TMO61 Transformation Coefficients

Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 03/11/2014 - 21:01

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

Affiliation
American Association of Variable Star Observers (AAVSO)
Quadratic terms are obviously

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

Affiliation
American Association of Variable Star Observers (AAVSO)
TM061 Transformation Coefficients 190224

Attached are updated transform coeffs from images collected on 190108..

description= TG - Version TG_V7.3 beta 5, Telescope= TM061, Time created (UT) = 2019_02_26_21:39:02
[Coefficients]
Tbv= 1.043
Tb_bv= 0.024
Tv_bv= -0.019
Tvr= 0.997
Tv_vr= -0.031
Tr_vr= -0.051
Tri= 1.032
Tr_ri= -0.049
Ti_ri= -0.034
Tvi= 1.005
Tv_vi= -0.017
Ti_vi= -0.014
Tr_vi= -0.028
[Error]
Tbv= 0.015
Tb_bv= 0.013
Tv_bv= 0.012
Tvr= 0.034
Tv_vr= 0.020
Tr_vr= 0.028
Tri= 0.029
Tr_ri= 0.028
Ti_ri= 0.071
Tvi= 0.017
Tv_vi= 0.011
Ti_vi= 0.033
Tr_vi= 0.017
[R Squared Values]
Tbv= 0.984
Tb_bv= 0.083
Tv_bv= 0.106
Tvr= 0.970
Tv_vr= 0.082
Tr_vr= 0.141
Tri= 0.952
Tr_ri= 0.094
Ti_ri= 0.142
Tvi= 0.988
Tv_vi= 0.083
Ti_vi= 0.126
Tr_vi= 0.102
 

Affiliation
American Association of Variable Star Observers (AAVSO)
TMO61 QHY600 Transformation Coeffs (220419)

TMO61 now uses a QHY600 camera. New coefficients have been generated. The infrared filter is a Sloan i' filter but the coeffs provided below transform the infrared magnitudes to a Cousins I magnitude.

[Setup]
description= TG - Version 6.8, Telescope= TMO61_QHY600, Time created (UT) = 2022_04_19_01:06:57
[Coefficients]
Tbv= 1.372
Tb_bv= 0.156
Tbr= 1.239
Tb_br= 0.104
Tb_bi= 0.082
Tbi= 1.190
Tv_bv= -0.098
Tvr= 1.039
Tv_vr= -0.185
Tr_vr= -0.218
Tri= 1.047
Tr_ri= -0.281
Ti_ri= -0.331
Tvi= 1.036
Tv_vi= -0.104
Ti_vi= -0.142
Tr_vi= -0.122
[Error]
Tbv= 0.016
Tb_bv= 0.015
Tbr= 0.011
Tb_br= 0.010
Tb_bi= 0.008
Tbi= 0.012
Tv_bv= 0.015
Tvr= 0.014
Tv_vr= 0.030
Tr_vr= 0.035
Tri= 0.025
Tr_ri= 0.041
Ti_ri= 0.056
Tvi= 0.015
Tv_vi= 0.016
Ti_vi= 0.026
Tr_vi= 0.019
[R Squared Values]
Tbv= 0.996
Tb_bv= 0.691
Tbr= 0.998
Tb_br= 0.693
Tb_bi= 0.691
Tbi= 0.996
Tv_bv= 0.432
Tvr= 0.990
Tv_vr= 0.398
Tr_vr= 0.435
Tri= 0.969
Tr_ri= 0.516
Ti_ri= 0.377
Tvi= 0.988
Tv_vi= 0.428
Ti_vi= 0.336
Tr_vi= 0.465