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| Joint Astronomy Centre |
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WFCAM OT templatesGeneral notesAll WFCAM templates allow use of microstepping and dithering. Due to the combination of the pixel scales of the science arrays and of the autoguider, only a pre-determined sequence of dithers can be used. All WFCAM templates use these sequences, so there is no need for the user to compute them again.All the templates use the DR recipe JITTER, which assumes that we have a separate flat field. If you want to self-flat, make sure you use a large number of pointing (ideally 25), and large offsets, and change the recipe to JITTER_SELF_FLAT. Paw print single pointing MSBsThe WFCAM library contains 3 MSB to obtain single pointing of WFCAM, using either 3, 9, or 25-points dithering sequences. These templates use a single filter. If you wish to use multiple filters, please flush the array after a filter change (see the template 3 filter survey with flushing).To use any of these MSBs, just enter the coordinates of your target in the Target Information eye, and specify the configuration of the camera in the WFCAM component. Note that if you are using non-standard exposure times you will have to take specific darks. Also, note that the coordinates you enter in the Target Information component are the coordinates of the centre of the mosaic, which is the centre of the autoguider. Offsets of 950 arcseconds both in RA and DEC are required to move the source to the centre of one of the science arrays. Single tileThis template is used to combine four WFCAM pointing in a tile. To use this template, click on the survey container, click on the first of the four positions shown on the right side, then click on the Target Information tab. In the "object" field, enter the RA and DEC of the centre of the tile. The offsets required to obtain the four pointings have already been entered for you, so all you need to do is to manually enter exactly the same coordinates (the centre of the tile) on all four positions. The next step is to define guide stars for each position. There is no way to use the same guide star for the four pointings. So again use the survey container, click on the first position, click on the Target Information tab, and select a guide star using the position editor.Note that you can replace the offsets sequence with any other offset sequence (like a 9-points, or a 25-points). Survey MSBsThese templates are use as input for the Survey Definition Tool to create surveys. They work in a similar way as the Single Tile MSBs, but there are no preset offsets that will move the camera to the four position of a tile. When used in combination with the SDT, these MSBs will be automatically setup with coordinates and guide stars.3-filter surveys with flushThis template shows how to obtain a survey of a large region of the sky (coordinates are in the survey container) in 3 filters. Note that it is more efficient to observe all the different position in one filter and then change filter, rather than keep the telescope in the same position and change filter many times. A filter change requires about 30 seconds.Narrow band imagingThis template is similar to the single paw MSBs described above, but uses NDR_1 read mode and 40 seconds, which should work better for narrow band imaging. |