- Art by Judy Schmidt

Messier 77 (2014)

Here is a lovely, dust-laden spiral galaxy with some large patches of star formation going on in its arms. I had previously processed this galaxy but I used a different set of data and I was still relatively new to processing. As such, looking at it again I decided to try a new take on it and this is the result. I still think the old one has its merit despite the odd colors. It’s easier to see the H-alpha structures in the old one because the H-alpha channel is not competing with as many datasets but this version is far easier for a human to understand, which one might call more natural, at least by human standards.

You may have also seen my friend AndrĂ© van der Hoeven’s version of this galaxy. He won second place in Hubble’s Hidden Treasures contest with it. Another version has also been featured at ESA’s Hubble website and at APOD.

Here, I’ve used all of my processing skills to make yet another version, this time utilizing available WFPC2 data to help the bluer stars really stand out, which was something I did not know how to do the first time I attempted it and was unsure if it was something I even should do.

The blue channel especially is challenging because two separate, somewhat different but close enough filters were combined for it. At F336W and F450W, the two peak wavelengths are over 100 nm apart from one another and the F336W dataset is considerably more noisy. Still, by fiddling with Photoshop’s curves adjustment a bit, it is possible to make them match nearly seamlessly against one another.

In some places, not all data was overlapping all three channels. In those places, pseudo color was generated with what data were available. There is a small patch of totally missing data at the upper right corner which I have filled in with dark gray.

These data were acquired during three separate proposals, namely:
Proposal 11128, Time Scales Of Bulge Formation In Nearby Galaxies
Proposal 9788, A Narrow-band Snapshot Survey of Nearby Galaxies
and Proposal 5754, Imaging and Spectrophotometry of Seyfert Nuclei (FOS 14): - Part II Cycle 4 Observations

Red: HST_9788_02_ACS_WFC_F658N_sci + HST_9788_02_ACS_WFC_F814W_sci
Green: HST_9788_02_ACS_WFC_F658N_sci + hst_08597_88_wfpc2_f606w_wf_sci
Blue: hst_08597_88_wfpc2_f606w_wf_sci + hst_11128_30_wfpc2_f450w_wf_sci

North is up.

Copyright information:
Hubble data is public domain. I do, however, request that you credit me for the processing of the image if you use it.

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 Unported License.