Galaxy Zoo Talk

Redshift data

  • thinhnh3009 by thinhnh3009

    When did Galaxy Zoo get the information of the spectrum, especially the redshift values ? Has it been updated yet ?


  • Budgieye by Budgieye moderator in response to thinhnh3009's comment.

    Sorry I don't understand your question.


  • thinhnh3009 by thinhnh3009

    I mean that in what year did the telescope get infomation about these galaxy ?


  • Budgieye by Budgieye moderator

    To get the date that the spectrum was taken, on the SkyServer page, eg

    Click on SpecObj, then Plate

    Find mjd which is 53144

    This is in MJD format (Modified Julian Date)

    Put it in the MJD box and press convert.

    so 18-05-2004 in the Gregorian calendar.

    You should get a date about 2000-2010 which is when most of the photos were taken.

    There is usually only one spectrum, since they are expensive to take. To see if there is second, press "All Spectra" Occasionally there is a spectrum in NED

    For photos

    Forum: Dating SDSS Images by waveney Sometimes it is useful to know the date that an SDSS image was created, for example, to check whether the current image could contain a supernova which exploded in a particular year. This procedure should work for all images. From the SkyServer Object Explorer page for the object in question, click on the “Field” link on the left under the “PhotoObj” heading. Scroll down to the “mjd_u” label and note down the value in the right-hand field. This is in MJD format (Modified Julian Date) and in scientific notation. Convert the value to standard decimal and add 2400000.5 to the value. As an example, if the original value is “5.26674166E4” it would become “52667.4166” then “2452667.9166”. Now enter this value into the “Julian Date” field on the following web site and click the button to get your date. Links: Julian Date Converter

    or use this website: Julian Date converter