Scope Doctor
Your gear problems solved.
What is the best telescope for a family of beginners with a budget of £300?
JIM EDWARDS
Although you may be tempted to buy a telescope and mount with all sorts of electronic wizardry built in, I would caution against this with your budget: a larger telescope with no frills would allow you and your family to see so much more, and would be the smarter purchase. The key to observing the night sky is aperture, the size of the lens or mirror that collects light for you to view through the eyepiece. The best aperture for your money would be obtained by purchasing a Dobsonian.
Your budget of £300 puts the 8-inch Sky-Watcher Skyliner 200P Dobsonian at £279 comfortably within your grasp, or the Revelation 8-inch F/6 M-CRF Premium Dobsonian at £275. Both are supplied with two eyepieces, so I’d recommend that you use the remaining money to buy the observing book Turn Left At Orion, which will help you locate and enjoy your first celestial objects.
If you really have your heart set on a Go-To telescope, then the Sky-Watcher Skyhawk1145P SynScan AZ Go-To, which also comes with two eyepieces and did well in our tests is right at the top of your budget but has a much smaller aperture of 4.5 inches. Alternatively at about £30 over your budget, the Celestron NexStar 130 SLT, with a single eyepiece but a larger aperture of 5 inches, would also be a good choice.
While on safari with my Vixen Polarie Star Tracker I had trouble avoiding trailing. Is it more difficult to polar align at the equator?
STEVE BOSLEY
It’s extremely difficult to accurately polar align at the equator, and typical ‘signpost stars’ – Polaris in the northern hemisphere and Sigma Octantis in the southern hemisphere – will not be visible. Performing a full drift alignment is time-consuming and probably not ideal when you are on safari!
It’s most likely that to align your scope you used the Polarie’s inclinometer to set the elevation to your safari latitude, and the supplied compass to align to the South Pole. Your poor results would indicate a calibration error, most likely in the compass heading. Most locations on Earth require a correction for ‘magnetic deviation/declination’ which can have a significant effect on compass accuracy.
The magnetic deviation for any location on Earth can be found at www.ngdc.noaa.gov/geomagweb/#declination . Deviation to the west should be subtracted from the compass bearing and deviation to the east should be added to the compass bearing.