What sort of telescope is best for observing the planets?

BBC Sky at Night Magazine's Scope Doctor Steve Richards solves your practical astronomy ailments.

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Published: March 31, 2020 at 8:07 am

I own a Sky-Watcher 200P Explorer telescope. Would a Celestron Nexstar 8SE be a good upgrade for planetary observing?

Steve says: "The Sky-Watcher 200P Explorer is a Newtonian reflector with a focal length of 1,000mm, whereas a Celestron NexStar 8SE has a focal length of just over double that at 2,032mm.

This means that the magnification available with any given eyepiece will be twice as high with the Celestron.

Planetary observing is best achieved using high magnifications as the objects of interest are relatively small so a Schmidt Cassegrain telescope like the NexStar 8SE would be a great choice for your purposes.

The NexStar’s single-arm altazimuth mount is substantial enough to carry the weight of an 8-inch telescope well, but it is likely that just touching the scope will disturb the view, so any movement will take a few seconds to dampen down.

It would be well worth considering the addition of an electronic motor for the focuser so that focusing can be carried out without physically touching the telescope – that way you limit the chances of vibration."

Email your astronomy queries to Steve atscopedoctor@skyatnightmagazine.com and they could get answered in a future issue of BBC Sky at Night Magazine.

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