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Tutorials for the Astropy Project
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FITS Tutorial Exercise #450

Open payneck opened 4 years ago

payneck commented 4 years ago

Exercise 2 with the Horsehead Nebula "Show the image of the Horsehead Nebula, but in units of surface brightness (magnitudes per square arcsecond). (Hint: the physical size of the image is 15x15 arcminutes.)" http://learn.astropy.org/FITS-images.html Not sure how to set tis up, no solutions available. Any help would be appreciated!

kakirastern commented 4 years ago

Yeah, a lot has been assumed in that tutorial. I will open a PR to follow up on it and add content to that notebook to clarify the assumptions made.

payneck commented 4 years ago

Thank you! I like the tutorials, as do my students, but this one exercise was a bit of a struggle.

On Wed, May 13, 2020 at 12:57 PM Kris Stern notifications@github.com wrote:

Yeah, a lot has been assumed in that tutorial. I will open a PR to follow up on it and add content to that notebook to clarify the assumptions made.

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/astropy/astropy-tutorials/issues/450#issuecomment-628118680, or unsubscribe https://github.com/notifications/unsubscribe-auth/AEZY4GJYWB4O24BZR52KWFLRRLGPPANCNFSM4M75XH4Q .

-- Charlie Payne, MEd Instructor of Physics, Computational Physics DEEP (Online) and Residential Head Cross Country Coach USATF Level II Coach: Endurance Specialty USATF Level I Coach, Track and Field

NORTH CAROLINA SCHOOL OF SCIENCE AND MATHEMATICS 1219 Broad Street | Durham, NC 27705-3577 | 123.456.7890 Igniting innovation, cultivating community. | NCSSM.EDU http://ncssm.edu/

kakirastern commented 4 years ago

You are welcome!

kakirastern commented 4 years ago

Will try to get this done within the next couple of weeks

payneck commented 4 years ago

Thank you so much. I actually talked about this resource yesterday to our Astronomy teacher, and I'd like to use it in the courses I teach, including Comp Phys. There is no hurry, and I'm really looking forward to the results.

Again, thank you. Stay healthy.

Charlie

On Wed, Aug 12, 2020 at 11:30 AM Kris Stern notifications@github.com wrote:

Will try to get this done within the next couple of weeks

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/astropy/astropy-tutorials/issues/450#issuecomment-672944888, or unsubscribe https://github.com/notifications/unsubscribe-auth/AEZY4GKTBCTS32DN2E7RDV3SAKYQXANCNFSM4M75XH4Q .

-- Charlie Payne, MEd Instructor of Physics, Computational Physics DEEP (Online) and Residential Head Cross Country Coach USATF Level II Coach: Endurance Specialty USATF Level I Coach, Track and Field

NORTH CAROLINA SCHOOL OF SCIENCE AND MATHEMATICS 1219 Broad Street | Durham, NC 27705-3577 | 919-416-2765 Igniting innovation, cultivating community. | NCSSM.EDU http://ncssm.edu/

kakirastern commented 4 years ago

Hi @payneck thanks for the reply! You are welcome. I will let you know once the proposed PR is approved and merged.

kakirastern commented 4 years ago

@mwcraig As discussed during telecon today, please have a look at the issue and let us know if any revisions need to be made on the FITS-images tutorial. Looks like the actual calculation involves more than just an inverse-square relationship, at least at the senior undergraduate level.

mwcraig commented 4 years ago

I have a few comments about the tutorial (which I suppose I should turn in to a pull request):

  1. The level is good for the most part.
  2. It would be helpful to link more to other resources. For example, the image sum done in the tutorial is fine but a link to ccdproc for other image combination methods would be good.
  3. The tutorial should probably have users also read in the header, not just the data.
  4. Perhaps consider reading in the image using CCDData instead of io.fits, or use the context manager with fits.open....
  5. That last exercise is a doozy.
    • It is unclear to me what is intended: are counts supposed to be converted to the standard magnitude system first? If so, what units is the image in?
    • Doing the conversion requires a bunch of astro knowledge that is out of scope for this notebook, potentially including how to go from flux to magnitudes, calculating pixel size, etc.
    • I would replace the example with something different...or add much more detail about how to go from whatever the units are for the original image to surface brightness.
kakirastern commented 4 years ago

Thanks @mwcraig for the comments! Let me open a PR and make some preliminary changes according to your suggestions so that it will be easier for you to follow up.

kakirastern commented 4 years ago

Just opened this Google Colab for the drafting part of the PR workflow: https://colab.research.google.com/drive/1rk9dig_LFw_XArLe0KJSFi8lOTKE5QPH?usp=sharing

Editing or commenting is currently by invitation only, but everyone with the link can view it

kakirastern commented 4 years ago

Checklist of things TODO in the Colab notebook:

kakirastern commented 4 years ago

@mwcraig Google Colab notebook ready for a review.

payneck commented 4 years ago

I'd love to check it out as I think it would be valuable to my Comp Phys students (high school, but public residential for NC's finest, NCSSM, part of the UNC System). I might not be able to get to this for a week or so, as grades and some recommendations are due this week.

Thank you! Stay healthy!

Charlie

On Wed, Nov 11, 2020 at 10:20 AM Kris Stern notifications@github.com wrote:

@mwcraig https://github.com/mwcraig Google Colab notebook ready for a review.

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/astropy/astropy-tutorials/issues/450#issuecomment-725482757, or unsubscribe https://github.com/notifications/unsubscribe-auth/AEZY4GJBTUP3XFLUC2HI2MDSPKTTDANCNFSM4M75XH4Q .

-- Charlie Payne, MEd Instructor of Physics, Computational Physics DEEP (Online) and Residential Head Cross Country Coach USATF Level II Coach: Endurance Specialty USATF Level I Coach, Track and Field

NORTH CAROLINA SCHOOL OF SCIENCE AND MATHEMATICS 1219 Broad Street | Durham, NC 27705-3577 | 919-416-2765 Igniting innovation, cultivating community. | NCSSM.EDU http://ncssm.edu/

kakirastern commented 4 years ago

Hi Charlie, Sure, I have just given you access to the Google Colab notebook. Feel free to comment.

kakirastern commented 4 years ago

Will add a solution to the Google Colab as suggested soon

kakirastern commented 3 years ago

Hi all @payneck @mwcraig,

Found out today the calculation is pretty standard according to some IAU definition: https://en.wikipedia.org/wiki/Luminosity#Relationship_to_magnitude

All we needed to do is to go from some measure of luminosity / flux density with an arbitrary scaling factor and then use the magnitude formula to compute the desired result. 😉

I am reading up on the relevant section(s) of the Wikipedia article before working out a solution for it, like the one I sketched out on the Astropy Slack workspace a while back. I read slow though so will be some time before I have everything properly worked out.

mwcraig commented 3 years ago

Thanks for the update @kakirastern -- another perfectly acceptable (and much shorter) solution is to change the exercise. As you are finding, though it is simple in principle, it is more complicated in practice.

kakirastern commented 3 years ago

@mwcraig My bad for procrastinating, feeling like taking my time around Christmas 🎄

mwcraig commented 3 years ago

@kakirastern -- not your bad at all! I just thought I'd dish you a way to vastly simplify. I whole-heartedly support taking whatever time you need.