On the Determination of the Quiet-Sun Center-to-Limb Variation in CA II K Spectroheliograms
Abstract
We present a method for the determination of the center-to-limb variation (CLV) for Caii K spectroheliograms. It is based on the calculation of intensity histograms for rings of constant area. Using a simple cutoff criterion in the cumulative histograms, we are able to derive CLVs of the quiet Sun regardless of the solar activity level. Using an example from the literature, we show in which way different methods of normalization of the quiet-Sun CLV may affect the results.
- Publication:
-
Solar Physics
- Pub Date:
- January 1998
- DOI:
- 10.1023/A:1004953032251
- Bibcode:
- 1998SoPh..177..287B
- Keywords:
-
- Solar Activity;
- Cutoff Criterion;
- Intensity Histogram;
- Constant Area;
- Solar Activity Level