CreatureOfPrometheus t1_jac48v6 wrote on February 28, 2023 at 10:53 AM

Reply to Trouble finding a orbital trajectory calculator by CosmosGamer99

You need to solve "Lambert's problem":

https://en.wikipedia.org/wiki/Lambert%27s_problem

The inputs will be Earth's position at some time t0, the time of flight ToF, and Saturn's position at time tf=t0+ToF.

https://ssd.jpl.nasa.gov/horizons/app.html#/

CreatureOfPrometheus t1_j7b1kpc wrote on February 5, 2023 at 1:36 PM

Reply to Is the yearly cycle of varying daylight durations from day to day throughout time consistent? Is the cycle we have today the same as in the 17th century? by meellowstar

The variation in day length is caused by Earth-Sun geometry, so any change from 1700 to now is negligible.

I can think of two factors that might contribute:

Was there summer time/winter time in that locale in 1718? If not, then "10pm dark" then should be like "11pm dark" now.
In 1718, there were probably no time zones, so 12pm was measured from local solar noon. Depending on where you are in your timezone, there could be a shift of clock noon from solar noon. It's usually mild (should be <30 min), but is worse in some places due to political boundaries. It would shift both summer and winter sunset times the same, though.

CreatureOfPrometheus t1_ix8m1wu wrote on November 21, 2022 at 4:16 PM

Reply to How do astronomers share coordinates with each other? by vaterp

Short answer: Right ascension and Declination are just like longitude and latitude, projected onto the sky and fixed with respect to the "fixed stars".

For a longer answer, look up the International Celestial Reference System (ICRS). It's (as far as I know) the latest standard-to-end-all-standards for celestial inertial coordinate systems.