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Filter For Rejection Refractors, Sct, Maksutov, Mewlon Or Other Telescopes

Filter For Rejection Refractors, Sct, Maksutov, Mewlon Or Other Telescopes

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Filter For Rejection Refractors, Sct, Maksutov, Mewlon Or Other Telescopes

Daystar Filters


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The prefilter rejection ERF has two functions:

  • reduces the heat transmitted to the filter reflecting UV and IR and transmits light of the desired wavelength
  • works as mask aperture to achieve the correct angle of incidence on the filter

    E 'can choose between two different types of pre-filters ERF: the standard working with 1/4 lambda and the Deluxe with processing 1/10 lambda.
    You can also install Professional irises 16 steel blades (exactly circular profile all openings) to obtain great advantages.
    In fact you can adjust the aperture allows you to:

    • make the system insensitive to turbulence on days with bad or mediocre seeing
    • emphasize and raise the contrast during the observation or photograph of particular H-alpha, increasing the diameter to, for example, for weak protuberances or decreasing the diameter to increase the contrast in areas of the solar disk. < li> the variation of the iris is also important to optimize contrast in the observation of particular details such as solar spicules or activity around sunspots or plage.
    • set up a single ERF for mounting more telescopes and therefore vary the opening so as to achieve the correct focal ratio
    • arrange the use of the telescope with different combinations of opening or greater focal length (through the use of a powermate). In this way you can for example have in one instrument more focal lengths to shoot the entire solar disk or high magnification the smallest details of a bulge
    • The iris is also important if you use on the same refractor an H-alpha filter and a Football K / H
    • The iris also serves as a protective filter ERF during inactivity

      The filters work Daystar efficiently with f / 30 or greater. A nominal focal ratio f / 30 can be achieved by selecting an appropriate filter ERF + barlow so diaphragm tool and extend the focal length if necessary. To calculate the configuration that allows you to use a particular front opening you can use the formula under riporatata but we advise you to contact our technical service highly specialized in H-alpha observations for accurate configuration of the entire system.

      Opening ERF filter = [opening of Telescope (mm) x focal ratio x multiplication factor of a possible or rather Powermate Barlow (telecentric optical system)] / 30

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