About this product
Model: baader_2961580
Part Number: 2961580
Baader 7.5nm Solar Continuum Filter (540nm)
IMPORTANT This Baader Solar Continuum Filter must be used ONLY with additional filtering (e.g. Baader Herschel prism or AstroSolar Safety Film). Failure to do so will result in serious eye damage or blindness.
Compared to the previous model with a 10nm half-band-width, this filter has a half-band-width of only 7.5nm, which increases the contrast even more. It thus replaces both the previous Baader 10nm Solar Continuum filter and the stacked 1 ¼" filter #2458392. The single filter is so good that stacking is no longer necessary - the contrast gain of a single 7.5nm filter makes stacking unnecessary, and this performance is now also available in 2".The Solar Continuum Filter is practically a narrow band photosphere filter for solar observation in white light.
It provides the highest contrast in the photosphere of the sun.
The filter works as a monochromator - suppressing the effects of the atmospheric turbulence and delivering images that are significantly sharper.
Lens systems (including those of apochromats, catadioptrics or eyepieces) are traditionally optimised for the spectral range around 540nm, since this is where our eye has the highest sensitivity. This narrowband filter therefore blocks everything with the exception of the spectral range in which a lens optic works most sharply and with the highest contrast. The effect is greatest on achromatic lens telescopes; but there is also an effect on apochromatic telescopes, catadioptric systems, and even pure mirror systems by reducing air turbulence.
As a monochromatic filter, it is ideal for use on monochromatic cameras and can even provide a tremendous gain on pure colour systems.
With a colour camera, as with deep-sky narrow-band photography, it is less effective as only the green pixels are used. Thus, although you still benefit from the improved image sharpness of the telescope that is optimised for green wavelengths (and the reduction of the influences of air turbulence), with a colour camera you cannot fully exploit the better image quality compared to monochrome cameras, as you are effectively working with reduced camera resolution.
The Baader 7.5nm Solar Continuum filter will also be included with the Baader Cool Ceramic Herschel prism Mark II, which is in preparation.
The Baader 7.5 nm Solar Continuum also offers all the advantages of the CMOS-optimized Baader filters:
- Increased contrast, matched for typical CMOS quantum efficiency and s/n ratio
- Reflex-Blocker™ coatings, for largest ever freedom from halos, even under most adverse conditions concerning aux-optics
- Identical filter thickness to existing standards, with utmost care for parfocality
- Blackened edges all around, with filter-lead-side-indicator in the form of a black frontside outer rim, to additionally eliminate any reflection due to light falling onto the edge of a filter
- Each filter coated individually, with sealed coating edge (NOT cut out of a larger plate with coatings left exposed)
- Life-Coat™: evermore hard coatings to enable a non-aging coating for life – even in a most adverse environment
Customer reviews
| Average Rating (1 Review): | |
Baader ASTF Photographic AstroSolar OD 3.8 filter 19 April 2024 | Anthony
I bought this Solar filter to help improve my Solar Imaging of the Photosphere using my new 127 Maksutov (FLO). I have only had a couple of occasions to try this little filter out and it has made a significant difference to my images! Both in the amount of detail/contrast captured and in fps (Frames per second) lost!
If you are serious about Solar Imaging of the Photosphere, it is a must, but it did significantly reduce the light falling on the cameras sensor. So the exposure needed to be increased and hence the loss of fps. I’m using a mono camera, so the fact that the filter gives a green tinge to the image, makes no difference.
I have previously been using a good quality “Thousand Oaks” glass filter to cover the objective lens, but have upgraded to a special photographic Baader ASTF AstroSolar OD 3.8 filter (FLO again). This can only be used for imaging and not for visual observing as it lets far too much light through for safe use.
I can’t as yet, give any exact figures to the loss of light I experienced, but what I lost by adding this little gem at the camera end, was made up for, by using the OD 3.8 Baader Solar filter at the objective end. So if you are using a similar set up to mine, I would strongly recommend using the two items together.
Thank you FLO for the advice, the ordering from Germany and the great service.
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