1. Home
  2. Forums
  3. Variable Star Observing
  4. Photometry

Which Company's Filters used with BSM and Takahashi Epsilon 180?

msheald
Affiliation
American Association of Variable Star Observers (AAVSO)
Sun, 03/15/2020 - 21:51

Hello! I see that the BSM has used the Takahashi Epsilon 180 f2.8 hyperbolic astrograph.

    Just curious. Which company's photometry filters were selected for such a fast scope? Interference or colored glass filters? Best regards.

Mike

msheald
Affiliation
American Association of Variable Star Observers (AAVSO)
Mon, 03/16/2020 - 13:26
Interference or Colored Glass?

Hello! I'm especially wondering if interference filters work with such a fast scope, and, if so, which company's filters were considered appropriate. Best regards.

Mike

HQA
Affiliation
American Association of Variable Star Observers (AAVSO)
Mon, 03/16/2020 - 13:45
BSM filters

Hi Mike,

We are using the Astrodon interference filters.  While they are not spec'd to go as fast as the E180, they seem to work all right over the field of view of the ASI183 camera.  I think Ken Menzies has calculated transformation coefficients for the E180 setup.  In theory, fast f/ratio telescopes should need special interference filters due to the fast beam.  If you worry about this, you can always use colored glass filters.

We will be doing some tests with the E180 and a QHY600 in a month or so, which will be a good test of the filter issue since we will use the entire 24x36mm FOV.

Arne