New Horizons, Pluto and the Kuiper belt Options

[djellison]

I'm waiting for you to get them - as there isn't a 'browse' folder with these - so I can enjoy the Emily-o-matic PDS-for-the-public amazing web-pages.

Doug

[elakdawalla]

OK, hope you can be patient! Might be a couple of days. In the meantime, the May versions are here:
http://planetary.org/data/nh/

I'm beginning to mess about with the MVIC data. Anybody else working with this? Reading the documentation on the disk, my impression was that each FITS file was supposed to contain two versions of the image, one "bias-subtracted and flattened" and one "bias-subtracted, flattened, and distortion-removed," plus a couple of other images containing information on errors and data quality. However, the tools I've tried to use to display the FITS images (ImageTOOLSca and DS9) seem to be showing me only one image for each FITS file. My understanding of how FITS format works is pretty shaky; is anybody else working with this data who can give me a little advice?

--Emily

[ugordan]

Reading the documentation on the disk, my impression was that each FITS file was supposed to contain two versions of the image, one "bias-subtracted and flattened" and one "bias-subtracted, flattened, and distortion-removed," plus a couple of other images containing information on errors and data quality.

Ahhhh... So THAT's what the four almost identical images are in each FITS file. I was under the impression those were 4 channels, but they looked the same. Maybe next time I should read some documentation first

I'm using the FITS Liberator 2 plugin for Photoshop but it seems to have slowed down on me after opening a whole bunch of NEAR calibrated images. I though it was a memory leak, but it's slow even after rebooting...

P.S. I, too, can't access the archives anymore...

[elakdawalla]

Thanks for the pointer to FITS Liberator, ugordan, it's letting me see the "distortion removed" images.

Now that I can open the images that I want, I have a question. DN in the images seems to vary from -999 to some number above 2000. I have choices when I import the image in how I stretch it. If I set the minimum DN to 0, the image looks black in all the right places; clipped pixels are in places that I think should be black space. So it seems I should set the minimum DN to 0. How about the maximum, though? Should I set it to the maximum value for the pixel in each individual image, or should I set it so some arbitrary number that is the same for all images that seems higher than the maximum DN I'm encountering in this data set, like maybe to 2400 or something?

--Emily

[ugordan]

I suppose it doesn't matter to what highest DN you set it, as long as you keep it constant if you want relative brightness differences between each filter preserved. Apparently the Red and NIR filtered images are the brightest so that can provide for an upper bound, especially the saturated pixels.

Here's a large swath of Jupiter's terminator from MVIC, red/blue natural-ish colors:


And a closeup of atmospheric waves the team reported as one of their findings:

[elakdawalla]

Which images did you use for that, the ones with or without distortion removed? I'm playing with some Io images (the ones in folder 20070228_003496) and attempting to use the distortion-removed versions and it seems there has been filter-to-filter distortion introduced in the process; I can align them to make a color pic only if I use the versions of the images that have not had distortion removed. Now I'm really confused.

--Emily

[ugordan]

I was using first images in the FIT files, that would be without distortion removal I guess. I don't think using "distortion-corrected" images for such a small target as Io is worthwhile. The rescaling involved could actually blur the original data.

[elakdawalla]

As a reality check, here's two Photoshop files, each containing the four Io images from that observation. Try to line up the mc0 and mc2 (Red and NIR) channels in the distortion-removed one; I can't do it.

http://planetary.org/emily/0034966318_0x536_sci_1.psd
http://planetary.org/emily/0034966318_0x53...ion-removed.psd

Guess maybe I'll stick with the non-corrected ones?

--Emily

[volcanopele]

Where are you getting the distortion removed files? I've been downloading the archives for MVIC at http://pdssbn.astro.umd.edu/holdings/nh-j-....0/dataset.html . Are those the ones?

[ugordan]

Yes, those are the ones.

BTW, are we sure this data is finally meant to be released, and not an accident like the last time? Seems odd the file access would suddenly be forbidden after just a day...

EDIT: Nevermind, I see it's just the http://pdssbn.astro.umd.edu/holdings/nh-j-...nhjumv_2002.tgz file that's broken.

[elakdawalla]

Yes. Opening them in Photoshop using the FITS liberator plugin, the distortion removed files are Image 2, plane 1. I think. See page 53 of the ICD from the document folder for an explanation.

--Emily

[volcanopele]

That is a great plugin for Photoshop! Wish I knew about it before I bought the license for ImageVIEWca...

[volcanopele]

BTW, it looks like archive files larger than 2 GB are not available at this time. This includes the first volume of the LEISA dataset and the second volume of the MVIC dataset (both calibrated).

[elakdawalla]

Although the archive files don't seem to be available (I've emailed Anne Raugh about this), it's easy to get the data files in question. They are all in one folder, so this wget command line will bring them down for you:

wget -r -np -e robots=off http://pdssbn.astro.umd.edu/holdings/nh-j-...0070228_003494/

--Emily

[ugordan]

Almost precisely one year ago, on January 24 New Horizons took one of its first Kodak moment shots capturing Io and Ganymede. Just for fun I tried to colorize the LORRI shot, using one of Christopher Go's awesome Jupiter color shots. Here's what turned out:



Whaddya think? It's a sort of a reminder to some exciting times we had last year around this time.