The current iteration of the Herschel orbit ephemeris has a duration of only 1003 days, cutting off at 2011 April 30th. This is significantly less than the expected duration of the Herschel mission and means that, at present, no visibility windows will be generated beyond this date.
- Implication for user: This should have little impact on the initial Key Programme call except for extended monitoring programmes and solar system objects that only have visibility towards the end of the mission.
- Recommended action: Please inform the Helpdesk (http://herschel.esac.esa.int/) if your programme is affected.
The estimated source flux density is limited to 10 Jy instead of 100 000 Jy. - Implication for user: i) the signal-to-noise cannot be calculated (but the noise estimation from HSpot is still valid) and ii) the low-gain mode is never activated, as the dynamic range of the high gain mode goes up to ~2000 Jy. - Recommended action: None, this parameter is not mandatory.
The size of raster maps is limited to 2x2 arcmin instead of 6x6 arcmin in chopping/nodding mode. - Implication for user: the map size is limited to 2x2 arcim. - Recommended action: to cover larger area, use the wavelength switching mode, which has no such limitation in map size. The AOR in this mode has a similar duration.
Time Estimation summary for PACS line and range spectroscopy AOTs does not provide "Instrument and observation overheads" (always zero) but this information can be obtained from the Time Estimation Messages. - Implication for user: overhead cannot be easily estimated. - Recommended action: if necessary, this information can be obtained from the Time Estimation Messages.
In the "pointed with dither" mode, HSpot returns the sensitivity for one of the 3 pointings and not the total for the AOR. - Implication for user: the sensitivity of the AOR is underestimated by a factor SQRT(3). - Recommended action: divide the sensitivity returned by HSpot by 1.7 to get the overall sensibility of the AOR.
In wavelength switching mode, the sensitivity returned by HSpot is underestimated by a factor SQRT(2). - Implication for user: sensitivity returned by HSpot too pessimistic. - Recommended action: divide the sensitivity returned by HSpot by 1.4.
No signal-to-noise calculation (the input flux is not being used). - Implication for user: the user has to compute the signal-to-noise himself. - Recommended action: compute the signal-to-noise by dividing the flux by the sensitivity returned by HSpot.
The line width is only as a warning limit to ensure the whole line profile is covered by the highest sensitivity part of the predefined wavelength range. - Implication for user: None - Recommended action: None
In wavelength switching mode, the parameter "number of cycles" is currently ignored. - Implication for user: the sensitivity cannot be increased by increasing the number of cycles.
- Recommended action: use the line repetition factor (up to 10) instead, in order to increase the sensitivity.
In range spectroscopy, if a very narrow wavelength range is entered, for instance for a fast raster mapping of an emission line, below a certain width the sensitivities returned by HSpot are overestimated by up to a factor two or more. The exact threshold depends on the wavelength and the order, but it is about 0.3 micron in the 3rd order up to 1.6 micron in the first order. - Implication for user: erroneous overestimated sensitivities - Recommended action: Contact the Helpdesk (http://herschel.esac.esa.int/) to get estimates of sensitivities for very narrow wavelength ranges.
No use of reference wavelength (no rms sensitivity provided and signal-to-noise calculation is made at this wavelength). - Implication for user: sensitivity cannot be estimated at desired wavelength. - Recommended action: defined a temporary AOR with small interval around the reference wavelength of only 3 microns to estimate the sensitivity in this range.
No signal-to-noise calculation (the input flux and line width information is not being used). - Implication for user: signal-to-noise cannot be estimated. - Recommended action: None.
No sensitivity estimates are provided for parallel channel data . - Implication for user: the sensitivity has to be estimated by the user. - Recommended action: consult the PACS Observer's Manual.
Mapping with off-position does not apply the off-position yet (as a consequence the footprint visualization tool does not show the off-position). Hence the time estimation is underestimated for this mode. - Implication for user: the AOR observation duration is slightly underestimated for this mode. The estimated sensitivity understimated as well by factor SQRT(2). Moreover the footprint visualisation tool does not show the off-position - Recommended action: to get the right sensitivity, divide the number returned by HSpot by 1.4.
Small map visualisation overlay is shifted by ~1 arcmin with respect to the target, see SPIRE Observers' Manual Figure 4.4 for correct image.
- Implication for user: AOR overlay is shifted by ~1 arcmin with respect to the target.
- Recommended action: When visualising imagine (for given observation date) the overlay to be centred on the target coordinates. Note that only a circle with radius of 2 arcmin can be guaranteed regardless of the time of the observation.
SPR-2921 Fixed in HSpot v2.0.2
The total on-source integration time can be out by up to 2 seconds due to a value being converted to an integer.
- Implication for user: In case of many SPIRE Spectrometer observations in a proposal this can be significant.
- Recommended action: Calculate the correction be multipling the on-source time per FTS scan by the number of FTS scans (for spectral resolution High and Low do this for each resolution). Use this to modify the Total Time that you request for the observations and proposal.
Repetition factors that are too large for the parameters selected will produce an error about "tp out of range".
- Implication for user: Only effects pointings lasting nearly 14 hours or more. The maximum Repetition factor needs to be work out for each combination of parameters used.
- Recommended action: Decrease the repetition factor.
SPR-3125 Fixed in HSpot v2.0.2
Re-loading of saved AOR does not work when inputted Source Flux Estimates include Estimated Continuum value(s) of 0 (or 0.0) or if the box is left blank for a row where other data have been inputted.
- Implication for user: On attempted re-loading an error message will appear and no AORs will be loaded.
- Recommended action: If you put in any Estimated line fluxes into the Source Flux Estimates, always also put in Estimated Continuum values of 0.1 or greater.
If you already have a saved AOR file that does not load, you should edit the file with a text editor as follows to enable reloading:
Save file to a different name.
Find <v05:continuum>0.0</v05:continuum> and replace with <v05:continuum>0.1</v05:continuum>
Find <v05:continuum>-1.0</v05:continuum> and replace with <v05:continuum>0.1</v05:continuum>
Now save the updated file and load it into HSpot.
Notes: -1.0 in the saved file represents a blank box. You can put in any value greater than 0.1. Note S/N values will be returned with this new value if you do a time estimate.
SPR-2956 Fixed in HSpot v2.0.2
The Observation Estimation for the settings Slow Scan Speed and Orthogonal Scan Direction gives an error.
- Implication for user: The results of the Observation Estimate calculation for those settings are not produced.
- Recommended action: Select Slow Scan Speed with Nominal Scan Direction and use those results instead as the times and sensitivities are the same as for the Orthogonal Scan Direction. Submit this as a sample AOR and say you also would do a coverage in the orthogonal direction and modify the total time of the proposal accordingly. Note that visualisation works correctly for both scan directions and should be used to compare the two areas covered.
The correction for the distance in the cross-scan direction (to work out the distance needed to ensure that both PACS and SPIRE cover the area properly) is subtracted rather than added to the required distance (SPR-2882).
- Implication for user: The height of the map is 26 arcmin smaller than requested.
- Recommended action: Please add 26 arcmin to the height of your map before you enter the number to enable HSpot to compute the correct time for your observation.
The Observation Estimation for the settings Slow Scan Speed and Orthogonal Scan Direction gives an error.
- Implication for user: The results of the Observation Estimate calculation for those settings are not produced.
- Recommended action: Select Slow Scan Speed with Nominal Scan Direction and use those results instead as the times and sensitivities are the same as for the Orthogonal Scan Direction. Submit this as a sample AOR and say you also would do a coverage in the orthogonal direction and modify the total time of the proposal accordingly. Note that visualisation works correctly for both scan directions and should be used to compare the two areas covered.
The efficiency value is computed incorrectly because of this. Look at visualisation to compare the common area mapped, with the area that is not common to get a visual estimate of the efficiency. Basically the larger the requested map, the higher the efficiency (SPR-2855).
- Implication for user: The mapping efficiency estimate in the Parallel Mode Time Estimation is incorrect.
- Recommended action: The efficiency can be calculated as the requested area divided by the area painted by one of the instruments ("Height" x "Length") / [("Height" + 13 arcmin) x ("Length"+22 arcmin)].
The PACS Red band sensitivity reported in HSpot is wrong.
- Implication for user: Ignore HSpot PACS red band sensitivity estimates for Parallel Mode.
- Recommended action: Please look at the SPIRE PACS Parallel Mode Observers' Manual for the correct values.
Sensitivities for SPIRE in this mode are pessimistic.
- Implication for user: A factor of ~0.63 improvement in map averaged SPIRE sensitivities has to be considered with respect the numbers provided by HSpot.
- Recommended action: Please look at the SPIRE PACS Parallel Mode Observers' Manual for the correction factor.
The maximum value that should be entered for the height is 240 arcmin (values much larger than this will give errors as a map that large cannot be made). [Note that the maximum length is 1173 arcmin] (SPR-2771)
- Implication for user: Map height parameters are accepted out of range.
- Recommended action: Limit the map height value to 240 arcmin.
Time Estimation Details window is entitled SPIRE Time Estimation Details: it should say SPIRE PACS Parallel Mode Time Estimation Details (SPR-2771).
- Implication for user: -
- Recommended action: -
In the Time Estimation Details the times sometimes do not agree with those in the Time Estimation Summary.
- Implication for user: Minor inconvenience when Time Estimation Details are displayed.
- Recommended action: The times given in the Time Estimation Summary are the ones that should be used.
If you display an AOR for a certain date and look at the pointings table, the roll angle displayed does not update if you then change the display to a new date.
- Implication for user: Important if you wish to define a constraint.
- Recommended action: Check the roll angle for the given date in the visibility window and use this value if defining a constraint.
SPR-2855. Fixed in HSpot v2.0.2
The Proposal cover sheet generated by HSpot V2.0.0 does not contain the name, affiliation and e-mail address of the proposal PI.
- Implication for user: This is a relatively minor issue with proposal identification.
- Recommended action: Ensure that any co-Users know your user-id so that they can identify the proposal in the database.
Proposals submitted to the HSC should be assigned to one, and only one Science Category. In HSpot v2.0.0 it is still allowed to select more than one Science Category without getting a proper warning message when leaving the Science Category selection window. Instead, the field appear as 'Incomplete' in the 'Proposal Submission Tool' window. The error message is only properly generated when the user tries to submit the proposal.
- Implication for user: Annoyance only. HSpot will not allow you to submit a proposal with two selected science categories.
- Recommended action: Follow the instructions in the HSpot Manual with care to avoid problems.
SCR-2774, Fixed in HSpot v3.0