Timeline for Calculating RA/dec from JPL ephemeris data
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
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| Apr 17, 2017 at 22:19 | comment | added | nealmcb | After the leap second on 2017-01-01, TT - UTC = 69.184 | |
| Apr 22, 2015 at 13:04 | comment | added | David Hammen | @NenadVukicevic - You're welcome. BTW, it's not the exact same results as Horizons. It looks like Horizons switched from using DE405 to DE431 about a year ago. DE405 is an outdated product from some previous millennium (1998, to be exact). It's about time they made that switch. The impact on backyard astronomy is negligible. The impact on spacecraft -- that's not so negligible. | |
| Apr 22, 2015 at 12:27 | comment | added | Nenad Vukicevic | A follow up: Following the advice from the answer, using Terrestrial Time, two corrections for light-time adjustment and calculating RA/Dec for Earth@T and Mars@T-Δt I get the exact result as Horizons! Beautiful. Thanks again David! | |
| Apr 22, 2015 at 10:55 | comment | added | Nenad Vukicevic | Thanks a lot for the answer! I assumed as much but got lost in the fine-print :) This helps me because I wasn't sure if I was starting from invalid assumptions, hence didn't know where to start. I'll take a stab at the light-time adjustment, just need to get my head around it. | |
| Apr 22, 2015 at 10:49 | vote | accept | Nenad Vukicevic | ||
| Apr 22, 2015 at 0:20 | history | edited | David Hammen | CC BY-SA 3.0 |
added 683 characters in body
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| Apr 21, 2015 at 23:57 | history | answered | David Hammen | CC BY-SA 3.0 |