Multicoating

In telescopes and eyepieces it is important to minimise the light UH HFWHG IURP WKH lens surfaces so WKDW PD[LPXP OLJKW passes through to the observer’s retina. Multi-coatings that UHGXFH UH HFWLRQV have been applied well on these Altair eyepieces.

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 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. Wirtanen proved to be a great object for observing at low power using the 30mm eyepiece in our 4-inch FLT 98.

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. 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.

At 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. The 18mm eyepiece produced a lovely framing of M42, the Orion Nebula, and the Running Man Nebula. We chose Betelgeuse as our star test subject and found that each eyepiece produced well-formed stars RXW WR RYHU SHU FHQW RI WKH HOG RI YLHZ LQ RXU )/7 98 refractor, which is very respectable but not what ZH G FDOO XOWUD DW

We liked this collection of eyepieces as they produced excellent views, although we didn’t particularly feel that they had a marked effect on HOG DWQHVV +RZHYHU WKH\ DUH VWLOO D JRRG UDQJH and we would recommend them to both beginner and intermediate observers.