Matlab ..... Amazing

[mbrickley]

Hi

I've just started using Matlab for a project I'm working on taking pictures of galaxy fields.

I would strongly recommend it to anyone with a interest in astronomy software and perhaps especially if you have an interest in the more science related side of things such as cataloging and classifying galaxies or photometry.

It's now pretty cheap £100-150 for personal use. The mindset is completely different to most software in that it is really a matrix based development environment but of course images and most data tables are actually just 2d matrices. It comes with a good set of basic image processing tools in the add on image processing toolkit. It it is incredibly powerful.

I've also just found a huge free repository of programs for astronomy that run under matlab at

http://www.weizmann.ac.il/home/eofek/matlab/

Looks good for a summer if getting ready for the next astronomy season come September.

Mark

[Joseki]

Hi, thanks for the heads up. I've used Matlab for work for years so it wouldn't be hard to give it a go here (though now I generally use IDL for reasons unrelated to Matlab ). It's got great flexibility and power.

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[davider]

MATLAB is really a wonderful software. I use it routinely for my work (mostly computer vision stuff) and I must say it is very handy and powerful. I can't look forward to have some astro images to process!

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[michael.h.f.wilkinson]

Matlab is great, but expensive. Octave can do much of what Matlab can, but not all Matlab plugins and functions provided for free in the scientific community work out of the box.

[mbrickley]

Matlab is great, but expensive. Octave can do much of what Matlab can, but not all Matlab plugins and functions provided for free in the scientific community work out of the box.

Hi

I would have agreed with you but matlab now offer a £99 package and £25 for the image processing toolbox for non commercial home use so it's much less expensive than it was. I csn only speak for me but it seems well worth that

Cheers

Mark

[michael.h.f.wilkinson]

That is a great deal. Well worth it. It does have a steep learning curve, but great package.

[AlexB67]

I have the mathematica home edition and love it too, I pay a yearly licence fee of around 95 pounds for that so get updated versions, it also a very good alternative.  You can also buy a home edition version but not get the upgrades for subsequent versions for around 200 pounds as a one off purchase. 

You can do with that version as you wish, it pretty much does everything the full version does, it is more like scaling and a limit on the number of CPUs it can use where it is restricted,  and it can only be used for non-profit.  Even the home edition has OpenCL and CUDA support and parallel computing.

In any case both are great tools, not used them in earnest for many a year for anything serious  except mathematica  many years ago for its symbolic algebra functionality, it was very handy for that in particular.

The wolfram site has many interesting little demos relating to astronomy, physics with code for free to download, very useful for educational stuff.

[mbrickley]

I'm thinking of getting mathematica too and there is a lot of crossover between the 2 although surprise given the name matlab is particularly good at handling matrix data like images!

Lots of fun to be had here I would say

[billhinge]

Hi

I would have agreed with you but matlab now offer a £99 package and £25 for the image processing toolbox for non commercial home use so it's much less expensive than it was. I csn only speak for me but it seems well worth that

Cheers

Mark

Hi Mark

Do you have a link? I have seen the £85 basic for Matlab but I assume there is VAT on top. Does the £99 package have anything else with it?

For info, I downloaded Octave (hadn't heard of it before) and it looks neat - those Matlab toolboxes could be expensive if you tried all of them

My interest is mainly the neural net packages, I want to compare with my own hand coded cocoa

[mbrickley]

Hi Mark

Do you have a link? I have seen the £85 basic for Matlab but I assume there is VAT on top. Does the £99 package have anything else with it?

For info, I downloaded Octave (hadn't heard of it before) and it looks neat - those Matlab toolboxes could be expensive if you tried all of them

My interest is mainly the neural net packages, I want to compare with my own hand coded cocoa

Hi

No the £99 was just a guesstimate of the 85 plus vat. Inconsistently on my part the 25 for each toolbox is ex vat so I suppose hey are nearer 30 with. I do agree about the toolbox costs .... Bit like pick and mix sweets.... The bag is always heavier than you think!!

[billhinge]

Thanks Mark

I may play around with Octave to see its limitations first before going any further

[AlexB67]

Thanks Mark

I may play around with Octave to see its limitations first before going any further

It may or may not matter to you, but the brief time I tried octave on the symbolic algebra side it was missing/lacking somewhat,

there again they do seem to be developing/working on that aspect quite a bit so quickly year by year.  I had lot of scripts from matlab to try that would not run in it. The numeric stuff was largely no problem with minor changes sometimes needed. 

In the end I always felt mathematica was a bit stronger in the area symbolic algebra when I used it for that, though the mathematica language has more of a learning curve than matlab I would say. Matlab is perhaps more like a language many are used to. Mathematica is just very different in many ways with symbolic manipulation in mind from the outset when it was designed.

Once I got over that hurdle a bit of the language, ( no expert in the mathematica  by any means but I get by   ) I learned to adore it, but some hate it.

[mbrickley]

Having been playing around with both these last few days one thing that seems strongly in favour of mathematica is the link into the online database Wolfram Alpha. In particular there is a language command AstronomicalData() which looks up data on a huge range of objects from the database which is curated and online and returns these values for use.

I'm working on a reduction system for wide scale galaxy images which are identified using Aladin. To give one example I would like to histogram the redshifted of detected galaxies. In this case assigning the retuned name of a galaxy in the text file from aladin to a string variable then doing a lookup AstronomicalData(name,"redshift") returns the redshift which can then be assigned to a column in the matrix holding the data. Repeat and histogram this column job done.

I can see myriad uses for this dynamic lookup of data and the available range of info is huge.

Mark

[NickK]

Mark - one point, if the tool is used in scientific analysis, then it may be good to understand which is better quality of data. Wolfram or strasbough (or another).

What I mean here is - one is probably synced off the other, and one is seen as the reference by the academic community. It's that reference that you'll probably want to use if the tool is to be used in academic or pro-am studies.

[mbrickley]

Hi Nick

Thats a good point and Wolfram do publish their sources (in this case the strasbourg site actually) but no its purely for fun on my part. Something to fill the dark night void thats coming up in June July. My idea is to see how deep in terms of redshift my relatively small refractor and a couple of different cameras are going but in truth I much prefer playing with data than making nice pictures and this is just a project that has piqued my interest.

Having said that I had  a look at the redshift data for a few returns and it matched the data from a manual search on the strasburg site so I would be fairly confident of the data.

Have a good evening

Mark