filters - Star Hunter - astronomer RUSLAN ILNITSKY

Venus in false color, February 14, 2020.

2020-02-17 / astrophotography, Venus, filters

Venus visibility conditions are getting better every day. The brightness of the planet is so high that under favorable conditions it can be found with the naked eye during the day. The angular size at the time of the capturing was 16.72 “, the angular distance from the Sun was 42 degrees. It is interesting that the distance from the Earth to Venus was exactly 1 astronomical unit (150,000,000 km).

Venus in false color, February 14, 2020.

Equipment:
-telescope Celestron NexStar 8 SE
-NPZ Barlow lens 2x cell
-ZWO ADC
-camera QHY5III178m
-filter Meade green CCD (red channel)
–ZWB2 + NPZ SZS-22 filter stack (blue channel)
Stacking 1500 frames with Autostakkert, wavelets with Registax 6.
Location: Russia, Anapa, backyard

Details of Venus’s cloud cover are best obtained when shooting with a light filter that transmits only ultraviolet light. There are special filters for shooting Venus (for example, Baader U-Venus), but they are very expensive. As a budget solution, I decided to use a bunch of ZWB2 filters with a diameter of 20.5 mm and a NPZ SZS-22 1.25″.

ZWB2 transmits ultraviolet radiation with a maximum at 365 nm. I bought it without a rim – an inexpensive 1.25″ filter perfectly fit as a housing. The disadvantage of the ZWB2 filter is that it also transmits infrared radiation, to which the camera is also sensitive. To reducing it, a second filter is used – the NPZ SZS-22.
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Optolong L-eNhance filter review

2019-12-10 / reviews, equipment, filters

Every year, the illumination from cities is becoming stronger and stronger, creating difficult conditions for shooting deepsky objects. However, progress does not stand still – various filters have appeared that make it possible to cut off spurious light. Narrow-band filters that allow only a specific wavelength (hydrogen H-alpha, oxygen OIII, sulfur SII) have been used by astrophotographers for a very long time and make it possible to capture gas nebulae even under the conditions of strongest exposure. The hero of today’s review is the Optolong L-eNhance filter, passing only the H-alpha, OIII and H-beta lines. In combination with a color camera, it allows you to get a full-color image at once with one frame. Optolong L-eNhance will be of interest primarily to owners of color cameras and aperture telescopes. I immediately warn that it is not suitable for shooting objects of stellar nature (galaxies, star clusters, dust nebulae).

График пропускания фильтра Optolong L-eNhance, заявленный производителем — Filter bandwidth declared by the manufacturer

Packaging, appearance
The filter is delivered in a cardboard box. Inside it is a transparent plastic box for storage and transportation. Filter weight 5.4 g, thread diameter 28.5 mm, filter thickness with thread 7 mm, without thread 5 mm, light diameter at the inlet and outlet – 26 mm.
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Light pollution filters test

2019-09-12 / astrophotography, filters

I have accumulated a sufficient number of different light pollution filters. I decided to conduct their comparative testing both with a spectroscope and in the illuminated city night sky. To take the spectra, we used an inexpensive spectroscope with aliexpress, Canon 550Da camera (a blue filter was removed), an Industar 50-2 lens, and the Sun as a light source. The night test was carried out in the center of Anapa, and the illumination from the Moon also prevented. The results are below.

Spectrums of astronomical light pollution filters.

Night sky test:
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Svbony CLS clip EOS-C filter review

2018-11-18 / astrophotography, reviews, products, filters

Фильтр Svbony CLS clip EOS — **Svbony CLS clip EOS-C filter**

The problem of urban illumination is becoming more and more important every year – new houses, new roads, illumination, thoughtless design of urban lighting lead to the fact that the sky turns into a solid orange canvas, and because of the bright background it is impossible to capture even bright nebulae. The situation changed dramatically after the appearance of specialized light pollution suppressor filters for astrophotography. The use of interference coatings made it possible to cut off unnecessary regions of the spectrum — for example, the emission lines of mercury and sodium lamps, and to transmit the regions of interest — emission lines of hydrogen and oxygen.

There are several varieties of light pollution filters — broadband and narrowband. In broadband filters include CLS (City Light Suppression), LPR (Light Pollution Reduction), UHC (Ultra High Contrast), UHC-S. They may be under different brands, but they have one task – to weaken the illumination of city. The UHC bandwidth is narrower in the green area, they are more suitable for heavily exposed areas, but it’s harder to get the corrent white balance. The usual bandwidth in the green region is from 20 to 75 nm. The narrower the filter, the darker the background is. Also, CLS UHC filters can pass the red region of the spectrum – this is not important for visual observation, but it is very important for photography, since the emission line of hydrogen nebulae (H-alpha) is in that area.

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Обзор фильтра Everest UHC 1.25″

2017-03-28 / reviews, filters

Протестировал по небу бюджетный широкополосный UHC фильтр Everest с Aliexpress. Данный фильтр также может попадаться под маркировками Solomark, T-optics. Главная задача UHC фильтра – выделение деталей в газовых туманностях, в том числе и планетарных. Также фильтр позволяет ослабить световое загрязнение, притемняя фон и выделяя туманность. По звездным скоплениям и галактикам UHC фильтр лучше не использовать. Резьба на фильтре – стандартная под 1.25″ (М28.5).

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