Data of Huairou Solar Observatory Station (HSOS) Access Help File (Last revised May 25th, 1999) 1. Directory structure Directory Description --------- ----------- pub The root directory, which contains the following: readme - This file. hrdata HSOS data Directory. There are three subdirectories of this directory: 1998 - data observated in 1998. 1999 - data observated in 1999. tab - Daily logs. software Programers to read HSOS data. 2. FIlename description The filenames in the HSOS public access area all contain information about the type of image, the location of spectra, the date of observation, and the number of active area, order of distribution. The names are in the format x1x2ddx3x4.dat, where: x1 = A letter describing the observation type x2 = A number indicating the location of spectra dd = The date of observation x3 = Three digits, the number of active region ( Begin with digits 001 from 1th January every year ) x4 = A letter presenting image order (from A to Z, A means the first image B is the second image, Z means the last image) All filenames end with the extension .dat. For example, filename is s517148a.dat, where: s = Monochrom image of logitudial magetic field 5 = Location of spetra line is 5324A 17 = Date 17th 148 = Huairou active region 148 a = First image filename is l517148a.dat, where: l = Logitudial magetic field 3. How to obtain HSOS images through the Internet Images from the BBSO archive can be obtained by using anonymous FTP in the usual way. The address is: www-hsos.bao.ac.cn Log in as user "anonymous" and send your complete e-mail address as the password. Once your login is ok, you enter command "cd pub","cd hrdata". Under the directory hrdata, you can see directories 1998,1999, tab and so on. you enter seperately these directorys, and then you can get what you want. You can also access the FTP archive using the World Wide Web. The URL is ftp://www-hsos.bao.ac.cn/. On the first page you choice item "Observational Data on Line", and then click "FTP-Archive", Observation logs are under directory Observation Tab. Image data are under directory Observation Data. Once your browser is properly configured, you have no difficulty accessing an image data or text file by click on the name of the file you want to get. Web browsers such as Netscape Navigator will have no difficulty accessing the archive. Internet Explore is better. 4. HSOS file format information The image at HSOS consist of 512x512 byte records (filename begin with s) or 512x512 interger (filename begin with l) records followed by 79 byte tailer records. The tailer record is divided into a 12 information. This is an example of a HSOS image file,d4 tailer information: 4861A = spectral line Jun-09,1991 = date 05:37:50 = time c = seeing 768.1 = sun disc coordinate x 1152.0 = sun disc coordinate y -2175.4 = orthogonal coordinate x -2967.9 = orthogonal coordinate y 768.1 = carrington coordinate x 1025.0 = carrington coordinate y 256 = frame 096 = huairou active region number 5. Reading HSOS data There is a programmer to read HSOS data under FTP site. It is made by IDL. By the programmer you can learn the way to read HSOS data and some observing information. ------------------------------------------------------------------------------- Questions about the HSOS image files and formats, problems with accessing this archive, suggestions, additions to or errors in or this file should be directed to: webmaster@sun10.bao.ac.cn Huairou Solar Observatory Station Beijing Astronomical Observatory Datun Rd. #20A, Chaoyang District Beijing,100012 P.R. China Tel:+86-10-6488-8769, +86-10- 6488-8710 Fax:+86-10-6488-8716 It will then be forwarded to the appropriate person.