ASTRONOMIK ProPlanet 642 IR Band Pass 1,25" Planetary Filter

ASTRONOMIK ProPlanet 642 IR Band Pass 1.25" Planetary Filter

The Astronomik ProPlanet 642 BP is the latest addition to the Astronomik ProPlanet IR band pass filter family. The filter excites with its wide range of applications for daylight IR photography, for high-resolution lunar and planetary imaging, and for taking beautiful, deep images of H-alpha regions when used for astrophotography.

"BP" is short for "Bandpass": the filter offers a 200 nm spectral window from 642 nm to 842 nm. In contrast to the other two ProPlanet filters, it blocks the longer infrared. Together with the Astronomik ProPlanet 742 and the ProPlanet 807, you now have three options to suit your IR imaging needs. The Astronomik ProPlanet 642 BP will be the right choice to get the best image quite often.

With the Astronomik ProPlanet 642 BP, you get three filters in one product: depending on the camera, it is a good tool for daylight IR photography with a digital camera, it reduces seeing and improves contrasts in high-resolution planetary and lunar images, and it is an economically priced H-alpha filter for the starter in deep sky astrophotography of H-alpha nebulae.

How it works:

The ProPlanet IR 642 reduces the disturbing atmospheric effects of dust when creating monochrome planetary and lunar videos. This is achieved by a transmission window in which the wavelength range has to meet a couple of requirements:

♦ the lack of sharpness caused by vertical air motion in the atmosphere (seeing) is minimized
the camera sensitivity is fully exploited
♦ the wavelength range is matched to the resolution and correction of the telescope.

The filter is designed for (astronomical webcams without built-in IR blocking filter or MC-modified DSLR cameras with video function. The wavelength range that the filter passes through is a mixture of filtering red and shortwave infrared. Therefore, the filter is usable for color imaging with Astronomik's L-RGB filter set to replace the L-filter in case of bad seeing, so that clearly sharper and less distorted images can be obtained. This considerably improves the usability of the images in post-processing. By including the H-alpha lines and [[S II]], it is a broadband, but economically priced, alternative to pure line filters of those wavelengths.

The focal range for optimum results is between f/1 and f/30.

Deep sky astrophotography:

In the well-known H-alpha emission line, the ProPlanet 642 BP reaches its maximum transmission of nearly 100%. While all photons from the beautiful H-alpha regions reach the sensor, the shorter wavelengths with most of the light pollution are blocked. If an astronomically modified camera is used, the bandwidth is reduced to 40 nm. The result is a huge contrast gain due to a darker sky background.

IR imaging in daylight:

One of the initial points in developing the ProPlanet 642 BP was daylight imaging with (modified) digital cameras.

For normal photography, an IR blocking filter is mounted directly in front of the camera sensor, as the sensors are sensitive up to over 1100 nm. By removing this built-in filter, the camera can be used for the very interesting IR photography.

The Astronomik ProPlanet 642 BP starts transmission in the deep red spectral range and lets all light through up to 842 nm. This results in images perfectly suited for channel selection and enables excellent color separation in post-processing, as the initial wavelength of 642 nm, combined with long wavelength blocking, provides particularly constrast images.

Other uses:

Planet IR 642 Pro BP is suitable exclusively for cameras without IR blocking filter.

Especially with color cameras without IR blocking filter, it is best for taking monochrome images, as the Beyer matrix is not defined in IR and the camera becomes "color blind". The Astronomik Planet IR 642 Pro BP is not suitable for solar observation or photography, even if used with a solar filter.

Alternatives:

For luminance exposures (monochrome cameras) or for color imaging in the visual range, we recommend the Astronomik L filter. For pure IR exposures, we recommend the Astronomik ProPlanet 742 IR pass filter or the Astronomik ProPlanet 807 IR pass filter.

If the seeing is mediocre and if the telescope is smaller than 10" (250 mm), we recommend the use of the Astronomik ProPlanet IR 742.

If seeing is very poor and the instrument is 10" (250 mm) or larger, the Astronomik ProPlanet IR 807 may be the best choice.

Suitability:

♦ Visual observation (dark skies): Unsuitable, the eye is insensitive to this spectrum
♦ Visual observation (urban skies): unsuitable, the eye is insensitive to this spectrum
♦ Film photography: depends on the film
♦ CCD photography: neutral, can be used as a cheap H-alpha filter
♦ DSLR photography (original): almost unusable.
♦ DSLR photography (modified astro): inexpensive alternative to H-alpha filters
♦ DSLR photography (modified MC): very good, for IR daylight photography
♦ Webcam / Video (Planets): luminance exposures at higher seeing
♦ Webcam / Video (Deep Sky): experimental

Technical data:

♦ over 95% transmission for wavelengths from 642 nm to 840 nm
♦ blocking wavelengths between 350 nm and 630 nm
♦ Parfocal with other Astronomik filters
♦ Glass thickness: 1 mm
♦ Completely resistant to high humidity, scratches and aging effects
♦ Diffraction limitation, the filter will not reduce the optical performance of your telescope!
♦ Astronomik filters are delivered in a high quality, long lasting filter box

Technical specifications:

• Transmission between 642 nm and 842 nm: more than 95 %
• In-line transmission: more than 90 % at H-alpha, S[II] and N[II]
• Blocking: wavelengths between 350 nm and 630 nm
• Support material: optically polished substrate
• Glass thickness: 1 mm
• Parfocal: With all other Astronomik filters
• Anti-reflective coating: No sensitivity to moisture, no aging and totally scratch-proof
• Cell: aluminum

ASTRONOMIK ProPlanet 642 IR Band Pass 1,25" Planetary Filter