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%\section {Starting up the INT}
\section {STARTING UP THE INT}
\label{ch5:INT-start}
Unless there are strong operational reasons, the observers should expect to
have access to the Telescope and its Instrumentation from 1600 Local Time
onwards. The Duty Technician  (DT) will have made a series of tests 
 on the Telescope, the Dome, the Computers and the 
Instrumentation before the INT is handed over to the Telescope Operator and the
Support Astronomer. 
(There should be a DT checklist available in the Control Room.)
The telescope will always be left by the DT in one of the
park positions, {\it i.e.\/} Zenith for Cassegrain, and ``Access'' for Prime
Focus configuration. Before the observers can start with preparing for the
night, the Telescope Operator will carry out several checks.

\subsection   {Initial action by Telescope Operator}
\begin{enumerate}
\item
Handover the telescope to the Telescope Operator (TO) normally takes place
at 1600 Local Time. By then the TO will have read the white board in the
coffee room (first floor) to find out who is the Support Astronomer (SA), and
who the observers are. He should find out whether the SA will be present on
the mountain that night, and in any case contact him, perhaps at dinner, to
discuss any particular problems which are to be expected.
\item
The telescope should be found in the following state after the DT checks:
\begin{enumerate}
 \item Power to both Telescope and Dome on.  (Section \ref{ch15:utility})
 \item Telescope Control program running.   (Section \ref{ch7:statenorm})
 \item Oil pump and air compressor on. (Section \ref{ch15:oilpump})
 \item Encoder Zeroset complete.(Section \ref{ch11:zeroset})
 \item Emergency Stop activated.
\end{enumerate}

\item
Inspect the telescope logbook (on the Control Desk) for the most
recent information about the condition of the telescope. Further information
may be found in the INT\?BEWARE leaflet, which must be kept 
with this manual in the Control Room.
\item
Note that the T/S~DOME \button{STOP} button is illuminated, indicating a 
stationary telescope.
\item
Make the ICONA Meteorological Station readings (Section \ref{ch14:ICONA}), but
only if this does not interfere with observing or the taking of calibration
data during twilight. Further, read the rain gauge if there has been any 
precipitation during the last 24 hours. 
\end{enumerate}

\subsection   {Preparation for observing by the Telescope Operator}
The following checklist is for normal operation in good weather conditions.
However, some of the following actions should be done also in bad weather.
Remember that the dome may {\bf not} be opened in adverse weather conditions, 
{\it i.e.\/} with strong winds over 80\,km/h, with more than 90 percent 
humidity, with ice on the dome (which can fall in), and with high outside 
dust levels. Note that, if at night the humidity drops quickly from 100 percent
(after rain or dense fog), the dome will be opened only at below 80 percent, 
in order to give the dome structure time to dry up.
\begin{enumerate}
\item
When convenient, {\it e.g.\/} in the afternoon, input any long catalogue files
that the observer may require, 
such as seeing standards or target lists for the observer, by typing 
at the user interface console:

\UI{INPUT filename}

where {\tt filename} is the name of the catalogue (Section \ref{ch8:catalogs}).
If a file extension is not specified, it is assumed to be `.CAT'.
A maximum of 500 objects can be entered. 

\item 
During or after dinner discuss with the observer(s) any special requirements 
they
may have, and determined at what time they want to open up. Good communication
between the TO and SA and the observer(s) is essential for a smooth operation
of the telescope.

\item
With the telescope at Zenith (Cassegrain) or Access Park (Prime) position, fill
the CCD dewar(s) with liquid Nitrogen. This is normally
the first thing the Telescope Operator does after dinner. Note that the dewars
have to be topped up whatever the outside weather conditions.

\item
Check that the INPUT fan on the ground floor and the EXTRACTOR fan on the 
second floor near the telescope base are both on. The latter fan can be reached
via the small Coude room, opposite the CLIP Centre (beware oil on the floor!).
 If the fan is not working,
switch it on by pressing the green start button. This will also
start the INPUT fan on the ground floor. Both fans are essential in the control
of the dome temperature and hence the dome seeing. 

Obviously, when the dome may
not be opened because of adverse weather conditions, these fans must be or
remain switched off.
\item  
Close all doors and pull down the blinds in the library and the restroom.
\item   
Switch off all unnecessary white lights. Safety lights will automatically come
on at various points in the building.
\item   
In the afternoon, as soon as the outside temperature becomes lower than the
inside temperature, open the dome as follows, in order to thoroughly ventilate
the dome interior: Turn the dome slit position to the East
(azimuth = 90 degrees) and raise the Upper Shutter to an aperture
of about 1 metre. Press the \doublebutton{RAISE}{MICRO} on the Engineering Rack
 until the MAIN OVER
TRAVEL indicator light switches off, and then press the
\doublebutton{RAISE}{MAIN} button until the required aperture is made.
\item 
Remove lids from the fan ducts (if necessary) and start the 
dome fans, subject to current practice. Replace fan covers if    
it clouds up.  
\item 
Open the dome fully by pressing again the \doublebutton{RAISE}{MAIN} for
about 10 seconds; the MAIN OVER TRAVEL light should now be on again. Further,
the dome lights should be extinguished to avoid throwing unwanted 
light in the direction of the other telescopes when the dome is rotated. 
\item
Execute the encoder ZEROSET procedure, in order to obtain the hardware 
zeropoints of the Ferranti Encoders. This procedure consists of carefully
moving the telescope in engineering mode through zenith in both RA and Dec,
and is described in detail in section \ref{ch11:zeroset}.
\item
Open the cover of the Finder by pulling the cord, and attach the ring to a 
rivet located on the mirror cell nearby. 
\item
If working at Cassegrain remove the Primary Mirror Plug as follows:
\label{ch5:pmplug}
\begin{enumerate}
\item
Change over to engineering mode by pressing the \doublebutton{ENG}{COMP} button
on the Telescope Control Desk.
\item
Move the telescope to the North Horizon Limit; use an Hour Angle of exactly
24.00 hours, so that the telescope needs to be moved in Declination only.  
\item
Press the Declination \button{QM} (Quick Motion) button on the Engeneering Rack
until the green light
comes on to signal that the mode is engaged. The corresponding light of the
\button{SM} (Slow Motion) button must be off. If wanted, one can adjust the
quick motion speed by turning the QM RATE dial just above these buttons.
\item
Press the Declination \button{$+$} button, which actually moves the telescope,
until the alarm sounds as sign that the telescope has run into a limit. Now
press the \button{Accept} button on the Control Desk to switch the alarm off.
\item
Turn the key-operated LIMIT switch on the Engineering Rack to the O/R position
(limit override). The key no.\,6 must be inserted before the switch can be
operated. (If the Key is not in the switch, it will be in the Key Press, which
in its turn can only be opened by the Duty Officer!)
\item
Repeat steps d) and e). This time there will be no alarm, but the telescope
will halt in horizontal position when it runs into a second limit switch.
\item 
Use the ladder on the observing floor to get at the primary-mirror plug. 
Place the ladder such that it fits within the two brackets on the bottom half 
of the cube. Climb into the cube and remove the plug. Put the ladder in a 
safe place on the dome floor.
\item 
Press the Declination \button{$-$} button to move the Telescope back to the
the pole position at declination 90\degs.
\item
Turn the LIMIT switch to the NULL position and push the Declination \button{SM}
button.
\item
Change over to computer mode by turning the spring-loaded key on the Control
Desk against the spring for a moment. Subsequently,
press the \button{ZP} on the System Control panel on the Control Desk
in order to park the telescope at zenith. 

{\bf Beware!} If no ZEROSET was done previously, or if there are problems 
with the encoders,
the telescope can move to an incorrect position when sent to zenith in computer
mode. Therefore, keep an eye on the RA and Dec gauges or check the telescopes
behaviour through the control room window. Alternatively, move to zenith in 
engineering mode.
\end{enumerate}

\item 
If not yet done before, change over to Computer Mode by turning the key on the
Control Desk to the right against the spring. The COMP light should come on and
the key will spring back to its original position. If the COMP light does not 
come on check that:
\begin{enumerate} 
\item
both RA and Dec slow motion (SM) clamps are engaged (indicator lamps
on Engineering Rack, bay 5).
\item 
the \button{RESET} button has been pressed after an emergency stop.
\item 
No alarms are active.
\end{enumerate}

\item
If it is dark enough, switch on the TV cameras and their corresponding 
monitors (Finder and, if appropriate, Cassegrain) and the Autoguider, using 
the buttons on the control desk (see figure \ref{ch2:fig5}).
\item
Open the secondary-mirror cover and primary-mirror 
cover IN THAT ORDER (something might drop from the Top End!), 
by operating the PRIMARY
MIRROR COVER and SECONDARY MIRROR COVER \button{OPEN} buttons
on the Engineering Rack. The 
secondary-mirror cover button needs to be pressed only once but the primary   
mirror cover button must be kept depressed until the OPEN light  
is illuminated.  Further, note that the secondary-mirror cover must also be 
opened when operating at Prime Focus.   
\item 
If SET, GUIDE or INCREMENT rates other than the defaults are to be used, enter
these via the User Interface
(see Section \ref{ch8:UICD}) and press the corresponding buttons on the
Telescope Control Desk to `activate' the new values.
\item 
Focus the telescope (section \ref{ch11:focus}). In Cassegrain mode, this is
done by visual inspection of the image of a bright star on the Cassegrain
TV (which is accurate enough). The focussing procedure for Prime Focus
work uses a sequence of 7 short exposures on the CCD 
(under ADAM control) of a star for different focal positions to determine
the best focus setting.  The FOCUS procedure is described
in detail in section \ref{ch11:focus}.
\item
Perform a Single star SNAFU on a star near the zenith in order to determine
a software zeropoint for the Pointing Model (see Section \ref{ch11:1-snafu}).
The Telescope Operator will normally take a star from the SAO Catalogue
within 2 degrees from zenith with an eye on the ensueing determination of the 
finder zeropoint (very important for Prime Focus work).

The SNAFU at the {\bf Cassegrain} Focus is done as follows:
\begin{enumerate}
\item
Enter the coordinates of the star at the User Interface (see section 
\ref{ch8:enter}): use the SOURCE command and use object name {\it e.g.\/} SS.
\item
Drive the telescope to the object: make the SNAFU star the next 
object with the command  {\tt NEXT SS} and  press
the \button{SRCE} button on the Telescope Control Desk.
\item
Wait until the telescope is tracking accurately.
\item
Type at User Interface:-

\UI{SNAFU}

\item
Turn up the gain of the Cassegrain TV until the star is clearly  
visible and use the handset to place the star at the required    
reference point (usually the Grinnell crosswires).   
\item
When satisfied with the SNAFU star's position, press the \button{ack} button 
on the Control Desk (Bay 2, Rack 3) to reset the collimation   
corrections in the pointing model. 
\end{enumerate}
The SNAFU at {\bf Prime} Focus is done completely differently by means of a
test GLANCE exposure on the prime focus CCD, under ADAM control (see section
\ref{ch11:pfsnafu} for more details):
\begin{enumerate}
\item Startup ADAM (See the Prime Focus User Guide)
\item Move the rotator to position angle 180\degs \  with the ADAM command
      ROTPOS 180.
\item Slew the telescope to the SNAFU star, as for Cassegrain mode.
\item Take a test GLANCE exposure of the field (1-5 seconds; use filters if
      the star is very bright).
      The CCD image will appear on the LEXIDATA and the star should be
      obviously visible near the centre of the chip.
\item Use the MOVESTAR command, and locate the star with the cursor.
      ADAM wil now calculate a position correction and send those via the
      link to the Telescope Control Computer. The telescope will move to
      the corrected position: the star will move on the Finder TV image.
\item Mark the position of the star now on the Finder TV screen with a felt
      pen or similar marker.
\item Now send the telescope again to the original position by pushing the
      \button{SCRE} button.
\item Type at the User Interface:

      \UI{SNAFU}

      and move the telescope with the handset such that the star 
      image on the finder will coincide with the position marker.
\item Press the \button{ACK}
\end{enumerate}
The reason behind the last three steps is that allthough ADAM sends the
corrections to the Telescope Control Program, this does not update the
pointing model zeropoint. That is done in the same way as for Cassegrain
mode during the last three steps.

\item
Finally, determine the Finder Zero Point with the telescope still pointing to
the SNAFU star:
\begin{enumerate}
\item
Select the Finder on the TV monitor on the Control Desk.
\item
The SNAFU star must now be visible at, or very close to, the centre of the
finder field. It's position corresponds to the centre of the Cassegrain field.
\item
Press the \button{MENU} button and select "SET FINDER ZERO POINT".
\item
Put  the cross upon the star with the Grinnell joystick (on the Control Desk).
\item
Press the \button{Enter} button; this sometimes has to be repeated.
\end{enumerate}
\end{enumerate}

\subsection   {Summary}
\begin{enumerate}
\item
Confirm handover with Duty Technician.
\item
Fill the cryostats.
\item
Check to see if the dome temperature is higher than that    
of the outside air. If it is then: 
\begin{enumerate}
\item
Move the dome to azimuth 90 degrees, and open up 1 metre.
\item
Check that the EXTRACTOR fan by the telescope base is on, and that the 
INPUT fan on the ground floor is on.    
\end{enumerate}
\item
Read the Telescope Logbook and check INT\?BEWARE documentation for 
reported faults or hazards.
\item
Check T/S DOME STOP is active.
\item
Take ICONA Meteorological readings (when the TO has some free time).
\item
Input files of standard stars and target objects into the
 PE\,3220 Telescope Computer.
\item
EXTRACTOR fan ON, if not already done.
\item
INPUT fan ON, if not already done.
\item
Shut all doors and window blinds.
\item
White lights out.
\item 
Remove dome fan covers, if not already done. Dome fans on.
\item
Dome access doors closed.
\item
Dome lights out.   
\item 
Open Dome fully. 
\item
Finder cover open.
\item
ZEROSET
\item
Primary mirror plug out (Cassegrain focus only).
\item
Secondary and primary mirrors open. 
\item
Telescope in Computer Mode.
\item
TV Camera(s) and Autoguider on.  
\item
Input SET, GUIDE and INCREMENT rates, if other than default values used.
\item
Focus the Telescope.
\item
SNAFU.
\item
Finder Zero Point
\end{enumerate}
\vfill
\eject
