Page 81 - BBC Sky at Night - September 2017 UK

SKILLS THE GUIDE SEPTEMBER 81

ALTAZ MOUNT VARIANTS

Single arms are the ‘standard’ but, as with EQ mounts, there are others

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The simplest altaz design, push-pulls have no For larger aperture telescopes, turn to a The TTS 160 Panther altaz mount from
drives on either axis. You manually move the dual-fork mount. By supporting the optical Track The Stars is a portable system
telescope on a simple tripod. These make tube between the two arms the weight is that has all the same features and
great, simple to operate and relatively cheap spread evenly between them for greater connectivity as other altaz Go-To systems,
systems for beginners. Birdwatching spotter stability. Many dual-arms support equatorial and with the addition of an optional
scopes on a tripod can also be used for visual wedges, meaning they can be used ‘telescope rotator’ it can also be used
astronomy in the same way. for deep-sky astrophotography. for deep-sky astrophotography.

and to beginners who don’t mind the of Solar System targets, a Go-To altaz setup adjustable tripod. There will be a
extra cost involved compared with basic could be an ideal choice. mounting bracket for either a Losmandy-
mounts and telescopes. All is not lost, however, if you do want or Vixen-style mounting bar, and
Unlike equatorial mounts, altaz to try out deep-sky astrophotography often ports for connecting a Go-To
mounts don’t follow the sky smoothly in with an altaz mount as two things can hand controller and an external power
an arc as they aren’t lined up with Earth’s help. First, camera technology. Many modern supply. Some will have extra ports for
polar axis. This leads to ‘field rotation’ DSLRs and CCDs can capture good detail other accessories. Most mounts also
in altaz systems, which poses a problem in short exposures, take a lot of them and have a battery compartment for
for anyone interested in deep-sky then stack them. Stacking software such as cable-free operation.
astrophotography. Field rotation occurs the free DeepSkyStacker can deal with the Computerisation has revolutionised
because the altaz view remains lined up in rotation you will see in the images. Second altaz mounts: some can now be controlled
relation to the horizon, whereas your is an accessory called an equatorial wedge, wirelessly, using an app on a tablet or
celestial target moves with the sky, so which some manufacturers produce for smartphone. Whether you want a
when you stack multiple images they won’t their altaz systems. This add-on effectively straightforward push-pull system, one
align. For visual purposes, this doesn’t turns the mount into an equatorial one, with Go-To, or one with dual arms, there
matter, you just keep on adjusting the making long-exposure imaging possible. is an altaz option out there for you. S
mount to keep your target in view. If your Single-arm mounts can usually hold
primary interest is simply viewing the telescopes up to 8 inches in aperture Paul Money is BBC Sky at Night
night sky, or perhaps taking short videos and are typically supplied with an Magazine’s reviews editor

skyatnightmagazine.com 2017