Astrophotography in the classroom
Download
1 / 49

Astrophotography in the Classroom - PowerPoint PPT Presentation


  • 119 Views
  • Uploaded on

Astrophotography in the Classroom. For SEEC 2014 at NASA JSS David O’Dell, Anderson HS. Goals of this presentation. Show you how to: bring real astrophotography into your classroom use image processing software use image measurement software All this AND get the kids to enjoy it.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Astrophotography in the Classroom' - tassos


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Astrophotography in the classroom

Astrophotography in the Classroom

For SEEC 2014 at NASA JSS

David O’Dell, Anderson HS


Goals of this presentation
Goals of this presentation

  • Show you how to:

  • bring real astrophotography into your classroom

  • use image processing software

  • use image measurement software

  • All this AND get the kids to enjoy it


Why take your curriculum this direction
Why take your curriculum this direction?

  • Real science

  • Software is free

  • Learning curve is low

  • Student driven activity

  • Personal challenge (to you AND students!)

  • Transfer of skills to other activities


Deciding which type of astrophotography will fit in your curriculum
Deciding which type of Astrophotography will fit in your curriculum

  • 2 types… each with their own set of hardware, price tag and challenges:

  • Deep Sky

  • Webcam


Deep sky astrophotography
Deep Sky Astrophotography

  • Most difficult, by far

  • Most expensive

  • Most rewarding (some say):

    • More objects out there than our solar system

    • “cooler looking” stuff like galaxies, colorful nebulae


Webcam astrophotography
Webcam Astrophotography

  • Super easy

  • Extremely cheap

  • Still very rewarding, just in different ways

  • … it’s what this presentation will cover!


You can do so much without a telescope you just need
You can do so much without a telescopeYou just need:

  • Access to a few (or many) PC windows-based computers

  • Permissions to install two small FREE software packages on those machines

    • AVI stack

    • http://www.avistack.de/download.html

    • Image J

    • http://rsbweb.nih.gov/ij/

  • Sample videos and images (simply search online for .avi files)

    • http://www.skyimaging.com/astronomy-videos.php


But much more with a telescope
…but much more with a telescope

  • All the previous items +

  • A single Windows XP or Win 7 laptop

    • Usually from your school, or your personal one

  • Low Luxor comparable Web cam

    • Usually less than $100

    • Philips SPC 900NC, or the 700NC

    • http://nightskyinfocus.com/equipment/philips-spc900nc00-webcam-for-astrophotography/

  • Sharp Cap web cam software

    • FREE

    • http://www.sharpcap.co.uk/sharpcap/downloads

  • 1.25 “ Web cam telescope eyepiece adapter

    • $15 to $30, search “1.25 web cam adapter” on EBAY

  • … and of course… ANY size telescope


Why do we need the stuff we need to do this
Why do we need the stuff we need to do this?!?


Well think about what scientists collect
Well… Think about what scientists collect…

  • Zoologists collect?

  • Animals!

  • Entomologists collect?

  • Bugs!

  • Philatelists collect?

  • Stamps!

  • Numismatics collect?

  • Coins!

  • Astronomers collect?????

  • LIGHT!


Astronomy specific issues
Astronomy specific issues

  • Astrophotography environment is special

    • At night mostly

    • Large contrast

      • Night sky objects are bright compared to dark space

    • Moist or cloudy air

    • Windy ground or upper altitude air turbulance

    • Objects difficult to find

    • Object difficult to focus

    • Objects appear to move as Earth rotates

    • Digital cameras generate waste heat, interference

    • Objects need long exposure times…


Deep sky ccd chip cameras
Deep Sky CCD chip cameras

  • Specially designed:

    • stay “cool” to reduce hot pixels

    • Keep shutter open for long exposure times

    • Large CCD chip that is extremely sensitive to very low light

    • Some only B&W, some color

    • Fit inside a telescope eyepiece tube

    • Software controlled capture settings


Ccd light sensitivity
CCD Light sensitivity

  • CCD will collect photons over a long period of time and produce a bright image from a dim object

  • Long exposures are only possible if the telescope “tracks” the object

  • If scope does not track object, the image is smeared across the CCD


Deep sky vs webcam imaging
Deep sky vs. Webcam imaging

  • Solar system objects are considerably closer and appear larger compared to deep sky objects thousands of light years away… We don’t need the extreme sensitivity of a CCD.

  • A planetary “webcam” is the best option for bright and relatively large solar system objects. Uses low power, less sensitive CMOS chip.

  • Instead of long risky exposure times, the webcam takes hundreds of millisecond frames that are processed later using software


Settings to pay attention to
Settings to pay attention to:

  • Focus – webcams and CCD cameras are particularly sensitive to focus shift!! Light travels a shorter distance than through an eyepiece, so focus is as if you had a 6 mm lens; very sensitive to any movement.

  • Might need a focal reducer: Antares 1.25" 0.5x Focal Reducer

  • Gain – # photons that fall on that pixel are multiplied by a certain amount; image might be brighter, but less accurate

  • Exposure – amount of time shutter is open, measured in seconds or the number of frames you record


Taking a set of darks
Taking a set of “Darks”

  • Cameras all leak voltage out of the image chip

  • This leakage occurs in a predictable pattern

  • A long exposure image with the lens cap ON is taken and the hot pixels are mapped and removed by software


The basic astrophotography process
The basic astrophotography process:

  • Setup scopes, camerasand computer; let cameras settle for 5 minutes to get used to the ambient temperature

  • Take a set of darks

  • Find object and focus using eyes

  • Place camera in eyepiece, reposition and focus using camera / computer

  • Choose settings and record video (using Sharp Cap)

  • Do not walk nearby or touch scope while imaging

  • Save file for processing later


Onto the processing process
Onto the processing… process

  • Frame selection

  • Alignment

  • Stacking

  • Post processing

  • Scientific Measurement & Comparison

Using AVI stack

Using Image J


The following process is to “get the job done”. For specialized tweaks, please read the AVI Stack manualhttp://www.avistack.de/downloads/AviStack2_eng.pdf


Loading a file into avi stack
Loading a file into AVI Stack specialized tweaks, please read the

  • Open .avi movie file from your webcam into AVI stack

  • Highlight file

  • Click PROCESS FILE

  • Frames will be counted


At any point you can make changes
At any point you can make changes specialized tweaks, please read the

  • Each segment of the process is compartmentalized

  • Simply click on a green folder in the Parameters and Settings window

  • Make the changes and move on


Frame selection my 1 tip
Frame Selection – my #1 tip specialized tweaks, please read the

  • More frames doesn’t mean a better image.

  • Remember, pixels are the carriers of visual information. Too much might be over kill.

  • You will NEVER need all the frames of video

  • For most webcam images of the moon and planets, you’ll need no more than 500 frames; and only end up selecting around 200 of those to process.


Frame selection
Frame Selection specialized tweaks, please read the

  • Using the video slider, scroll through the frames and find ones that have problems such as dust, blur, birds, shakes and wild changes of position

  • On frame selection panel, highlight, then ‘X’ them out in bulk using ‘shift’ key or one by one

  • Click OK


Frame alignment parameters
Frame Alignment Parameters specialized tweaks, please read the

  • Using frame selector slider, scroll to the clearest frame

  • Select “planet”, or “surface” for close-up lunar surfaces

  • Adjust “area radius”

  • Left click to place 1st alignment box, right click for 2nd box.

  • Boxes should be on top of unique features

  • Click OK


Alignment deviation the one graph you get to play with
Alignment Deviation – specialized tweaks, please read the the one graph you get to play with

  • Too much deviation is bad.

  • You want to reduce the number of frames used that have large alignment deviation from the previous frame


Reducing deviated frames
Reducing Deviated frames specialized tweaks, please read the

  • Click and drag the top axes of the top graph and pull the red line down, this will be the new cutoff.

  • Frames that deviate too far (over 4 pixels in this example) will not be stacked

  • Click OK


Framed aligned movie
Framed Aligned Movie specialized tweaks, please read the

  • This is where the software first shows its true power

  • Using the movie slider, scroll through the frames

  • You’ll see that the image doesn’t move very much at all now

  • Click OK


Roi region of interest selection
ROI (Region of Interest) Selection specialized tweaks, please read the

  • Simply drag a selection box around the part of the image you want to stack

  • Click OK


Initial stack reference point settings for most images
Initial specialized tweaks, please read the Stack Reference Point settings for most images

  • Used to help stacking and quality management process

  • Minimum distance below 18 is not recommended

  • Structure threshold around 70 recommended

  • Lower cut off 0

  • Upper cut off 1

  • Tweaking these is most often used only with extremely noisyimages


Quality analysis
Quality Analysis specialized tweaks, please read the

  • Some frames contain better, sharper information in certain parts MORE than other frames.

  • AVI stack can break up each frame into areas and make a quality judgment for use in the stacking process


Quality analysis settings for most images
Quality Analysis settings for most images specialized tweaks, please read the

  • Standard quality method selected

  • Noise reduction is suggested to be 1 unless you have extremely noisy

  • Quality area set to above 50, default is 84.

  • Click OK


Frame quality diagram
Frame quality diagram specialized tweaks, please read the

  • Shows a quality vs. frame curve.

  • The highest quality frames will be first in the sorted list


Quality sorted movie
Quality sorted movie specialized tweaks, please read the

  • Simply scroll through the frames of the movie and you will see that sharper, high quality frames are first

  • Low quality frames are last

  • Click OK


Final reference point alignment
Final reference point alignment specialized tweaks, please read the

  • Area radius around 25

  • Search radius is best left automatic since this is calculated

  • Quality cut off IS EXTREMELY IMPORTANT, choose to use first 30% of frames, or, use a specific number of frames by checking frame cut off


Frame stacking
Frame Stacking specialized tweaks, please read the

  • Screen will be black, this is normal

  • Click OK and watch the quality sections appear and stack piece by piece

  • Some errors and dust specks might disappear!


Why stack the picture looks pretty good
Why Stack? The picture looks pretty good! specialized tweaks, please read the

  • You might have one single color image, however, it may not be enough pixels to make a truly magazine quality image

  • You need LOTS and LOTS of combined images

  • You need to STACK your images


Image stacking no pixel left behind
Image Stacking – No Pixel Left Behind! specialized tweaks, please read the

  • Image stacking is a process where many frames of an image are placed on top of one another to increase the amount of pixel coverage


Stacking examples
Stacking specialized tweaks, please read the Examples


Saving stacked image
Saving stacked image specialized tweaks, please read the

  • Choose the filename and directory you want to save to

  • Click Save

  • You’re not done…


Post processing
Post-Processing specialized tweaks, please read the

  • Click the “post processing” green folder

  • Wavelets, Levels, Histogram and Clipping

  • Only Wavelets and Levels are needed


Wavelets and levels
Wavelets and Levels specialized tweaks, please read the

  • Adjust the wavelet sliders to sharpen your image or bring out certain surface details

  • Top slider of a layer is the amount, bottom slider is amplitude

  • Levels are easily adjusted to help control color contrast


Saving post processed image
Saving Post Processed image specialized tweaks, please read the

  • You will need to save this image as a new image

  • AVI stack will automatically append the suffix _pp to the end of your filename


Great results either way ready for scientific measurement
Great results either way, specialized tweaks, please read the ready for scientific measurement!!

  • Stacked ONLY

  • After post-processing


Basic measurement with image j
Basic measurement with Image J specialized tweaks, please read the

  • Image J only recognizes pixel dimensions, it has no idea the scale of any image

  • First priority is to set some sort of scale of pixels to km or miles

  • Easily done as long as the object has a known diameter

  • Diameters of all planets, moons, volcanoes and major craters are on Google


How to set scale using a known distance
How to set scale using a known distance specialized tweaks, please read the

  • Open image into Image J

  • Using the line segment tool, draw a diameter line across the object

  • Click ANALYZE > SET SCALE

  • Type in the ‘known distance’

  • Set units

  • Click OK


Choosing measurements to display
Choosing measurements to display specialized tweaks, please read the

  • Click ANALYZE > SET MEASUREMENTS

  • Check fields you want to display and measure

  • Click OK


Making measurements
Making measurements specialized tweaks, please read the

  • Using the line segment, freehand, or ellipse tool find a feature and draw over or around it

  • Click ANALYZE > MEASURE

  • A new results window will appear

  • Repeat process and new measurements will appear in window


Comparison of scale
Comparison of Scale specialized tweaks, please read the

  • Astronomical measurements are usually on extreme scales

  • It helps students comprehend scale by comparing the measured object’s size to something familiar on Earth, such as:

  • Distance to a nearby city

  • How many New England states could fit into…

  • Or simply, number of Earth diameters


Any questions contact me
Any Questions, Contact me! specialized tweaks, please read the

  • David O’Dell

  • Anderson High School, Austin TX

  • [email protected]


ad