[Jane Clark]

Ian, I am tremendously impressed by your work following this supernova.

In addition, I think we can make your “It’s turned back up again!” statement a little more quantitative. The rate of change over time of brightness (mathematical jargon term first time derivative of brightness) for all three colours is negative, and has been since about day 18. The rate of change of the rate of change over time of brightness (mathematical jargon term second time derivative) is what has changed sign in the last few days.

It would not be difficult to plot these quantities, but to do so accurately would require your data, rather than my guessing the values with a printed graph and measuring calipers.

• This reply was modified 8 months, 3 weeks ago by Jane Clark.

Jane Clark

[Jane Clark]

Hi:

Since type II supernovae are hydrogen-rich and type I are hydrogen-poor, would shooting through a hydrogen alpha filter be a quick-and-dirty way to distinguish them without spectroscopy?

Thanks,

Jane.

Jane Clark

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