diff --git a/doc/html/doc/ctobssim.html b/doc/html/doc/ctobssim.html
index e5991d6..21dded0 100644
--- a/doc/html/doc/ctobssim.html
+++ b/doc/html/doc/ctobssim.html
@@ -50,7 +50,7 @@ astrophysical sources and the instrumental background.</td>
 <tr>
 <td width="50">&nbsp;</td>
 <td width="25">&nbsp;</td>
-<td width="525">Output event list.</td>
+<td width="525">Output event list or observation definition file.</td>
 </tr>
 <tr>
 <td width="50">&nbsp;</td>
@@ -59,6 +59,23 @@ astrophysical sources and the instrumental background.</td>
 </tr>
 <tr>
 <td width="50">&nbsp;</td>
+<td colspan="2"><span class="irafpar"><strong>(prefix
+= "sim_")
+[string]</strong></span></td>
+</tr>
+<tr>
+<td width="50">&nbsp;</td>
+<td width="25">&nbsp;</td>
+<td width="525">Prefix for event list in
+observation definition file.</td>
+</tr>
+<tr>
+<td width="50">&nbsp;</td>
+<td>&nbsp;</td>
+<td width="525">&nbsp;</td>
+</tr>
+ <tr>
+<td width="50">&nbsp;</td>
 <td colspan="2"><span class="irafpar"><strong>caldb
 [string]</strong></span></td>
 </tr>
@@ -218,7 +235,8 @@ TeV).</td>
 </tr>
 <tr>
 <td width="50">&nbsp;</td>
-<td colspan="2"><span class="irafpar"><strong>(deadc = 0.95)
+<td colspan="2"><span class="irafpar"><strong>(deadc
+= 0.95)
 [double]</strong></span></td>
 </tr>
 <tr>
@@ -314,7 +332,7 @@ the executable will dump any log file output in the console.</td>
 <br>
 <hr size="1">
 <p class="Body">Last updated by: J&uuml;rgen
-Kn&ouml;dlseder 3 April
+Kn&ouml;dlseder 14 September
 2012
 </p>
 <br>