Continued SDSS issues

While remote access to the UKIDSS server was restored shortly after our last message we are continuing to have problems with the SDSS. In addition to the problems with the metadata found in the SDSS SIA service, there has been some overloading of SDSS servers and it was recommended that we switch from http://data.sdss3.org/… urls to http://data.sdss.org urls which points to a different and more robust set of servers.

We enabled this capability and switched to the new servers in our test version 3.2.1. This failed initially. The new URLs were in turn being redirected to https://data.sdss.org. Java network connections do not follow redirects to a different scheme (i.e., from http to https) and so we weren’t getting the data. We put in some code to handle this kind of redirection and also tried simply making the initial request to the https addresses. All of this worked fine in our test environment and failed miserably when we tried to run it on the operational systems.

The current problem seems to be that the GSFC network firewall is quite restrictive and is not allowing SkyView general HTTPS access to the outside world. It does allow general outgoing HTTP. It may take a few days before we can get this switched.

In the meantime we have a dilemma. The SDSS3 links fail frequently when used from our web site, e.g., as I write this the initial SIA requests are failing due to some database error, but they do work some of the time. The SDSS links work very nicely when used in the JAR file but don’t currently work at all from the web site…

So for the nonce we are leaving SkyView at v3.2.0 but recommend that Jar users extract the jar from v3.2.1 (i.e.,
http://skyview.gsfc.nasa.gov/v3.2.1/jar/skyview.jar) where they are more likely to get a version of SkyView that addresses all of the problems we have seen.

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