonians.