Good IPD range
With an IPD (interpupillary distance – the distance between the pupils of the eyes) ranging from 56mm to 74mm, these binoculars will suit a variety of faces. At the minimum of 56mm there is only 10mm between the chunky eyepieces, but the pliant rubber eye-cups will comfortably fit the bridge of your nose.
that it became obtrusive. We did notice, however, that when the Moon was within about 10° of the target area, there was sufficient stray light to degrade the image.
Away from the Moon, we found there to be good image contrast and colour rendition. Albireo was conveniently placed and we found that its two components stars – one bright gold, the other dimmer blue – showed good colour contrast and were cleanly split almost to the edge of the field of view. Despite its low elevation, we were able to detect the crescent of a rising Venus, and Jupiter’s glare at opposition was controlled well enough to enable us to see the Galilean moons close to the planet.
Deep-sky delights
Where the Spezial Astro SF 15x70s really come into their own, however, is with deep-sky objects. You would expect the Andromeda Galaxy, M31, to be bright, and so it was. The companion galaxies, M32 and M110, were obvious, as was the more abrupt light cut-off due to the dust lane on the nearer edge. The much fainter galaxies that we tried, M33, M51 and M101, were all easily identified, even when the binoculars were handheld. The North America
Nebula, NGC 7000, required them to be mounted, when it too became obvious.
Testing the binoculars during the short summer nights meant that we had access to views of the southern Milky Way. A particular delight was being able to directly compare the large clusters IC 4756 and NGC 6633 in the same field of view. Even the Ptolemy Cluster, M7, was visible as it skirted the southern horizon. These successes tempted us to go on a dark nebula hunt in the constellation of Aquila. This too was fruitful: the ‘C’ part of Barnard’s E dark nebula, B142, was particularly easy to make out, which also revealed the sinuous curve of Barnard’s Black Lizard, B138, as it wove its way south from 23 Aquilae.
The manufacturer has obviously responded to observers’ calls for a no-nonsense pair of binoculars with useful features. The Spezial Astro SF 15x70s will appeal to both the binocular observers and those with more experience who wish to step up from budget models.