Celestron Omni XLT 150 R review

Looking exceptionally smart, the Omni XLT 150 R is a sleek, short focal length achromatic refractor with a blue tube and a white CG-4 mount.

It has a reasonably sturdy tripod with tubular steel legs that settles down quickly when accidentally knocked.

The system comes with a 6x30 finder, star diagonal (1.25-inch) and – surprisingly – just one eyepiece, a 25mm.

The mount does not come with a polarscope.

The CG-4 mount looks a little small for the size of telescope but did the job well.

We found that we had to slide the tube rings high up the tube and then adjust the Vixen dovetail down a little on the mount to get the telescope to balance, but after this adjustment it worked fine.

The axes were slightly loose but the clamps worked well, although the RA axis clamp was positioned on the top of that axis, a position that sometimes felt a little awkward to find in the dark.

Despite not having a polarscope we were still able to align the axis well enough for visual work, and there’s space for a polarscope to be added at a later date.

While the slow-motion controls didn’t have flexible arms, the telescope tube was so short that we didn’t have any trouble using them to make fine tweaks to where the scope was pointing.

The Celestron has a multicoated objective lens and we were pleased to note few, if any, internal reflections from bright objects.

The star Procyon was used to gauge the quality of the field of view.

With the supplied 25mm eyepiece we got a similar field of view of around 1.5°.

We found it sharp across 70 per cent of the view, trailing off steadily towards the field edges with some distortion and colour fringing present in the last 30 per cent.

Splitting stars

We turned to the double star 38 Gemini, but it wasn’t split with the 25mm, so we added our own 10mm Plössl and were able to split it.

Our 2x Barlow also improved the view.

On turning to the tighter double star Castor, we split it with the 10mm eyepiece, but there was a blue halo around the stars.

Using the 2x Barlow and the 10mm we also got a clean split, but the two stars looked a little green where they are normally white.

Mars was also quite small with the 25mm eyepiece, and although it exhibited some interesting detail, there was some colour fringing when we used our 10mm and 2x Barlow.

In exploring the deep sky, this short-focus telescope gave very good views of the Orion Nebula and the Trapezium Cluster at its heart.

The wide field of view was particularly useful for the Pleiades Cluster and with averted vision we noted the faint Merope Nebula.

Messier 1, the Crab Nebula, appeared bright but small in the 25mm, but it looked great through our 10mm eyepiece.

The Messier pairing of M81/82 stood out well against the inky blackness of space; indeed, with higher magnification there was some subtle detail along M82’s disc.

Overall, we liked the Omni XLT 150 R, but felt a little let down that there was only one eyepiece supplied with which to take advantage of its wide-field views.

This review first appeared as part of a Group Test in the April 2010 issue of Sky at Night Magazine