In January 2008 I bought this used Meade ETX-70AT 70mm f/5 Refractor Telescope, complete with Autostar Controller, Dew Shield and Red Dot Finder, but without mount, with the intention to use it as a travel scope.
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Meade ETX-70AT 70mm f/5 Refractor Telescope, complete with Autostar Controller, Dew Shield and Red Dot Finder; no mount. Meade eyepieces: 9 and 25mm. |
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A leftover piece of square aluminium tube [4x2 cm], 2 bolts and the ETX-70AT is ready to ride the dovetail of my Astro-3 mount
so now the ETX-70AT has not only found a mount but also a wedge and thus can be operated in Polar Mode now. The original clamping bolt of the dovetail was too short, but a piece of threaded rod and a knob quickly solved this problem. |
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The focuser knob cannot be reached when the OTA is pointing upwards: it disappears between the forks. I used a piece of flexible aquarium air tube [inner diameter 8.5mm], put one end of it in boiling water to soften it and forced it over the focuser knob. It seemed to be done, but later I found out that the plastic tube had the annoying habit to rotate back after focusing, so I have dismissed this approach and I have started thinking about an electric focuser, maybe somewhat like I made for my TAL-2M |
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From Matthias Meijer I bought this adapter, which allows me to connect SCT-thread compatible acessories to the ETX-70AT via the rear camera port. This means that - via another ring - I can also attach my M42-thread based SC3 cameras A quick test showed that I can even use a 0.6 Focal Reducer, which gives me an approximate focal length of 210mm: very nice to image the sun and moon! |
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This is the first real startest of my ETX70. I used my SC3a b/w camera, attached via the cameraport with the above mentioned adapter. The result is not too bad [the small dots most likely are dust particles in the optical train]. I can forget to image via the flip mirror: all the stars looked like comets ..... I noticed that in order to track correctly I had to setup my ETX70-AT as follows: Telescope|Tracking Rate|Custom at +2.0 |
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First light for my ETX70-AT: my smallest Mars ever ! January 22, 2008 18:56 UT. Imaging: ETX70-AT, 70mm, f/5 with 2x Vixen HQ Barlow operating at f/10 [focal length 700 mm]. Altitude :43.7 degrees, True distance: 0.7117137 AU [106 million km]. I noticed that in order to track correctly I had to setup my ETX70-AT as follows: Telescope|Tracking Rate|Custom at +2.0 |
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ETX70 Piggy Back Platform with Coronado PST mounted atop. |
Inside the ETX-70AT
Here you can see the inside of the ETX-70AT, as revealed by Matthias Meijer.
Power Supply
Originally the ETX-70AT is powered by 6 AA batteries of 1.5 Volt each; alas: they do not last long, and a solution was required.
I demolished an old [empty] 9 Volt battery and used the top of it as a connector between my ETX-70AT and - via a cable - my Einhell EGS 3500 12v DC 18Ah power station, which luckily has 9 Volt output.
Warning: make sure you have the polarity correct !
Recommended website: Mike Weasner's Mighty ETX site
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