SP 470 SCHULER

Manufacturer's curve (courtesy Chet Schuler)

The SP470 is a shortpass filter, whose transmission runs from UV to blue light. It can be interested to image the planets is short wavelenghts with a better separation from green light in comparison with the blue filter. Its advantage over similar filters is the absence of any IR leakage.

INTEREST

- Good for deep blue images of moderately bright planets such as Jupiter
- Useful to block the IR leak of the W47 without losing UV light
- No IR leak

PROBLEMS

- Sensitive to sky transparency and to light scattering from the atmosphere ; loss of image sharpness
- Blue transmission too much important for the venusian details that will not be contrasted
- Incomplete blocking of green wavelenghts for Mars, the surface details are still visible
- Moderate amount of light available
- Filter looks to be not sold anymore

Mars
13 september 2005 - Mewlon 210 and B&W webcam
Good contrast of white clouds but a better result can be expected with true violet filters..

Saturn
22 april 2006 - Mewlon 210 and Lumenera LU075M
Doesn't really show more than a blue filter with less details ; no interest for that planet.

Jupiter
25 april 2004 - Newton 180 and ATK-1HS
Interesting for Jupiter, to image the higher layers of the atmosphere. Dark belts and bright zones.

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