The Lord of Uraniborg: A Biography of Tycho Brahe

A new look at the position of the 1604 Supernova (V843 Ophiuchi)

“…Recent estimates put the distance to 3C 358 at 3000-6000 pc (e.g., Schaefer 1996; Stephenson and Green 2002, who refer to the remnant as G4.5+6.8). Van den Bergh and Kamper (1977) found that the center of the supernova remnant exhibits a proper motion of 0 .013 ± 0 .003 yr −1 northward. This would indicate a motion since 1605 of ≈ 4 .8 ± 1 .1, a value far too small to account for any discrepancy between the center of 3C 358 and the derived position for V843 Oph.…”

“…The adopted center of 3C 358 is from radio and x-ray observations (cf. van den Bergh and Kamper 1977;Matsui et al 1984;DeLaney et al 2002). Figure 2 shows a plot of various reduced positions from the present study, with the outline of the current-day remnant shown for comparison.…”

“…As noted elsewhere (e.g., Brahe 1602, p. 341;Thoren 1990;Green 2004), even when a straight-edged instrument is securely fixed (i.e., not handheld), such alignments are fraught with problems due to parallax inherent by the eye moving along the edge connecting the celestial objects and due to the constant diurnal motion of the sky. The only hope to get some reasonable convergence to the true location of the unknown object (V843 Oph, in this case) is to have as many different alignments as possible to look for a mean position.…”

“…Even on the one or two occasions where local clock time was specified by an observer, it is well known from Tycho Brahe that clocks were notoriously prone to errors of many minutes by evening, even after having been set by the sun at noon that same day (e.g., Thoren 1990 o -11 o in the southwest sky about an hour after sunset, so the observers were obviously making their measurements about the time that it was getting dark enough to do so.) Ultimately, one cannot really correct for refraction because of the many variables, which include local atmospheric uncertainties due to the general low altitude of the supernova (< 10 o ) and numerous reference objects when measurements were made.…”

The great Martian catastrophe and how Kepler fixed it

“…There his wife and children could inherit his wealth. 2 About a year after his arrival, Tycho added a young assistant to his staff: Johannes Kepler, a Lutheran high school teacher who suddenly found himself underemployed when the Catholic Counter Reformation swept into southern Austria. In Tycho's employ, Kepler was assigned the recalcitrant problem of Mars.…”