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Showing results for tags '8-24mm'.
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This is a 8-28mm zoom eyepiece, 1.25" fit, branded as "Starguider" and sold by "Sky's the Limit". The claimed spec includes fully coated lenses, FOV 40-60 degrees (24-8), eye relief 18-15mm (24-8), internal blackening, and a T42 thread under the eyecup rubber. The suppliers claim that it is the same as the Sky-watcher and Celestron ones which it physically resembles. It also resembles the Seben 8-24mm zoom. The price was £42 + postage, which would be cheap even for a decent fixed eyepiece. The eyepiece comes in a truncated cone shaped protective case and looks well finished. However It had an internal rattle sounding as though a lens was not clamped down tight. The zoom sleeve was very stiff to turn but freed up a bit in daytime use. A daytime test in the 102mm Startravel revealed that the eyepiece worked and that the 40 deg field did not feel obnoxiously small. I was able to try the eyepiece on the night sky the same evening in the C8 SE Nexstar. Conditions: urban sky with moonlight, poor seeing. I used the eyepiece in a double star hunt with the following conclusions: Optically it seemed to work as well as my 8mm Celestron X-Cel (old model), and 10mm Baader Classic Ortho. Mechanically, I found that the stiff zoom action was a nuisance as it was hard to know if I was twisting hard in the right direction, and I had at times to shine a red light on the zoom scale, or grip the body to stop it rotating. The 6/8SE mount has some backlash, and does not take kindly to heavy-handedness at the eyepiece end, resulting in the desired object disappearing from the FOV. The eyepiece required re-focusing after a change in zoom level, which I found to be a nuisance especially when going to higher power. In the C8 SE the actual field of the zoom at 24mm is not wide enough to guarantee finding objects by GoTo in random parts of the sky, (even when I remembered to set the zoom to 24mm) so I had to use the 25mm kit Plossl for locating and then swap in the zoom eyepiece. At one point I found I was twisting hard in an effort to zoom the Celestron X-Cel, which has (in the dark) a similar look and feel and weight. This did not go well. I split several faint double stars at around 3" separation. This isn't a severe test, of course. I also looked at the Epsilon Lyrae double-double near the zenith, which was easily split (as it ought to be) at 8mm (250x) with the stars well separated and showing signs of an Airy disc and diffraction rings. In summary, the stiff zoom action was a nuisance, and the need to refocus after zooming was disappointing. Both reduce the attractiveness of this device vs separate (possibly parfocal)eyepieces. I would be interested to hear if owners of similar pattern 8-24 zoom eyepieces had the same issues. http://www.ebay.co.uk/itm/Starguider-8-24mm-1-25-Zoom-Telescope-Eyepiece-/162523741115?hash=item25d72b7bbb:g:AOUAAOSw5cRZIVNn