Late one afternoon, after days of rainy weather, I glanced out my south-facing window and noticed a crescent Moon high in the sky. It was a welcomed, but unexpected sight. Unfortunately, I wasn’t able to take advantage of this fleeting opportunity for some Moon gazing. Here’s why.
My favourite lunar-and-planetary scope is a Sky-Watcher 150mm Maksutov-Cassegrain. However, the Mak has one significant downside: it can take an hour or more to acclimatize when it’s cold outside. I knew that by the time I lugged the scope onto my deck, aligned the go-to mount and waited for the optics to adjust to the cool night air, clouds would roll in and cover the Moon. Indeed that’s exactly what happened. I missed what could have been a brief but pleasant session exploring the Moon.
And that wasn’t the only opportunity missed. Sometimes the problems were logistical. I recall an early morning planetary conjunction that would have meant either getting up at 4 a.m. to set up the scope and give it sufficient time to cool, or leaving the gear outside overnight and run the risk that someone might walk away with it.
What to do? The obvious answer was to get a telescope that could be used on short notice—what is often referred to as a grab-and-go scope. The ideal instrument is basic and highly portable. It has to be ready for action in an instant. A moderate-sized refractor on a simple altazimuth mount seemed like the perfect solution. There’d be no cool-down time required, no optics to collimate, no power supply to worry about, no need to polar align the mount or locate alignment stars—just grab and observe.
After reviewing the options available at my local telescope store, I settled on a Sky-Watcher 120mm refractor on an altazimuth mount. Nothing could be simpler. Sure, it’s smaller than I’d want for my main scope, but I have other options (including the aforementioned Mak and a 10-inch Dobsonian) for nights when I have the time for an extended viewing session. The refractor allows me to take advantage of fleeting opportunities when the clouds part and a patch of clear sky presents itself. That’s where this scope really shines—it enables me to spend my time observing rather than preparing to observe.
David A. Rodger observes the sky from his North Vancouver townhouse. He was the first Director of Vancouver’s H.R. MacMillan Planetarium, and served in that capacity from 1967 to 1980.