Physics
Scientific paper
May 1999
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999soph..186...25h&link_type=abstract
Solar Physics, v. 186, Issue 1/2, p. 25-41 (1999).
Physics
11
Scientific paper
Sunspot umbral positions and areas were measured for 82years (1906-1987) of daily, full-disk photoheliogram observations at the Kodaikanal station of the Indian Institute of Astrophysics. The measurement technique and reduction procedures used were nearly identical to those used earlier for the reduction of Mount Wilson daily full-disk photoheliograms, covering an overlapping interval of 69years. In this paper we compare the differential rotation of the Sun from the analysis of the Kodaikanal data with the Mount Wilson results. In addition, we analyze the data set formed by combining the data from the two sites for differential rotation. While doing this, it has become apparent to us that small, subtle optical effects at both sites produce systematic errors that have an influence on rotation (and other) results from these data. These optical effects are analyzed here, and corrections are made to the positional data of the sunspots from both sites. A data set containing the combined positional data of sunspots from both sites, corrected for these optical aberrations, has been constructed. Results for both sunspot groups and individual sunspots are presented. It is pointed out that optical aberrations similar to those found in the Kodaikanal data may also exist in the Greenwich photoheliograph data, because these two sets of solar images were made with similar telescopes.
Gupta Sourendu
Howard Robert F.
Sivaraman K. R.
No associations
LandOfFree
Measurement of Kodaikanal White-Light Images - II. Rotation Comparison and Merging with Mount Wilson Data does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Measurement of Kodaikanal White-Light Images - II. Rotation Comparison and Merging with Mount Wilson Data, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Measurement of Kodaikanal White-Light Images - II. Rotation Comparison and Merging with Mount Wilson Data will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1193954