IPHAS - Observing Manual
v2.4 24.October.2005
- Opening up
See the WFC observing manual
To improve the dome seeing you should open the south doors (if weather
conditions permit) and the dome (point away from the sun !) about 1-2 hours
before sunset.
Make sure the IPHAS standard star catalogue is
included in the TCS. To include the catalogue give the command
USER>incl iphas_stds
You can use the following coordinates as input to
staralt to see which IPHAS
regions you can observe when during the night. These coordinates refer to the
first field in each region. A catalogue with field centres generated by Janet
Drew can be found here.
- Evening twilight sky flats
Order of filters: Ha, r, i
Try to get at least 3 flat field exposures (20000-40000 ADU) for each filter.
- Focusing
Use the r filter to focus.
Once the correct focus position is found (the nominal focus is 43.95) then
change the value used by the focus command in the
/home/intobs/ha_survey/filter_wrap.csh
script to the focus value used for the night.
- Standard star observations
These are really only necessary if the night is photometric. But as the
pipeline needs the observation of standard stars to figure out if the observing
was done in cloudy or dusty conditions, they should be taken every night.
Standard star exposures in the evening are taken in twilight when the sky
is getting dark and the telescope has been focused.
Try to take 2-3 standard stars in each filter distributed in airmass.
- Survey observations
The fields that should be observed are read from the file fields.todo in the
/home/intobs/ha_survey directory. The already observed fields are listed in
the file fields.done in the same directory.
- Copy the correct fields.todo.??? file to fields.todo
- SYS> /home/intobs/ha_survey/survey_noguide_err.csh
- If you want to change the observed sky region, change the fields.todo
file while the Ha or r exposure is being taken or read out.
- To stop the script (after all 3 exposures of a field have been taken),
copy the file empty.dat to fields.todo
One standard star should be taken in all filters every 2 hours during the
nights observing.
To get a real time display of the frames as they are coming in, use the command
iphas_rtd in IRAF on the data reduction computer.
Note: Although the quicklook pipeline is running during the IPHAS survey
nights (eg. to determine the seeing) no data is copied back to the data
reduction computer to reduce the network traffic.
Important
If the seeing is good (<1.7 arcsec) and there are no clouds then please do
re-observations. Re-observations are done in fields that are listed as 100%
complete for observations on the
regions status
page. Re-observations have highest priority. Currently (08 December 2005)
the following regions are set up for re-observations:
Sct, Aql, Sge, Cyg1, CygX, Cyg2, Cep1,
Cas1, Cas2, Per1, Aur1, Tau1, Mon2
Try to observe with the following constraints:
- Distance from the moon > 30 degrees (must)
- Airmass < 1.4 (if possible)
- Standard star observations
Standard star exposures in the morning are taken in twilight when the sky
is starting to get bright and the observing of IPHAS fields has stopped.
Try to take 2-3 standard stars in each filter distributed in airmass.
- Bias
While you wait for morning twilight to come this is a good oportunity to take
some bias frames. Put the Halpha filter in (to prevent light leaking through
the shutter) and take a maximum of 5 bias exposures. If you are in danger of
loosing morning twilight flats then forget about the bias frames - flats are
more important.
- Morning twilight sky flats
Order of filters: i, r, Ha
Try to get at least 3 flat field exposures (20000-40000 ADU) for each filter.
- Closing down
See the WFC observing manual