Clarification on errors in the EDI literature

5. "The First Extrasolar Planet . . . Doppler Instrument",

J. Ge, J. van Eyken, S. Mahadevan, C. DeWitt, et al., ApJ accepted (2006)<LINK>

This is of minor importance, but for the record, the Barker and Hollenbach (1972)<
LINK> were shock physicists measuring a laser illuminated laboratory target, and did not measure Doppler velocities of sunlight as implied by the paper.

4. "First Planet Confirmation . . . Fixed-Delay Interferometer",
J. van Eyken, J. Ge, S. Mahadevan, and C. DeWitt, ApJ, 600, L79-82 (2004)<

This paper mistakenly describes Edser and Butler (1898)<
LINK> using a Michelson interferometer with a post-disperser. Actually the interferometer used by Edser and Butler was a Fabry-Perot type, as can be seen in their second Figure, which generates spike-like non-sinusoidal fringes.

The distinction is significant since the EDI is based on the use of sinusoidal fringes. The advantages of sinusoidal fringes includes allowing the use of both complementary interferometer outputs, the elegant use of trigonometry and dot products for analysis, the mathematically simplest instrument response for greatest robustness to instrumental drifts, and simple Fourier analysis of the moire patterns to extract high resolution information.

3. "Externally Dispersed Interferometer . . . Theory and Demonstration on Sunlight",
D. Erskine, PASP, 115, 255-269 (2003)<

The value of the interferometer delay used in the theoretical model associated with Fig. 8 was not mentioned. It was 1 cm, (similar to the 1.1 cm value used in experiments).

2. "Fixed Delay Interferometry for Doppler Extrasolar Planet Detection",
J. Ge, ApJ 571, L165-L168 (2002) <

In announcing the EDI technique, seemingly as his own, the solo author Ge omits mention of important earlier EDI demonstrations by Erskine at Lick Observatory in 1999, and in which Ge himself participated. He neglects to reference Ge, Erskine & Rushford (2002) <LINK> or its work. Instead, only Ge's work at Mt. Palomar and Hobby-Eberly in 2001 are mentioned as first light experiments.<LINK to Ge's own erratum>

1. "Novel INterferometer Spectrometer for Sensitive Stellar Radial Velocimetry",
D. Erskine and J. Ge, ASP Conf. Series, 195, 501-507 (2000) <

For historical clarity, it should be noted that the photograph Fig. 1 of the EDI apparatus and Figs. 2 and 3 of the solar fringing spectra were made in the segment of the project prior to Jian Ge's arrival.


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