![]() Although field curvature is a big issue for astrophotographers, it isn’t for observers as eyepieces and the human eye and brain tend to compensate. The further off-axis you look, the greater the amount of distortion in the star shapes. The 18mm eyepiece produced a lovely framing of M42, the Orion Nebula, and the Running Man Nebula. The Pleiades star cluster was beautifully displayed in the 24mm mounted in our FLT 98, and a small slew to the east on 16 December brought us back onto the comet for another enjoyable look.Īt around this time we also enjoyed some fantastic views of the Moon using the 10mm and 15mm eyepieces and caught tantalising glimpses of Mare Humboldtianum on the northeastern limb. Three days later, at the crack of dawn, with the 10mm eyepiece in our Megrez 72FD we observed the brilliant planet Venus enjoying a really distinct crescent set against a delightful blue backdrop. Wirtanen proved to be a great object for observing at low power using the 30mm eyepiece in our 4-inch FLT 98. The review period coincided with comet 46P/Wirtanen being well placed and a break in the cloud cover on the night of 13 December, coinciding with the comet traversing Taurus, was too good an opportunity to miss. ![]() We put the eyepieces to the test by observing a range of objects using our own William Optics 2-inch Dielectric Diagonal attached to both our observatory-mounted William Optics FLT 98 apo refractor and our grab-and-go Megrez 72FD scope. The field stop in all of the eyepieces was sharply defined and, with the rubber eyecups folded down, could be seen in all of the eyepieces when wearing glasses. The 30mm version required an extra 11mm of outwards focus travel as we would have expected because its 2-inch barrel didn’t, of course, require the 1.25-inch adaptor which has a depth of 11mm.Ĭolour correction was generally good, although the 10mm eyepiece displayed a little false colour even on axis. ![]() The 18mm and 15mm versions were fully parfocal, with the 24mm and 10mm requiring the smallest of adjustments with less than a millimetre of focus travel to cover them all. We tested the eyepieces to see if they were parfocal – that is, that the focus point stays exactly the same while you zoom the lens – as this can be a very useful attribute when swapping from one eyepiece to another to minimise focus adjustments. The eyepieces all include filter threads in their respective sizes. To make use of the whole collection you may therefore require an eyepiece adaptor to accommodate both sizes. ![]()
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