adding legacy asc2 files

README.md

@@ -20,6 +20,8 @@ configs:
     data_files: [data/cda/lvl1/1998/*.parquet]
   - config_name: cda_2001_lvl1
     data_files: [data/cda/lvl1/2001/*.parquet]
+  - config_name: cda_cal_legacy
+    data_files: [aux/cda/cal_legacy/*.asc2]
   - config_name: cda_dnconversion
     data_files: [aux/cda/dnconversion/*.txt]
   - config_name: cda_psu
@@ -44,6 +46,11 @@ This repository contains calibration data for the Cosmic Dust Analyzer (CDA) ins
 
 ### Auxiliary Files
 
+#### Legacy Calibration Data
+- **`aux/cda/cal_legacy/`**: Legacy calibration data files (9 files)
+  - Text files with `.asc2` extension from 1998 calibration campaigns (January 27 and February 10)
+  - Files contain impact event data extracted from binary files
+
 #### DN Conversion Tables
 - **`aux/cda/dnconversion/`**: Digital Number (DN) to unit conversion tables
   - `dn2unit.FS.MP.txt`
@@ -64,6 +71,7 @@ The repository provides multiple data configurations for easy access:
 - **`cda_2001_lvl0`**: 2001 Level 0 binary calibration files
 - **`cda_1998_lvl1`**: 1998 Level 1 processed calibration files
 - **`cda_2001_lvl1`**: 2001 Level 1 processed calibration files
+- **`cda_cal_legacy`**: Legacy calibration data (text files with .asc2 extension)
 - **`cda_dnconversion`**: DN conversion reference tables
 - **`cda_psu`**: PSU evaluation data