Abstract
THE PARALLAX OF NEBULA h 2241.—At the time when Dr. Wilsing took photographs of the nebula B.D. + 41°˙4004 for the determination of parallax, he obtained also a series of negatives of B.D. + 41°˙4773 (h 2241) for the same purpose. This nebula is almost ring-shaped, and displays a central condensation. The latter appears more distinct on the photographic plates than can be seen by eye observations, and its contour is only sufficiently sharp for micrometric measurements on the best plates, so that the centre of the whole apparent disc has been generally used. From June 1892 to August of the following year, 33 plates were obtained, 31 of which have been used in this research. Six comparison stars, the positions of which were taken from the Bonn zones, have been adopted. In the account of the result obtained (Astro. Nach. No. 3261), Dr. Wilsing gives a table showing the deduced distances of the nebula from the two comparison stars 3 and 6. A second table contains the mean monthly values of these distances with their differences from the whole mean value obtained from all the measurements, together with the most probable errors of the measurements.
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Our Astronomical Column. Nature 51, 114 (1894). https://doi.org/10.1038/051114a0
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DOI: https://doi.org/10.1038/051114a0