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目前顯示的是 11月, 2017的文章

TAIR 3 300mm telephoto lens

with the pistol like mount, has been named as a photosniper Replaceable telephoto lens. It is equipped with an iris diaphragm (for the photodetectors - platoon, closing from the camera, for which an appropriate lever was added to the camera). Enlightened optics or multiflexification (" MC " index). Was recommended for all types of shooting; It was noted that it is especially valuable when shooting, requiring special clarity of all the details of the image. At the World Exhibition in Brussels in 1958, a set of lenses, which included Tair-3, was awarded the highest award - " Grand Prix ". In 1959, the lens was awarded the Diploma II degree VDNH USSR. The ZOMZ (Zagorsk Optical and Mechanical Plant, Sergiev Posad) - version " A " (Tair-3 4,5 / 300-A or Tair-3A) - was also manufactured with a replaceable "A-adapter", which allows using a lens with cameras with connecting thread M42 × 1 / 45.5 and M39 × 1 / 45.2. T

Lumieres Hong Kong

new CCDs of 2017

Dicussions on  four new small CCDs IMX183, IMX294 IMX385, IMX390, ( and a bit on GSense2020 BSI ) From Albéric posted on Webastro : For reading noise figures, be careful it depends on the gain and it also varies a bit from one sensor to another. In rapid CP,  one works with high gain (60 to 90% approximately) values,  but not at max gain.   On the noise values, I would rather set the sliders to these values, looks more reasonable to me:    IMX183: 1.3 e-   IMX224: 0.75 e-   IMX290: 1 e-   IMX178: 1.5 e- Then a sensor with tiny 2.4 micron pixels is anything but soft and versatile. In deep sky it is limited to fast and expensive astrographs or a SC (Schmidt Cassegrain) equipped with Hyperstar. Want to equip a conventional Newton at F / 5 with an expensive reducer dedicated type ASA, it is also often embarking in a big galley side settings ...   With 4.63 micron pixels, you can easily use classical instruments telescope / telescope to F / D of 5 or 6. Or SC / Mak with