Svbony has released an interesting light filter against light pollution — SV240 Multi-Narrowband Filter Galaxy & Nebula NIR 2″. It passes the ranges H-beta + OIII, H-alpha, and the near infrared range. According to the manufacturer, the filter is universal, since it allows you to shoot not only emission nebulae, but also galaxies due to an additional signal in the infrared range, but this requires a color camera with good sensitivity to infrared rays (imx462, imx464, imx585 sensors), while the protective glass in the camera should be just AR (without IR-cut coating), and the telescope used should have good chromatic aberration correction at near IR range.
Meade ACF 6″ is a Schmidt-Cassegrain mirror-lens telescope. The declared aperture is 152 mm (6 inches), focal length is 1524 mm, and the focal ratio is 1:10. The exclusive UHTC multilayer coating and mirror reflectivity of 95% are declared. The optical design features coma elimination (ACF technology – Advanced Coma Free) due to the use of an aspherical secondary mirror instead of a spherical one. This provides better image quality across the field. The telescope has not eliminated the field curvature, and it does not interfere with visual observations, but when shooting with a large APS-C sensor, a reducer-corrector (Meade ACF 0.68x or Optec Lepus ACF 0.62x) must be used.The tube came with a Meade LX85 mount.
Meade ACF 6″
The tube is supplied in a cardboard box. The kit includes an optical tube with a front protective cover, 26 mm and 9.7 mm eyepieces, a diagonal mirror, an 8×50 finder, a visual adapter, and a finder mounting platform. The finder’s alignment is adjusted using 6 screws. The crosshair in the finder is very thin. The finder mounting platform is non-standard.
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A night vision device (NVD) is an electro-optical device that allows observation in low-light conditions. The main application of night vision devices is, of course, military, but NVDs are also used for hunting, for observing wild animals, for protecting territory, in astronomy, physics, medicine, etc. I got a Night Vision GL521 night vision device from Eyeskey for review. This NVD is based on an image intensifier tube (ITT), which amplifies light by several tens of thousands of times. That is, it is not a thermal imager, but actually an “amplifier” of the light flux.
Eyeskey Night Vision GL521
In absolute darkness, such a device will not show anything, but even a weak source of illumination (sky, stars, Moon) is enough to show what is not visible to the eye. Eyeskey GL521 is a passive night vision device – it does not have infrared illumination, as in security cameras and inexpensive NVDs based on CMOS matrices, but it perfectly sees the near infrared range (up to 1000 nanometers for sure).
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Strain wave gearing is a type of gear mechanical transmission, the peculiarity of which is the multi-link engagement. For comparison, in a conventional cylindrical involute gear the torque can be transmitted by two teeth, but wave transmission provides the load transmission by approximately half of the teeth. Another name for strain wave gearing is harmonic.
The main advantages of the strain wave gearing are reliability, compactness, high gear ratio, efficiency, service life, resistance to impact loads, as well as simplicity and maintainability of the design. With regard to astronomical mounts, one of the main advantages of using wave reducers is the refusal to use counterweights even under heavy loads. However, if the mount is heavily loaded, there is a risk of the telescope tipping over, so when using a heavy tube, it is advisable to use a counterweight. Another important advantage of the strain wave gearing is the absence of backlash (significantly increases resistance to wind) and the absence of the need for maintenance and adjustment. The disadvantages of mounts on a srain wave gearing include worse tracking accuracy than mounts on a worm gear, but when shooting with long exposures, this issue is solved by fast autoguiding (exposures of about 1 second), or software and hardware (correction of periodic error, encoders).
Sky-Watcher Wave 100i
Sky-Watcher Wave 100i is an astronomical mount, in the design of which wave reducers are used, and on two axes. Judging by the declared characteristics, a wave reducer of size 17 is used on the AZ (R.A.) axis, and a size 14 on the ALT (DEC) axis. This mount can operate in both alt-azimuth and equatorial modes. At the same time, the mount is distinguished by its small size and moderate weight (4.3 kg) for such a lifting capacity (up to 10 kg without counterweights, up to 15 kg taking into account the counterweight). The manufacturer recommends not to overload the mount and to avoid breakages, the weight of the entire observation structure, INCLUDING THE COUNTERWEIGHT, should not exceed the maximum permissible load on the mount.
Another interesting feature of the Sky-Watcher Wave 100i mount is the ability to place two tubes simultaneously on different sides of the mount (instead of the counterweight axis). Not only the mount head arrived for review, but also an extension column, a tripod, a counterweight with an axis (not included in the kit, purchased separately).
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Ко мне на обзор поступил телескоп Sky-Watcher BK 1025AZ SynScan GOTO. Это компактный линзовый телескоп-ахромат с диаметром объектива 102 мм и фокусным расстоянием 500 мм. Монтировка у телескопа с автоматическим наведением, управление осуществляется при помощи пульта.
