A slew or dither pattern file can be used to slew the telescope between targets, dither, change exposure times, change filters & the number of exposures. Technically all fields are optional but a pattern without exposure time does not make sense. If a user wishes to simply cycle through a series of filters, the input file can be very brief and only include exposure time and filter names. Not all options to the exposure command are allowed in the pattern file so it is recommended that the user takes one test image with the desired parameters such as binning factor so these values are cached in LOIS and will be used while the pattern is running.
These patterns needs to be on Baggins, the computer for the LMI interface, before you will be able to use it. Avoid using TextEdit to make these files; there is an issue with the quotes. Emacs, Vim, & other text editors that do not use smart quotes should be fine.
- These can be written before your run and moved over to Baggins before/during the night.
- They can also be written on site/whilst observing and moved over to Baggins as well (email, thumbdrives, etc ... can be helpful here)
The format to follow is below starting with the metadata at the beginning of the document. This particular example is a dither pattern. More info can be found on the Automated Functions page. Appropriate string names for the filters are listed in LMI Filter Information.
| No Format |
|---|
#title=false ra=false dec=false exposureTime=true numExposures=true filter=true muRA=false muDec=false epoch=false dRA=false dDec=false rotatorPA=false rotatorFrame=false xi=true eta=true comment=true
#
60.0 1 SL-g 0.0 0.0 "Centered SDSSg"
120.0 1 SL-r 0.0 0.0 "Centered SDSSr"
120.0 1 SL-i 0.0 0.0 "Centered SDSSi"
60.0 1 SL-g 15.0 30.0 "dXi,Eta = 15,30 SDSSg"
120.0 1 SL-r 15.0 30.0 "dXi,Eta = 15,30 SDSSr"
120.0 1 SL-i 15.0 30.0 "dXi,Eta = 15,30 SDSSi"
60.0 1 SL-g 33.0 -5.0 "dXi,Eta = 33,-5 SDSSg"
120.0 1 SL-r 33.0 -5.0 "dXi,Eta = 33,-5 SDSSr"
120.0 1 SL-i 33.0 -5.0 "dXi,Eta = 33,-5 SDSSi"
60.0 1 SL-g 0.0 0.0 "Centered SDSSg"
120.0 1 SL-r 0.0 0.0 "Centered SDSSr"
120.0 1 SL-i 0.0 0.0 "Centered SDSSi"
60.0 1 SL-g -30.0 15.0 "dXi,Eta = -30,15 SDSSg"
120.0 1 SL-r -30.0 15.0 "dXi,Eta = -30,15 SDSSr"
120.0 1 SL-i -30.0 15.0 "dXi,Eta = -30,15 SDSSi"
60.0 1 SL-g -5.0 -33.0 "dXi,Eta = -5,-33 SDSSg"
120.0 1 SL-r -5.0 -33.0 "dXi,Eta = -5,-33 SDSSr"
120.0 1 SL-i -5.0 -33.0 "dXi,Eta = -5,-33 SDSSi"
60.0 1 SL-g 0.0 0.0 "Centered SDSSg"
120.0 1 SL-r 0.0 0.0 "Centered SDSSr"
120.0 1 SL-i 0.0 0.0 "Centered SDSSi" |
| Info |
|---|
It may be helpful to end dither scripts with a 0,0 offset. Otherwise, the last offset values will stay in and alter the pointing of the telescope until explicitly cleared. |