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Nelson Excel Sheets for EBs

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Ed Wiley_WEY
Ed Wiley_WEY's picture
Nelson Excel Sheets for EBs

Bob Nelson’s Excel Workbook sheets are valuable to those of us who calculate ToMs. However, they lack documentation in two important cells.

1. In C5, does the cell take into account DST? For example, in my time zone (Central) do I input “6” or “5” when daylight savings is in effect?

2. In Column F19: May I assume this is UT date and time?  No local time, correct?

Ed

Eric Dose
Eric Dose's picture
Yes to both

1. Yes, but only as given in the comment (starting) in cell D5. You have to put in your own observing site's offset from UTC (actually, its negative).

2. Looking into cell F19's formula: Yes the My Time Zone offset is included, so this date time should be UTC.

The cover page notes that these files haven't been updated for 2 years.

Ed Wiley_WEY
Ed Wiley_WEY's picture
A bit more clarification, please Eric

Eric,

1. Are you saying that I should put -6 into cell D5?I put 6.

2. I note that some worksheets have "Local Time" below the ToM prediction.  An example is BK Vul. Others do not have this statement. For example V0879 Aql / GSC 1030-3758. This confuses me, I assume no "Local Time" entry refers to UTC, but having "Local Time" below the ToM prediction is confusing if not explained (perhaps it refers to other data to the left in that row?).

Ed

Eric Dose
Eric Dose's picture
Looks like Local Time in these 2 cases

I had nothing to do with making these spreadsheets; I'm only writing what I see in their cell formulas.

1. If you're in US Central Standard Time or Mountain Daylight Time, you would put +6, which is the negative of the offset from UTC (-6). [US and Canada offsets from UTC are negative.] See the guidance in cell D5, which unfortunately has a typo, the first "MDT" should read "MST" for Mountain Standard Time.

2. I can't speak for the Local Time vs other times in every spreadsheet. In BK Vul's case, the formula that renders the date&time (cell E17) ends in "-$C$9/24", where cell C9 is your "My time zone" entry. So the date&time indeed appears to be adjusted for your time zone and so is expressed in Local Time. Same for V0879 Aql in cell F19, so it's also Local Time. [corrections added in edit]
 

Ed Wiley_WEY
Ed Wiley_WEY's picture
Thanks Eric

Eric,

I know you had nothing to do with the spreadsheet and greatly appreciate your help I will check in with Bob Nelson to see if he can illuminate me on the time variations.

Ed

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