Baader 1'/4" IR-PassFilter (685 nm) (optically polished)
Baader 1'/4" IR - PassFilter (685 nm) (optically polished)
The secret of good planetary images, the IR-Pass filter can greatly improve image sharpness by reducing the effects of seeing.
Description: A top image during the Mars opposition of 2003!
Using these filters, the best Mars images in the world were created when using Web cams.
The trick: for a colour image an additional exposure for the 'Luminosity channel " was taken, however not in the usual spectral range of 400 - 700nm, but moved into the red - starting at 670nm. The transmission window begins at the deep red 670nm. That is still in the visible range, so you can focus properly.
The effect: the atmospheric air turbulence (seeing) has much smaller effect on the sharpness in the long wave spectral region! Dark structures on Mars, Jupiter as well as the Moon and Sun are thereby rendered much more sharply and can be used as a fourth image information in the coloured (RGB-install) recording. Every CCD camera owner should have this very interesting extension of its "arsenal" against air turbulence.
Of course, fine-optically polished and perfectly tempered!
* The term refers to a leading edge of exactly 50% transmittance at the specified wavelength
Never use any eyepiece filter for solar observation without objective front filter!