Tag Archives: MPC

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

by Anura Guruge

Click to ENLARGE.

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.

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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


American Astronomer Maria Mitchell’s 195th Birthday Google Doodle.

Anura Guruge, June 8, 2013.

Anura Guruge

MariacometGDthLast Google Doodle post:
>> Rosalind Franklin’s 93rd Birthday … — July 15, 2013.
≡ ≡ ≡ ≡ Check CATEGORY ‘Google Doodle’ for other posts —>>> (side bar)


Click on images to access.

Link will be updated after August 1, 2013
for access from the Google Doodle Archive.

Click for Wikipedia entry.

Click for Wikipedia entry.

Here is the Wikipedia entry.

The official Minor Planet Center (MPC) data for the comet she discovered: C/1847 T1.

Click to ENLARGE.

Click to ENLARGE.

So it perihelioned, i.e., went around the Sun (at its closest) on November 14, 1847, three weeks after it was discovered on October 26, 1847. Not like today when we can spot comets 18 months away.

Note the eccentricity. Just over 1! That is significant. That means that it was on an escape orbital path — meaning that it could leave the solar system. But, we now know that eccentricity can fall, i.e., drop below ‘1’, once a comet like this gets further out into space, i.e., beyond Jupiter. Check out my comet books.

She is NOT the first woman to discover a comet. This is from my ‘Comets: 101 Facts & Trivia‘ book.

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