This is a short-tube instrument with a mirror which is nominally about f/4 but with a negative lens at the base of the eyepiece tube -- essentially a Barlow lens. This is what gives the telescope its 'catadioptric' name -- it does combine a mirror with a lens that corrects for the shortcomings of the mirror, but it does not have a full-aperture corrector plate at the top of the tube like a Schmidt-Cassegrain or Maksutov.
A Barlow lens does have the property of helping to correct for spherical aberration of a mirror (the fault that gives poor images from a spherical mirror when you get away from the centre of the field of view). So the idea of this instrument is to have a long focal length (and hence give more magnification) with a short tube. Sadly, the optical arrangement is not up to the task, and the images from the model I tried were just poor. They were OK using the 25 mm eyepiece supplied, but as soon as I used the 10 mm eyepiece I couldn't get a perfect focus on star images and with the additional 2x Barlow lens they were just useless. There is no point in having a telescope of long focal length if you can't use it at high power, so I can't recommend this telescope other than as a fairly portable instrument for use at its lowest power of x 40.
For comments on the eyepieces, see my review of the Sky-Watcher 130M.
The EQ1 mount is a very simple equatorial mount, but it has its uses for lightweight telescopes. If you are following astronomical objects it is always worth having an equatorial mount for ease of observation (or at least a mount that tracks objects automatically). The telescope mentioned has a weight of just 2.2 kg (5 lb), and the counterweight is slightly heavier, so this is a sensible limit for an instrument for this mount. What weighs that little? Well, a small solar telescope, for one thing. At a sky camp I came across people observing with a £2500 Coronado solar telescope on top of an old EQ1 mount that had cost £15 secondhand. Incongruous, but effective. The EQ1 mount is not available separately from importers but you might well see them secondhand.
The tripod as well as the equatorial head is lighter than that on the EQ2, but it also extends to a height of about 1.2 m. This is needed for most purposes, as the sort of instruments you can use on this mount are rather small in their own right. The EQ1 mount is also available in a tabletop option, consisting of a different base with a set of three short, thin legs. The head is attached to the base using a 3/8-inch photographic tripod thread so that the head can also be mounted on a professional photographic tripod. It is possible to buy, with some difficulty from photographic suppliers, an adapter ring between the larger 3/8 inch thread and the more common ¼-inch thread, in which case you could put an EQ1 on a standard photo tripod. This is not likely to be a very stable alternative, however, as the surface area of the circular base is quite small, and would only be worth doing as an option for avoiding having to carry two tripods when travelling.
As well as the slow-motion cables supplied, there is an RA motor drive option on the EQ1. This consists of a single self-contained box that contains the 9-volt battery, of the sort that is used in smoke alarms (which we used in the UK to call a PP3, and Duracell call MN1604). It has an on-off switch, a N-S switch and a small knob that varies the drive rate from zero up to about 2x. Experience suggests that battery life will be fairly short so this could be an expensive way to drive a telescope as these are not cheap batteries. I have been unable to discover the capacity of ordinary alkaline batteries, but I have a rechargeable battery with 100 mAH. (milliamp-hours). I measured the power usage of the motor at 42 mA, and in a test it ran the motor for three hours. You could use the motor for driven piggyback exposures if you constantly monitored the tracking rate through the eyepiece.
Rechargeable cells (a pair, so you can have one charging while the other is in use) would be more cost-effective than buying single batteries. Most AC adapters don't give you a snap connector output either, but these are readily available from components shops such as Maplin and Tandy so you could wire up your own device.
There are token setting circles, but it is hard to think of a use for them as they are very small -- the Dec circle is calibrated only in 2½º intervals, for example. You could use them to get to the location of Venus in the finder, I suppose, if the finder were good enough to show Venus in daylight. But for finding elusive deep-sky objects they would be of no use at all.
The central struts of the tripod are collapsible, so it is possible to fold it down when not in use without having to undo fiddly little wing nuts which get lost, though the optional accessory tray does use these.
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