Author Topic: Processing Hubble Legacy Archive images  (Read 11403 times)

Offline Eddy Timmermans

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Processing Hubble Legacy Archive images
« on: 2012 September 27 07:33:26 »
On Youtube there is a movie of someone processing Hubble Legacy Archive images using Pixinsight. The only problem is that this movie runs very fast.
I have been able to reproduce some of the actions, and make a reasonably good image myself, but does anyone know if this movie is available at normal speed ? I was unable to see some of the actions at the end of the movie, where the final processing techniques are used.

Eddy

Offline Jules

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Re: Processing Hubble Legacy Archive images
« Reply #1 on: 2012 September 27 12:24:31 »
Eddy

Can you post a link please as I cannot find it.

Thanks

Julian

Offline Eddy Timmermans

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Offline Jules

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Re: Processing Hubble Legacy Archive images
« Reply #3 on: 2012 September 27 14:49:58 »
Thanks Eddy.

Offline pavel

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Re: Processing Hubble Legacy Archive images
« Reply #4 on: 2012 September 29 09:46:32 »
Hi Eddy!At normal speed, unfortunately no, but there is a solution to this problem-downloadthe video itself and view MP4s through media player, using the pause button.The author makes a final treatment in PS.
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Offline pavel

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Re: Processing Hubble Legacy Archive images
« Reply #5 on: 2012 September 29 23:53:29 »
http://sdrv.ms/POxgoz     -  Here the result NGC4038 of HLA in the PixInsight 1.7.PS don't use themes. Carefully -50 MB! ;)
« Last Edit: 2012 September 30 00:00:11 by pavel »
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Offline Josh Lake

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Re: Processing Hubble Legacy Archive images
« Reply #6 on: 2012 October 07 10:58:53 »
Hey, that's my video!  :D  Sorry, I haven't checked the forum as often as I could over the summer.

Eddy, here's the first part of the video at normal speed, and I'd be happy to show you any of the others. Better still, I could give you some pointers not shown in the video for dealing with the often-challenging HLA. Finding something interesting in the archive was actually one of the biggest challenges of the contest for me!

Feel free to email me directly at rootlake at Gmail for more info, videos, or tips.

Offline marekc

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Re: Processing Hubble Legacy Archive images
« Reply #7 on: 2012 October 07 11:11:00 »
Hi Jake,

To the extent that you've got time to teach us a bit about exploring the HLA for PI-process-able stuff, that would be greatly appreciated! I need to start up that learning curve one of these days. I can't imagine how they pre-process the raw FITS files. I wonder how they shoot flats? I once heard that they point at the Earth from time to time and take a blurred image of it.

(I may email you directly for some more pointers, actually. I teach at a community college, and I'm currently writing the labs for an astronomy lab class. My `pet' lab exercise will be on image-processing, and I ought to learn about finding, getting, and processing Hubble data. I suppose I should read the FITS Liberator docs, too, even if I don't use that program to work with the FITS files.)

- Marek

Offline Josh Lake

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Re: Processing Hubble Legacy Archive images
« Reply #8 on: 2012 October 08 16:14:19 »
Hey, marekc, I'm a teacher too, right there with you on creating labs.

I didn't mess with any of the *raw* Hubble data, that would be incredibly difficult to use as you note.

My first step was going to WikiSky. In the DSS menu, I selected Astro Photo Survey, which allows you to see Hubble and lots of other imagery. From there, you basically just dive deeply into a given object and look for two kinds of frames: the classic 'stair step' frame of Hubble's WFPC2 camera and the double-paned rectangular frames of the Advanced Camera for Surveys (ACS).

The trick with the contest was to find nice, rich areas without duplicating an image they had already done. This proved to be the most time-consuming part of the contest! I actually did a full process on one nice galaxy only to find that the European Hubble team had already done it. From that point on, I was careful to cross check every press release to make sure the image wasn't done. For a lab, you wouldn't have that problem!

Once I had a promising frame that looked like it had some good features, I did the HLA search on it. I stuck to only ACS frames because I didn't want to deal with the differing quality of the tiny center portion of the WFPC stairstep.

In HLA, I went right to Advanced Search, then unchecked All Instruments and only selected ACS. I filled in the object name (NGC 1763 for the winning image) and specified that I only wanted Combined (Level 2) from the pull-down menu. The Level 1 data is just too difficult to clean up, especially when the experts have already done it. Above Level 2, there are a lot of already-combined images.

From there, I used the Images tab almost exclusively to see what I was looking at. The whole field can be inspected with the nice Footprints interface, and when I do this for a lab, I'm going to incorporate a view from it.

Once a promising set of frames is found in the pages of images, the Interactive Display link can be used to really look at the data. Here is the Interactive Display for the field that I used for the winning image. It can be zoomed, panned, and even contrast-controlled with the FITS2web interface. You might even be able to make a lab right there without bringing frames into FITSLiberator.

The downloads for the data take place with a 'cart' system where you queue them up to be downloaded in sequence. I had never used something like that for downloading, but Chrome supported it just fine after a warning. The resulting FITS files may contain multiple frames, and the downloads can be hefty.

Once I had the data files, I brought them into PI and away I went! But yes, I'll probably get my students to use FITSLiberator and Photoshop on the lab machine as well.

Hope this helps, you actually inspired me to start getting my talk about the HLA and the imaging contest together.

Offline sleshin

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Re: Processing Hubble Legacy Archive images
« Reply #9 on: 2012 October 08 16:37:07 »
Marek,

If you have access to back issues of Sky and Telescope, the July 2012 issue includes an article by Robert Gendler on "Processing your own Hubble Images".  A very nice summary article to help one get started with the HLA.

Steve
Steve Leshin

Stargazer Observatory
Sedona, Arizona

Offline marekc

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Re: Processing Hubble Legacy Archive images
« Reply #10 on: 2012 October 08 19:59:44 »
Hi Steve,

Thanks for the reminder - that should be quite useful. I may have that issue, and if not, we'll have it in the library here at school.

- Marek

Offline marekc

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Re: Processing Hubble Legacy Archive images
« Reply #11 on: 2012 October 08 20:03:24 »
Hi Jake,

Thanks very much for that writeup! It sounds like the Hubble data isn't so fearsome to find or download as I had feared. I'm now looking forward to the time when I get around to writing that particular lab... it should be fun to dive into the world of Hubble.

- Marek

Offline Eddy Timmermans

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Re: Processing Hubble Legacy Archive images
« Reply #12 on: 2012 October 09 00:52:41 »
Hi Jake,

I haven't had the time yet to look at the link you sent me, but I will very soon.
To me it seems that PI handles these images much more easily than PS, in my experience anyway.
With Pixel Math the stacking is quite easy, most of the work is getting the colors and contrast right.
And checking the image for artifacts ! I use the Clone Stamp tool, is that the right way to go ?

The search for a reasonable object is not easy, but sometimes you find a real gem. I use Burnhams Celestial handbook to find interesting objects. Most of the time there are pictures in the book you can use to look for interesting objects.
That way I found NGC 2623 a very beautiful distorted galaxy.

Eddy

Offline Josh Lake

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Re: Processing Hubble Legacy Archive images
« Reply #13 on: 2012 October 09 07:47:34 »
Marek -- I agree, it's intimidating at first and then gets pretty easy to use once you have the options down. The WikiSky site really helped me find areas rich with Hubble data. Here are the pics for the contest that I ultimately came up with.

Eddy -- PI for processing is definitely the way to go over Photoshop for this (or any  >:D) data! Yes, you can use the CloneStamp tool in PI for fixing artifacts, but I'll admit that I used the RAW Camera mode in Photoshop for the final touch-up steps in my video image. I haven't tried Burnham's for the object search, but I'll have to give it a try. I know that WikiSky was my one and only destination when I went 'digging for treasure.'

Offline Geoff

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Re: Processing Hubble Legacy Archive images
« Reply #14 on: 2012 October 13 23:00:32 »
I've had a look at the site.  Some things work, but I'm having trouble with the footprint tab. The footprint panel is black and doesn't show any image.  Any hints?  I am using windows 7 and firefox v15
geoff
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