Please ensure that you have access to this software before accepting assignment. Checklist: Refer to the Instructions for Phase 1, Phase 2, and Phase 3 for more-complete descriptions of all of the

Please ensure that you have access to this software before accepting assignment. Checklist: Refer to the Instructions for Phase 1, Phase 2, and Phase 3 for more-complete descriptions of all of the
Phase 1 Instructions First, you will need to have a working copy of Adobe Photoshop.*. If you are unable or would prefer not to install a new application on your computer at this time, the site www.photopea.com offers a free Photoshop-like interface and image tools.  As for the previous projects in this course, you are not required or expected to purchase anything to complete this project! (* or a similar program, if you are familiar with and prefer another — e.g., GIMP, Pixelmator / Pro, Paint.net, etc.) The instructions that follow will be based on the assumption that you are using the most-recent Adobe “Creative Cloud” version of Photoshop.  The instructions, starting below for Phase 1 2 and 3, will take you through the steps of using Photoshop for the image composition portions in this project.   We begin with some … ————————————————————————————————————   Science Background  —  Constructing multi-wavelength images of astronomical objects    When the Hubble Space Telescope takes science images they are not the same as what we would see with our eyes when we look through it.  Instead, astronomers quantitatively measure the colors of stars, gas clouds, and galaxies by observing through different color filters.  A color filter actually blocks most of the light from the detector and allows only a small range of colors to come through.   For examples:  a filter might allow only the blue light to pass through it, or allow only the red light to pass through it. If we are looking at a star cluster the consequence of this is that the blue filter image would “look” black and white, but it would only show stars that are blue.  Recall from lessons in the video game’s Units 3 & 4 that these represent the young stars.  The red filter image would also “look” black and white, but would show light in different positions — those positions where there are old, red stars or red giant stars near the end of their lives. Scientists can measure the different filter images separately and compare different regions to each other.  However, in order to make an image to release to the public it is possible to choose a color to represent each separate filter image and then superimpose them to combine the colors and see the different regions as different colors, but all at once again in the same image.   These images are made both to clarify the science and to be aesthetically appealing and/or interesting.   You should now watch the following 3-minute video to show how the different images are superimposed:   Creating a Hubble Galaxy in Two Minutes – https://www.youtube.com/watch?v=p5c1XoL1KFs   Now, on to …   ————————————————————————————————————   Phase 1  —  Construct a multi-wavelength red/green/blue (RGB) image of an astronomical object Please be sure to read carefully and follow along with all of the instructions, as you proceed.  Many of the steps involve clicking menu options, or checkboxes in pop-up windows, that might be easy to overlook if you are trying to work through too quickly.  There are several screenshots to accompany the steps; you can zoom-in or expand these images to see details in them.   You can also click here for a video demonstration – https://www.personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/Astro7N_Art-Project-4_Phase1_Photoshop_demo.mp4 of completing this phase of the project in Photoshop. If you are using the free “photopea.com” site, refer to this video- https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/Astro7N_Art-Project-4_Phase1-2_PhotoPea_demo.mp4 instead of the one above (please ignore if in the videos some pages or files appear to refer to “art project 3”; what used to be project 3 in previous semesters is now project 4)     Select one of the following astronomical objects to work from; click the link to download the set of files.  If you have trouble right click the link and then select Open in New Window.  That will begin your download.  M16 Eagle Nebula “Pillars of Creation” — (preview) https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/Astro7N-AP4_-_Eagle_Nebula_Pillars.zip M31 “Andromeda Galaxy” — (preview)- https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/Astro7N-AP4_-_M31_Andromeda_Galaxy.zip M42 “Orion Nebula” — (preview) https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/Astro7N-AP4_-_M42_Orion_Nebula.zip NGC 1068 Barred Spiral Galaxy — (preview) https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/Astro7N-AP4_-_NGC1068_barred_spiral.zip M17 “Omega Nebula” section — (preview) https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/Astro7N-AP4_-_M17_Omega_Nebula_section.zip   Make a note in your Art Project 3 Submissions Form for which object you chose. Also:  check out the “preview” image, linked above, of your object.  It shows what your image should look like by the end of “Step 18,” below; if your image at the end of Step 18 does not look like the preview, you may need to re-trace the steps to be sure you have not missed anything.  Quick aside:  If you happened to choose “M16,” “NGC 1068,” or “M17,” and are wondering, “What’s up with that one corner being cut off in the picture?” — Actually, it is supposed to look like that; explanation, here. https://www.universetoday.com/142352/why-do-some-hubble-images-have-that-chunk-taken-out-of-the-corner/  The step-by-step directions, below, use a sample set of images which are not included but are similar in nature to the images sets linked, above.   Extract / un-zip the downloaded archive of source images on your computer.  This is just like unzipping the video game or other downloaded files on your computer, before.  Your browser may automatically unzip the archive for you, or you may need to double-click it (macOS), or right-click and choose “Extract…” (Windows) The ZIP file should extract or unzip to a folder containing three images (PNG files).  Each of these images files will be named for the object, which wavelength filter the picture was originally was taken in (may be a letter code, like “B,” “V,” or “I,” or the wavelength in nanometers, nm), and the color channel (red, green, or blue) to which it should be assigned in this first phase.  example images:     ⟶   Open/run Adobe Photoshop.  Again, these instructions will assume you are using the most-recent Adobe Creative Cloud version of Photoshop, available through Penn State.   If you are using another version of Photoshop, or a different but similar program, your specific methods may vary slightly.     Click to “Create New…”;  Change Units to Pixels, if it is not already set to such (it may be first listed as inches, centimeters, etc.); Set width to 1024 (pixels); Set height to 1024; “Resolution” (e.g., pixels per cm) can be left alone — it will not matter for this assignment; Set “Color Mode” to RGB, 8-bit; Set “Background contents” to “Black.”   ⟶   With those settings specified, click “Create.”  Your next view, once the new file is created in Photoshop, may look like the following screenshot.    If it does not — specifically, if it does not show the “Layers” palette (like in the lower right in the example screenshot — open the “Window” drop-down menu and choose to enable the Layers palette, there.     Select “Open…” from the top “File” drop-down menu.  Navigate to where your extracted downloaded source images are located. Select all three images (may be able to drag a box around all of them, or hold the shift key+click to select multiples, or tap control/command+A to highlight them all. Click to open all three.   ⟶    Your next view may be like the following, where you can only see one image at a time.  Arrange the windows so that you can see all the images at once by clicking-and-dragging on the individual images’ name tabs down slightly, to “pop out” each image into its own window.    Drag the windows to arrange them such that you can look at them all at once.    You may need to change the window zoom setting to fit them all into one view, by either clicking-and-typing to adjust the zoom level in the lower-left of each window, or just by pressing the command (or control) and “-” keys (command/control plus the “+” keys zooms the view back in, too).     Take a minute to examine the differences between the three images.    While they are labeled as the “red,” “green,” or “blue” channel intended source images, they are all in grayscale at first.  Each image represents the astronomical object’s light intensity across the picture at that specific wavelength (i.e., from very low intensity — black or darker grays, … to higher intensity — lighter grays up to white) Some features (such as stars, or dust lines, etc.) may stand out in one image and not in others.   Perhaps one image looks overall brighter or dimmer than another.    Click anywhere on the window for the “red” image, to make it the active one.    Then, choose “Select > All” from Photoshop’s top drop-down menus.    Copy (by “Edit > Copy”) the contents of the red image.    Click anywhere on your new / untitled image, to make it the active window again.  “Edit > Paste” the contents copied from the red image into your new file.  You should see the grayscale image duplicated there, in a new Layer (which shows up in the Layers palette you enabled, earlier).   ⟶   In the Layers palette, double-click the name of the newly-pasted layer (“Layer 1,” initially), and then you can rename it to the name of the source image (wavelength & color-channel designation are used in this example, as a handy way to remember which it is supposed to be, eventually).   ⟶   Also, click the Layer Mode drop-down menu (in the Layers palette itself), where it initially says “Normal,” and change it to “Screen.”     At this point, probably a good idea to Save your work!  (not a bad habit to get into, in general — save after series of steps, major changes, etc.)   Repeat Steps 9 – 12, for each of the “green” and “blue” channel source images, until…    You should see, when each additional layer is copied/pasted and also changed to “Screen” mode (important!), that the overall resulting image will get brighter.   ⟶  When you are done, you can close the three individual source images, and enlarge the single layered composition for better visibility.    Again, good time to Save your work!    Since the “blue” channel layer is the active one, we can work with that one, first (looking at  the Layers palette — you can click on the blue layer to make it the active one if it is not highlighted)…  From the top drop-down menus, choose “Layer > New Adjustment Layer > Hue/Saturation”    In the pop-up menu, you can name the layer, assign it a color tag, and Be Sure to Check the Box for “Use Previous Layer to Create Clipping Mask”; then, click “OK”      Another pop-up menu with the Hue & Saturation controls will have appeared as well; here, change the following…  Check the box for “Colorize”;    For the blue channel layer, either drag the “Hue” slider until it reads “240” in the box, or just click the box and type in “240”; If your “Hue” slider seems to only go from -180 to 180, double-check that you clicked the “colorize” box, as above; For users of “photopea.com”:  your Hue slider will remain -180–180, so for blue slide it left to -120;   Drag the “Saturation” slider all the way to the right, for “100” (or type “100” in the box);  Drag the “Lightness” slider left to “-50” (or type “-50” in the box — note the negative sign, here);  Afterwards, you can click the little “>>” button in the upper-right corner of that pop-up window, to minimize it for now.      Repeat steps 14 & 15 in a similar fashion to “colorize” the green and red layers, but with the following changes…  For the “green” channel image, use “120” for the “Hue” value.  The rest can be the same for now as it was for the blue layer — i.e., Saturation up to 100, Lightness down to -50. As before, remember to check both those little boxes — the first for “Use Previous Layer to Create Clipping Mask” in the new adjustment layer properties window, and the second for “Colorize” in the Hue/Saturation window; they are important, but also easy to miss!   ⟶ ⟶  For the “red” channel image, use “0” for the “Hue” value.  The rest can be the same for now as it was for the blue or green layers — still Saturation 100, Lightness -50.   ⟶ ⟶  (again, you can click the little “>>” button in the upper-right corner of that Hue/Saturation pop-up window to minimize it, if it is in the way of your image)  When you are done, your overall picture should start to resemble something like you may be used to seeing in science articles, posters, and the like.     Save your work!  Photoshop saves as .PSD files.  You do not have to upload a copy of that, but it is a good idea to save it.  You may wish to save a second copy of it, too, to use separately for Phase 2.   At this point, Export a copy of your composition (Photoshop defaults to a PNG file, in this example — which is just fine for our purposes), which “flattens” all of those individual layers and adjustments into a single image that you can share.    example result:      Again, check your resulting image in Photoshop against the “preview” for your astronomical object: preview image for M16 Eagle Nebula “Pillars of Creation”  – https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/M16_RGB_preview.png preview image for M31 “Andromeda Galaxy” https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/M31_RGB_preview.png preview image for M42 “Orion Nebula” https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/M42_RGB_preview.png preview image for NGC 1068 Barred Spiral Galaxy https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/NGC1068_RGB_preview.png preview image for M17 “Omega Nebula” section https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/M17_RGB_preview.png If your image at this point does not look like the preview, you should re-trace the steps above to be sure you have not missed anything!  Make careful note of essential drop-down menu options like setting “Screen” mode for each layer (in Step 11), or the required checkboxes for things like “Use Previous Layer to Create Clipping Mask” when making the Adjustment Layers (Step 14), “Colorize” in the Hue/Saturation menu (Step 15), and so on. If instead your image looks about right, then…   You can at this point insert this exported (png/jpg/pdf) imageinto your document to be submitted, as “Image 1.”    Below Image 1, answer the following questions, about this first image you uploaded.   Which object did you choose to work with?   (from the list of five potential astronomical objects)  In just a couple of sentences, briefly describe what differences you can see between how the object looks across the three separate images included. (Suggestions:  You might look for such things as stars or other small features that are extra-bright in one wavelength and dimmer in others, or clouds of gas or dust that are overall brighter in one image than another.  Your description can be very general, focusing on appearances only and not concerned with scientific interpretation of why there are those differences; that’s in the next question.)  Again, in just a couple of sentences, briefly consider the reason for visible differences between one wavelength image’s contents versus another’s. (Hints:  Recall previous lessons on the relationship between temperature and color, of stars’ ages, and — if applicable — of where in galaxies certain kinds of stars are more likely to be found.)    When done saving your work so far in your Art Project 4 document-in-progress, with Image 1 and the written portion beneath it, move on ahead to “Phase 2.”       [OPTIONAL]  In case of interest, …  If you are having some fun with this, feeling a little adventurous, and/or would like to practice adding a bit of extra “polish” to some kinds of images like was shown in the video above — in a way that you could carry over to using Photoshop on your own in the future — read on…    We can “improve” upon the look of this image with additional adjustments, …  “Curves” and “Levels” are two handy tools (additional kinds of adjustment layers) in Photoshop that individually or together can help accentuate the central subjects of images, or otherwise diminish the effects of background noise, and so on.  As you work through this section, you may recall back in the YouTube video, linked above in the science discussion, there were multiple Curves and Levels processing steps involved in preparing the source images there as well, in addition to all the scaling, alignment, and cropping steps that we have conveniently left out of this exercise.  In the following series of steps, we can see how to apply these adjustments in this example to (1) reduce that yellow-ish/gray background to more of a “deep-space black” like we might usually expect, and (2) help make some of the central object’s finer details pop out a little better.   The following series of images goes through adding and making adjustments to “Curves” adjustment layers, one for each of the color channels (first to the red layer, then green, then blue).    ⟶ ⟶  In this initial curves adjustment, I clicked the “Auto” button near the upper-right corner.  But, not really satisfied by how that reddened the overall background, next I started clicking on the curved line itself to create some additional “anchor” points, and then moved those around to re-shape the curve and make some finer adjustments…    Notice that the new shape of the curve now reduces the background red (by having the low point of the curve centered on that “spike” in the mini-palette’s graph), but this keeps some red visible in the central object in the image — as evidenced by the background being more strongly green with a little blue (and not a red component).  Next, a Curve adjustment for the green channel (remember to click on the “green source image” Layer first, to make it the active one, before going to add the Curves adjustment layer) …   ⟶ ⟶ ⟶  And now, a curves adjustment layer for the blue channel, …   ⟶ ⟶ ⟶  This yields a picture with the background looking more like it has the “expected” blackness of deep space over most of the field of view, and the central object beginning to stand out a little better.  A bit of follow-up curve adjustments, going back to the curve layers already made…  red:   ⟶ green:   ⟶ blue:   The result has some of the extended “arms” of the central object a little better visible than before:     Depending on the nature of the object you chose (from the options, above), the need for these kinds of adjustments may be less, or more; just play around with it until you find a result you consider “aesthetically-pleasing.”   The next series of images goes through adding “Levels” adjustment layers — again, beginning with one linked to the “red” channel…    ⟶  Again, first I tried the “Auto” setting, to see what happens…    … but not really going for that, I click-&-dragged the two end sliders just below the center “plot area” of the mini-window to the outer edges, and then fine-adjusted the position of the center slider around near the left-of-midpoint of the “spike” — the result:      The background stays near black, but some of the extended red features in the central object stand out pretty well.  Continuing to the green layer, …   ⟶ ⟶ ⟶  … and blue, …   ⟶ ⟶ ⟶  The result:        Now, that I think is beginning to look a little more like a Hubble Space Telescope image.  As previously said, these fine-tuning adjustments — as in steps # 19 – 22, here in this example — are optional, but I think kind of fun to play around with and can be rewarding in the end, with images that some might consider more pleasing to look at, as well as more like “what you would expect” of an astronomical object featured in a news article or similar context.  Feel free to experiment!    Next … Phase 2- Modify your multi-color astronomical object composition. If you have been working from one of the sets of images in Phase 1 where the individual layers have wavelengths labeled in nanometers (nm), you may have noticed that those wavelength values are not really “red,” or “green,” or “blue.”   What we usually consider “Red” (or reddish) colors actually covers the range of wavelengths about 700–635 nm. “Green”-ish colors fit in around 560–520 nm. “Blue” occupies the span of about 490–450 nm. … with the other colors — orange, yellow, indigo, violet, etc. either occupying wavelength spans within or outside of those ranges, above. We may assign red/green/blue colors to those source images, whatever their original wavelength detection region was, for the sake of making differences in details more obvious from one layer to another.  For some of the telescopes’ color filters the actual wavelength differences — from one filter to the next — are pretty narrow; for example:  two color filters may actually both be in the reddish end of the visible light region, but we exaggerate the differences that may show up between the images by assigning one of them to “red” and one to “green” color channels in composing the multi-layered image. What results is what is often referred to as a false-color image.   If you happen to have chosen the famous “Pillars of Creation” (a section of the Eagle Nebula, you may recall visiting in an early part of Unit 4) in Phase 1, note that the more-famous image of it is not rendered in colors like we might see with our naked eye.  Were we able to see the fuller range of saturated “natural colors” for it, like over a longer-time camera exposure, it might look less like the familiar image on the left, below, and more like the one on the right:     (left:  “Pillars of Creation” image from NASA/HST, prepared by Jeff Hester & Paul Scowen, ; right:  approximated natural-color image, prepared by artist Don Davis)   As long as we are assigning potentially-false colors to some of these color-filter images, anyway, …  how about choosing your own alternative colors?   You can click here for a video demonstration https://www.personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/Astro7N_Art-Project-4_Phase2_Photoshop_demo.mp4 of completing this phase of the project in Photoshop. If you are using the free “photopea.com” https://www.photopea.com/ site, refer to this video https://personal.psu.edu/jds255/teaching/astro7n/Astro7N_ArtProject4/Astro7N_Art-Project-4_Phase1-2_PhotoPea_demo.mp4 instead of the one above. (please ignore if in the videos some pages or files appear to refer to “art project 3”; what used to be project 3 in previous semesters is now project 4)   Return to your image composition from “Phase 1,” in Photoshop again, but this time change up the assigned layers’ colors (“hues”), in a manner similar to the following example:    Click on one of the “Hue/Saturation” adjustment layers in your Photoshop document to make it active.  In this example, I have clicked to focus first on the “blue” one.    If the Hue/Saturation adjustment palette is minimized, click the little  icon here to re-expand it.   ⟶  Make adjustments to the “Hue” slider to reassign the color associated with that source image.  You may change it to any other Hue you would like; in this example, I chose to offset it by 180 (hue scale goes 0 – 360) in order to make it the “opposite” color from what it was, before…    Note the immediate change in the general color of the central object.  I similarly offset the hues assigned to the other two color channels by 180…   ⟶  … so that now instead of being mostly reddish, the nebula looks rather cyan.  You can really change these sliders to whatever you wish, in this Phase 2 part of the project.   You can adjust the Saturation and Lightness sliders, as well, to make colors more or less vivid.    As in Phase 1, Export or Save a “merged” copy of your composition from Phase 2, to include in your document (as “Image 2”).    example image to be submitted for “Phase 2.”      Come to think of it:  the colors in this now remind me more of a curiously-symmetric “irregular galaxy,” than of a planetary nebula…  After inserting “Image 2” into your document, below it write a short statement (a couple sentences) about your changes from the first image:   Why did you make your choices for hue/saturation/lightness for your second image?   Are any particular details more or less visible in your Image 2 than in Image 1?       Now, on to …