Hubble's Hidden Treasures Contest 2012

[geckzilla]

"Elliptical" galaxy NGC 524

NGC 524

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[Beyond]

Geckzilla, at the rate you're turning these out, you must not have a lot of time on your hands anymore.
This one is like looking down a tunnel and seeing the light at the other end.

[rstevenson]

"Elliptical" galaxy NGC 524

This is beautiful. Now what I'd like is one about 1680 x 1050 pixels.

When you settle on an image like this, is it possible to find one on either side of it? Or are they often just the single square frame?

Rob

[geckzilla]

It depends on what detector was used. For this one, the whole thing looks like a staircase. I don't know how to explain it, but it's like 4 detectors in one with the smaller one, as I understand it, being more sensitive.

Here, go to this URL. It should bring up all the data for NGC 524.
http://hla.stsci.edu/hlaview.html#Image ... 2CGHRS&ds=

Note that the staircase ones are original 4 different "panes" which have been automatically stitched together. The single square ones are actually the small square from the staircase looking ones. In this case, I only used the small square since there wasn't much of interest in the other panes and combining the little one with the three bigger ones is difficult and the little one never quite matches colors / shading with the other two. Also you should notice there are a lot of duplicates. Some are taken with different filters and others (the ones with the purple font) are closer to originals that haven't had automatic artifact removal applied. I've only worked with the green font ones so far since the automated removal seems pretty spiffy. I assume the others are there just in case something is accidentally removed when it shouldn't have been.

Take my explanation with a grain of salt, please. I'm sure I'm using the wrong terms to explain it. Hopefully I haven't said anything totally wrong, though.

[rstevenson]

Thanks for that. I tried downloading a couple of files and realized I had no idea what to do with them. It makes me appreciate even more the extraordinary images we get from the Hubble folks and others who process their data. I'm going to look into the ways and means of doing this over the next few weeks.

Rob

[geckzilla]

I figured it all out by reading a lot of the stuff linked in bystander's original post. The data can be extracted into the more familiar TIFF format using the FITS liberator. Make sure you save them in 8 bit ... my computer was tanking with the 16 bit ones for some reason. Maybe something to do with my 64 bit Photoshop. Might be worth looking into getting that working a bit better since I'm usually stretching the levels of the individual channels ridiculously and maybe 16 bit would make things a bit smoother? Not sure on that.

Anyway, IIZw28. It's a weird ring galaxy with nearly invisible friends (unless you look around it in H-alpha, which I don't have and don't know how to get)

IIZw28

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[geckzilla]

IC356 ... seems to be a bit more red than usual galaxy? Warning: 2.6 megabyte download upon clicking.

[bystander]

IC356 ... seems to be a bit more red than usual galaxy?

IC 356 is a relatively nearby galaxy at around 39 million light years away. However, we view this galaxy through the disk of our own. Its appearance is dimmed and reddened by the intervening clouds of gas and dust of the Milky Way.

[geckzilla]

Oh, thanks, bystander. That makes a lot of sense. I was wondering the whole time why it was like that.

[geckzilla]

I'm really surprised this one wasn't already on the Hubble site. I'm still expecting to have somehow missed it. Anyway, this is the heart of NGC2146 but the more specific target is SN2005V. I assume the supernova has faded by the time Hubble took this picture or it would be much more obvious. I don't know where the supernova is, actually. If anyone can figure it out I'll put a circle around it on an image hover.

NGC2146 (SN2005V)

[geckzilla]

Sometimes what initially appears to be another rather featureless glowing ball turns out to be much more. I had to be extremely careful with the colors on this. View it on a dark background, if you can. I can't make it any brighter without destroying some vital parts of it. Normal and giant versions.

Shells of PGC10922

[Beyond]

Geckzilla, the giant version only lasted about a second or so, then went to the normal version size. I tried it again, but the second time only got the normal version when i clicked on giant, and no giant at all.

[starsurfer]

Does anyone know if this kind of thing is common or not? It seems to be a bunch of green stuff around a star. I don't know if I'm understanding it wrong or I'm inexperienced but it does seem weird to me. Why is it so green?

It's called PK208+33D1 but if you try to search the HLA for it it won't work. You have to use the advanced search and put 5404 in the proposal ID field.


R = hst_05404_01_wfpc2_f588n_pc
G = hst_05404_01_wfpc2_f502n_pc
B = hst_05404_01_wfpc2_f469n_pc

I'm not 100% sure but I think that might be the centre of the planetary nebula Abell 30. The green colour is surely false colour and results from the colour mapping. I don't know too much about this object but I think it is a rare example of a "born-again" planetary nebula where a central star undergoes a helium flash event that makes it "born-again" for a few years. I think the structures are knots and cometary filaments that might be being influenced by the central star.

[geckzilla]

Geckzilla, the giant version only lasted about a second or so, then went to the normal version size. I tried it again, but the second time only got the normal version when i clicked on giant, and no giant at all.

In most browsers if you click on the image after it's done loading it will zoom in.

[Beyond]

Geckzilla, the giant version only lasted about a second or so, then went to the normal version size. I tried it again, but the second time only got the normal version when i clicked on giant, and no giant at all.

In most browsers if you click on the image after it's done loading it will zoom in.

Well how about that! Thanks!!

[geckzilla]

Does anyone know of any list like the one on the right side of this picture that covers all (or at least the more common ones) of the filters?
http://www.spacetelescope.org/images/potw1216a/

Edit: I also wish they had the full name of the filter instead of just the wavelength... it's very confusing to me.
Edit2: And I also cannot figure out for sure what the letters U, B, V, R, etc mean.

[bystander]

Edit2: And I also cannot figure out for sure what the letters U, B, V, R, etc mean.

http://en.wikipedia.org/wiki/Photometric_system

[geckzilla]

Did you notice that at this link it lists 450 nm as Ultraviolet, yet B means blue? What does this mean? Is it a mistake?

[bystander]

Did you notice that at this link it lists 450 nm as Ultraviolet, yet B means blue? What does this mean? Is it a mistake?

450 nm is definitely at the blue end of the visible spectrum. Maybe the bandpass of the filter allows uv, also.

[geckzilla]

I have leveled up my pestering skill and sent an email to ESO asking for clarification on the matter.

[Ann]

Fascinating, geckzilla. I really like the similarities but also the small differences between apparently elliptical galaxies NGC 524 and PGC10922. Both have dust clouds rotating near their nuclei. But the dust rings around the nucleus of PGC10922 are much "coarser" than the dust rings of NGC 524. Also, there is a strong color difference between the nucleus and the dust rings in PGC10922, where the nucleus is obviously yellow and the dust rings are blue, with blue knots. I think there is definitely star formation in the nuclear dust rings of PGC10922. There does appear to be clusters in the dust rings of NGC 524, too, but I'm far from convinced that the pale bluish color of the dust rings corresponds to a truly young stellar population. The color could be a product of the filters used and the way the colors are mapped.

As for the colors of IIZw28, I'm baffled. I wont make any sort of guess until I know what filters were used. But the image looks fascinating.

IC 356 is an intrinsically fairly red galaxy whose overall color looks even redder because we see it through the dust of the Milky Way. Nevertheless, we may compare IC 356 with the better-known foreground "neighbour" spiral galaxy IC 342. IC 342 is, if anything, probably more obscured than IC 356, but its colors are much bluer. In particular, IC 342 is much more ultraviolet than IC 356, suggesting that it contains many more hot young stars than IC 356. You picture really shows that IC 356 doesn't contain very much star formation, at least not in its central parts.

NGC 2146, oh my! Talk about a dusty galaxy. I'm all but certain that NGC 2146 is a product of two colliding galaxies, and it's choking with dust that the smash-up has kicked up. Again I would need to know something about the filters used, and the way the colors were mapped, in order to say something about the colors of the picture. But the image sure looks striking.

As for PK208+33D1, I'm stumped. I agree with you that it is probably a planetary nebula of some sort, but planetary nebulae aren't my forte.

Great images, though, geckzilla!

Ann

[geckzilla]

Just a note on the colors of NGC524 and PGC10922 - I'm not sure how much faith you can put into the blues on them. If I recall correctly, the blues in NGC524 especially were an aesthetic choice for me. Like I said before, the blue end of the spectrum often gets stretched a lot to help bring some dynamics to the hues in the image. It's largely an aesthetic choice. Despite trying hard to understand exactly what I'm doing I can't honestly say I am much better than Dog (though I hope I am just a bit). Anyway, don't think of the colors being informative about what's going on in the picture is what I'm trying to say. You were right earlier about 814 being infrared so the only thing really certain is that the reds in most of these are heavy on the infrared side of things.

Anyway, I am getting better at this. On the last few I could tell you more about what I did since I didn't flatten the layers at the end. Before, I just didn't realize how to do it without flattening near the end to get the results I desired. I'll make sure I mention what filters went to what channels in my new images here. I have been mentioning what data I use on the flickr submissions so if you really want to know you can look there.

Here is a portion of the LMC. It's about 4 arcminutes wide.
R = F814W
G = F606W
B = F435W
(So yes, everything green is actually red.)


Just because I was curious I shifted the green channel up to the red one a bit because that's where it's really "supposed" to be. Note, that doesn't make it anymore natural than the previous version. It's more like artificially natural, which is artificial, I think. Which is better is all in the eye of the beholder.

[geckzilla]

Forget all that other stuff, I just rediscovered the channel mixer. How in the heck did I manage to forget about the channel mixer? Looks much better to me, now! And sorry for spamming the thread. I didn't intend for it to become some kind of "geckzilla learns astrophotography processing" diary type thing.

[owlice]

geckzilla, you're taking a journey and including anyone who want to tag along; I think that's great!!

[Beyond]

What she hooted up there. ^