March 25 2019, Stefan Taube
Luminescent emission nebulae, supernova remnants and planetary nebulae are all particularly beautiful objects pertaining to the night sky. This applies both to the simple process of visual observation, as well as to astrophotography. Nature illuminates such nebulae in specific spectral colours: the red light of hydrogen, the blue-green light of oxygen ions and also in the colours of sulphur and nitrogen ions. Nebula filters enable these colours to pass through whilst blocking the diffused light of the natural luminance of the sky and of light pollution. The result is a marked increase in contrast.
With the Nebula Booster NB1, the filter specialists IDAS are introducing a new, very high-performing filter of this type onto the market, and one that is not overly expensive! As the transmission curve shows, the filter has high transmission and is permeable for all relevant spectral lines, with a surprisingly narrow passband: A real nebula intensifier!
Transmission curve IDAS NB1
The filter is ideal for photographing large nebula regions since it enables the typical colours of these objects to pass and blocks the disruptive skyglow. The filter quickly and completely cuts off near infrared up to 1100 nanometres. This is important since cameras are sensitive to this range, but telescopic lenses are optimised for the visible spectral range and are faulty in the infrared range.
IDAS Nebula Booster NB1
The Nebula Booster NB1 is available with two versions which cover both of the common filter thread sizes and can be screw-fitted to the housings of eyepieces or cameras.
July 31 2017, Stefan Taube
Northern German company Astronomik is a specialist for astronomical filters for astrophotographers or purely visual star gazers. Clip filters are a special innovation of Astronomik. These filters have a special mounting shape, which allows them to be placed directly into a DSLR or system camera – without using any tools!
Astronomik currently offer clip filters for:
The camera mentioned last is designed with extremely high sensitivity. We offer this camera as a specially astro-modified camera. For more information please follow this link: Sony Alpha 7s Astro.
For APS-C Format EOS cameras from Canon, Astronomik have now developed a new series. A special feature of these new XT filters is the very thin carrier with a thickness of only 0.3 mm, to which the filter layer is applied. When using filters with thicker glass carriers, image faults may become visible in the corners of the photos. Stars appear slightly dash shaped. This can be particularly noticed when using short focal lengths. So if you would like to use a Canon EOS with the camera lens on a camera mount to take wide angle shots of the night sky, an XT filter might be the right investment.
XT filters are available in the usual versions, from CLS to H-alpha all the way to SII filters. For novices we especially recommend the CLS filter, which suppresses artificial light pollution.
The red transmission curve reveals: The CLS filter blocks the light from the yellow street lamps.
By the way: Removing a clip filter from the camera housing is just as easy as putting it in.