30 April 2017 at 2:05 pm #573740
Before I embark on a homemade solution can I ask if the BAA spectra database can import echelle spectra in the IRAF FITS “multispec” format? I suspect not in which case does anyone have a solution to convert it to a set of single spectra that it can import? It can within or outside IRAF.
I know it is a long shot but worth asking. If not it is heads down in astropy to see what I can come up with.
Building the echelle was a lot simpler that reducing the spectra!
I attach an example spectra. Note it is not compliant with BSS and is just a test from the IRAF documentation.30 April 2017 at 4:05 pm #578170
You are correct in your assumption that the BAA Spectroscopy Database does not support IRAF multispec format at this time. However, it is possible to build in support. The big question is how long it would take me to build, noting I already have some outstanding development work for the VSS Database.
It may take until the second half of May or June to take a proper look at the file format. Then I can assess whether a ‘quick’ change is possible.
Note of course that the other header fields would need to be BeSS compliant. If this is going to be a problem then it won’t be worth going down the route of building IRAF multispec compatibility.
Andy, BAA Spectroscopy Database Manager30 April 2017 at 4:15 pm #578171
Andy leave it with me. I would benefit from fixing it myself so I can use other tools.
Regards Andrew30 April 2017 at 4:42 pm #578172
Give me a shout if you get stuck. It would be nice to have a single fits file format for the multiple orders in Echelle spectra, but I suspect agreeing that amongst the community would be no small task.
Andy30 April 2017 at 7:00 pm #578173Robin LeadbeaterParticipant
Hi Andrew, Andy
I come across this format from time to time and it would be nice to be able to convert multispec format spectra to single orders. Storing them in the database in multispec would probably not be a good idea unless they can be output as separate orders as none of the usual amateur fits reading programs can handle them as far as I know.
I have used a very long winded approach involving dismantling the multispec files and importing them into Excel but Otmar Stahl, the professional on the German VdS spectroscopy forum, kindly converted some to separate orders for me a few years back using an IRAF script I believe. You could ask on there or if you get no joy I can try contacting him and see if he would share the script.
Robin30 April 2017 at 8:07 pm #578174
Thanks Robin I have asked there and Otmar has responded. He proposed an IRAF method I had already tried but it seems ISIS did not like the 1D result. It could have been a specific issue with the data I had.
In any even I have cracked the key issues in getting a Python program to read the data so I can write it out in an acceptable FITS format. Just need to complete the program and test it out.
Thanks for the advice.
Regards Andrew1 May 2017 at 8:25 am #578175
That is a good point about ensuring that amateur software should be able to read the files.
Glad to hear you are making progress. Python with astropy are fantastic for programming with fits files. So far I’ve only been using them on a Mac, but I must get around to trying them out on Windows.
Andy1 May 2017 at 8:51 pm #578177
Yes Andy I am making progress. I am using astropy on Windows in a very amateur manner.
Nonetheless,I have managed to extract the first of the test spectra from the multispec format and saved it in a form that ISIS will open and display correctly. It helped when I opened the .FITS file in ‘update’ mode then I could add the extra header data. Just need to put it in a loop to get all the orders out and tidy up the header data. (Tim Lester’s PlotSpectra currently objects to the date and time format!) I will need to read the BSS spec carefully.
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