public class ExposureTime extends ExpressionCalculator implements Serializable
ExpressionCalculator. Formula used:
S/N = tge/sqrt(s+gte),
where t is the exposure time, g the gain,
KEY_GAIN, s is the source term, KEY_SOURCE, and
e is the intensity in R magnitude of the star compared to a 10th
mag star, i.e.
e = 10-0.4(R-10)
If the R magnitude is not given, the approximation R = V - 0.5(B-V)
may be used.
| Modifier and Type | Field and Description |
|---|---|
private static double |
DEFGAIN
The default gain.
|
private static String |
DEFINITEXPRESSION
The default forward expression to get exposure time.
|
private static String |
DEFREVERSEEXPRESSION
The default backward expression.
|
private static double |
DEFSOURCE
The default source.
|
static String |
KEY_GAIN
The key to the gain value of the S/N calculator.
|
static String |
KEY_REVERSEEXPRESSION
The key to the gain value of the S/N calculator.
|
static String |
KEY_SOURCE
The key to the source value of the S/N calculator.
|
KEY_INITEXPRESSIONKEY_LISTSEPARATOR, KEY_MAPKEYVALUECHAR, KEY_MAPSEPARATORCONFIG, KEY_CLASS| Constructor and Description |
|---|
ExposureTime(Map info)
Constructs a new exposure time calculator.
|
| Modifier and Type | Method and Description |
|---|---|
Double |
getTimeFromSN(GlobalGrouping set,
TargetDefinition td,
Number sn)
Calculates the exposure time required to yield a target S/N.
|
evaluate, getExpression, init, initCalculatoraugment, augment, augment, augment, augment, clone, defaultBoolean, defaultChar, defaultDouble, defaultFloat, defaultInt, defaultLong, defaultObject, defaultObject, defaultProperties, defaultProperty, getAsBoolean, getAsChar, getAsDouble, getAsEnums, getAsFloat, getAsInt, getAsList, getAsLong, getAsMap, getAsMap, getAsObject, getAsObject, getProperties, getProperty, has, initProperties, isNew, parseObject, parseObject, reload, reload, removeProperty, requires, rescanned, setObject, setProperties, setProperty, stringProperties, toStringpublic static final String KEY_GAIN
public static final String KEY_SOURCE
public static final String KEY_REVERSEEXPRESSION
private static final double DEFGAIN
private static final double DEFSOURCE
private static final String DEFINITEXPRESSION
private static final String DEFREVERSEEXPRESSION
public ExposureTime(Map info)
public Double getTimeFromSN(GlobalGrouping set, TargetDefinition td, Number sn)