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Since the AOS corrects for zenith distance automatically, the focus obtained at the above position should hold good elsewhere.
ARGUMENTS LIST
inplace_focus x y title bin exptime filter focstep focbase flags
If the user button is used for this command, there should be neither quotes nor curly braces embedded in the fields for these arguments. The arguments are ordinarily single strings without embedded blanksspaces, or empty strings (all blanksspaces) in each button field. In additionBut, the exptime, focstep title and flags fields can accept strings with multiple tokens, ie, embedded blanksi.e., separate options separated by one or more spaces.
x | x coordinate in pxls of star on a full frame image at the selected binning; there is no default. |
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y | y coordinate in pxls of star on a full frame image at the selected binning; there is no default. |
title | this is used for a heading in the focus log; may be multiple tokens- default is empty string |
bin | integer for binning factor- LMI default is 2. Other values not tested. |
exptime | exposure time in seconds for acquisition and focus sweep images. |
Exptime is a floating point value for exposure time in seconds, defaulted as 1.0. If specified as two tokens, the second value is the number of singles to be taken- default , defaulted is 1. If specified as three tokens, the second value is the number of basic occultations to be taken, and the third value is the number of frames (NAXIS3) for each occultation. Occultations not currently available for LMI.
filter | name (like "R") of the filter setting to do the focus sweeep. (Acquisition?). Defaults on LMI to nominalsweep. "Nominal" means use the filter as previously set. Leave this blank for LMI. |
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focstep | delta for focus setting per sweep position. |
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focbase | setting of focus for acquisition and sweep center. | |
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flags | strings, all optional, defined in any order, as follows: | |
| save | put images taken in focus sweeps in a subdirectory in the main image directory. |
| conditioning | focus run is a dry-run; the final focus setting is always focbase. |
The name of the save subdirectory includes timestamp; the file names used include the focus setting.
Script runs to completion with conditioning irrespective of image contents; it can be run without any star.
Examples
Do a simple focus run for a star located on an LMI test single binned 2:2 at pixel 1578, 1322. The run is
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being started at 05:13 UTC. A first guess of 900 microns offset will be adopted for the focus, with a coarse step size of 100 microns.
x | y | title | binning | exptime | filter | focstep | focbase | flags |
1578 | 1322 | first focus |
| 3 |
| 100 | 900 | save |
The title is put into the header for this run in the focus log testlmifocus.log. The binning is defaulted to 2:2, and the filter is defaulted to "nominal" which means the filter wheels will be left where they are.
Because of the save flag, there will be a subdirectory of the data directory called 05:13:12
with files
fstep500.fits | fstep600.fits | fstep700.fits | fstep800.fits | fstep900.fits | fstep1000.fits | fstep1100.fits | fstep1200.fits | fstep1300.fits |
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each of which is a subframe image for the corresponding focus stepScript runs to completion with conditioning irrespective of image contents.