Tag Archives: fractional date

Time In Fractional Day As Used In Astronomy (e.g., MPC)– Excel Spreadsheet For Conversion (Both Ways).

by Anura Guruge


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What my Excel spreadsheet looks like. It is converting ‘.67810’ into a time format we can understand.


Time that comets are discovered are specified in this ‘fractional day’ format.

So, for example, time when C/2020 F3 (NEOWISE) was discovered per the ‘Minor Planet Center’ (MPC).

The .67810 used above is FROM this example.

Click to ENLARGE.


The Excel FORMULAS used in the Spreadsheet.

So, now you can quickly & easily create your own Spreadsheet.

Click to ENLARGE.


I had trouble deciphering this time format. I had to seek help from a professional astronomer — Jeff Mangum. [Thank YOU, Jeff.]

I then dashed off a quick Excel for MY use. Then I decided I should create a version that I can SHARE.

Yes, of course, I could make it a download — but many would be leary of downloading it. So, intead, I am sharing the simple Excel formulas you will need to create your own. Yes, it can be made simpler. SMILE. I just wanted to show YOU the steps so you could see where I was going. SMILE. Plus, I am, at 67, not the hotshot programmer I was when I was in my 20s. SMILE.


Related posts:
Check Category ‘Astronomy.


by Anura Guruge