equipment

ZWO ASI183MC astronomical camera

The ZWO ASI183MC is a dedicated camera originally designed for photographing celestial objects. It does not have built-in memory, like household cameras, and information from the camera is recorded on a computer using a USB cable. The videos are quite voluminous; a minute of video in full resolution at the maximum frame rate can take 20-21 gigabytes. To successfully record videos with this camera, you need a computer with a USB 3.0 bus and a fast SSD drive.

ZWO ASI183MC

The ZWO ASI183MC camera is made in a “puck” form factor. The camera is lightweight, the body is completely metal. There is a 1/4-inch hole in the back (for example, for mounting on a photo tripod). Color sensor – Sony imx183. Shooting resolution 5496×3672 (20.18 megapixels). A 12-bit digital-to-analog converter is declared, a maximum frame rate of 19 fps in full resolution at 8 bits, a small pixel of 2.4 micrometers, a high-speed USB 3.0 bus, an autoguider port. The front sensor is covered with coated protective glass without IR-cut coating, so an additional IR-cut filter is necessary to obtain adequate color balance. Connection to the telescope is carried out using the included 1.25″ T-adapter, or using a T2 thread, or by directly installing the front black metal ring into a 2-inch focuser, or through third-party adapters.

Обзор бинокля Pentax SD 7×42 ED

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 7x42 ED
Pentax SD 7×42 ED

Svbony MK105 telescope review

Svbony MK105
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
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.

SVBONY SV213 1.25″ 3x Barlow lens review

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
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


SVBONY SV216 1.25″ 2x Barlow lens review

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
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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