SkyView Blog SkyView how to get rid of ants in the house News and Discussion

Access to the TGSS ADR1 survey has taken a bit how to get rid of ants in the house of a hit in the past couple of weeks. The TGSS data is served remotely by skyview: we provide a resampling proxy to the underlying archive. As discussed in our previous blog post, the archive moved from http: to https: addresses which caused one problem. A few days after we fixed that issue, the format of the simple image access (SIA) response from their server changed. We use SIA to find data at remote archives. This change had also broken our ability to serve the how to get rid of ants in the house data. SkyView V3.4.0 is now available and should be released on august how to get rid of ants in the house 22. It should fix this problem.

Simple image access is the primary protocol through which we how to get rid of ants in the house access remote services. It’s used for many of our most popular surveys including how to get rid of ants in the house the SDSS, 2MASS and the TGSS. Basically it allows us to send a query to the how to get rid of ants in the house remote archives indicating that we’re looking for data in a given region and having how to get rid of ants in the house the remote archive tell us about the images it has how to get rid of ants in the house available nearby. We then download the files that seem useful (if we haven’t already done so in some earlier request) and do whatever resampling and mosaicking that seems appropriate.

The initial response to our SIA request is in a how to get rid of ants in the house format called votable. There are several different structures that votable can use internally. The TGSS had been using the most common of these, the TABLEDATA/DATA structure. However they apparently switched to using BINARY/STREAM structure. This is often a little more efficient in bytes, though with most data transmission compressed it doesn’t usually make much difference.

Unfortunately earlier versions of skyview could not support this structure, so we’ve added a couple of classes to enable skyview to how to get rid of ants in the house do so. Now it shouldn’t matter which of these two structures is used (though there are still other votable structures that we’ll worry about if we find a service the uses how to get rid of ants in the house them). This reuses code that we’d originally developed for the HEASARC’s xamin service so adding things in wasn’t too painful. We apologize to skyview users for these interruptions.

SkyView V3.3.4 has just been released. The new version includes a set of maps from the how to get rid of ants in the house galactic and extragalactic all-sky MWA survey (GLEAM). The GLEAM survey was taken at the murchison widefield array how to get rid of ants in the house (MWA) and covers most of the sky south of 25 degrees how to get rid of ants in the house north, about 25,000 square degrees.

The image above is an example field: two degrees around RA=0,dec=-80. SkyView includes four wider bands from the GLEAM survey ranging how to get rid of ants in the house from 71 to 231 mhz. These and many narrower bands are available from the GLEAM how to get rid of ants in the house cutout service. More details are available from the survey documentation in skyview how to get rid of ants in the house or the GLEAM website itself.

There are a few new capabilities in skyview as well. A new setting, trackedinputs, can be used to transfer values from the input FITS how to get rid of ants in the house files to the outputs. The value should be one or more comma-separated FITS keywords which are assumed to be real-valued. The pixel-weighted averages of these keywords are computed as the input how to get rid of ants in the house files are read, and the averages are written out to the output file. The new keyword is used in the GLEAM survey to how to get rid of ants in the house average the beam characteristics.

A new survey name, average, may be used when generating RGB images. Previously, when one wished to create an RGB image from only how to get rid of ants in the house two surveys, one could pick only two colors, or one could use one of the surveys in two how to get rid of ants in the house of the RGB colors. Users now have a third choice, to use the average image of the two inputs as how to get rid of ants in the house the third color. This can give a pleasing image while still evenly weighting how to get rid of ants in the house the two input surveys. Only one average survey can be specified and there should how to get rid of ants in the house be two other surveys specified. The position of the average survey indicates which color is how to get rid of ants in the house to be averaged. E.G.,

A new smoother is also available in skyview.Data.ThresholdMedianSmoother. This smoother (which can be used as a postprocessor when using skyview-in-a-jar), does a median filtering of the image using some specified how to get rid of ants in the house box size. However the median filtering is thresholded, so that a pixel is replaced with the median value how to get rid of ants in the house only if it deviates from the median by more than how to get rid of ants in the house some specified offset or ratio. This filter is essentially what is used in the popular how to get rid of ants in the house dust and scratches filter in photoshop. One could, e.G., use this filter to get rid of point sources in how to get rid of ants in the house an image while keeping a diffuse background. There are lots of options in this filter. E.G.,

The parameters used to set the heap size limits for how to get rid of ants in the house skyview web requests have been updated so that users will how to get rid of ants in the house generally be able to create larger images than before — although the exact size is a complex combination of he how to get rid of ants in the house source data format, the requested output region and other traffic on the site. Images up to 10,000 x 10,000 pixels should be feasible though you may run out how to get rid of ants in the house of time rather than memory — the connection will drop if nothing happens in 20 minutes. One particular problem was that skyview ran out of memory how to get rid of ants in the house if you requested multiple planck surveys (which are very large single files). You can now retrieve as many planck datasets as you how to get rid of ants in the house like! Thanks for ignacio cisneros for alerting us to this problem.

The big change for users is a new button that how to get rid of ants in the house will appear below every image. One of the defining characteristics of skyview is that it how to get rid of ants in the house always mosaicks and resamples the input survey data into whatever how to get rid of ants in the house geometry the user requests. We now provide a button so users can easily see how to get rid of ants in the house what input data was used for this resampling/mosaicking. This will usually give you a link to the source how to get rid of ants in the house data that was used in generating the skyview image. This isn’t necessarily the fundamental source data, it’s just whatever dataset skyview uses for a particular survey. Currently there are five cases depending on how the data how to get rid of ants in the house was derived:

Two caveats: many of these datasets have some level of copyright. Please look at the documentation for the survey for more how to get rid of ants in the house information. Also, to forestall a profusion of browser windows, we have defined a particular browser window in which the how to get rid of ants in the house link information will be displayed. If you use a tabbed browser, then the second and subsequent times you click on one how to get rid of ants in the house of the link buttons the tab may be updated, but probably will not be given focus. So it may look like nothing has happened….

Internally this version considerably reorganizes the various mosaicker classes minimizing how to get rid of ants in the house duplication of code. The listing of which files were used in the FITS how to get rid of ants in the house headers has been somewhat reorganized and now gives the number how to get rid of ants in the house of pixels resampled from each image.

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