Christmas present: zoom eyepiece, 9 – 27 mm. And eventually, last night, a clear hour to test it in. Not a very rigorous test, complicated as it was by flashing Christmas lights on houses, numerous passing cars, failing battery in red dot finder, bedroom lights going on, moon shining in a glaring haze through the trees … you get the idea.
We used the 5 inch scope, and looked at Jupiter first. The 27 mm setting gave a widish field of view to find the planet, then we zoomed slowly in to 9 mm – the idea is, of course, that using this you don’t have to keep taking eyepieces in and out to change powers. The image was fairly good but the sweet spot seemed quite small. I don’t think this zoom eyepiece will replace the others for planetary observing: last night we tried a number of eyepiece combinations, and the most useful for seeing detail on Jupiter was a 12 mm eyepiece with a 2x Barlow, effectively 6 mm, and on really good nights the 5 inch scope will bear a 10 mm eyepiece plus 2x Barlow (i.e. 5 mm).
Using it for M42 in Orion was more promising, however, as you don’t necessarily want a high magnification for nebulae and such. Here it seemed helpful to turn the ring slowly and seek the best available view of stars and nebulosity (such as it was on this unpromising night). This would have been quite irritating to do with multiple eyepieces and Barlows being swapped in and out.
I was unable to try my new toy to observe the moon, as cloud was coming in before the moon rose properly, but I suspect it may be quite good for this too. And of course I’m curious to see how it does in the 10 inch … one fine night … maybe?