DS9 and Remote Files

by Jessica Lu on August 12, 2009

For the longest time, one of my major computing hurdles has been to figure out the best approach for viewing remote FITS files with SAOImage DS9. Currently, using DS9 over ssh is painfully slow, if not impossible for interactive color scaling for example. So I have often resorted to copying files to my local machine and then opening them in DS9. While this solves the problem, it is a dirty solution.

I had hoped that sshfs (or MacFUSE) would solve this issue. MacFUSE allows you to mount a remote directory via ssh. It works moderately well (although file editing is a bit of a nightmare when you aren’t the only one editing). However, it has a major flaw when it comes to DS9 and FITS files… when I attempt to open a FITS file that has been mounted via sshfs, the FITS file comes up blank in ds9 (X11 version) or spits out an error message (Mac version).

So this post is a cry for help. Has anyone else had luck with DS9 and displaying remote FITS files? I would love something that is similar to Tramp for Emacs where you can open files from within Emacs via ssh.

{ 3 comments… read them below or add one }

1 John August 13, 2009 at 8:39 am

I think the best way to go about doing this is with XPA, but it’s a little obscure.

On the machine you’re running ds9 (call it the “server”), configure it as per the FAQ. Then, on the machine with the FITS file, you should be able to send the file by running:

$ xpaset -i ‘server_ip:port’ ds9 fits < filename.fits

That should transport the FITS data over the network, and then use the local DS9 to display it, so it’ll be nice and fast.

That said… I’ve not actually had much success trying to get this to work for myself. DS9 seems choosy about what network interfaces to listen on, and there will probably be all sorts of nasty issues with firewalls etc. Has anybody actually made this work reliably?

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2 Shashikiran Ganesh November 23, 2009 at 4:53 am

It works. Initially the client side gave me an error : ‘authentication failed’. The FAQ suggests running the following initially to allow access:

xpaset -p ds9 -acl clienthost +

on the server host. Thereafter it worked well!
Thanks for this tip…

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3 Michael Wood-Vasey December 4, 2015 at 9:07 pm

http://ds9.si.edu/doc/faq.html#XPA

is the current location of the XPA section of the ds9 FAQ.

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