Remote Observing with the Arecibo Telescope

The following protocol has been devised for remote observations with the Arecibo telescope. Users should also consult the accompanying on-line manual to the graphical user interface which is available at the following URL: http://www.naic.edu/~cima.html. For pulsar observers, there are detailed instructions for the use of the CIMA/WAPP combination in pulsar mode.

Getting an account at Arecibo

The most important thing to be able to observe remotely with the Arecibo Telescope, is, of course, to have an account at the Arecibo Observatory (AO), otherwise, you can't do any of what is described below.

If you don't have an account at AO, and wish to have one, call Arun Venkataraman at extension 340, or just "arun" (at naic dot edu) for e-mail. Explain clearly why you need an account, and when your observations are scheduled.
To gain access to your account at AO, type

> ssh -X (myusername)@remote.naic.edu

The "X" variable sets up all the environment variables relevant for the transmission of graphics across the link. An efficient and equally secure alternative is to use "slogin".

The more conventional remote shells, like "rlogin", will very probably be refused, as they are not as secure.

Using VNC at Arecibo Observatory

By far the best way of running complex graphical interfaces on any remote computer is to use a vnc server. This applies to almost any work you might want to do at AO, but it applies particularly to observations with CIMA and any practicing you might want to do with the offline version of CIMA. Apart from the fact that vnc will make things go much faster (it uses bandwidth very efficiently), it is also robust to temporary disruptions of your (or AO's) Internet link.

From the computer where you login at AO, login to some other computer, say

> ssh dataview

From that computer, type

> vncserver -geometry 1280x1024

The geometry parameters can be anything you like (they don't have to be "normal" values like 1024x768 etc. They can be 1200x900 or 1500x1100, etc). It is best to make it slightly smaller than the resolution of the monitor that you are working on.

If the computer replies "vncserver: program not found", or if it fails to produce any graphics, make sure that the directories /bin and /usr/X11R6/bin are in your path (you can check this by typing echo $PATH).

If you've never started a vnc server, it'll ask you for a password; make it one that you won't have a problem sharing with others - in other words, _not_ your usual pass! This way, if you need help from someone else with your observation, the person helping you might view the same vnc server, and view how things are going from your own perspective.

The command above will return something like "dataview:4" <- this is the vnc server number. It is quite important!
Back at your own local computer, type

> vncviewer -via (myusername)@remote.naic.edu dataview:4

(replace "dataview:4" by whatever computer and vnc server number you're using)

This assumes you're using a regular version of linux. For Mac, Windows and some Linux versions, the -via option is not available.
On a Mac, run

> ssh -f -L 590N:dataview:590N (myusername)@remote.naic.edu sleep 14400

in a terminal window. Then open Vncviewer (just use the icon) and select
```
     display > open -- localhost:N
```
in both lines, N is the vnc server number from above.

For some versions of Linux, use the same first line; then run

> vncviewer localhost:N

For Windows, download tight vnc and Putty. Running Putty, set
```
     Session
        Host name              = remote.naic.edu
        Protocol               = ssh
     Connection > data
        Auto-login username    = (myusername)
     Connection > SSH > Tunnels
        Source port            = 590N
        Destination            = dataview:590N
```
Then press 'ADD'. Open the putty remote window by introducing your username and password, otherwise you can't make the vnc connect. In VNCViewer, type, exactly
```
     localhost:N
```
(not the name of the computer you're logging into). Again, N is the vnc server number described above. In any case, you'll be asked for 2 passwords; the first is your regular AO password; the second is the one you made in "dataview" when running vncserver, and that you'll be comfortable sharing with others.

Now you should have a big window on which you can open xterms, etc, and soon you'll start CIMA and do the observing from here. Very usefully, anyone else can hook into your vnc server (if you give them your vnc password) and see all that you're doing (or do it for you!) and offer advice, by doing the following from their computer (linux examples):

> vncviewer -geometry 1200x900 -via (theirusername)@remote.naic.edu dataview:4

Another nice advantage is that, if there is a temporary disruption in the link to AO, your vncserver will still be running safely at AO. When communications are re-established, you can always call the vnc viewer in your local computer,

> vncviewer -via (myusername)@remote.naic.edu dataview:4

And re-start viewing the same vncserver at AO. On that server, everything will be as you left it before the disruption. This is a major improvement over running CIMA directly from an ssh shell, where even a temporary disruption might kill CIMA and force you to start telescope setup all over again.
At the end of the session, you log out of CIMA as per the observing instructions, within the VNC session. Then you kill the VNC window (by clicking on the x at the top right hand corner of your large window, or something similar). Finally, you must log into "dataview" from an xterm in your computer and do the following, in order to not monopolize resources:

> vncserver -kill :4

Things to do days before the observation

If you are the PI on a scheduled proposal, you will be sent automatic e-mails reminding you of your incoming observation at several given intervals before the observation is supposed to occur. However, it is a good idea to contact your assigned "Friend of the Telescope" in case there is any new information regarding your time slot. You can also check the receiver status on-line to make sure everything is fine.

Know exactly when you are supposed to start your observation!
The times indicated in the Telescope Schedule are indicated in Atlantic Standard Time (AST). This is:
- UTC - 4 Hours
- EST + 1 hour (EST is observed in wintertime in Eastern US)
- Equal to EDT (which is observed in summertime in Eastern US).
Before observing, you can practice your observations by calling the offline version of CIMA from your AO account. In a vnc server at AO (being viewed by a vncviewer in your local computer), open an xterm.
In this xterm, type:

> cima

You can do this on any AO computer except "observer2". It does not matter if it is a linux or solaris machine. If you practice your observations with this offline version of CIMA, you will be in a much better position when you start the observation. This offline version does not affect the pointing or LO status of the telescope.

The CIMA version that actually runs the telescope can only be called from the "observer2" machine, to which you log in as "dtusr". This should be done before your scheduled observation starts. If you are doing this remotely, you will do this login from an xterm in your vncserver window.

Things to do 1/2 hour before the observation

You don't need to waste telescope time doing this! You can and should take your time to do these steps BEFORE your scheduled observation time starts. When that happens, you will be much better prepared.

Have a vnc server running at AO and a vncviewer running in your computer viewing it, and open at least one xterm inside it.
Call the operator at (+1) 787 878 2612, Ext. 211, and make sure you learn what is the password for user "dtusr" at "observer2". You should also ask him about the status of the receiver(s) you are about to use.
In the xterm in your vnc session, type:

> ssh -X observer2 -l dtusr

... and then enter the password obtained from the operator.
This will be enough for most purposes. However, if you want extra monitoring capability and a have a fast link, you can do the following:
From this or another xterm at AO, type

> /home/aoui/bin/aostatus

(or just "aostatus", if /home/aoui/bin/ is already in your $PATH environment variable). Like CIMA. this shows you the present attitude of the telescope, but with a lot more variables being displayed. See details here.
Then, on the same window, you can also type:

> rxview &

This will let you know the status of the IF/LO system: sky frequencies allowed in by the receiver filters, Intermediate frequency path (from telescope to control room) as translated to a sky frequency, filter and backend frequencies as translated to sky frequencies. This program is now being fully supported.

NEW! IF you want to have access to the engineering screens instead, which provide detailed information on the IF/LO setup, telescope pointing parameters and tie-down status, as seen in the control room, but with a nice friendly format, then call, on observer2:

> monallsm &

This program will only run on Sun workstations, like observer2. If you have a slow connection, you can setup the refresh time for these screens. Alternatively, you can request larger screens, exactly the ones you see in the control room. Click here for more information.

Start Observing!

You are now ready to start! You can now call the version of CIMA that runs the telescope.
Take another deep breath... When your observation time starts, just type, in "observer2":

> cima

It will ask you to choose a version of CIMA (we recommend "normal"). After you introduce your name and project number, you will be authorized by the operator, if this really is your scheduled time. If there is an observing session still going on, you should call the operator and ask him what is happening.

In addition to all the features of CIMA available to on-site observers, the version that is run remotely has a "chatterbox" facility, in which you can send written messages to the operator and read his replies. This is specially important if there are any problems with the observation.
On completion of the observing run, the observer informs the operator that they are finished observing and are about to hand back control of the telescope. If the observer is still in control of the telescope AFTER his/her alloted time and has not received authorization to do so, the operator has the option to abort their data-taking process.
After you log out of CIMA you kill the VNC window running on your computer. Finally, you must log into the AO computer where you have the vncserver session running from an xterm in your computer (or the same terminal you used to create the vnc server) and do the following, in order to not monopolize resources:

> vncserver -kill :4