equipment

Обзор бинокля Pentax SD 7×42 ED

2023-11-15

Мне удалось протестировать бинокль с весьма редкой формулой – Pentax SD 7×42 ED, где 7х – кратность, а 42 – диаметр объективов. Бинокли с формулой 8х42 более распространённые, однако у формата 7х42 есть потенциально свои плюсы – лучшая стабильность изображения за счёт меньшей кратности, а также более яркое изображение по сравнению с 8х42 биноклем.

Pentax SD 7×42 ED

Заявленные технические характеристики с сайта производителя:

Тип	Влагозащищенный бинокль с внутренней фокусировкой и “roof”-призмой
Увеличение (кратность)	7x
Диаметр объектива	42 мм
Поле зрения с 1000 м	131 м
Диаметр выходного зрачка	6.1 мм
Вынос выходного зрачка	18.2 мм
Относительная яркость (светосила)	37.2
Цвет	Темно-зелёный
Наглазники	Выдвижные
Высота	147.6 мм
Ширина	136 мм
Глубина	54 мм
Комплект поставки	Крышки окуляров, крышки объективов, чехол, ремешок, гарантийный талон
Вес	715 г
Влагозащита	Защита от влаги 6 класс JIS: продукт максимально защищен от сильного дождя, пыли, запотевания, вызванного быстрой сменой температур. Такие бинокли и зрительные трубы имеют уплотнительное кольцо и азотонаполнены. Их можно кратковременно погружать под воду на глубину не более 1 метра. * Продукция PENTAX не предназначена для использования под водой
Аксессуары	Штативный адаптер PENTAX TP-3 (арт. S0069554)
Покрытие линз	Многослойное просветление всех оптических элементов
Минимальная дистанция фокусировки	3.0 м
Угол зрения	7.5°
Межцентровое расстояние глаз (Расстояние между центрами зрачков)	56 – 78 мм

Заявлено использование стекла со сверхнизкой дисперсией (ED – Extra-low Dispersion), Roof призмы из стекла BAK4 и защитное покрытие передних линз (гидрофобное).
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Svbony MK105 telescope review

2023-05-27

svbony, reviews, equipment, telescopes

Svbony MK105

At the end of October 2022, Svbony announced the release of a mirror-lens telescope of the Maksutov-Cassegrain system with an aperture of 105 mm. This was quite unexpected, since before that among Svbony telescopes there were only lens telescopes (refractors). And so, Svbony kindly provided me with a MK105 telescope for testing.

Svbony MK105

The meniscus optical system was invented by the Soviet scientist and optician Dmitry Dmitrievich Maksutov in 1941. In the Maksutov-Cassegrain system, the primary mirror is a spherical high-aperture mirror. Spherical aberration of the primary and secondary mirrors is compensated for with a full aperture lens corrector (meniscus) at the front of the tube. In this case, a convex spherical secondary mirror can be deposited directly on the meniscus, but then the relative aperture of the telescope should be in the range of 1:12–1:15 to eliminate spherical aberration as much as possible. For the first time I looked into the meniscus telescope around 2007 and since then I have fallen in love with the “poppies” for their compactness, the complete absence of chromatism, the absence of rays in the image and unpretentious maintenance. However, despite the apparent simplicity (all optical surfaces can be spherical!), increased requirements are imposed on the mechanics, mirrors, and especially the meniscus, otherwise the telescope will not be able to provide alignment stability and diffraction image quality.
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SVBONY SV213 1.25″ 3x Barlow lens review

2023-03-31

svbony, reviews, equipment

I tested a 3x Barlow SVBONY SV213 lens with a 1.25″ barrel. The manufacturer claims a three-element optical design and blackening of the lens edges. Thanks to the three-lens design, the image quality across the field should be better than that of simple two-lens Barlows. At the same time, the SVBONY SV213 is not telecentric:
– magnification can be increased using an additional extender tube
– increases the eyepiece eye relief
– works worse with eyepieces (especially with wide-angle ) than a telecentric lens like Svbony SV216 2x.

SVBONY SV213 1.25″ 3x Barlow lens

SPECS

Brand	SVBONY
Model	SV213
Barrel Size	1.25 inch
Magnification Factor	3X
Number of Lens Elements	3- Elements
Lens Coatings	Fully multicoated
Outside Length of Upper Body	2.30inch / 58.5mm
Insertion Depth	1.02inch /26mm
Max Diameter Excluding Thumbscrew	1.57inch / 40mm
Net Weight	3.14oz / 93g
Filter Threads	M28.5×0.6
Barrel Material	Aluminum Alloy
Number of Thumbscrew	2PCS
Thumbscrew Thread Specification	M4x8
Compression Band/Ring in Eyepiece Holder	Yes

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SVBONY SV216 1.25″ 2x Barlow lens review

2023-03-18

svbony, reviews, equipment

I received for test Barlow lens Svbony SV216. The Barlow lens is an optical accessory that allows you to increase the focal length of the telescope several times. It can be used both for visual observations and for astrophotography. The manufacturer claims consistent 2x magnification, fully multi-coated 4-element construction, blackened lens ends, a flat field of view, and a 1.25″ fit with M28.5 x 0.6 filter threads.

SVBONY SV216 1.25″ 2x Barlow lens

However, constant magnification implies another important property – telecentricity, that is, this Barlow lens does not change the slope of the rays coming from the lens. The telecentric Barlow lens cannot be “overclocked” by an additional sleeve, does not increase eyepiece eye relief, introduces less distortion and works better with wide-angle eyepieces.

Specs

Brand	SVBONY
Model	SV216
Barrel Size	1.25 inch
Magnification Factor	2x
Number of Lens Elements	4- Elements
Lens Coatings	Fully multicoated
Outside Length of Upper Body	2.34inch / 59.5mm
Insertion Depth	1.55inch /39.5mm
Max Diameter Excluding Thumbscrew	1.73inch / 44mm
Net Weight	7.72oz / 219g
Filter Threads	M28.5×0.6
Barrel Type	Straight Barrel
Barrel Material	Stainless Steel
Number of Thumbscrew	3PCS
Thumbscrew Thread Specification	M3x10
Compression Band/Ring in Eyepiece Holder	Yes

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Svbony SV705C astronomical camera test

2023-02-14

svbony, reviews, equipment

Svbony provided me with a Svbony SV705C color astronomical camera based on a Sony imx585 sensor for testing. This is a widescreen sensor with 4K resolution (3856 x 2180) and 1\1.2″ diagonal, introduced in 2021, which is an improved version of the similar Sony imx485 sensor.

The Svbony SV705C camera is of particular interest for shooting planets, the Moon, the Sun, including for creating videos in 4k resolution. Low read noise, high resolution, very large sensor, as well as the claimed absence of the sensor’s own glow (“amp glow”) make it also attractive for shooting comets and bright deep sky objects, including EAA (Electronically Assisted Astronomy). The camera does not have active cooling.

Specifications declared by the manufacturer

Model	SV705C
Sensor	IMX585
Total Pixels	8.3 Mega Pixels
Diagonal	12.85mm
Max Resolution	3856×2180
Pixel Size	2.9μm X 2.9μm
Chip Size	11.2mm×6.3mm
Frame Rate	45FPS
Shutter	Rolling shutter
Exposure Range	32μs-2000s
Readout Noise	6.5e~0.7e
QE Peak	≈90%
Full Well	38k e
ADC	12 bit
ROI	YES
BIN	1X1 2X2
Digital noise reduction	HCG
Compatible OS	Windows , Linux OS Raspberry Pi，Mac os, Chrome os
Caching	128M
Guiding Port	ST4
Data Port	USB3.0
Adapter	1.25″/2″/ M42X0.75/CS/C
Back Focal Length	6.5mm/12.5mm
Protective Window	AR Coating
Working Humidity	30%-80%
Storage Humidity	20%-90%
Operating Temperature	-10℃ to +50℃
Storage Temperature	-20℃ to +60℃
Net Weight	575g
Product Size	Ø58×38.3mm

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