Junior Memberhi,my eclipse used to work just fine, until about a few days ago. When i open it, it says: an error has occurred, see.workspace.metadata.log.
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Senior MemberOn 5/1/2010 9:01 AM, Andrew Macrae wrote: it's all very well to use a new workspace - works like a charm! But what about the many hours I've spent configuring my workspace?
Junior MemberHi everybody,i created a new workspace and able to import my project successfully.but when i close the eclipse and try to reopen the same workspace it is showing 'information' popup with no buttons. I go to task manager and able to kill the eclipse. When i retry it same information popup is appearing and this time even in task manager also eclipse is not showing to kill.in this stage i have to restart my computer to kill the eclipse.any suggesstion would be appreciated.attached the screen shot.
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CanariCamCanariCam is a mid-infrared (7.5 - 25 micron) imager withspectroscopic, coronagraphic, and polarimetric capabilities, which will be mountedat one of the Nasmyth foci of the GTC. It is designed to work as a diffraction-limitedimager at 8 microns. The instrument uses a Raytheon 320x240 Si:As detector which coversa field of view of 26'x19' on the sky. Most mechanism motors and optics areinside a cryostat which is cooled down to 28K using a He cryo-cooler system.Temperature control of the detector ensures that its optimum operating temperature (9K)is stable in the mK range.CanariCam is designed to reach the diffraction limit of the telescopeat mid-IR wavelengths. However, to do this routinely the telescope will have to beequipped with a fast-guiding mode that will allow for fast tip-tilt correction.Currently fast guiding is not yet available and hence initially the very best imagequality cannot be guaranteed.The following table summarizes all observing modes available forCanariCam. Top: Unfolded optical layout of CanariCam indicating relationshipof powered components to image and pupil planes.
Bottom: 3D-view of the optical layout.Instrument DetectorThe following table summarizes some basic parameters of the detector.DetectorRaytheon CRC-774 320 x 240 Si:As IBCFiel of View25.6'x19.2'Physical Pixel Size50 x 50 μm (0.0798'±0.0002')Full-well Capacity1.0e7 or 3.0e7 electrons (high or low gain)Array ReadnoiseDeep well: 9 ADU or 5116 e-Shallow well: 9 ADU or 1705 e-Dark Current≤ 100 electrons/sec @ T = 6 KDwell depth14106 - 41106 e-Quantum Yield40% at peak Number of Output Channels: 16A plot of the quantum efficiency and an image of the detector can be found below. Detector dirt as seen on July and August, 2013. Note some new dirt particles that appeared on August, 2013,were located in the areas bewteen pixels (20,50) and (40,100), (80,180) and (90,230), and atapproximately pixel (295,55).Users were advised at the time of appearance of these dirt particles not to place their targets near the lower-leftcorner of the detector. A cleaning operation was performed in October 2013 by which the largest dirt particles were removed.The result is shown in the next figure. CanariCam detector cosmetics from October 25 th 2013.Therefore, the large dirt particles will appear only in data taken from August, 2 nd to October,25 th 2013.Readout ModesTo date, the Raytheon device remains the largest format mid-IR arrayin astronomical use. However, this device displays several unwanted effects when exposedto a very bright source. Below we discuss these effects as well as readout methods usedto reduce them.Each contiguous group of 20 vertical columns is read out through oneof the 16 output channels (i.e., columns 1-20 are readout through channel 1, columns21-40 are readout through channel 2, etc.).
In addition, the first pixel read out ineach channel is the lower-left one and the last is the upper right one. Single-Point Sampling (S1) Advantages: Minimum frame time - 5 msDisadvantages: Vertical 'level-drop' patterns appear for brigth sources.Horizontal 'level-drop' patterns appear for bright sources. Correlated Quadruple Sampling (S1R3) Advantages: Verticallevel-drop patterns are removed. Disadvantages: Minimum frame time is increasedto 20 ms - Broad-band imaging may be difficult or impossible with this mode.Increased readout noise - May reduce sensitivity in high-resolution spectroscopy.NOTE: Artifacts are only. Cross talk features seen in the CanariCam detector in the S1R3 readout mode.Observing ModesImaging Observing ModeImaging with CanariCam is diffraction-limited at 8 micron over thefull 26'x19' field of view.
The detector plate scale (0.08 arcsec/pixel)ensures the diffraction-limited Point Spread Function is Nyquist sampled at 8 micron.During factory acceptance testing, image distortion accross the FOV has been proved tobe less than 2 pixels center-to-corner.CanariCam FiltersCanariCam mounts 6 medium-band Silicate filters and 12 narrow,medium and broad band filters that were specified by the VISIR filter consortium.Filters were provided by the University of Reading.A very slight, but noticeable, difference among some of the filtersin the optical beam direction after passage through the filters. CANARICAM estimated sensitivity (in mJy) for a 5-σ detection in a 30-min on-source timeas a function of wavelength and night mean measured PWV.
Data points are stacked up at eachfilter central wavelength, as shown in the figure in red (filter name and centralwavelength). For a certain filter, the sensitivity values correspond to differentdates with different PWV measured by the GPS monitor (PWV values in milimeters in greencolour), with higher values of sensitivity (thus, poorer) at higher PWV.
For the sake of clarity, thePWV has been included only for certain points (Figure taken fromFrom this plot we can identify the filters which are severely impacted by the increase of PWV,that have been marked with and ellipse. We can also see the severe effect of even low amountof PWV can have in the instrument sensitivity when operating at longer wavelenghts in the Qband: an increase of 1 mm in PWV represents a degradation in the sensitivity by a factor of morethan 2 in the Q8 filter and close to 3 in the Q4 filters.It is important to notice that when the PWV is increased from 7mm to 20mm (plus calima) the sensitivity in the 10-micron filters is degraded by a factor of about 4 while the sensitivity in the Q1-17.65 filter, which is in the 20-micron atmospheric window is degraded by a factor of about 55.
Note also that the FWHM of the PSF is slightly worse in the data taken on August 18 th than on January 29 th, which also contributes to the sensitivity degradation. These data reinforces the idea that the effect of the PWV in the sensitivity is reatively small in 10-micron observations while it is critical in 20-micron observations.Image QualityThe image quality of diffraction-limited data is a combination of the FWHM and ellipticity of the PSF, and the Strehl ratio. The Strehl ratio is defined as the ratio of the measured PSF peak and the peak of the theoretical diffraction-limited PSF, which gives us an idea of how concentrated the energy is within the PSF. The following table shows the FWHM and ellipticity of the PSF as well as the Strehl ratio measured in all filters using images of the standard star HD3712 taken on January 29 th, 2013. A chop/nod throw of 8' along the detector diagonal was used during the observations.
The FWHM, ellipticity, flux and peak of the PSF was measured using IMEXAM in IRAF. In oder to calculate the Strehl, a theoretical normalized (i.e. Total flux equals 1) monochromatic PSF of the GTC was created for the specific wavelength of each filter using a theoretical pupil image of the telescope (without including the gaps between segments and the M2 support spider). The theoretical PSF was sampled to the pixel scale of CanariCam (0.08'/pixel).
Then the PSF total flux was measured in all filters in the images of the star HD3712. The images were normalized to the measured total flux and the PSF peak was measured in each of the normalized images. The Strehl ratio was obtained as the peak of normalized PSF measured in the real data divided by the peak of the normalized PSF in the theoretical PSF images. The last column in the table shows the theoretical FWHM of the diffraction-limited PSF as λ/D, where D is the diameter of the pupil, which is 9.4 meters because an inscribed circular pupil stop is used in CanariCam observations to minimize the background emission.AccumulationShift and addFilterEllip.FWHM (')StrehlEllip.FWHM (')StrehlDiff. 5-σ sensitivity in 30 minutes on-source in 10-μm low-resolutionspectroscopy mode.The figure shows that the sensitivity in 10-μm low-resolution spectroscopy moderanges from 50 mJy to 150 mJy depending on the night and the star used.
In one of thenights the PWV was 4 mm but in the other two the nights the PWV was over 8 mm.The airmass was ranging between 1.0 and 1.4 depending on star and night and theslit correction factor was ranging from 1.1 to 1.9. Two different slits were used,0.52” and 0.36”. It is important to bear in mind that these sensitivity values were obtainedusing a trace of constant aperture across the whole wavelength range. This meansthat at bluer wavelengths, where the PSF is narrower, there is a higher contributionfrom the background within the aperture than at redder wavelengths.The following figure shows the 5-σ sensitivity for an integration of 30 minuteson-source as a function of wavelength using three different standard starsobserved in two different nights. 5-σ sensitivity in 30 minutes on-source in 20-μm low-resolutionspectroscopy mode.The figure shows that the sensitivity in 20-μm low-resolution spectroscopy moderanges from 300 mJy to 800 mJy. In this case, there is a stronger dependency of thesensitivity with wavelength than in the 10-μm window, due to the presence of strong waterlines in the 20-μm atmospheric window.Wavelength CalibrationWavelength calibration is performed in CanariCam spectroscopic data using the sky lines availabe inall scientific and standard star spectral data. This wavelength calibration calibration method is thestandard that we recommended.
An additional form of wavelength calibration (only for 10 μm spectroscopy)is to introduce in the optical path a Polystyrene plate that CanariCam has in the sector wheel. Wavelenghcalibration using the Polystyrene plate is rarely necessary and therefore it will only be taken if requestedand justified.The following table shows the sky emission lines at 10 and 20 microns that can be usedfor wavelength calibration.Wavelength (A)Wavelength (μm)Line ID746007.460Sky0787507.875Sky1817408.174Sky1a851408.514Sky2880208.802Sky3949009.490Sky410260010.260Sky511728011.728Sky612540012.540Sky6a12877012.877Sky717586017.586Sky818298018.298Sky918648018.648Sky.015Sky.310Sky.890Sky.322Sky.653Sky.175Sky.855Sky.595Sky.941Sky.199Sky20. Polystyrene emission lines.A linear transformation between the pixel and the wavelength scale is recommended whenperforming the wavelength calibration of the observed spectra.PolarimetryCanariCam permits dual-beam polarimetry in the 10 micron window byinsertion in the optical path of a half-wave plate, a field mask and aWollaston prism.During an observation, the half-wave plate is rotated to four position angles(0°,45°, 22.5° and 67.5°), which results in the rotation (relativeto the Wollaston prism and detector) of the plane of polarization.
The Wollastonprism separates the two planes of polarization (the ordinary and extraordinary rays),which are subsequently imaged on the detector. The focal-plane mask prevents overlapof the orthogonally polarized images for extended sources.The field of view is reduced by a factor of 2 through theinclusion of a polarimetry mask in the aperture wheel.
This is required so thatthe orthogonally polarised light (o and e rays) from the source (sky) do not overlaponto each other.As there is some chromatic birefringence, the 'slots' of thepolarimetry mask in CanariCam are slightly oversized. The useful exposed field ofview is 320x25 pixels per slot per polarised beam, corresponding to 25.6'x2'.A total of 2.5 slots can be cleanly used, hence providing a field of viewof 25.6'x5' in imaging polarimetry mode. Image polarimetry of a black body (laboratory ambienttemperature) taken with CanariCam. The light has passed through the HWP, polarimetricmask and Wollaston prism. Narrow and very dark stips are due to the mask slots beingoversized.During an observation in polarimetry mode, the HWP rotatesautomatically between the four position angles of 0º, 45º, 22.5ºand 67.5º. The rotation of the HWP is synchronised with the chopping andnodding so that the final raw image cube is composed of several extensions, eachone of them corresponding to a wave-plate angle (see next figure).
Due to thebirefringence in the Wollaston prism, for each HWP image, we can see two imagesof the astronomical source, corresponding to the ordinary and extraordinary rays,respectively. The Stokes parameters for the astronomical source can be recoveredfrom a combination of the ordinary and extraordinary images for each value of the HWP. Raw polarization image extensions corresponding tothe first nod position in an observation of an unpolarized standard star for whicha 100% linear polarization has been imposed by introducing a wire-grid in the opticalpath.
The HWP angle rotates from one extension to the next, which causes the brightnessof the ordinary and extraordinary images of the star (upper and lower images of thestar in each image, respectively) to change from one HWP angle to the next, since thesource is polarized. The same observation of an unpolarized source would show thesame intensity in both rays. A chop/nod throw of 10' along the polarization maskslots was used. Therefore, both, the negative and positive images of the star can beseen because the on-source and off-source chopping images were subtracted.Polarization Accuracy and SNRThe first point that we need to bear in mind whenpreparing an observation in polarimetry mode with CanariCam is what is the SNR requiredto reach a given polarization accuracy. The polarization accuracy that we may need toreach will depend on the expected polarization in the target of interest.The following formula relates the SNR needed to reacha given polarization accuracy (ΔP):sqrt(2)/ΔPIf the science target has an expected degree ofpolarization of 3%, the observer may want to be able to reach a polarization accuracyof 1% in order to ensure a 3-sigma detection of the expected polarization. Therefore,in this case, a SNR of sqrt(2)/0.01 = 141 would be needed forthe observation. These calculations are included as part of the.Polarization Measurement EfficiencyThe polarization measurement efficiency was alsomeasured during June 2012 commissioning run.
The polarization measurement efficiencyis given by the actual polarization measured on the instrument when it is illuminatedby a 100% polarized source. The following table summarises the efficiency in all Silicate filters:FilterPolarization Efficiency (%)Si1-7.872.1Si2-8.790.0Si3-9.897.3Si4-10.399.2Si5-11.695.5Si6-12.588.3In the previous table the filter name also shows its central wavelength in micron. The previous data showthat wave plate efficiency peaks at about 10.3 micron.Instrumental PolarizationThe instrumental polarization of CanariCam and GTC was first measured during the commissioning run heldbetween June 1 st and 6 th, 2012. Since that commissioning period, we have measured it severalother times to keep monitoring its value. Measurements have been done in all Silicate filters and the N-10.36 broadfilter.
The instrumental polarization can be obtained by observing a star which is not known to have intrinsicpolarization using the CanariCam polarimetry mode.The following table shows the instrumental polarization corresponding to two different measurements madein two different nights. Each night a different standard from the Cohen list was used, both of which are not known tohave polarization, so that they can serve as non-polarized stars. The orientation of the detector on the sky, orinstrument position angle (IPA), in each of the nights was different in order to find any dependency of the instrumentalpolarization angle (see below) with the detector orientation. Instrumental polarization measured in two different nights. The columns represent the (1) filter name, (2) FWHM of the PSF in the image, (3) percentage of polarization (P), (4) error in P, (5) polarization angle (PA), (6) error in the PA, (7) SNR of the data, (8) expected polarization accuracy from the measured SNR.The data were reduced using an automated set of Pyraf scripts specifically created to measure the polarizationof point sources. The Stokes parameters were determined using the formulae described in the book AstronomicalPolarimetry by Tinbergen (2005), known as the ratio prescription method.
The results of these scriptswere cross-checked with POLPACK, which was producing the same results within the errors. The errors shown in thetable are the result of propagating the photometric errors in the formulae.The following figure shows the whole set of instrumental polarization measurements taken in the period betweenJune 2012 and September 2013. Degree of instrumental polarization for different filters taken during the period betweenJune 2012 and September 2013. The size of the symbols is proportional to the degree ofinstrumental polarization.
Data with the larger error bars correspond to June 2012 because theSNR of the images was very low.The previous figure indicates no clear trend between the values obtained with different filters.The dispersion is high amongst the values with higher error bars, corresponding to lower SNR inthe images. However, most of the values with small error bars are consistent with a degree ofinstrumental polarization of 0.6% - 0.7% across the 10-micron atmospheric window.The previous tabular data indicate that the instrumental polarization angle (PA) varies considerably from one measurement tothe other. The reason of such a variation is that CanariCam is located in the Nasmyth-A focus of GTC. There is areflection at the GTC flat tertirary mirror (M3) with a 45 degree angle of incidence, which is expected to produce most of theinstrumental polarization.
The orientation of this reflection in the detector reference frame changes when the instrument positionangle is changed and also varies as the elevation of the star evolves with time.We have used most of the data shown in the previous plot (removing the ones that did not have a high enough SNR)from non-polarized stars to try to find an empirical relationship between the instrumental polarization PA and therest of angles that vary during an observation. The following plot shows that there is a clear correlation betweenthe instrumental polarization angle and the quantity RMA+Elev, where the RMA is the Nasmyth rotator mechanicalangle and Elev is the average telescope elevation during the observation. It turns out that the angle RMA+Elevis the telescope pupil angle plus a constant that depends on the instrument position angle (IPA) on the sky. Dependency of the instrumental polarization angle with the RMA+Elev angle. The size of the symbols isproportional to de degree of polarization.
The colors represent different dates. Observationswith all Silicate filters and the N-10.36 filter are included in this plot.
Wave plate efficiency curve measured with CanariCam in spectropolarimetry mode together witha polynomial fit to the data (diamonds).The wave plate efficiency curve is totally consistent with thewave plate efficiency results.The efficiency peaks at approximately 10.4 microns, which is the central wavelength of the Si4-10.3filter.Instrumental PolarizationThe behavior of the instrumental polarization measured in spectropolarimetry mode is consistentwith the imaging polarimetry results, as expected. The CanariCam degree of instrumental polarization seems to be ratherflat accross the whole 10-micron window, with values ranging on average between of 0.5% and 0.7%. Top panel: Instrumental polarization measurement of Sirius with polynomial fit (solid) and wave-plate efficiencyprofile (dashed). Bottom panel: Instrumental polarization divided by the wave-plate efficiency.We have also checked that the angle of instrumental polarization obtained from spectropolarimetry observationsof non-polarized standard stars is flat accross the whole 10-micron spectral window and varies with thepupil angle in the same way as described in thesection for imaging polarimetry.Required CalibrationsPolarized standards are required to calibrate the degree and angle of polarization of the scientifictarget. It is recommendable to observe these standards using the same configuration as the in thescience target. Comparison of the spectropolarimetry of the BN object taken with CanariCam/GTC inJune 2012 (small symbols with error bars) and with the UKIRT/UCLS in September 1987(filled circles).The previous figure shows a polarization emission feature associated with the presenceof silicate in this well studied star forming region.
The BN object is one of thebrightest and stronguest mid-IR polarized sources, with an average flux in the 10 micronband of 300 Jy and a maximum degree of polarization of 12%. CanariCam/GTC data have anon-source integration time of 15 min and the typical polrization error achieved was 0.1%.Atmospheric ConditionsTo extract the Stokes parameters from the polarizationdata it is necessary to relate images taken at different half-wave-plate orientationsduring the whole observing sequence. In this sense, polarimetric observations can beconsidered as relative photometry observations.
Therefore, it is important that theconditions are as stable as possible during the whole observing sequence. It is advisableto request nights with photometric or clear conditions. Clouds with variable thicknessand temporal changes in other atmospheric parameters such as PWV and seeing in scales ofminutes may lead to wrong polarization results. Window tranmissions measured using an infrared FTSspectrograph. KBr and KRS-5 factory transmission curves at 20 microns can be seenin the.Observing StrategyIn-depth information of the observing strategy is given in theand also in the. A summary of the main features is given in this page.Mid-IR sources normally are over 4 orders of magnitude fainterthan the background emission. Time variations in the noise associated with the detectorelectronics, and telescope and sky background make imperative the use of a quasi-realtime subtraction of the background contribution.
The technique used to achieve anaccurate background subtraction is the combination of chopping the telescope secondarymirror and nodding the telescope (chop-nod). The chop-nod technique ensures the removalof the radiative offset, a background emission that remains after subtraction ofchopping on- and off-source images, due to the fact that the background seen by CanariCamdetector is not the same in both orientations of the telescope's secondary mirror.The chopping profile is defined by the chop angle and and chop throw.The chop angle is the orientation of the chop direction on the sky. The chop throw isthe angular separation between the on-source and off-source positions on the sky. General case for the chop profile.It is possible to chop off the detector or tochop on the detector. In the former case the source will not be presentin the off-source image, while in the later case the source will appear in the off-sourceimages.
There is not advantage on using one or the other method regarding the finalsignal-to-noise ration achieved on the target (see details in the. However, chopping on the detector is more recommended forcompact targets, because with this technique only 1/4 of the array FOV can be used.Chopping off the detector is normally recommended in the case of extended sources.Figure below shows the case of chopping off the detector. Differentbackground contributions are represented by different background colors in the detector.The radiative offse is represented by a triangular section on the detector. The radiativeoffset in the second step (second row of detectors) is approximately the same but withoposite sign. By adding up On(A)-Off(A)+On(B)-Off(B) exposures the radiative offsetcontribution is removed. Case of chopping on the detector with nodding perpendicularto the chopping direction.Image Quality and ChoppingWhen performing chopping it is important to note that in at leastone of the chop positions of M2 the telescope optics are not perfectly aligned,resulting in some optical aberrations.For the GTC/CanariCam system, the image quality was optimized duringthe design using the guideline that CanariCam should image the beam delivered by theGTC with minimal aberration.
However, due to this misalignment when chopping thedelivered image quality (at I0) degrades. The level of degradation of the GTC/CanariCamsystem was characterized using Zemax in terms of Strehl ratio for various chop angles,as illustrated in next figure (calculations correspond to a wavelength of 8 micron).
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