Astro LPR Type II
Kenko Astro LPR Type II filter is designed for photographing of astronomical celestial bodies, stars and constellations.
Kenko Astro LPR Type II cuts off light pollution from artificial lighting of city streets (mercury and sodium gas charging lamps), and transmits only the light spectrum of stellar objects.
The filter does not affect the color balance of the image.
Note: It is recommended for beginners to obtain some basic knowledge in astrophotography about the use of astronomical filters before practical use.
Why you need Astronomic filters?
Often, when photographing the night sky with a long exposure the pictures happened to be overexposed or low-contrast. The reason is in camera that receives polluted light from artificial light sources of the cities. Astronomic filters effectively cut off this unnecessary light making image clear and of high-contrast.
Every astronomical filter has its own purpose of use and differs by specifications or light transmittance characteristics.
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Light transmission
Beside is a light transmission chart of Kenko Astro LPR Type II filter. Colored vertical lines indicate the points of the spectrum coming from city lighting:
- red line - gas charging mercury lamp
- green line - gas charging sodium lamps
The chart shows that Kenko Astro LPR Type II filter cuts these spectrum of light coming directly from the street lamps.
Coating technology
Kenko Astro LPR Type II adopts precision coating based on Ion Assisted Deposition technology. In order to achieve the desirable coating specification each coating layer is sprayed on the surface of the filter with the help of ion particles creating coherent multilayer surface more durable, more harder comparing with the common coating.
Restrictions on the use of lenses
Unlike Type I model Kenko Astro LPR Type II is not changing the color balance, so it is primarily designed for photography.
However, when shooting with wide and standard angle lenses color shift can occur in peripheral areas of the image. For this reason the we recommend using Kenko Astro LPR Type II filter with 100mm telephoto lenses or more (converting to 35mm film).
Below is a sample shot with wide angle lens (24 mm for 35mm full size cameras).
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However, if you leave only the central area of the frame, you can see how the filter effectively suppress light pollution.
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Sizes
Kenko Astro LPR Type I features 6 sizes: 1.25" (american size) for eyepiece, 48mm, 52mm, 67mm, 72mm, 77mm to screw on the objective lens of telescopes, SLR cameras and spotting scopes.
General care and handling of the photographic filter
- Use filter carefully and always keep it clean. When cleaning use cleaning tissue or cleaning cloth. But before that remove as much dust and dirt as possible from the lens with a blower or brush.
- Avoid unnecessary cleaning of your filter.
- Filter is made of glass. When it is broken glass fragments may injure.
- Do not disassemble filter by yourself.
- When the filter is not attached to the lens, store it away from sharp objects. They may damage the filter glass.
- Keep filter away from children.
- Keep filters in plastic hard-sided case or filter pouch.
- Keep filters dry and away from direct sun light.
- Avoid storage in high humidity environment. Moisture drops due to the high humidity or dew on the filter can burn the coating and create traces on the glass surface that can be hardly wiped off.
