Mandatory parameter. A unique range identification label. It has to be at least one character different for each subsequent line. Default values are "Range 1, Range 2, ... Range 10". User defined Range Ids can contain any character string, including spaces, up to 40 characters. If the user removes a range from the table (see below) the Range Id will not change for the remaining set of ranges.

Mandatory parameter. The starting wavelength of the range to be observed. The PACS grating will perform an up and down scan starting at this wavelength.

	Note
	The "Blue Edge" must have a shorter wavelength than the "Red Edge", the minimum permitted separation is 1 micron. The wavelength order of the spectral ranges entered in the PACS Range Editor has no effect on the duration of the observation. The AOT backend logic sorts the observing sequence for the spectral ranges to minimise grating overheads.

Mandatory parameter. The longest red wavelength of the range to be observed. The PACS grating will perform an up and down scan terminating at this wavelength.

Mandatory parameter. The PACS sensitivity could have a significant variation over the selected wavelength range or SED domain. In order to support a custom way to calculate signal-to-noise, the HSpot dialogue allows to set up a fiducial reference wavelength where the line flux, continuum flux density and line width parameters are interpreted. The PACS Time Estimator provides the minimum and maximum sensitivities for each of the ranges (or SED domains) and signal-to-noise for the reference wavelength. Be careful to specify the reference wavelength within the boundaries of the spectral range you fill.

	Tip
	Figures on spectrometer sensitivity variations as a function of wavelength can be found in the PACS Observers' Manual (http://herschel.esac.esa.int/Docs/PACS/html/pacs_om.html).

	Note
	In SED mode you have to add a line to the Range Editor Table in order to specify the reference wavelength. The PACS time estimator will raise an error message if reference wavelength is not provided.

This menu gives the flexibility to switch between physical input units supported by the PACS AOT logic. The pull-down menu allows the unit of line flux to be defined:

The "Line Flux" parameter of the PACS Range Editor is interpreted in the selected units.

	Note
	In cgs units the flux is measured in erg s^-1 which can be converted to watts, 1 watt = 1 x 10^7 erg s^-1.

Optional parameter. User supplied line flux estimate in units specified by the "Line Flux Units" option. Line flux input is used for signal-to-noise estimation at the given reference wavelength as well as for optimization of the dynamic range. Leaving the parameter as the default 0.0 value means the PACS Time Estimator will not perform signal-to-noise estimation (sensitivity estimates are still provided) and default integration capacitor will be used with the smallest dynamic range.

For bright sources where the default integrating capacitance will result in saturation you need to enter the expected continuum flux, line flux and line width at a reference wavelength in the selected spectral channel: this can be either the nominal or parallel channel. We advise to select the reference wavelength at the highest risk of saturation (see section on saturation limits in PACS Observers' Manual http://herschel.esac.esa.int/Docs/PACS/html/pacs_om.html). You may check parallel ranges in the “PACS time estimator message”. The provided continuum flux estimates are used to scale a Rayleigh-Jeans law SED. Then the RJ- law SED is evaluated at the wavelength of the peak response in the red and in the blue range, and in case a non-zero line flux is provided then the peak flux falling on a single resolution element will be added to the continuum (after the RJ-law extrapolation). These flux estimates are used to select the optimal integration capacitor. If an observation contains nominal and parallel ranges that fall in different flux regimes, the largest capacitance will be chosen for the entire observation. If ranges in the same observation fall in different flux regimes, it is recommended to split the observation into separate observations per flux regime.

Warning

If continuum and expected line fluxes are higher than the saturation limits for the default capacitance, it is mandatory to enter the expected continuum and line flux for every line in HSpot. Observations that are saturated because no HSpot flux estimates were entered by the observer will not be considered as failed for technical reasons. Saturation limits are presented in PACS Observers' Manual (http://herschel.esac.esa.int/Docs/PACS/html/pacs_om.html)

	Note
	Line flux estimates are not possible in SED modes.

Optional parameter. Continuum flux density estimate at the reference wavelength. The value of this parameter is interpreted by the PACS Time Estimator as flux density for a spectrometer resolution element. Leaving the parameter as the default 0.0 value means the PACS Time Estimator will not perform signal-to-noise estimation (sensitivity estimates are still provided) and default integration capacitor will be used with the smallest dynamic range.

	Tip
	The PACS spectrometer spectral resolution as a function of wavelength and gration order can be found in the PACS Observers' Manual (http://herschel.esac.esa.int/Docs/PACS/html/pacs_om.html).

This menu gives the flexibility to switch between physical input units supported by the PACS AOT logic. The pull-down menu allows the unit of line width to be defined:

The "Line Width" parameter in the PACS Range Editor is interpreted in the selected unit.

Optional parameter. The spectral line full width at half maximum value in units specified by the "Line Width Units" pull-down menu. Line width input is used only for signal-to-noise estimation at the reference wavelength. None of the instrument or observing mode settings can be influenced by this parameter. Leaving the parameter as the default 0.0 value means the PACS Time Estimator will not perform signal-to-noise estimation for an unresolved line.

The relative range strength (fraction of on-source time per range) is taken into account by specifying the grating scan repetition factor for each range. In total, a maximum of 10 repetitions can be specified in the table. For instance, if 10 ranges are selected then the "Range repetition" factor has to be 1 for each range; if 3 ranges are selected the total of the 3 repetition factors has to be less than or equal to 10 (e.g. 4+5+1 or 2+3+3, ...). If the sum of repetitions exceeds 10 you must either remove spectral range(s) or reduce the scan repetition factor(s).

The following considerations have to be made when specifying the repetition factor:

	Tip
	You can specify an observation with more than ten grating scans per pointing position by grouping AORs.

This mode allows a classical three position nodding observation to eliminate inhomogeneities between the telescope and sky background. The PACS focal plane chopper is moved between the on-target and the off-positions during a grating scan. The whole sequence of spectral line scans is then repeated in the nod position. In total, one half of the integration time is spent on-source. This mode is always enabled.

The chopper throw and chopper avoidance angle can be selected. The choice of throws "Small", "Medium" and "Large" refer to 1.0, 3.0 and 6.0 arcminute chopper throws on the sky respectively. The chopping direction is determined by the date of observation, the observer cannot directly influence this parameter. If a source of emission falls within the chopper throw radius around the target, the observer should consider setting up a chopper avoidance angle constraint. The angle can be specified in Equatorial coordinates, anticlockwise with respect the celestial North (East of North). The avoidance angle range can be specified up to 345 degrees.

Warning

Setting up a chopper avoidance angle requires an additional constraint on mission planning, therefore this parameter should have to be used only for observations where it is absolutely necessary. Specifying the chopper avoidance angle place restrictions on when the observation can be scheduled. This constraint might reduce the chance that your observation will be carried out, especially targets at low ecliptic latitudes could be inaccessible for certain chopper angles. You should use chopper avoidance angle only if a constraint is essential for your observation (see Section 10.5, “Position angle and chopper avoidance”). You may check your observation's footprint orientations by clicking in the HSpot's "Overlays" menu (see Chapter 19, Fixed Target and AOR Visualisation and Chapter 20, Moving Target Visualisation ).

	Note
	This is a 2nd generation observing mode in HSpot v5.0 and later versions.

The unchopped grating scan is an alternative to the chopping/nodding mode if by chopping to a maximum of 6' the off position field-of-view cannot be on an emission free area, for instance in crowded-fields or for spectral line mapping of extended objects with diameter larger than 5' respectively. This mode is not recommended for faint lines, target lines needs to be above typically ~1 Jy peak-to-continuum and the continuum level can be recovered in a reliable way only for bright sources, i.e. at a minimum continuum level of ~ 20-30 Jy.The continuum level can be determined by off-position subtraction which could efficiently eliminate the telescope background for bright objects.

	Note
	Unlike in Line Spectroscopy, this AOT does not provide OFF-position as part of the measurement. If the observer requires OFF-position for background subtraction the a separate AOR has to be crated covering the same wavelength range.

The centre of the map is at the coordinates given by the target position. The map size along a raster line can be expressed as the number of raster points per line times the raster point step. In perpendicular direction, the map size is given by the number of raster lines times the raster line step. Mapping parameter ranges are defined as:

	Note
	The maximum map size is restricted to 6 arcminutes in chop/nod mode to allow for clean off-positions with the chopper for each raster position. Only the large chopper throw is allowed; sparsely sampled maps are possible. The maximum map size is 2 degrees in unchopped grating scan mode; sparsely sampled maps are possible.

Selecting the chop/nod mode the map (raster line) orientation is defined by the chopping direction, the observer has no direct access to the map orientation parameter (disabled field). However, the observer has two choices to influence the map orientation:

The sky reference frame can be selected only in unchopped grating scan mode. Please note, in unchopped grating scan mode the HSpot default option is 'sky' reference, but we highly advise to switch to 'instrument' mode if suitable for the science case. In unchopped grating scan mode, if an AOR raster covers an elongated area (e.g. a nearby edge-on galaxy) then the observer might have no other option then using sky reference frame and turn the raster to the right direction. If the target is at higher ecliptic latitudes then you may select instrument reference frame and put a time constraint on the AOR. The appropriate time window can be identified in HSpot "Overlays/AORs on images..." option by changing the tentative epoch of observation. This way the array can be rotated to the desired angle by the time dependent array position angle.