May 2001 Observing Plan
version 1.0 2000-May-25; (rgm@ioa)
This is heavily based on the June, 2000 plan
How much time do we have available
Each night there is 6.9hrs between astronomical twilight. However we may
be able to get 7.9hrs is we observe between 12degree twilights. We should
aim for this. This means do a snafu on a V=5 star soon after sunset.
Lets assume 7hrs per night and 50% of time is used for science observations.
This gives:
CIRSI Grid and Tiling Pattern
The nominal size of filled CIRSI tile is 29.6'x29.6'. The chosen
step size for the tiling is 28'x28'
see cirsi_grid.pl for the tiling pattern.
Other useful material:
Version 1 observing plan for the May PATT run
Standard stars required are listed in the INT CIRSI Observing Guide
Defocus by 0.2units for standards REMEMBER TO SET IT
BACK AFTERWARDS. Best do a standard just before you start or at the
end survey regions ie before a long slew.
Focus after every long slew eg around 3 times per night in total
The ELAIS N1 and N2 regions are covered by the WFS. CIRSI covering
144 pointings have been determined.
One of these tiles is centred on a deep XMM pointing. To maximise the
CIRSO overlap with the WFC tile lists given below should be used. The
grids are plotted on the previous WWW page.
WARNING Note although the Tile grid is the same as the pattern used by Eduardo Eglez, the Tile numbering system is different
- ELAIS-N1 complete a grid of 5x5 CIRSI tiles in J [N1 in H is complete]
The tile centres are
- 53, 54, 55, 56, 57
- 65, 66, 67, 68, 69
- 77, 78, 79, 80, 81
- 89, 90, 91, 92, 93
- 101, 102, 103, 104, 105
- ELAIS-N2 complete a grid of 5x6 CIRSI tiles in H
The tile centres are
- 40, 41, 42, 43, 44
- 52, 53, 54, 55, 56
- 64, 65, 66, 67, 68
- 76, 77, 78, 79, 80
- 88, 89, 90, 91, 92
- 100, 101, 102, 103, 104
- Avoid the 9 tiles that have been completed .i.e
- 66,67,68
- 78,79,80
- 90,91 92
- Thus the 21 CIRSI tiles needed; they are
- 40, 41, 42, 43, 44
- 52, 53, 54, 55, 56
- 64, 65
- 76, 77
- 88, 89
- 100, 101, 102, 103, 104
- There are no finding charts for these; use a GSC star to check the
pointing if you like or use gaia and the DSS. Take care when offseting
using the apertures.
- 3 loops of 30sec [or 4 of 22sec when sky is too bright for 30sec]
- 4 dithers
- 4 pointings per tile
- on sky time is 6mins per pointing; 24mins per tile
- to do 21 tiles requires 480minutes on sky
- SSA22 WFS/CFHT Survey region
- 1 tile
- J and H
- 4 loops of 30secs per band
- 5 dithers per position
- 10 minutes per tile
- requires 80minutes on sky
- WFS dec=0 strip 2200 to 2300
- 3 loops of 30sec [or 4 of 22sec when sky is too bright for 30sec]
- 4 dithers
- 4 pointings per tile
- on sky time is 6mins per pointing; 24mins per tile
- assume on average 1 tile per night
- requires a minimum of 168minutes on sky
- Standards
- observe the LCIRS standard stars in J and H at least twice
during the run so that we can compare the system throughput
at the INT and the DuPont directly. [see last years log sheets]
What did we say we would do in our proposal
- we said we would expose for 300second per pointing
- assumed 8.4hrs per night scheduled in mid-May; this
should have said 7.4hrs!
- 60% observing efficiency
- asked for 14nights of 8.4hrs => 117.6hrs
- proposed to cover 25deg^2 in J and H.
- actual allocation was 7 nights of 6.9hrs => 46.2hrs
- i.e. 39.3% of requested amount
How do we get some J coverage
To get some J we have a number of options;
- descope of the H coverage
- reduce the H band exposure times
- reduce the observing overheads
One option would be to cover 1.5degx1.5deg regions in the ELAIS N1
and N2 regions in J for 360secs per pointing. This would give us
around 4.5deg^2 of J data. It would require:
- 72 pointings of 360seconds
- 432minutes on sky
Going shorter than 360seconds with the current CIRSI software is
quite inefficient.