- To display the images on the DS9 screen properly, flip the images in x
and y.
- Use the Marconi-CCD always with binning = 2. Write careful observing logs
and note also the observng conditions (photometric, cloudy etc.). Pls. scan
the obslogs after the run (if you use the printouts available at the
telescope) or use the new Open Office based obslogs available
here and mail them to
me.
- Do a set of 5 biases each at the beginning and end of the night.
- Do always twilight flats in all four PA in the evening and morning. Best
PA-order is PA = 0, 45, 135, 90 in the evening and PA = 90, 45, 0, 135 in
the morning. At last three flatfields per PA and session.
In general, the exposure level should be between 5000 and
50000 ADU, ideally around 30000 ADU. In case you do not
want to take your flats manually, there is the script
polima_flat.macros available. It can be loaded within the Polima-GUI
(load_macro) and is in the folder "observa". The macro takes automatically 5
flats in each PA with an level of about 30000ADU and does the scaling
automatically.
Flatfield time starts about 10-15min after sunset and about half an hour
before sunrise.
- Check the pointing of the telescope at the beginning of the night and
correct the the coordinates at the telescope.
You can either use the eypiece (the small black finder at the telescope)
or the finder camera
in the control room (the screen to the right of the guiding screen). Don't
forget to open the white finder telescope for the latter in the dome.
This way you have basically always the object in the field (or at least very
close to) of Polima for sources with Dec <
50deg. For higher dec-sources, the telescope has often a large offset of about
10arcmin to the east and about 5arcmin to the north.
Here is a list of bright stars close
to most sources of our project.
- For easier observing, we have prepared a catalog, which you can use
directly to control the telescope. It can be loaded in the "Control de
Telescopio" panel under "Catalogo" (button "archivos"). The catalog has the
name SPM_poli-targ-find-stand.obs
and can be found in the folder Catalogs.
This catalog contains not only the names and positions of the targets, but
also their 5 char code (1st column), recommended exposure times (column NF
EXTRA), as well as identification on whether the source is of high priority
or low priority (1.0 or 2.0 in column mag, respectively) and further
down in the column NF EXTRA whether the source is a high-pol or zeropol. std.
There in the column mag the brightnesses of the standard stars are given.
In addition, for most of our targets positions of bright stars next to them
are given which can be used in case of pointing problems.
- For sources with integration times less than 10min do always a series of
2 polarization measurements with PA = 0, 45, 90, 135, 135, 90, 45 and 0. For
integration times of 10min and above one series with PA = 0, 45, 90, 135 is
OK. For your convenience, the scripts
polima_objeto.macros (2 polarization measurements, 8 images) and
polima_objeto_short.macros (1 polarization measurement, 4 images)
which can be loaded within the Polima-GUI (load_macro) are available.
They are in the folder "observa".
- For integration times of up to two minutes, no autoguider is
required. For the other sources, suitable guide stars are indicated (if
already available) in the
finder chart via the
target list. If you have to
search for a guider star by your own, pls. try to find one in the
upper part of the GUI. Guider stars in the lower part of the
GUI cause reflexes on the CCD!
- Very rarely the telescope gets stuck when moving from a high-dec source
to a low-dec source. In that case, try first to set the telescope back to
zenith. If that fails, turn off the "ventilatores" and the "motores" and
turn them on again. After that you should be able to put the telescope
back to zenith. Check the pointing first before continuing with the
observations.
- Until we have fully understood the instrumental polarization behaviour of
Polima, do one polarized and one unpolarized standard each night. Standards
and finders can be found either in the target and standard polarization list
section or
here .
- We now have an IRAF-based pipeline for automatic data reduction
of POLIMA data available. It is installed at the "gama"-computer.
You can find the description of it and the
pipeline for download in the "internal
section" of our SPM-WEB.
Although the pipeline is able to identify the objects by their coordinates,
you may not only gain by carefully written observing logs but also by
putting the proper 5 char name as filename in the Polima-GUI.
The IDs for each source can be found in the
target list (label 5 Char) or in the 1st
column of the source catalog for the telescope control.
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