Students request images from the MicroObservatory Robotic Telescope network and then assemble them into a three color composite using an online tool (JS9). Students have limited control over what they get from those telescopes, and no experience on what things should look like, but results can be good! Telescopes are often oversubscribed, so students sometimes need to use example images.
Rubric is simple: we should see final RGB image and a “professional” image of the same object for comparison (with citation). Brief paragraph about your object (Where is it?, What is it?, Why did you choose it?). Don't worry too much if their image is bad (off target, blurry, etc.).
This lab is adapted from the one Katie Berryhill generously shared, who adapted it from the curriculum, From the Ground Up!, which was developed by the Harvard-Smithsonian Center for Astrophysics. From the Ground Up! was supported by the National Science Foundation under Grant No. 9730351. Additional support was provided by the National Aeronautics and Space Administration, Harvard University, and the Smithsonian Institution. More information about From the Ground Up! can be found at this URL: http://cfa-www.harvard.edu/webscope/
In this lab, I will show you how to request images from a robotic telescope, assemble them into a color picture, and write up your results.
There is a catch--It's a real telescope, and it might be cloudy! Or there might be more requests than it can get to in one night! Because of this, it can take several tries to get images. If you don't get images back the next day, resubmit your request.
After you have good images, go on to The Astro Imaging Lab: Step 2.
So, with many thanks* to Katie Berryhill, and the Harvard-Smithsonian Center for Astrophysics, here's how to get started.
Navigate to http://mo-www.harvard.edu/OWN/training.html (Links to an external site.) and click “How to request an image” to watch a short video that will explain how to task the MicroObservatory.
As show in the video, click "Control Telescope".
You will see a list of targets. Any object that is greyed out is not visible in the sky tonight. Choose one that has the option to take observations in "multiple filters", and click “Observe.” Only objects that can be observed in red, green, and blue filters will allow you to create a three-color image, which is required for this lab.
Here is a partial list of objects that will work. The designation in parentheses after each object's name is its Messier number, a catalog of beautiful deep-sky objects compiled by Charles Messier in 1771.
Stars and Nebulae
Hercules Cluster (M13)
Orion Nebula (M42)
Ring Nebula (M57)
Dumbbell Nebula (M27)
Trifid Nebula (M20)
Lagoon Nebula (M8)
Eagle Nebula (M16)
Crab Nebula (M1)
Messier 46
Omega Centauri
Rosette Nebula
Galaxies (only two are bright enough for full-color observing)
Andromeda Galaxy (M31)
Whirlpool Galaxy (M51)
Select your field of view (some objects will have a choice, others won't).
Select your Exposure Time (the website may suggest that your selection might result in an under- or over-exposed image...select accordingly).
Select “Multiple Filters”. You want all three filters (red, green, and blue), so that you get three images that can be combined into a color image. If that isn’t an option, choose a different image.
Click “Continue.”
Enter your email address (links to your images will be emailed to you), answer the demographic questions if you wish, and click “Submit.”
The next day, when you should receive your images, follow the "Access your image..." link for each file and download the "high-quality FITS format" image. If you are familiar with digital photography, this is similar to the RAW format. Your computer almost certainly cannot open these images, but you can still download them. These images aren't kept for long, so don't wait to do this step! Rename each image so you can tell which filter it was taken through, but retain the ".FITS" ending.
Look ahead to The Astro Imaging Lab: Step 2 to see how to open the FITS images in JS9. Check to make sure that you can see your target. An image that looks blank in the preview can actually show an image when opened in JS9, but sometimes images come back out of focus, or even apparently blank. If you still can't see anything even after this step, then you'll need to request new images.
In this assignment, you will take the images you obtained from part 1, assemble them into a color composite, and write up your results. If you have not been able to get images, you may use the example images as demonstrated in the video below. For more information, please see MicroObservatory's Tools & Training (Links to an external site.) page.
Assemble the Color Composite
Once you have three images (one taken in each of the red, green, and blue filters) you'll probably see that each one is black and white. The general process for making a color composite is:
Adjust the brightness and contrast of each image
Color each image red, green, or blue.
Stack the images.
Align them.
Save the composite as a new file (a gif or jpg).
You'll need to start with the raw data, which you should download by following the "Access your image..." link, and then downloading the "high-quality FITS format" image. If you are familiar with digital photography, this is similar to the RAW format. Rename each image so you can tell which filter it was taken through, but retain the ".fits" ending.
Your computer probably can't open FITS images, but the MicroObservatory website has a tool that can: JS9 (Links to an external site.). You can get to it anytime by clicking the Analyze Images tab on the MicroObservatory website.
The video, below, shows you how to use JS9 to create your very own three-color image!
"How to Create a Simple RGB Image" (Links to an external site.)
This is how most astronomical images are taken, although sometimes with images taken through additional filters. For example, the SDSS constructed their images using five filters.
Write-Up
Your write-up should should include your final RGB image, and a “professional” image of the same object for comparison. Don't worry if the professional image looks more "zoomed in", chances are it was taken with very different equipment than MicroObservatory's 6" (15 cm) mirrors. We don't mind how you find the professional image, but be sure you cite* it. Write a brief paragraph about your object (Where is it?, What is it?, Why did you choose it?).
You're welcome to any tool that can arrange pictures and text on a page, but please submit something Canvas can open (Microsoft Word or a pdf) to The Choose Your Own Lab assignment.
* Do not cite a search engine. In other words, do not write "Andromeda Galaxy - Google Search. Google. 30 May 2015. Web. 26 May 2015." This is why (Links to an external site.).