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TMO61 Transformation Coefficients

HQA's picture
HQA
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Joined: 2010-05-10

Here are the transformation coefficients for TMO61:

Tv_bv = -0.075 +/- 0.004

Tv_vi = -0.065 +/- 0.007

Ti_vi = 0.029 +/- 0.009

Tbv = 1.273 +/- 0.022

Tvr = 1.004 +/- 0.014

Tri = 0.816 +/- 0.011

Tvi = 0.911 +/- 0.008

Note that Tbv is quite large.  The KAF8300 does not have very good blue response, which shows up when you are transforming.  I did not see any nonlinearity in Tbv over the color range of standard stars that I was using, but when the coefficient gets large, it is usually useful to think about a quadratic fit rather than a pure linear fit.

Arme

Quadratic terms are obviously
wel's picture
wel
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Joined: 2010-07-26

Quadratic terms are obviously the next step, but it is useful to remember that cool-enough stars can have huge molecular absorption bands which can only be roughly approximated by the next term in a polynomial expansion.


There is a qualitative difference between how well one can expect a very-reddened star to be transformed relative to a very cool star.

Cheers,

Doug

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484