Next: CCD data Up: Special problems Previous: Marginal nights . If the program complains that you have negative intensities, this is usually due to misidentifying star observations as sky. ... Another problem with sky occurs when the program cannot find a suitable sky observation to subtract from a star datum. ... Finally, as the sky-modelling algorithm does not try to model twilight, it uses the ``nearest-neighbor'' method to correct star observations made during twilight for sky. ...

... Let us first find out which way -- rise in spectral resolution with some loss in the S/N ratio or increase in the S/N ratio with a fixed spectral resolution -- is better for the purpose of reduction of equivalent width determination errors. ... N -- number of counts for 1 ? ... line equivalent width, . ... Thus if the spectral resolution is managed to be increased (i.e. to decrease )without loss in the number of counts falling at 1 ?, the equivalent width measurement error is then proportional to . ...

... Meta Index / Home Page / Errors . ... warning . ... For instance, if the PROPOSAL information record is missing the user can add a fake one to the SOSF without this having any effect on the data reduction. corrective action: Continue. ... For a certain exposure in the ODF one of the parameters was not found in the housekeeping data. ... RGS, EPN, OM : the current exposure is found to contain more than one distinct calibration mode. corrective action: In the summary file: MODE = UNDEFINED . ... error...

Next: Ionospheric Corrections in AIPS++ . ... Previous: AIRY: Astronomical Image Restoration in interferometrY . ... Calculate residual images for all facets (using 2-D transforms). Partially deconvolve individual facets and update the image model for each facet. ... The image in Figure 1 was made using the AIPS++ widefield algorithm with 225 facets. ... In calculating the residual image the residual visibility re-projection for the different facets can be estimated independently. ...

... Please note the following problems and workarounds: . ... Arrow keys . Arrow keys are used in SAOtng to move the mouse or markers. ... Unfortunately, error messages are generated if both sets are defined in the SAOtng code but are not supported by X. To get around this problem, we have added the -kbprefix command switch (and the SAOTNG_KBPREFIX environment variable) to SAOtng. This switch allows you to specify which arrow keys you want to use (assuming your version of X supports both). ...

... To be read in conjunction with Section 4.11 of the WFPC2 Instrument Handbook , -Version 4.0. ... 1 The second study found evidence that CTE loss for faint stars has increased with time (Whitmore, 1998). The primary observational consequence of CTE loss is that a point source at the top of the chip appears to be fainter than if observed at the bottom of the chip, due to the loss of electrons as the star is read out down the chip (see Figure 1 ). ... Last updated: 06/16/98 10:38:00 . ...

... The effect of the bug has been that timestamps indicating when data was taken (FITS-header keyword CRVAL5) may be off by one second. ... DETAILED DESCRIPTION -------------------- AFFECTED KEYWORD: The affected keyword is: CRVAL5 (time stamp indicating start time of subscan) Synchronisation errors between the 1PPS pulses and the NTP-controlled system clocks have frequently caused the timestamps indicating the start of each subscan (CRVAL5) to be off by one second. ... That problem has also been fixed...

... Contact A Problem of an estimation of accuracy of the asteroid CCD observations . The Minor Planet Center supported by the Interntional Astronomical Union is the main office for keeping observational data of the small Solar System bodies and their investigations. ... At Pulkovo Observatory we are estimating an accuracy of the CCD asteroid observations obtained by amateurs and professional astronomers all over the World using the MPC database. ...

... PPTA timeline . ... List of projects . ... RedGW . ... One of the main goals of pulsar timing array projects is to limit the existence of a background of gravitational waves (GWs). Jenet et al. (2006) developed a method to determine such a limit if (and only if) the pulsar timing residuals were statistically white. In the paper we used data from six pulsars from the PPTA project to obtain a limit. The remaining pulsars were rejected because their timing residuals were not white. ...

... I would several points which we faced during our everysolved for better quality of individual ACs' and EOP products · There are two main EOP products provided by two IERS Product Centers on Earth Orientation (Earth Orientation Center (EOC) and Rapid Service/ Prediction Center (RSPC)). ... However, the latter is not provided by the IERS. ... ITRF · Using ITRF in computation of EOP series produced by various ACs seems to be a necessary condition to provide the consistency between the IERS products. ...

... Mosaicing may be used in aperture synthesis to map large fields of view. ... A CLEAN-based method has been developed, in which the components are located in a modified expression. ... Mosaics . ... We present here a CLEAN-based method for the mosaic deconvolution. ... This is a basic problem in mosaic deconvolution: if we intend to apply CLEAN on , the risk of taking a noise peak as a CLEAN component is too important. ... A new CLEAN-based algorithm for mosaic deconvolution has been developed. ...