Observing scripts can be generated automatically through the
Observing Script Generator
or crafted manually. If done through the web, the script will be uploaded and within a few minutes available in
~obs/scripts/proposal-ID, where proposal-ID refers to the proposal ID entered in the web
form (e.g. 38-042). If the directory does no exist, it will be created. If you make your observing scripts manually,
first make the proposal ID directory (using mkdir) and place them therein.
The scripts are executed from the sequencer window, from the directory where they are placed.
Note that if you are saving scripts or files elsewhere in the ~obs account, the directory
will be cleaned up after every run and it will not be possible to recover them.
Create a TCS Target Catalogue
A source catalogue can be made well in advance of your observations by using the web interface,
NOT Source Catalogue Creation.
Note that it is also possible to enter targets on-the-fly and create a catalogue directly on the
TCS while observing (See section, Loading Target Catalogue).
Exposure Time Calculator
The Exposure Time Calculator
can be used to estimate the required exposure times for ALFOSC, NOTCam, FIES, MOSCA and StanCam (both in
imaging and spectroscopy mode, where it is available).
In the ALFOSC sequencer switch to the directory
associated with the override program, for instance
[obs@selena][ALFOSC]$ cd ~obs/scripts/38-035
Run any calibration scripts that are required by the
Loading the TCS Target Catalogue
On the TCS, press the catalogue button CAT to view the object catalogue.
If you want to erase the current catalogue that is displayed, type
erase-catalogue on the TCS.
Load a source catalogue by typing read-catalogue catname.cat on the
TCS, where catname is the name of the catalogue. A source catalogue can
be created by using the
or the objects can be added directly to the current TCS catalogue by pressing
the key, Enter Object (2) and then type according to the example below:
Name RA DEC Epoch ProperMotionRA ProperMotionDec Magnitude
SN1995N 14:49:28.27 -10:10:15.40 2000.0 0.00 0.00 0.00
The proper motion should be given in arcseconds/year
Add a catalogue of blank fields, if needed, for obtaining twilight flats fields
by typing read blanks on the TCS.
To select an object, press the catalogue button CAT on the TCS, and then use key
number 1 or 7 to move to the next or previous object, or use the
Prev/Next buttons to scroll up/down an entire page. The telescope will move
to the selected target when pressing the key Preset to selected (4), or if
observing on the parallactic angle, pressing the key Preset to par ang (6).
TCS access code
Any instrument computer which needs access to the TCS, for instance
to move the telescope during slit acquisition or dithering, will ask
for the current TCS access code at start-up. This
code is updated every day (around lunch time). When you are asked to
supply the TCS access code, do the following:
On the TCS VT510 terminal, make sure that the brightness
is turned up
On TCS type: Show-Page and then 1 (or type
sh-p 1 for short)
The TCS access code is shown on the top part of the screen
as: AccessCode xxxxxxxxxx
Starting the FIES and STANCAM software
On lisa choose selena in the XDMCP host-menu and log in as
user obs .
This will start the FIES and STANCAM observing software. For
each instrument there will be 2 white Sequencer windows where
commands can be entered.
Aditionally the FIESTA status window, the Sequencer's Talker
window, and the TCS Status Display are started. These programs
allow to monitor system status.
Finally a small window with an orange 'handset' is started,
which allows to tweak the star towards the fiber.
In the Talker you will find information about the correct start of
the different software components or a corresponding error. If any
errors about a program not starting are seen, please shut down the
observing system and start it again.
In all the SEQUENCER windows change the working directory to the one
assigned to your program, for instance
[obs@selena][FIES]$ cd ~/scripts/38-053
as in this directory your FIES observing
scripts can be found, created, and executed.
In a FIES SEQUENCER window set the OBSERVER FITS header
to hold the name of the actual observer(s):
[obs@selena][FIES]$ observer "Your Name"
and do the same in one of the STANCAM SEQUENCER windows:
[obs@selena][STANCAM]$ observer "Your Name"
This will remove the RED
"no-observer-specified" alert in the small "FIES Run Selector"
window, and will show the new value of the OBSERVER FITS header
nicely in GREEN instead.
The "FIES Run Selector" window is the one bottom-left on the screenshot below.
For a list of available SEQUENCER commands type 'help' on the
SEQUENCER terminal windows or see
For FIES it is recommended to obtain at least one set
of calibration frames. This can be done using the script fies-calibs,
which by default will obtain 7 biases and 21 flats. The script takes
about 30 min to run, and can be issued from the
FIES sequencer in the following way:
Once the telescope power is on, and possible ALFOSC flats have
been taken, run the script
in a FIES/STANCAM Sequencer window. The script
needs to be run after every swap between instruments (e.g. for
overrides) as well.
When it is dark outside, switch on the two guiding monitors, and
activate the guider at the TCS terminal :
Note that tv-on needs to be issued every time the telescope
has been parked at zenith.
Telescope Startup Procedure
Return to the dome at least 30 minutes before twilight and follow the instructions below.
> 90% - Close telescope
After 20min < 90% the telescope can be reopened.
12 m/s - Close sideports and lower hatch
10 m/s - Close sideports and lower hatch
If the humidity is > 90% and the temperature is < 0° C close telescope and do not open until all ice has melted on the outside of the dome.
15 m/s - Observe down wind: at least 85 degrees in AZ away from wind
12 m/s - Close telescope
20 m/s - Close telescope
Telescope Control System (TCS)
Turn up the brightness of the TCS screen (on right-hand side, below the screen).
Look at the top-left of the TCS screen. If the item ST isincrementing, then the TCS is running, if
not - then the TCS needs rebooting
(rebooting the TCS
should be done under guidance of a staff member). Type refresh if the screen looks strange.
Telescope power-on and Dome Opening
Check the safety system in the computer room.
Reset the system by turning the left key (marked as "First") and then the right key (marked as "Second"),
one at a time (See TCS Manual Sect. 10.1
for procedure). If you hear a repeated clanking sound then the system has not reset, check the red lights
above the keys to see if a safety stop or other item is set.
Type on the TCS, power-on and confirm with y for yes. Look at the status page number 1 (type sh-p 1).
On this page the status of the power units for the telescope motors can be viewed. When the TopUnitPower
is on and the telescope is Idle, the telescope is ready to use. The power-on procedure takes about
one minute in total.
Dome can be opened about an hour before sunset if you first turn telescope to the hoist position tcs.Building-Hoist-Position or point to a blank field which is away from the sun tcs.goto Blankxx+xx. Upper hatch and lower hatch can be opened normally, but leave north sideport closed tcs.open-side-ports-fully west south east. After sunset open north sideport as well tcs.open-side-ports-fully.
At sunset, if weather conditions are OK, open the upper hatch with the mirror covers closed.
Press the key, START/STOP on the TCS and then the key Open Upper Hatch (7). Confirm by typing y
for yes. It takes about 3.5 minutes to open the upper hatch.
In the dome (While the upper hatch opens) check that nothing is in the way of the telescope motion (altitude: 6.5° - 90°)
Open the side ports (only if
weather conditions are OK and the sun is under the horizon).
Type on TCS, open-side-ports-fully. Look at the TCS status page number 3 (type sh-p 3). Status page 31 shows more
details, but is delayed in updating.
For manual opening procedure of the sideports see
Sideport Operation .
The side ports can be operated individually and opened before sunset by typing in TCS
open-side-ports-fully south or respectively east, west, north based on the sun position.
Open the lower hatch (only if weather conditions are OK).
On the TCS, press the keys Start/Stop
and Open Lower Hatch (8). Confirm with a y. It takes about two minutes to open the lower hatch. The TCS
will not allow opening of the lower hatch before the upper hatch has completed opening. In case you can only open the
upper hatch, the maximum zenith distance for unvignetted observing is 55°, and at a zenith distance of about
70° roughly half of the mirror is vignetted.
The mirror covers can be opened at the same time as the lower hatch. On the TCS, press the keys
Start/Stop and Open Mirror Covers (9). Confirm with a y. It takes about 50 seconds to open the
mirror covers. Please note that the power for hatches and mirror covers is completely independent of the telescope
power and the electronics in the control room.
Set default telescope parameters
This should be done in any sequencer terminal with
This sets amongst other items, the default telescope focus and rotator
angle, and auto-pos-full for fully automatic autoguiding when pointing
to an object.
In an alt-az telescope the field rotator is used to keep the orientation on
the sky fixed while tracking. When the field rotator is in automatic mode,
which is the default, the TCS command field-rotation value sets
the rotator such that value is the angle between the sky and
The default value of the Field Rotator is different for each
instrument and can be found in Table 1.
The field-rotation value will be set to the default angle when executing the script
The rotator-position is the physical position of the rotator
with respect to the telescope fork, and it has a limit at +- 200
degrees. Its current value is shown on the TCS status display together
with the time-to-reach-limit in minutes.
Before reaching the limit, the TCS will send a warning and suggest you
to turn the rotator 360 degrees at any convenient moment. This can be
done manually with the TCS command ro-tu-360 after switching
off autoguiding with ag-off. Note that this is possible only
in the overlapping ranges [-200,-160] and [160,200].
If the limit is reached, the TCS will eventually, after repeated
warnings, perform the full rotation automatically (whether or not an
observation is ongoing).
The exposure commands for ALFOSC, FIES, MOSCA
and StanCam check whether the rotator limit is reached within the exposure time,
if this is larger than 300 seconds. For NOTCam, where typically multiple short
exposures are made, this is not the case.
If you want to follow the same target continuously for
many hours, and you wish to avoid having to turn the rotator, for
instance because you want your target on exactly the same pixels all
the time (transit light curves), you might consider using a different
field-rotation value, based on the time-to-reach-limit value displayed
on the TCS UIF.
For the case that right after the telescope pointing the rotator will
start off in the overlapping rotator range, the telescope can be told
to automatically point using the rotator position that allows for
maximum tracking time, with tcs.set-rotator-standard, which is
the default behaviour. For details see
the TCS documentation.
If you have many pointings with relatively short exposures or you keep
pointing towards the same region of the sky, you may save some
pointing overheads by making the TCS choose the fastest rotator slew
to reach either of the overlapping rotator ranges: set the rotator to
fast mode using tcs.set-rotator-fast, which is a sticky
command. To go back to the default mode, use the command
Note that for FIES programs that aim for accurate radial-velocity
measurements we point the telescope using a fixed rotator
position. This is achieved when using the command
tcs.guide-object-with-parallactic in the sequencer, or
preset-with-parallactic in the TCS interface.
The Camera Probe is used for the standby Camera (StanCam) and for FIES and should be
put in park position for all other instruments. Put the Camera Probe in the correct position
by typing the TCS command as indicated in Table 1.
The correct Camera-Probe position will be set when executing the script
It is recommended to have the telescope autoguide on an optical source
close to your target object. The TCS is automatically selecting a star
from the HST guide star catalogue. The guide probe is then
automatically placed at the correct position to auto-guide on this
After obtaining sky flats, switch on the two Guide
TV monitors above the TCS monitor. When it is dark outside, type
tv-on on the TCS to power on the TV guide camera.
Alternatively, use in any Sequencer window
The TCS command tv-off switches the TV camera off.
On the TCS, type auto-pos-full to choose the fully automatic guiding mode.
Note that this is the default guiding mode as set in
In this mode, a guide
star will be automatically found, centered on the screen and
autoguiding will be switched on (ag-on). If the guiding
does not start automatically but you see a guide star on the TV
monitor, type auto-pos-retry.
The TV filter can be adjusted to the intensity
of the guide star by typing tv-filt name on the TCS,
where the options for name is Open, Closed, Grey, Red,
Yellow or Blue. Choose an appropriate TV filter based on
the brightness of the guiding object and keep an eye on the guide
monitors during your observations so you can change TV filter after weather conditions and
brightness of the guide stars.
The autoguider TV focus is also set by the script
tcs.setup-tel-<inst>. The TV focus is depending on
instrument and can be adjusted by typing tv-foc value on
the TCS, where the value for default focus is found in Table 1.
If you wish the TV-focus to follow the telescope focus type
au-t-f (Automatic-TV-Focus, default setting) on the TCS, else
to restrict to only manual TV-focus settings type ma-t-f
In automatic mode, after every pointing of the telescope the TV-focus
will be set to a default value that takes the telescope-focus position
into account. If that value is not adequate, you can recalibrate the
TV-focus on the spot: after adjusting the tv-focus type
calibrate-tv-focus in the TCS interface.
Note, do not change the TV-focus while integrating or while placing
an object on a slit. For example, the position of a star on ALFOSC CCD
can move up to 1 second of arc by adjusting the TV focus by 25 units.
If you want to choose a new guide star, type
get-guide-star 2 (or 3,4,5, etc.) to get a new guide star from the guide server
at the current pointing, followed by auto-pos-retry.
On the TCS, the signal strength from
the autoguider is shown as a number. A guiding value between 1 and 23
is useful. Put in a filter if the signal is above 24, otherwise the TV
filter will be set to grey automatically.
If the signal is close to 1 the autoguiding is not reliable
(e.g. clouds and/or bad seeing).
Set tv-filt open and check for
Make sure that the smaller box, the sky box is
placed outside the star box. If needed, move the sky box by selecting
the function Sky Box with Change move mode (5) and move
the box with the keystroke combination, Alt Function + arrow
Always turn-off autoguiding (ag-off) before moving
Hints for manual guiding and tweaking of telescope pointing
If guiding mode is set to auto-pos-off, the guiding has to be activated
manually. Furthermore, in case that the pointing is not optimal, some
manual tweaking may be required.
For manual choosing of a guide star, start with preseting to
target. Find a guide star on the screen and move the star box to the star
by pressing the key change move mode (5) on the TCS several times until
the option Star Box is shown. Move the box by using the keystroke
combination Alt Funtion + arrow keys. Alternatively, choose the move mode
Guide Probe to move the star into the box, or use the command move-g.
To set the step size of the Guide Probe, type probe-step-size x y on the
TCS, where x and y are in arcseconds.
In case the telescope pointing is not optimal, in particular if the guide star
ends up outside the screen, a pointing correction can be made with the move
mode called Telescope: press the key change move mode (5) on the TCS several
times until the option Telescope is shown, and move the star by using the
keystroke combination Alt Funtion + arrow keys. The step size of the
Telescope is set with the command offset-size on the TCS UIF.
Alternatively, if no guide star can be found on the screen, use get-guide-star
2 (or 3,4,5, etc.) to get a new guide star from the guide server at the
If still no guide-star is seen on the guide TV,
tool allows to identify suitable guide stars: in "Guide probe" view, use the pointer
to read off (GP_X, GP_Y) coordinates of a suitable guide star inside the red-lined GP area,
and then use the TCS UIF to move the guide-probe to those coordinates with commands
x GP_X and y GP_Y.
When the star is placed in the starbox, type ag-on on the TCS
to switch on autoguiding. To switch off the autoguiding, type ag-off.
As of the Summer of 2014 we have activated a new guiding mode, using
the FIES target itself to give additional low-frequency guiding
corrections. This mode can only work properly when normal guiding
(see above under AutoGuiding) is enabled.
Apart from giving additional guiding corrections, the fiber
guider can position the star on the fiber much faster than in
manual acquisition mode (the orange buttons, see the Target
Acquisition section below).
In order for the fiberguider to work properly, the observer has to
check the position of the fiber at the start of the acquisition
procedure. If necessary, the command stancam.fibpos-man fiberNr (with fiberNr either 1,3,4)
should be used to interactively reposition the guiding hotspot,
i.e. the green cross. This is especially important after switching
to another fiber, or after putting a different filter in the STANCAM
During acquisition and the subsequent FIES exposure, the fiber guider
will analyse the continuously incoming STANCAM fiberviewing images,
and will overlay the derived positions of the target and fiber on the
postprocessing DS9 display:
green cross: guiding hotspot, should be placed on the center of the fiber
blue cross: computed fiber position (only after a few movie images are
red cross: computed target position
In case more than one object is visible in the on-fiber guider FOV,
the fiberguiding needs to be switched off manually on the
Focusing the Telescope
Focusing the Telescope
The telescope focus depends on temperature and zenith distance. These
relations have been measured to a high accuracy and the corresponding
corrections are applied in real time by the TCS (note
that you will not see these corrections in the focus value displayed on
the TCS since this value is kept constant to avoid confusing the observer).
The telescope should be focused while in fiber-viewing mode (camera-probe-fies).
Note that this means that the images will not be in focus in
For routine operation of FIES, use the default telescope focus for FIES (see
The default telescope focus will be set when executing the script
For more detailed information, follow the link and read about how to
focus FIES manually.
When the telescope is focused it is time to start the observations.
Visit the individual pages for instrument specific information:
Run any scripts that are required by the override program
When ready, switch back to FIES. In a FIES/STANCAM Sequencer
window, run the script
The Atmospheric Dispersion Corrector (ADC)
If you plan to observe targets at airmass larger than 1.5 you may consider using
the ADC. The ADC consists of a pair of rotating wedges that
counter the effect of atmospheric dispersion, and thus ensure minimal
wavelength-dependent fiber losses. The wedges have to be adjusted
according to the altitude and rotator angle of the telescope.
To use the ADC, issue the following commands before pointing
to a new target:
The goal of target acquisition is to get the star
on one of the fiber apertures.
Target acquisition: a 100x100 pixel StanCam (camera-probe-fies) window around hole 1 (low-res
fiber, 2.5 arcsec aperture diameter), with the star 5 arcsec away from
the aperture (left) and almost centered on the fiber (right).
Circumstantial info for target acquisition
Image scale on StanCam with camera-probe-stancam: ~0.18 arcsec/pixel
Image scale on StanCam with camera-probe-fies: ~0.24 arcsec/pixel
Approximate telescope focus with camera-probe-fies : 26880
Approximate guide-tv focus with camera-probe-fies: 550
Approximate FOV diameter of holes in fiber mask: 20 arcsec
Approximate diameter of hole in mirror of the low-res fiber: 2.5 arcsec
Approximate diameter of holes in mirrors of the med- and
high-res fibers: 1.3 arcsec
Field orientation for 'field-rot = 0' on the initial full-frame StanCam acquisition image with
Field orientation for 'field-rot = 0' on the windowed StanCam 'movie' images with
Note the flip in Y between these two acquisition modes. For acquisitions with a different
rotator angle, e.g. when using the 'parallactic' option, the orientation will be correspondingly rotated.
To setup the telescope for FIES run the following script
after switching on the telescope power, or after using other
instruments for science exposures:
Note that these commands are already done as part of the script setup-tel-fies .
Set the default focus for FIES, put in the
blue STANCAM filter, and set the default rotator angle
You have to use either a BVR or the Clear filter (filter
positions 2, 3, 4, 8): else the fiber entrance will not be in focus
If using the the ADC, make sure the ADC is in the beam and the corresponding focus offset is applied.
See above for instructions.
Slew the telescope to a target, and start guiding.
For programs that require an accurate radial-velocity
zero-point (planet-host RVs, etc.) we advise to make minimal
use of the telescope rotator.
In this case the telescope
pointing should be achieved with
Take a full frame image with StanCam
(e.g. binned by 2). The image will be grossly out of focus, but that
does not matter.
[obs@selena][STANCAM]$ bin 2
[obs@selena][STANCAM]$ exp 0.1 (or longer for faint stars)
Move the star close to the projected X,Y coords of the fiber of
choice (see top of this page), using the fiboff routine:
[obs@selena][STANCAM]$ fiboff N
where N is 1,2,3,4. This uses the postprocessing DS9 display; please follow
the instructions in the Sequencer terminal to tweak the telescope position.
After the telescope moved, press
'q' in the postprocessing DS9 window to stop the fiboff routine.
Switch to fiber-viewing, and switch on STANCAM 'movie mode'
where N is 1,2,3,4, exptime∼0.5, and hicut∼500
You can tune the color cuts while the movie is ongoing, using the
Sequencer commands hicut, locut, and zscale.
You can tune the fiber-viewing exposure time, while the movie is ongoing, using the
Sequencer command expmovie 10, for 10 seconds exposure time.
Note that at any time you can restart a movie, for instance to reset
the exposure time, using the fibNmovie
or fork-fibNmovie commands; any ongoing movie will be safely
killed automatically by these commands.
in case Fiber Guiding is not activated,
use the orange guide-probe offset keys to move the star onto the
dark spot (= fiber).
The star can be held centered on the fiber with or without TCS autoguiding
In both cases, the telescope will be offset to center the star.
If autoguiding is on, the guideprobe will be used to improve the precision
of the offset.
The window with the orange buttons also has an information field and two
buttons ("AG on" and "AG off") apart of the arrow buttons.
Messages to the user are shown in the information field.
When the "AG on" is pressed, the TCS autoguiding is turned on.
Similar, when the "AG off" button is pressed, the TCS autoguiding is
turned off. When the autoguiding has been found to be turned off, a orange
message in the information field saying that "autoguiding is off" will be
blinking. Every time a button has been pressed and the TCS is busy executing
the requested action, a message saying "=== Wait ===" will appear in the
in case Fiber Guiding is active, the FibGuider
will pull the star onto the fiber.
Check that the green cross is properly pointing at the center of the
fiber, and if it is not then use the command
stancam.fibpos-man fiberNr to interactively reposition the
guiding hotspot, i.e. the green cross.
If you have to start at step 1 then the whole process can take about
10 minutes. Experienced users will manage to do target acquisition in
less than 3 minutes.
Making target and calibration exposures: short guidelines
When you have centered the target on the fiber, and have autoguiding switched
on, you can either expose on the target or take calibration frames.
To make on-target exposures:
[obs@selena][FIES]$ object "my favourite object"
[obs@selena][FIES]$ exp 1200 (for example)
Calibrating the science fibers
The special SEQUENCER script called fies-calibs can be used to automatically obtain a full set
of calibration images in the afternoon and in the morning.
Simultaneous-ThAr mode: science exposures and calibrations
As the distance between the echellograms of the target and
the ThAr lamp is only several pixels, some ThAr light will scatter
onto the target spectrum. This is particularly evident in spectra
of faint stars. Affected spectral regions may have to be avoided in
the analysis of the spectra.
For this reason the use of Simultaneous-ThAr mode is discouraged.
The best precise radial-velocity observations can still be obtained using ThAr frames
taken just before and just after the science exposure(s).
For this mode there is a special SEQUENCER script called simulthar to
automatically allow some ThAr light into fiber #5 during a science exposure,
at fixed intervals.
The special SEQUENCER script called fies-calibs can be used
to automatically obtain a full set of calibration images, including a minimal
set of 1 ThAr and 1 halogen both through fiber #5.
Alternatively, the SEQUENCER scripts setup-fib5-halo,
setup-fib5-thar can be used to simplify the calibrations.
Required calibration: to trace the ThAr spectrum you need a
separate flatfield exposure with fiber #5.
lamp 1 off
Required calibration: to calibrate the wavelength offset between
the science fiber and the calibration fiber #5 you need an exposure
with both ThAr lamps directly after eachother (e.g. in the afternoon).
Note that we do not yet have much experience with the
reduction of data obtained in this mode.
The distance between the target and sky echellogram orders is only
several pixels. Due to the fact that the inter-order distance
decreases towards the red, the sky and target spectra of neighbouring
orders will get too close for comfortable reduction redwards from
Note that there is little scientific use for this
observing mode. This, because FIES is typically used for stars
brighter than V=15, for which the sky level in worst conditions is
around 10% of the target flux level. Directly subtracting such a
measured sky spectrum will result in a (very) noisy sky-subtracted
To observe in this mode the target should be centered on fiber 3,
while the fiber mask needs to be positioned such that both fiber 3 and
2 are opened. This is achieved with:
For calibrations we advise to calibrate fibers 2 and 3 separately, as
Using the exposure meter
Since fall 2008, FIES is equiped with an exposure meter that can be
used to monitor the count rates during an ongoing exposure. The
exposure meter picks off light inside the spectrograph that otherwise
would have fallen outside the bottom of the CCD. As the red orders
are longer than the blue orders, and hence more red light is falling
off the CCD, the exposure meter is more sensitive for red stars than
for blue stars.
Use the FIES exposure-meter count
calculator (EMCC) to find out what is the exposure-meter count
value that corresponds to the required peak S/N in the FIES spectrum
of your star. The dark current of the exposure meter is on the
order of 150 counts per second, and has not been accounted for in the
exposure-meter count calculator.
The most useful Sequencer commands to operate the exposure meter are
the exposure command 'exp-count', and
the counter commands 'expmcount' and
For example, to expose an M star to reach CCD counts corresponding to
a peak S/N=200, the EMCC tells you that 6 million exposure-meter
counts are needed. Then use the command
[obs@selena][FIES]$ exp-count 6000000 1800
which will readout when the exposure meter has reached 6,000,000 counts
or when 1800 seconds exposure time have elapsed.
Above the expected S/N per extracted spectral bin is computed as
S/N=sqrt(peak-ccd-counts * ccd-gain * profile-width), with the profile
width 7 pixels for the low-res fiber, 4 pixels for the med-res fibers
and 4 for the high-res fiber. For CCD15 the gain is around 0.14 e-/ADU.
See the FIES EMCC.
The exposure meter counts and count rates can be monitored graphically
on a separate page of the FIESTA window.
Using the exposure meter readings to compute a
photon-weighted midtime of an exposure
Since the start of P59, our OB-generator has been updated to always
have the exposure meter switched on during regular exposures with
user-defined exposure times. The readings of the exposure meter
have a cadence of about 4 seconds, and can be used to compute a
photon-weighted midtime of an exposure.
The (afternoon) calibration script fies-calibs switches on the
exposure meter during the sequence of bias frames, to record the dark
current of the exposure meter.
The readings of the exposure meter are published on a nightly basis on
End of the night
Overview of things to do at the end of the night
In case of an ALFOSC override:
Switch to ALFOSC. In the ALFOSC
Sequencer window, run the script
Run any sky-flat and/or calibration scripts that are
required by the override program
When observations finish and the sky is brightening turn the guide TV off
by typing tv-off on the TCS, i.e. before potentially taking morning skyflats.
Put the telescope to zenith by typing zenith or pressing the key
Start/Stop and then Zenith (0). This will park the guide probe and it also sets
rot-man. Wait for Rotator -90°.
Park the building by pressing the key Start/Stop and then the
key 4, Park Building. This process can take up to 8 minutes. Building will stop at Az
≈ 119°, Alt ≈ 90°.
Close the mirror covers with the TCS command c-m-c or by pressing
key 3, Close Mirror Covers (if you are in the Start/Stop menu).
This takes 42 seconds.
Close the lower hatch by typing c-l-h or pressing key 2, Close
Lower Hatch. This takes about 3 minutes.
Close the upper hatch by typing c-u-h or pressing key 1, Close
Upper Hatch. This takes about 5 minutes. If timeout occurs or hatch does not move, see
TCS Manual p. 43. NB: When the upper hatch has closed the dome cooling
will start and the staircase cooling will stop.
Close the side ports by typing on the TCS UIF close-side-ports.
Check that all sideports did close by checking status in TCS page 3, type sh-p 3. If a
sideport does not close, go to the dome and flip the black knob from remote to local and press
the green button to move the sideport in question. For more details, see
Power down the telescope. After all of the above have been completed, type
power-off on the TCS, then type sh-p 1 to display the telescope power units.
Wait until all the telescope power displays show "off".
Run the calibration script (if you observe with ALFOSC or NOTCam),
i.e. alfosc-calibs ALxxxx or notcam-calibs NCxxxx, where xxxx refer to the file prefix
for the night.
Turn down the TCS screen brightness. Use the knob on the right-hand side of the TCS
monitor, near the power switch. Never turn the TCS monitor off.
Turn off monitors. Turn off the two autoguider monitors and dome TV camera monitor.
Turn on the control room webcam and the dome webcams. Make sure that the webcams in
the control room as well as in the dome are turned on before you leave.
Have a look in the dome at hatches and telescope, to check for any faults that
might have occurred.
Complete the WWW report forms. Fill in and submit Internet
NOT End-of-Night Report.
Be sure to include any faults that occurred and submit a
so we can attend to problems promptly. If it is the last night of the observing run, also fill in and submit
Internet NOT End-of-Run Report.
Lockup the dome. Lock the outer dome door when you leave the building.
Clean up the kitchen/lounge area in the service building and switch
off all lights when you leave.
Lockup the outer door in the service building before leaving for the Residencia.
Only principal investigators have direct access to their data on the data server.
The principal investigators can grant access to their data by generating and
distributing a shared link. Details on how to do so can be found in the instructions.
General information on NOT FITS-headers can be found
Accessing raw and reduced data at night
The computer called florence is setup for you to make a quicklook analysis of
the incoming data, e.g. by starting up DS9 and IRAF:
> cd newiraf
> xgterm -sb -fn 9x15 -sl 400 -cr red -title IRAF -e ecl &
For the different instruments we have on-line reduction programs running, that
deposit the reduced products on a disk accessible on florence.
The raw and reduced data files can be found on florence under directories
Copying data products from florence over the wifi in the NOT control room to your
own mobile computer is no longer feasible. Use the
Data Download tool.
To obtain NOT data from our archive, first compile a list of file
names of the calibration and science data to be retrieved, using our FITS archive.
Note that this archive does not show the
data obtained in the latest twelve months, due to the propriatary
Then please contact staff and send the list of file names to be
retrieved, such that we can locate the data in our archive and make
them available through FTP.
Compensation for override observations
If your program was interrupted by a Target-of-Opportunity or
another override observing program, you are entitled to payback
time. Such compensation for time lost during your allocated
observing run (whether in visitor or service mode), is claimed
back through the submission of Observing Blocks (OBs) using our
OB Generator. The observations will be executed accordingly
in service mode by staff during Nordice Service nights, and you
will be informed by email when observations are made and where
to retrieve the data.
Using the OB generator to claim payback time
Observing Block Generator and login to your account, or if
you are a new user, please register. When you are logged in, add
your proposal for which you claim compensation time.
There are help buttons at every level of the OB generator, and you
can also get support and give feedback through
If you have questions about how to define OBs and/or Observing
Sequences, please contact
For your OBs to be carried out as compensation for time lost to
overrides, please make sure to select OB Group type "Payback".
Press the keypad key labelled Log and then keypad 2 to see the latest entries in the
... acquisition: slitoff/fiboff unresponsive
Using the mouse to set the contrast while image is loading?
Using the mouse to set the contrast while this process takes place can cause DS9 to crash. Best procedure is to wait tuning the contrast level until the image has been fully loaded into DS9, and zoom / contrast levels set.
A DS9 crash while in 'imexam' while leave the postprocessing system in a non-workable state.
Rather than shutting down the whole observing system to recover, it is in most cases sufficient to run the sequencer command 'killimexam'.
See also next item.
... ds9 shutting down while doing acquisition
Using the mouse to set the contrast while image is loading?
Using the mouse to set the contrast while this process takes place can cause DS9 to crash. Best procedure is to wait tuning the contrast level until the image has been fully loaded into DS9, and zoom / contrast levels set.
A DS9 crash while in 'imexam' while leave the postprocessing system in a non-workable state. Rather than shutting down the whole observing system to recover, it is in most cases sufficient to run the sequencer command 'killimexam'.
... "sequencer/obssys" does not respond or behaves badly:
Standard procedure in such circumstances is to restart the observing system using 'shutdownobssys'
(from a terminal window) followed by 'startobssys'.
... lisa frozen, not responding, e.g. can not log out using the foot icon
if you have a working terminal, try "$ killall panel", wait until the panel restarts and then logout as usual
if there's no terminal available, you can use florence to ssh as obs into the observing computer you've been using,
and type the killall command.
if you have no terminal available, etc. press the "Ctrl" and "Alt" keys and then press "Backspace".
That will kill the X server and force a logout
If you encounter a fault or a problem with the instrument, the computers or the telescopeduring the night, then fill in a
Table 1a shows the values of the: field rotation(field-r), instrument-parallactic-angle (i-p-a),
ccd probe, focusposition (foc-pos), TV focus (tv-foc), field orientation andcounter weight height (c-w-h) for
the different instruments. On the TCS, type thecommand followed by the value, for instance field-r -90.
The default focus value stated for NOTCam is for the K band in imaging mode using the WF camera (internal camera
focus of 5650).
ALFOSC no filter
StanCam R-filter (#10)
MOSCA R-filter (#106)
StanCam R-filter (#10)
NOTCam Ks-filter (WF)
StanCam R-filter (#10)
Table 1b shows the default focus offsets between the instruments.
Commonly Used Instrument Commands
kill ongoing command or script
kill ongoing exposure
Sets the value of the FITS keyword OBJECT to text
Turns on autosave. For off, type autosave_off
Sets the remote saving path to specified link
Turns on remote saving. For off, type remsave_off
Sets the binning factor in both X and Y directions to n
Sets the X beginning to n (use ybeg for y).
Sets the X size to n (use ysize for y).
Makes an exposure of t seconds. To abort the exposure press Ctrl-C
and type abort in the sequencer window.
mexpose t n
Makes n exposures of t seconds
Makes an dark exposure of t seconds
mdark t n
Makes n dark exposure of t seconds
teloffset n m
Offsets the telescope in the CCD X,Y direction by the amount n in the X direction
and m in the Y direction. n and m are given in arcseconds.
At the NOT there are two main modes of tracking a moving object (planet, comet, asteroid, satellite):
1) differential tracking with auto-guiding and 2) differential tracking without
auto-guiding. Which of these to use, depends in practice on the target speed and how long the
observations take. We have been working with speeds as high as 700"/hour with auto-guiding.
Since September 2019 the OB generator
allows for non-sidereal tracking.
The differential rates are given in the FITS headers in the keywords DTRCK_RA and DTRCK_DE.
Differential tracking with auto-guiding
In this mode, the telescope tracking is set to the differential rates, and in addition,
the auto-guider is used with the star-box set in motion with the same rates. This works for
as long as the box stays within the auto-guider TV-screen (approximately 70" field). When
the limit is reached, auto-guiding is no longer working. It is possible to reposition the
star-box and guide probe without affecting the telescope tracking, but there is a limit to
how many times this can be done before reaching the limit of the available guide probe area.
on the RA/DEC rates, the field-rotator angle, and the initial location of the guide star
inside the guide probe area. If this happens, you have to repoint to the target again.
If your target moves less than 70" over the execution time of your observations, you
can relax. If it moves more, you need to keep an eye on the star-box and manually re-position
it as described under step 3 below.
Both the telescope tracking rate and the box-motion rate are given in RA/DEC coordinates,
i.e. dDEC/dt and dRA/dt (in arcsec per hour), and the cos(DEC) correction is taken care
of internally by the TCS. (In other words, if your RA-rate is given as dRA*cos(DEC), you
have to divide by cos(DEC) before entering its value.)
From ephemeris get the target's position and coordinate motion for the time of
observation. Coordinate motion is the RA and DEC rates (dRA/dt and dDEC/dt)
in arcseconds per hour. We recommend to use the sequencer script:
tcs.asteph -n TARGET
where TARGET must be the official JPL Horizons name and surrounded by
escape double quotes if it contains a space.
The script looks up JPL Horizon and finds position and rates for this moment
at the location of the NOT (Z23), converts from dRA/dt*cos(DEC) to dRA/dt, as required by
our TCS, and lists the sequencer commands you need to point to target and start differential
tracking AND differential auto-guiding.
It is highly recommended to test tcs.asteph in the afternoon.
See example below (in green). Type tcs.asteph to get a listing of input parameters,
note that all optional parameters must be given before the "-n TARGET".
-t default type is "asteroid"
option "planet" selects for instance the Jovian satellite Europa instead of the asteroid Europa
-m default mode is "ima" using the default field rotation for imaging
option "para" for spectroscopy orients the slit along the parallactic angle
option "along-slit" orients the slit along the tracking direction of the target
option "optimal-ll" orients the field to maximize the number of guide-probe repositions
option "optimal-lr" 180 degrees rotatated to above, both recommended for fast targets or long observations
-r default tracking rate is "full"
option "half" gives the half-rates of the differential tracking (sometimes requested)
-n \"target name\" is mandatory (if it contains a space, use escape double quotes)
The two modes "optimal-ll" and "optimal-lr" are intended for very fast objects or very long observations.
[obs@selena ~][11:28][ALFOSC]$ tcs.asteph -n \"C/2019 Q4\"
* REMEMBER TO ESCAPE DOUBLE QUOTES. OTHERWISE YOU WILL OBSERVE WRONG TARGET
* For instance: tcs.asteph -n \"2019 K2\"
cd /home/postprocess/telescope/v3; source /home/postprocess/.virtualenvs/27/bin/activate; bash JPLHOR_to_NOTcat.sh -n "C/2019 Q4"
Your input target is - C/2019 Q4
Your observatory is Nordic Optical Telescope, La Palma.
Retrieving data from JPL Horizons...
Data retrieved successfully from JPL Horizons.
The object being searched for is Borisov_C-2019_Q4
Prefix for file names will be 2022-May-27.Borisov_C-2019_Q4
Today is 2022-05-27
Your computer says time is 11:28 UTC.
These tasks should be given to the TCS:
tcs.append-object Borisov_C-2019_Q4 17 41 17.92 -58 15 21.8 2000.0 0.0 0.0 25.612
tcs.reposition-guide-probe -12.5412 -0.46244
Cut and paste the three first sequencer commands listed by tcs.asteph (or point to your
target in the normal way), wait until guiding, and then cut and paste the fourth command or run it
tcs.reposition-guide-probe RA-rate DEC-rate
This is a script which will 1) stop auto-guiding and box motion (if it was set in motion), 2) move
the star box to an optimal position on the TV screen, 3) set the telescope tracking rates to RA-rate
and DEC-rate, 4) start the box motion to the same rates, 5) move the guide probe to put the star in
the box, and 6) start differential auto-guiding.
If this is a relatively fast target, i.e. moving more than 70" during the
time your observations take, you will have to keep an eye on the star box.
When it reaches the other edge of the TV screen, it will stop guiding. The
TCS will send warning beeps when there is 120, 90 and 60 seconds left.
Make sure you take action before guiding stops by re-running the command:
tcs.reposition-guide-probe RA-rate DEC-rate
in another sequencer window. You can do this while exposing, although it is
optimal during readout, in between exposures. This
repositions the box and the guide probe and continues differential autoguiding
without affecting the telescope tracking.
There is a limit to how many times you can reposition the guide probe due to the
limited guide probe area. If this happens, you have to start again from point 1.
The telescope resets to the sidereal tracking rates at every new telescope preset/pointing so nothing
is needed at the end of the observation.
However, for your information, you may stop the differential
guiding by tcs.box-motion-stop (or in short on the TCS UIF b-m-sto). This does not reset
the telescope tracking rates, and if you wish to stop the differential tracking, going back to normal
tracking rates, then on the TCS UIF type set-rate 0 0.
Tracking without auto-guiding. Rapidly Moving Targets
For more rapidly moving targets, use the set-rate command on the TCS to continuously move
the telescope from a pre-calculated change in position. RA-rate and DEC-rate as above. In this mode
auto-guiding is not used.
We are also upgrading the possibilities for very fast tracking (without autoguiding), and the
software speed limit has been increased from 17"/s to more than 5000"/s. Observations were made of
fast satellites where the RA/DEC rates were updated every second.
Preset to your object.
Set the rate of change by set-rate RA-rate DEC-rate (rate in arcsec per hour). The
maximum differential rate is 20000000 arcsec/hour (≈ 5500 arcsec/s).
Make the exposure.
Reset by typing set-rate 0 0 on the TCS.
For Experts Only
If the target has an unknown or rapidly changing motion, you might
want to adjust the rate of change in RA and DEC while tracking. Use
the set-rate command on the TCS and use command recall with the
up/down keys and edit the set-rate.
Preset to object.
Guess the starting set-rate RA-rate DEC-rate values.