Assumption and Fact in the Theories of Solar and Stellar Proper Motions

The discovery and measurement of stellar proper motions has always been associated with machines: for proper motion measurements involve four activities: observation, recording, comparison and measurement. Participation by the astronomer in these activities has step by step been replaced partically or wholly by machines. First the observation and recording functions changed from visual to photographic – with the fine guiding done by the astronomer; then the comparison by the blink microscope and the measurement by visually operated measuring machines. On a comparative time scale, the next step – automation of the comparison and measurement function – has been much money, time, and effort away from the previous steps, but as this presentation and other presentations at this conference will show, machines of varying degrees of automation and astronomer participation are now in operation.

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Proper Motions With Respect to the Extragalactic Reference Frame

Symposium - International Astronomical Union ◽

10.1017/s0074180900087179 ◽

1990 ◽

Vol 141 ◽

pp. 407-417

Author(s):

A. R. Klemola

Keyword(s):

Reference Frame ◽

Proper Motion ◽

Milky Way ◽

Proper Motions ◽

Stellar Proper Motions

The Lick proper motion program, one of several using galaxies as a reference frame, is summarized with a statement of work accomplished for the non-Milky Way sky. The problem of identifying relatively transparent regions at low galactic latitudes is discussed, with tabular results presented for 41 windows from the literature having observable galaxies. These fields may be helpful for attaching stellar proper motions directly to the extragalactic frame.

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THE EARLY GREAT DEBATE: A COMMENT ON IBN AL-HAYTHAM‘S WORK ON THE LOCATION OF THE MILKY WAY WITH RESPECT TO THE EARTH

Arabic Sciences and Philosophy ◽

10.1017/s0957423917000078 ◽

2018 ◽

Vol 28 (1) ◽

pp. 1-30 ◽

Cited By ~ 1

Author(s):

Andreas Eckart

Keyword(s):

Milky Way ◽

Last Millennium ◽

The Moon ◽

Proper Motions ◽

Stellar Proper Motions ◽

The Earth ◽

Great Debate ◽

The Galaxy ◽

Early Translation ◽

Critical Translation

AbstractAt the very beginning of the last millennium Ibn al-Haytham greatly contributed to the investigation of the Milky Way. Here, the only three currently known versions of his work on the location of the Milky Way are compared to each other and discussed. A comparison of the texts and an early translation into German by E. Wiedemann in 1906 reveals several differences that triggered a new critical translation of the passed down text. We give detailed comments on the work and check the validity of Ibn al-Haytham's arguments. We also discuss his work in the framework of the ‘Great Debate’ on the Milky Way that took place around 1920, more than a decade after Wiedemann's translation. We find that Ibn al-Haytham's work is certainly at the peak of the unaided-eye era of the Milky Way's discovery. Through his own argumentation and in comparison to Ptolemy's observations Ibn al-Haytham clearly identifies the Galaxy as an extraterrestrial body that is not part of the atmosphere but much further away than the Moon. With some of his statements on the stellar positions passed down by Ptolemy, Ibn al-Haytham also anticipates the concept of stellar proper motions.

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Proper Motions Of 47 TUC And NGC 362 Relative To The Small Magellanic Cloud

Symposium - International Astronomical Union ◽

10.1017/s0074180900140033 ◽

1988 ◽

Vol 133 ◽

pp. 465-468

Author(s):

H.-J. Tucholke

Keyword(s):

Globular Clusters ◽

Magellanic Cloud ◽

Small Magellanic Cloud ◽

Proper Motions ◽

Stellar Proper Motions ◽

Galactic Globular Clusters

The proper motions of the galactic globular clusters 47 Tuc and NGC 362 are currently being measured relative to the background of the Small Magellanic Cloud. This paper reports on the reduction routines developed so far for the simultaneous computation of several thousands of stellar proper motions. A preliminary result for NGC 362 is given.

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