A quick guide to getting started on HEASARC 
 

			Ann E. Hornschemeier

		(All information based on the user's guide 
		distributed by the High Energy Astrophysics
		Science Archive Research Center, October 24,1994)




Where to find HEASARC: 

  	1.  http://heasarc.gsfc.nasa.gov/

 	2.  
    	   a. telnet heasarc.gsfc.nasa.gov
    	   b. log in as "xray"
           c. give your HEASARC username (or invent one)
           d. The first time, you will be prompted for your email
              address and postal address.  

       	      **NOTE: Give the email address that you will be using the
		most often.  In the future, if you log in from a 
		different address, type "email" at the HEASARC
		prompt and change the address.  This avoids a lot
		of confusion.





Where to find help: 

 	1. Email request@legacy.gsfc.nasa.gov
 	2. help command_name 
 	3. command ?   <- This is for instances that a command has options and
		          you can't remember your options.  It will list some
		   	  options.  Type 'exit' when it asks a second time if
		   	  you do not want to perform this command.
 




How to begin a session in BROWSE: 

 	browse database_name




Good, vague, starting data bases: 
 	ALLDATA	      -  3 guesses...
 	XRAY		  -  X-ray Catalogs
 	RADIO            -  Radio Catalogs
 	OBSLOG           -  Observation Logs 
 	OPTICAL 	 -  Optical Catalogs




The prompts: 
 	HEASARC> 		-You're _not_ in BROWSE, most commands here 
				 are BROWSE commands.

 	DATABASE_SAMPLE_PARM> 	-You're in BROWSE.  This lists the present 
				 data base, the present sample, and the present
				 search parameter (default is declination).	



Aliases: 

 	1. To make an alias:
		 > alias name command_string 
 	2. To list out aliases:
		 > alias/show



 
Searching a data base: 

 	1. To get a listing of possible search parameters, type lparm for
		"list parameters" :

 	2. Searching by name:

		There is an alias "sname" for this purpose:
	
	   		>sn 3c39*    -wildcards will work  
				     -Note: Everything found when searching by 
			 	      parameter will be displayed, so limit your 
			              search as much as possible.

 	3. Searching by coordinates:
	   
	   >sc 		-This is "search in a cone."  RA and Dec are
			 given in h min sec and deg min sec, respectively.
			 An outer an inner radius can be selected if you want
			 a "hollow" cone search.

 	4. Searching by another parameter:

	   >sp PARM low high  
	   >sp LII  0.0 2.0	-Searches the present sample for objects 
				 between 0 and 2 degrees galactic latitude.

		 



Sorting data: 

 	>sort/ascending PARM
        >sort/descending PARM



Filtering data: 

	>sef ? 		     -This lists out all possible filtering parameters.
	>sef PARM low high   -Exclusive filter
	>sef PARM low high   -Inclusive filter



Displaying your findings: 

	>dsam 		     -displays everything in your sample 
	>dsam 1-10 20-30     -displays only entries 1-10 and 20-30



Plotting an image: 
	1.  Set the plotting device.  This is done with "cpd", change
	    plot device.  i.e.  cpd /xterm 

	2.  ximage/im 1 

		Plots the FITS image of the first item in the present
		sample..  The default is contour, add /nocontour otherwise.




Making a plot by parameter: 

	>ps/plt PARM1 PARM2  	-plots PARM1 versus PARM2
	>ps/aitoff		-makes an equal area projection


 
Histograms 

	There's an alias, phisto, for "ps/histo":

	>phisto PARM		-makes a histogram of PARM for given sample
	>phisto/bins=100 PARM	-default is 30 bins, this can be adjusted 




Extracting files: 

	1.  Type "lfiles" to find out if there's anything to extract.
	2.  If there are files to be extracted, figure out what you want.
	    You can get anything from FITS images to photon counts.  The
	    available files for a data base are listed in the _Available
	    Databases_ guide.
	3.  Type xp/all to get all files.



Basic spectral analysis: 

	>xspec/int 1		-Run xspec in an interactive mode, using
				 the first item in the present sample.

	>model ?		-This will list both the additive and 
				 multiplicative models.  You must specify
				 at least one additive model and as many
				 multiplicative models as you like.

	>fit			-make the fit
	>plot model 		-plots the best fit
	



Sending files: 
	1.  "exit" to get out of BROWSE then type:
	
		HEASARC> send filename

	2. This sets up an ftp connection for you, wild cards will work.






		A short list of possible data sources:
	
Einline 
 	This page at http://hea-www.harvard.edu/einline/einline.html	
  	gives access to Einline, the data archive of the Einstein mission.

	If you telnet to einline.harvard.edu, log in as "einline" and you
	will be connected to this service directly.

	Files can be obtained through anonymous ftp to einline.harvard.edu

Leicester Database and Archive Center 
	This database can be found at http://ledas-www.star.le.ac.uk/
	It covers ROSAT and GINGA.

NASA Astrophysics Data System Home Page 
	The ADS can be reached at http://adscat.harvard.edu/
	It contains abstract and article searches (which eventually will
	include ApJ back to 1975), a data archive, and a catalog service.

Astronomical Data Center Home Page (Goddard) 
	Through this page, HEASARC and other services can be accessed.
	The address is http://nssdc.gsfc.nasa.gov/adc/adc.html

	If you telnet to nssdc.gsfc.nasa.gov, log in as NODIS and you will
	be connected directly to the NSSDC Online Data and Information Center.
	
	Files can then be obtained through anonymous ftp to nssdc.gsfc.nasa.gov

Astronomy and Astrophysics Abstracts 
	Table 13 in the D.H. Hill reference section and QB460.A87 in the stacks.
	An object index is included, with listings by nearly every naming 
	convention known to the universe as we know it.