{
  "id": 69526,
  "title": "Flux difference by passband or not?",
  "url": "/competitions/PLAsTiCC-2018/discussion/69526",
  "author_name": "",
  "post_date": "2018-10-24T13:57:58.678279400Z",
  "votes": 2,
  "comment_count": 2,
  "views": 0,
  "content": "<p>I understand that flux is obtained by difference with background/previous images: </p>\n\n<blockquote>\n  <p>Second, if the pre-survey image actually contains a flux brighter than its true ‘zero’, this can lead to a negative flux when the difference is computed. </p>\n</blockquote>\n\n<p>But, is this done passband per passband, i.e. is current flux compared to a pre-survey image obtained with the same filter, or is the same pre-survey image used for all passband values?</p>\n\n<p>I reckon the former is used, but I'd like a confirmation&nbsp;if possible</p>",
  "messages": [
    {
      "id": "409570",
      "postDate": "10/24/2018 13:57:58",
      "content": "<p>I understand that flux is obtained by difference with background/previous images: </p>\n\n<blockquote>\n  <p>Second, if the pre-survey image actually contains a flux brighter than its true ‘zero’, this can lead to a negative flux when the difference is computed. </p>\n</blockquote>\n\n<p>But, is this done passband per passband, i.e. is current flux compared to a pre-survey image obtained with the same filter, or is the same pre-survey image used for all passband values?</p>\n\n<p>I reckon the former is used, but I'd like a confirmation&nbsp;if possible</p>",
      "rawMarkdown": "I understand that flux is obtained by difference with background/previous images: \n\n&gt; Second, if the pre-survey image actually contains a flux brighter than its true ‘zero’, this can lead to a negative flux when the difference is computed. \n\nBut, is this done passband per passband, i.e. is current flux compared to a pre-survey image obtained with the same filter, or is the same pre-survey image used for all passband values?\n\nI reckon the former is used, but I'd like a confirmation&nbsp;if possible",
      "votes": null
    },
    {
      "id": "409574",
      "postDate": "10/24/2018 14:09:02",
      "content": "<blockquote>\n  <p>But, is this done passband per passband, i.e. is current flux compared to a pre-survey image obtained with the same filter</p>\n</blockquote>\n\n<p>Yes - each passband has its own template/pre-survey reference image.  </p>\n\n<p>Cheers,</p>\n\n<p>-Gautham on behalf of the PLAsTiCC team</p>",
      "rawMarkdown": "&gt; But, is this done passband per passband, i.e. is current flux compared to a pre-survey image obtained with the same filter\n\nYes - each passband has its own template/pre-survey reference image.  \n\nCheers,\n\n-Gautham on behalf of the PLAsTiCC team",
      "votes": null
    },
    {
      "id": "409580",
      "postDate": "10/24/2018 14:21:57",
      "content": "<p>Thanks!</p>",
      "rawMarkdown": "Thanks!",
      "votes": null
    }
  ],
  "comments": [
    {
      "id": 409574,
      "author_name": "gsnarayan",
      "author_url": "",
      "post_date": "10/24/2018 14:09:02",
      "content": "<blockquote>\n  <p>But, is this done passband per passband, i.e. is current flux compared to a pre-survey image obtained with the same filter</p>\n</blockquote>\n\n<p>Yes - each passband has its own template/pre-survey reference image.  </p>\n\n<p>Cheers,</p>\n\n<p>-Gautham on behalf of the PLAsTiCC team</p>",
      "votes": null,
      "replies": [
        {
          "id": 409580,
          "author_name": "cpmpml",
          "author_url": "",
          "post_date": "10/24/2018 14:21:57",
          "content": "<p>Thanks!</p>",
          "votes": null,
          "replies": []
        }
      ]
    }
  ],
  "raw_markdown_by_id": {
    "409570": "I understand that flux is obtained by difference with background/previous images: \n\n&gt; Second, if the pre-survey image actually contains a flux brighter than its true ‘zero’, this can lead to a negative flux when the difference is computed. \n\nBut, is this done passband per passband, i.e. is current flux compared to a pre-survey image obtained with the same filter, or is the same pre-survey image used for all passband values?\n\nI reckon the former is used, but I'd like a confirmation&nbsp;if possible",
    "409574": "&gt; But, is this done passband per passband, i.e. is current flux compared to a pre-survey image obtained with the same filter\n\nYes - each passband has its own template/pre-survey reference image.  \n\nCheers,\n\n-Gautham on behalf of the PLAsTiCC team",
    "409580": "Thanks!"
  },
  "source": "meta"
}