TAO - Image acquisition with the MU script

	File locations and telescope name
	Station data
	Basic parameters which determine script behavior
	Dome parameters
	Filter parameters
	Safe telescope position/parking option
	Image compression parameters
	CCD camera parameters
	Telescope slewing parameters
	Telescope slew limits
	Pointing corrections
	Timing tolerance/ waiting times
	Bias frame parameters
	Dark frame parameters
	Flat field parameters
	Image shifts for binned calibration files
	Weather station parameters
	Focus parameters Page 1 Page 2
	Aiming exposure parameters

Starting MU

Sequence of events
during an observing
run using MU

Timing Refinement

Collecting timing
data

Analyzing timing
data

Adjusting the
empirical timing
correction

Other Tools

Slew time
measurement script

Minor Planet Checker
query script

Etc.

Image acquisition with the MU script

Customizing the MU script (continued)

Focus parameters

' FOCUS PARAMETERS
enableFocusMax = True                 ' Set this to True if you wish to use FocusMax, and
                                      ' to False if you don't wish to use FocusMax or if
                                      ' it is not installed on your system
FocusDec = +23.                       ' Declination (deg) where focus images will be taken
FocusHA = 0.                          ' |HA| (h) where focus images will be taken
FocusSearchRadius = 5.                ' Radius (deg) around (FocusDec,FocusHA) where focus
                                      ' stars will be sought
FocusCatalog = 0                      ' Catalog where focus stars will be searched (0=GSC)
FocusCatalogPath = "c:"               ' Path to focus star catalog
FocusMinMag = 7.                      ' Magnitude of brightest allowable focus stars
FocusMaxMag = 8.                      ' Magnitude of faintest allowable focus stars
FocusMinExpTime = 0.3                 ' Exposure time (sec) to be used with focus stars of
                                      ' magnitude FocusMinMag
FocusTemplateImage = "c:\TAO\obs\blank.fit"  ' Template image used in search for focus stars
focusSampleSize = 1                   ' Number of repeated focus determinations which are 
                                      ' averaged to determine an average focus position
minHFD = 1.                           ' Minimum acceptable half-flux diameter of focused stars
maxHFD = 10.                          ' Maximum acceptable half-flux diameter of focused stars
useTempFocusRelation = False          ' True to use a linear temperature vs. focus relationship;
                                      ' this relationship will be used both for computing default
                                      ' focuser positions and for rejecting measured focuser 
                                      ' positions which deviate too much from the expected 
                                      ' values; this has no effect if weatherStation is set to 
                                      ' False
FocusIntercept = 2690.1               ' Coefficient A in the relationship 
                                      ' Focuser position = A + B * Temperature (deg C)
FocusSlope = 7.504                    ' Coefficient B in the relationship 
                                      ' Focuser position = A + B * Temperature (deg C)
FocusTol1 = 30.                       ' Maximum acceptable deviation of a focus measurement from 
                                      ' the default focuser position given by the above linear 
                                      ' relationship; this value is used if useTempFocusRelation 
                                      ' is set to True 
defaultFocus = 2700                   ' Default focuser position to be used if 
                                      ' useTempFocusRelation is set to False or if 
                                      ' useTempFocusRelation is set to True and the weather
                                      ' station fails to provide the current temperature
FocusTol2 = 400.                      ' Maximum acceptable deviation of a focus measurement from 
                                      ' the default focuser position given by defaultFocus; this 
                                      ' value is used if useTempFocusRelation is set to False or 
                                      ' if useTempFocusRelation is set to True and the weather 
                                      ' station fails to provide the current temperature
focusTimeOut = 3.                     ' Timeout (min) for individual focus determinations
SetDefaultFocusAtStart = True         ' True to set focuser position to defaultFocus 
                                      ' (or to a position computed from the focus-temperature 
                                      ' relationship, if enabled) before imaging starts
focusAtCurrentPosition = False        ' True to focus at the current telescope position, without 
                                      ' slewing to the position defined by FocusHA and FocusDec; 
                                      ' this has no effect unless focusSampleSize = 0
giveUpFocusIfFMGoesBad = True         ' True to give up all further focus operations in case
                                      ' FocusMax gives signs of weird behavior (which it does
                                      ' on occasion)

enableFocusMax. Set this parameter to True if you wish to perform automatic focusing of the telescope using FocusMax, otherwise set it to False (in which case the remaining parameters in this section will have no effect).
Note: If you set enableFocusMax to True (False), you should also enable (disable) focus breaks in the scheduler configuration file.
FocusDec. This parameter specifies the declination (in degrees) where focus images will be taken.
FocusHA. This parameter specifies the absolute value of the hour angle (expressed in hours) where focus images will be taken; it should always be positive or zero. If FocusHA is positive, the script will decide on which side of the meridian to perform the focusing operation, in an attempt to minimize the time spent slewing the telescope (this is especially important in German equatorial mounts, which take a long time to slew between opposite sides of the meridian).
Note: If you wish to focus the telescope relying solely on a focus-temperature relationship (so that no focus images will need to be taken), and focusAtCurrentPosition was set to False, the telescope will slew to the sky position specified by FocusDec and FocusHA before adjusting focus. This is convenient when the telescope control software automatically compensates for focus changes due to altitude variations (as is the case with the SciTech telescope control software), so that focusing should be performed at a standard altitude (such as at zenith).
FocusSearchRadius. This parameter specifies the radius (in degrees) of a circle centered at the sky position defined by FocusHA and FocusDec where focus stars will be selected.
FocusCatalog. This parameter specifies the star catalog from which focus stars will be selected. The allowed values are given in the following table:

Value Catalog

0 GSC 1.1

1 USNO SA2.0

3 GSC-ACT

4 Tycho-2

5 USNO A2.0

6 UCAC2
FocusCatalogPath. This is the complete path to the catalog specified in the previous parameter.
Note: If you use either the GSC 1.1 or GSC-ACT catalogs, FocusCatalogPath must be the complete path to the directory which contains the catalog subdirectories, \gsc and \tables.
FocusMinMag, FocusMaxMag. These two parameters define a range of magnitudes in which focus stars will be selected. The value of FocusMinMag should be such that a star of this magnitude reaches a high signal-to-noise ratio (but does not saturate) in an exposure of duration FocusMinExpTime. The chosen range of magnitudes should be such that at least several catalog stars are available in any circle of radius FocusSearchRadius at declination FocusDec.
FocusMinExpTime. This is the exposure time (in seconds) to be used with focus stars of magnitude FocusMinMag. The exposure time will be automatically increased for fainter focus stars.
FocusTemplateImage. This is the complete path of a blank FITS image which is used by PinPoint in the process of retrieving potential focus stars from the catalog. A suitable blank FITS image is provided at TAO\obs\blank.fit.
focusSampleSize. This parameter is the number of independent focus measurements which are to be performed in each scheduled focus break. The various focus measurements (which are made using different focus stars) are averaged to produce the new focus position. Making more than one focus measurement may be useful to reduce the effects of the internal variation between successive focus determinations with FocusMax. It may also serve as insurance against failures in some of the focus measurements, since only successful focus measurements are included in the final average. On the other hand, too many focus measurements per focus break will consume significant amounts of telescope time. If you set focusSampleSize to 0, no focus measurements will be made. In this case, if you set useTempFocusRelation to True, focus will be adjusted using a linear focus-temperature relationship defined by parameters FocusIntercept and FocusSlope. This assumes that you have a working weather station which is supported by the MU script.

Previous: Shifts for producing binned calibration files, weather station parameters
Next: Focus parameters (continued)

© 1999-2004 Paulo Holvorcem