PDA

View Full Version here: : Arp 273 Interacting Galaxies


Jeff
15-11-2018, 08:54 PM
After a few weeks in Melbourne without clear evening skies, I have gotten a bit of "cabin fever" and attempted to download and process some Hubble data for the first time.

Data for this image was acquired through the Hubble telescope in December 2010 using the Ultraviolet-Visible channel of WFC3 (Wide Field Camera 3).
http://www.stsci.edu/hst/wfc3/documents/handbooks/currentDHB/wfc3_dhb.pdf

The WFC3/UVIS instrument on the Hubble is quite peculiar, in that it comprises two imaging chips, separated by a distance of 30 pixels. As a result, the calibrated and distortion corrected stacks include a 30 pixel "dead-zone" through the middle of them with data missing. To compensate for this, the Hubble acquires a 2nd (slightly offset) image on the next day with the "dead zone" between chips in a slightly different position (see first 2 image revisions).

15 hours of data through the F600LP filter (599->996nm) was mapped to the Red channel.
18 hours via the F475X filter (378->650nm) was mapped to the Green and Blue channels.
UV data was quite weak and extremely noisy, so has been discarded.

To assemble complete images for each filter, a "mosaic scrapbook" approach was adopted using DynamicCrop, NewImage, PixelMath plus a few other processes to match gradients.

The result is nowhere near as good as APODs of this object …. as I continue to build my fledging skills in PixInsight. But I have enjoyed the process nonetheless!

Higher resolution version here (https://www.astrobin.com/376742/C/?nc=user).

alpal
15-11-2018, 10:16 PM
Hi Jeff,
you've done well - it's a very interesting picture.

I will be very sad when Hubble ends up in the Pacific ocean.
I wish we had a dozen Hubbles out there.


cheers
Allan

multiweb
16-11-2018, 08:25 AM
Nice one Jeff! :thumbsup: When I saw the thumbnail I thought someone got a new toy, then opening the pic I thought BS! :lol:

RickS
16-11-2018, 10:01 PM
A good result, Jeff. Even professional data isn't perfect :)

Jeff
16-11-2018, 10:12 PM
Thanks Allan.
Yes …. it's been almost 20 years.
Will be sad to see it eventually go.



Thanks Marc.
Yes, certainly a different look. I think I may have seen that shape before in one of those expensive ice cream brands!

Jeff
16-11-2018, 10:23 PM
Thanks Rick.

Was certainly more difficult than I expected.
And true … I was surprised to see a large "sensor dust" artefact on each image, and seriously poor SNR on the UC channel, despite 19 hours.

Paul Haese
17-11-2018, 10:53 AM
Wouldn't we all love this sort of resolution. Damn atmosphere. Oh well it makes breathing easier. I have never tried Hubble data, there never seems time lately to even process data.