Sky-Watcher Evostar 150ED DS-Pro

The popular Evostar 120ED’s bigger, bolder but not much pricier sibling has arrived

Anticipation and excitement have surrounded the launch of Sky-Watcher’s Evostar 150ED DS-Pro, a new, 6-inch, f/8 refractor. Competitive pricing has also caught the astronomy community’s attention, especially among those familiar with the impressive quality of the optics in the smaller, 120ED Evostar. As this new scope has the potential to be an excellent all-rounder, we decided to test it across a number of tasks: planetary and lunar viewing; double stars; deep-sky observation; and photographic performance.

The first thing that strikes you is the size of the thing, but thanks to the aluminium tube it’s surprisingly lightweight and easy to handle. To help with the balance we fitted our 50mm finderscope to the shoe provided, and – after some speedy basic collimation – we decided to use the new Moon period to first try some astrophotography, using an optional 0.85x focal reducer on loan for the review.

DSLR cameras fit directly onto the focal reducer with the supplied Canon T-ring. When we tested this configuration out on a star field, the result was a very impressive flat field, with good, round stars right into the corners of our full-frame DSLR, and only minor vignetting. Targeting the Dumbbell Nebula, M27, just 40 minutes’ worth of 45 second exposures revealed quite reasonable details and, importantly, no annoying colour rings on bright stars. We went on to photograph NGC 7789, Caroline’s Rose, and NGC 6992, the Eastern Veil Nebula, again with pleasing results.

Swapping to our monochrome CCD camera meant we could no longer use the reducer, and without it the star shapes elongated a little in the corners of our small ICX694 camera sensor. On the plus side, the CCD allowed us to test the colour correction of the doublet lens in the 150ED. After finding the point of sharpest focus through a luminance filter, we used parfocal filters to take pictures through red, green, blue and narrowband filters. The results were very good; close to the best that can be expected from a doublet lens.

Excited by the scope’s performance so far, we were keen for some time at the eyepiece, but patiently used two nights of limited summer skies for some narrowband imagining. Just four hours total exposure was enough to reveal the very faint outer gases of the Dumbbell Nebula under average skies.

Observing the planets

With four major planets on offer, we could no longer resist a visual session, and fitted our 2-inch diagonal. Under twilight conditions Venus showed its phase well, our 4.5mm eyepiece giving a just-about acceptable 266x magnification. At best focus we could barely detect any false colour on the bright edge, just the standard red blue effects of atmospheric refraction.

As it darkened we moved to Jupiter and were admittedly a little disappointed at the initial view. It seemed to lack contrast and surface definition, even at 120x. Of course, this season Jupiter is very low, and softer views might be expected, so giving the scope the benefit of the doubt we decided to do a star test instead. Our green filter and 4.5mm lens