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Testing the Baader Fringe Killer and Continuum Filter

Last week I tested a few Baader filters with the 4-inch TAL refractor mounted on the EQ6. I only used the Baader Solar Filter (ND=5). I started with a 32 mm plossl. This eyepiece gives a magnification of 31x. The sun’s granulation was very easy to detect. The big group of sunspots (652) was near the western limb of the Sun. There where some

big fields of faculae around this group. To the south of 652 was another group of faculae visible. I tried other magnifications, but the best view visual was with the 32mm Televue plossl. There was great detail in the sunspots and faculae.

In the 4-inch TAL refractor, the image of the Sun is small, with some sky left around it. This telescope gives a more “stable” view of the Sun, compared to the 8-inch Klevtzov. The 4-inch is my favourite for observing the Sun. The fringe Killer softened the colour fringe around the Sun, but the colour fringe did not completely disappear. 

With the Baader Continuum filter the views are even better. The sunspots, faculae and granulation ore shown some more contrast. The green image is very pleasing to the eyes. I prefer this to the white light image.

Later I shot some images of the sun, but the 32mm is not very useful. I did not get any satisfying results with this eyepiece. With the 25mm Vixen Lanthanum, the results immediately improved. I got the best overall pictures in white light with the following settings: f 4.7, ISO 100, 1/2000s, spot metering. With the Baader Continuum filter in place I used the following setting: f 4.2, ISO 100, 1/60s, spot metering.

On the digital images I noticed a difference with the visual observing I made. On the photographs, the details are better in white light, while observing visually the details are better when using the Continuum filter. The next time I will shoot the white light images using the ND=5 solar filter and the “green light” (Continuum filter) will be used to shoot images using the ND=3.8 solar filter.

image

Posted by Math on 08/04 at 02:28 AM
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