Mailman 3 March 2016 - AstroPy

Re: [AstroPy] AstroPy Digest, Vol 114, Issue 12
by Pistacho Datil April 1, 2016

April 1, 2016

thanks Eric For the midpoint I went for def midpoint(coord1, coord2): ra1 = coord1.ra dec1 = coord1.dec ra2 = coord2.ra dec2 = coord2.dec delta_ra = ra2 - ra1 bx = np.cos(dec2) * np.cos(delta_ra) by = np.cos(dec2) * np.sin(delta_ra) dec_term1 = np.sin(dec1) + np.sin(dec2) dec_term2 = np.sqrt(np.power((np.cos(dec1) + bx), 2) + np.power(by, 2)) decMid = np.arctan2(dec_term1, dec_term2) raMid = ra1 + np.arctan2(by, np.cos(dec1) + bx) return SkyCoord(raMid, decMid, frame='fk5') not my code but it calculates the midpoint on sky. Thanks again, Frank On Thu, Mar 31, 2016 at 5:00 AM, <astropy-request(a)scipy.org> wrote: > Send AstroPy mailing list submissions to > astropy(a)scipy.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.scipy.org/mailman/listinfo/astropy > or, via email, send a message with subject or body 'help' to > astropy-request(a)scipy.org > > You can reach the person managing the list at > astropy-owner(a)scipy.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of AstroPy digest..." > > > Today's Topics: > > 1. calculate a new coordinate on sky given RA and Dec offsets > and midpoint coordinate between two targets on sky (Pistacho Datil) > 2. Re: calculate a new coordinate on sky given RA and Dec > offsets and midpoint coordinate between two targets on sky > (Eric Jensen) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 30 Mar 2016 17:22:23 -0700 > From: Pistacho Datil <datilp(a)gmail.com> > To: astropy(a)scipy.org > Subject: [AstroPy] calculate a new coordinate on sky given RA and Dec > offsets and midpoint coordinate between two targets on sky > Message-ID: > < > CABH4OQKtS1s7js1s5823_EO4xJgOj8j19c1scTgTVeNK-jJFvA(a)mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Hi, > > First of all apologies if these two questions are too simplistic. > > 1) I wonder if there is a way in astropy, given a target and an offset in > RA and Dec to calculate a new target on sky. > > 2) Given two targets t1 and t2, is there a way using astropy of calculating > the midpoint coordinate also on sky? > > Many thanks in advance, > > Frank >

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calculate a new coordinate on sky given RA and Dec offsets and midpoint coordinate between two targets on sky
by Pistacho Datil March 31, 2016

March 31, 2016

Hi, First of all apologies if these two questions are too simplistic. 1) I wonder if there is a way in astropy, given a target and an offset in RA and Dec to calculate a new target on sky. 2) Given two targets t1 and t2, is there a way using astropy of calculating the midpoint coordinate also on sky? Many thanks in advance, Frank

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Request (and vote for) features for the Astropy project!
by Thomas Robitaille March 29, 2016

March 29, 2016

Hi everyone, The Astropy project now has a site on which users can easily request and vote on significant features: http://astropy.userecho.com The aim of this site is to have a place to collect feature requests from users and gauge the Astronomy community's priorities in our Python-based coding efforts. We welcome requests for the astropy package, any affiliated packages, and any other functionality which you think would be widely useful to the Astronomy community. We would for example be interested in finding out what IRAF or IDL features are currently missing from the Python astronomy ecosystem. Note that this forum should not be used to report bugs or request small improvements to existing functionality. For these, please use the GitHub issue trackers for the relevant package (for example https://github.com/astropy/astropy/issues for the astropy core package). Please feel free to suggest any features and vote on all features that would be useful to you! Thanks! Tom

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Problem with compound models using AiryDisk2D
by Yee, Jennifer March 22, 2016

March 22, 2016

Hi, I am trying to fit a PSF with an Airy function. If I use AiryDisk2D alone, it works fine, but if I try to create a compound model, for example a constant+AiryDisk2D, the compound model cannot be evaluated because it has "no attribute _rz". Is this a bug? Does anyone know how to fix it? (Note I have no problems creating compound models with Gaussian2D). Example code and full error message below. python version: 2.7.5 numpy version: 1.10.4 astropy version: 1.1.2 Thanks, Jennifer EXAMPLE CODE: from astropy.modeling import models class Airy_with_Background(models.Const2D+models.AiryDisk2D): pass x,y = np.mgrid[:200,:200] airy_init = Airy_with_Background() airy_init(x,y) ERROR MESSAGE: Traceback (most recent call last): File "test_airy.py", line 20, in <module> airy_init(x,y) File "/Path/lib/python2.7/site-packages/astropy/modeling/core.py", line 407, \ in __call__ __call__, args, [('model_set_axis', None)]) File "/Path/lib/python2.7/site-packages/astropy/modeling/core.py", line 403, \ in __call__ return super(cls, self).__call__(*inputs, **kwargs) File "/Path/lib/python2.7/site-packages/astropy/modeling/core.py", line 708, \ in __call__ outputs = self.evaluate(*chain(inputs, parameters)) File "/Path/lib/python2.7/site-packages/astropy/modeling/core.py", line 2514,\ in evaluate return self.__class__.evaluate(*args) File "/Path/lib/python2.7/site-packages/astropy/modeling/core.py", line 1997,\ in evaluate result = cls._evaluate(inputs, params) File "/Path/lib/python2.7/site-packages/astropy/modeling/utils.py", line 448,\ in <lambda> g(inputs, params))) File "/Path/lib/python2.7/site-packages/astropy/modeling/core.py", line 2438,\ in <lambda> (evaluate(*chain(inputs, islice(params, n_params))),) File "/Path/lib/python2.7/site-packages/astropy/modeling/functional_models.py\ ", line 1622, in evaluate r = np.sqrt((x - x_0) ** 2 + (y - y_0) ** 2) / (radius / cls._rz) AttributeError: type object 'AiryDisk2D' has no attribute '_rz' -------------------------------------------------------------- Dr. Jennifer C. Yee Office: P-344 Harvard-Smithsonian Center for Astrophysics 60 Garden St, MS-15 Cambridge, MA 02138 --------------------------------------------------------------

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ANN: Release of ccdproc v1.0
by Steve Crawford March 16, 2016

March 16, 2016

Dear colleagues, We are pleased to announce the release of ccdproc v1.0. Ccdproc is is an Astropy affiliated package for basic data reduction of CCD images. Besides basic data reduction, some of the useful features in ccdproc include: - propogation of uncertainties and tracking of bad pixels - ImageFileCollections for easy sorting images by FITS keywords - combination of images based on WCS - easily built pipelines The new release features many updates that provide it with nearly all basic features available in other data reduction packages such as IRAF. We expect this version to have a stable API and long term support for bug fixes. More Information, repository, and issue tracker https://github.com/astropy/ccdproc Documentation http://ccdproc.readthedocs.org/en/latest/ Installation http://ccdproc.readthedocs.org/en/latest/ccdproc/install.html Special thanks to all the new contributors since the last major release including Christoph Deil, Forrest Gasdia, Carlos Gomez, Hans Moritz Günther, Nathan Heidt, Anthony Horton, Jennifer Karr, Stefan Nelson, Joe Philip Ninan, Punyaslok Pattnaik, Evert Rol,William Schoenell, Michael Seifert, Sourav Singh, Brigitta Sipocz, Connor Stotts, Ole Streicher, Erik Tollerud, and Nathan Walker. We would also like to thank the contributions to astropy especially the NDData package, astroscrappy, reproject, numpy, scipy, and the astropy-helpers package. Feedback, contributions, and comments are welcome. We would especially be interested in contributions of examples of using ccdproc and comparisons to other reduction methods. Cheers, Steve Crawford and Matt Craig

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How to disable astropy warnings (in particular IERS precision warnings)?
by Evert Rol March 16, 2016

March 16, 2016

How do I disable (the logging of) astropy warnings? From the astropy logging documentation, I thought that `log.disable_warnings_logging()` would do it, but it looks like it doesn't. Setting the log level to 'ERROR' doesn't do it either. See below. (I also find it a tad odd that I get warned twice about the same issue, though granted that they are not the same error message.) I have managed to silence this, with the following construct: import warnings from astropy.utils.exceptions import AstropyWarning with warnings.catch_warnings(): warnings.simplefilter('ignore', category=AstropyWarning) <code that issues AstropyWarnings> but that seems rather complex compared to a simple `log.disable_warnings_logging()` call. What am I missing? Thanks, Evert Example that I thought should shut up the IERS warnings: >>> from astropy import log >>> from astropy.time import Time >>> from astropy.coordinates import get_sun, EarthLocation, AltAz >>> log.disable_warnings_logging() >>> log.setLevel('ERROR') >>> t = Time.now() >>> frame = AltAz(obstime=t, location=EarthLocation(lon=0, lat=0, height=0)) >>> get_sun(t).transform_to(frame) /usr/local/lib/python3.5/site-packages/astropy/coordinates/builtin_frames/utils.py:93: AstropyWarning: Tried to get polar motions for times after IERS data is valid. Defaulting to polar motion from the 50-yr mean for those. If you need enough precision such that this matters (~<10 arcsec), you can use the latest IERS predictions by running: >>> from astropy.utils import iers >>> iers.IERS.iers_table = iers.IERS_A.open(iers.IERS_A_URL) warnings.warn(wmsg, AstropyWarning) /usr/local/lib/python3.5/site-packages/astropy/coordinates/builtin_frames/utils.py:107: AstropyWarning: (some) times are outside of range covered by IERS table. Assuming UT1-UTC=0 for coordinate transformations. If you need enough precision such that this matters (~<10 arcsec), you can use the latest IERS predictions by running: >>> from astropy.utils import iers >>> iers.IERS.iers_table = iers.IERS_A.open(iers.IERS_A_URL) warnings.warn(msg.format(ierserr.args[0], _IERS_HINT), AstropyWarning) <SkyCoord (AltAz: obstime=2016-03-16 04:49:49.619741, location=(6378137.0, 0.0, 0.0) m, pressure=0.0 hPa, temperature=0.0 deg_C, relative_humidity=0, obswl=1.0 micron): (az, alt, distance) in (deg, deg, m) (91.26098425, -20.60224434, 148825375564.27697754)> >>>

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Re: [AstroPy] APLpy color bar for markers
by Ke Wang March 7, 2016

March 7, 2016

It works now! Thanks a lot !!

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Re: [AstroPy] APLpy color bar for markers
by Ke Wang March 7, 2016

March 7, 2016

Thank you Thøger! I got this error, which I don't understand. Any idea ? In [19]: f.colorbar(ax=a, use_gridspec=True) --------------------------------------------------------------------------- TypeError Traceback (most recent call last) <ipython-input-19-a7064055af74> in <module>() ----> 1 f.colorbar(ax=a, use_gridspec=True) TypeError: colorbar() takes at least 2 arguments (3 given) --- Dr. Ke Wang Associate, European Southern Observatory http://www.eso.org/~kwang On Mon, Mar 7, 2016 at 6:55 PM, Thøger Emil Rivera-Thorsen < trive(a)astro.su.se> wrote: > Sorry for flooding, but I just worked out a better solution: > > import matplotlib.pyplot as pltimport aplpy as ap > > f = plt.figure() > fig = ap.FITSFigure('/path/to/myimage.fits', figure=f) > a = fig.axes[0] # Or alternatively, a = plt.gca() > x, y = fig.world2pixel(ra, dec) > > points = a.scatter(x, y, c=velocity, cmap='rainbow') > f.colorbar(ax=a, use_gridspec=True) > > This should give you what you want, and look a good deal nicer than my > first suggestion. > You can set the width etc. of the colorbar in the f.colorbar() call, just > read the documentation (f.colorbar? in IPython). > > On 03/07/2016 06:38 PM, Thøger Emil Rivera-Thorsen wrote: > > I would do this by tapping directly into the Matplotlib/pylab api to do > this: > > import matplotlib.pyplot as pltimport aplpy as ap > > fig = ap.FITSFigure('myimage.fits') > fig.show_grayscale() > > f, a = plt.gcf(), plt.gca() > x, y = fig.world2pixel(ra, dec) > > points = a.scatter(ra, dec, c=velocity, cmap='rainbow') > fig.colorbar(points) > > The colorbar is not as neatly aligned as the APLPy function does, but this > can be refined and tweaked, if you read the matplotlib docs (or you can > just use it as-is). > > On 03/07/2016 04:52 PM, Ke Wang wrote: > > Hi, > > This should be a simple question, but I just don't find an obvious > solution: > > I use APLpy to plot a FITS image with nice wcs coordinates support, and > overlay color coded markers: > > fig = aplpy.FITSFigure('image.fits') > fig.show_colorscale(cmap='gray') > fig.show_markers(ra, dec, c=velocity, cmap='rainbow') > fig.add_colorbar() > > This will plot a gray color bar (for the image). But I want to display the > rainbow (for markers). Any idea would be appreciated. > > Cheers, > Ke > > > _______________________________________________ > AstroPy mailing listAstroPy@scipy.orghttps://mail.scipy.org/mailman/listinfo/astropy > > > > > _______________________________________________ > AstroPy mailing listAstroPy@scipy.orghttps://mail.scipy.org/mailman/listinfo/astropy > > >

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APLpy color bar for markers
by Ke Wang March 7, 2016

March 7, 2016

Hi, This should be a simple question, but I just don't find an obvious solution: I use APLpy to plot a FITS image with nice wcs coordinates support, and overlay color coded markers: fig = aplpy.FITSFigure('image.fits') fig.show_colorscale(cmap='gray') fig.show_markers(ra, dec, c=velocity, cmap='rainbow') fig.add_colorbar() This will plot a gray color bar (for the image). But I want to display the rainbow (for markers). Any idea would be appreciated. Cheers, Ke

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UserWarning When Opening FITS File
by j. vickroy March 6, 2016

March 6, 2016

Hi, My system is: Microsoft Windows 10 (64-bit) Python 3.5.1 AstroPy 1.1.1 (from http://www.lfd.uci.edu/~gohlke/pythonlibs/#astropy) NumPy 1.10.4 (from http://www.lfd.uci.edu/~gohlke/pythonlibs/#numpy) The following is an interactive session illustrating the warning: PythonWin 3.5.1 (v3.5.1:37a07cee5969, Dec 6 2015, 01:54:25) [MSC v.1900 64 bit (AMD64)] on win32. Portions Copyright 1994-2008 Mark Hammond - see 'Help/About PythonWin' for further copyright information. >>> import astropy.io.fits >>> import numpy >>> astropy.__version__ '1.1.1' >>> numpy.__version__ '1.10.4' >>> sourcefile = r'C:\Users\jgv\Pictures\Astro\Calibration\Darks\DARK_5m_001.fit' >>> HDUs = astropy.io.fits.open (sourcefile) C:\Users\jgv\AppData\Local\Programs\Python\Python35\lib\site-packages\astropy\io\fits\util.py:578: UserWarning: Could not find appropriate MS Visual C Runtime library or library is corrupt/misconfigured; cannot determine whether your file object was opened in append mode. Please consider using a file object opened in write mode instead. 'Could not find appropriate MS Visual C Runtime ' >>> I would appreciate feedback about what is wrong with my setup and how to repair it. Thanks, --jv

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