title: Finding SP 500 index members with Rbbg package for specific date
body: <p>I'm trying to extract the index members of the S&amp;P 500 Index for a specific date in time with the help of the Bloomberg package Rbbg:</p>
  
  <p>Here is a small example which will provide me with the SP500 constituents of today:</p>
  
  <p>configurations </p>
  
  <pre><code>index &lt;- "SPX Index" 
  
  Sys.setenv(TZ="GMT")
  
  require(Rbbg)
  require(tcltk)
  library(rJava)
  
  date &lt;- as.POSIXct("1990-01-01")
  </code></pre>
  
  <p>connection to bloomberg station</p>
  
  <p><code>conn &lt;- blpConnect(jvm.params = c("-Xmx256m", "-Xloggc:rbloomberg.gc", "-XX:+PrintGCDetails"))</code> </p>
  
  <p>members of index and their tickers</p>
  
  <pre><code> tickers &lt;- bds(conn, index, "INDX_MEMBERS")[,1]
  </code></pre>
  
  <p>Now I would like to insert a specific date into the bds() function, so that I get the index constituents as of January 1, 1990.</p>
  
  <p>Thank you for your help.
  Best Regards
  Jann</p>