Astronomik UHC-E Lens Filter, M58 Thread

Astronomik UHC-E Lens Filter, M77 Thread

This filter is suitable for visual observation from areas affected by artificial light pollution. Even in small telescopes, it enhances the contrast between emission nebulae and comets and the sky background.

Excellent for observing comets! Also increases contrast for nebular objects and reduces the brightness of stars and the sky background. The useful range extends from focal ratio of f/2 to f/15 for telescopes with apertures up to 5" (125 mm).

Main use:
The filter is designed for observing and photographing diffuse nebulae and planetary nebulae from cities and areas with artificial light pollution.

Unlike most other UHC filters, the UHC-E also transmits the Swan band lines (C2) at 511 nm and 514 nm. This makes it suitable as a comet filter, because dicarbon is produced in the coma and ion tail, which emits these lines. The dust tail, on the other hand, is attenuated.

How it works:
The filter completely blocks the emission lines of low- and high-pressure lamps (mercury (Hg) and sodium (Na)) and the lines of the airglow. This increases the contrast between the sky background and the object being observed. However, due to the larger bandwidth, this is less than with the UHC filter, but the greater total amount of light allows for practical use even with smaller telescopes. The filter´s transmission range includes an emission line that occurs primarily in the tails of comets.

Other uses:

Well suited for comet observation from the city with telescopes of all apertures.

Experimental for Jupiter cloud observation.

Better separation of double stars.

Allows photography with DSLR cameras without damaging the color balance.

Alternatives:
If you use a telescope with an aperture larger than 5", we suggest the use of an Astronomik standard UHC filter because of its greater contrast enhancement capabilities. If you use a telescope larger than 8", you can try the Astronomik [O III] filter for even better results when observing specific nebulae.

Suitability:

Visual observation (dark skies): Reasonable, an UHC filter is more suitable

Visual observation (urban skies): Good, for telescopes up to 125 mm aperture and medium exit pupil

Film photography: Good, but very long exposure times

CCD and CMOS photography: Good, when used with an additional IR blocking filter

DSLR photography (original): Good, colour balance is near perfect

DSLR photography (astro modified): Good, colour balance is near perfect

DSLR photography (MC modified): Good, when used with an additional IR blocking filter

Webcam / Video (Planets): Unsuitable

Webcam / Video (Deep Sky): Very good, if light pollution is a big problem

- 1 Filter
- Storage box

Safety informations: PDF Download