Huya  18/03/2019


Observation tips:

- Shadow moves from **South to North**;

- The nominal occultation time on the map, corresponds to the big red dot, the closest approach
- Each red dot is separated by one minute;
- Dark gray is night and light gray is astronomical twilight (Sun at less than 18 deg below the horizon);
  - *Absolute time accuracy is essential** (see important note below);

- Observations are requested from 00:35 to 01:00 Universal Time.   Huya has a satellite with unknown orbit, it can be up to four minutes ahead or behind the main body. So please observe 10 minutes around the prediction time of your site.

After the observation, please fill the form available on this link (
form), and send it to ribas(at)

Useful information:
Star J2000 coordinates:
   RA   16 41 06.4260
DEC -06 43 34.575
Day coordinates of the object:
   RA   16 42 07.7004
DEC -06 45 44.689

Star G mag 11.5
Star R mag 11.1
Magnitude drop in R  8.0
Maximum duration
56 sec
Moon   | 86% illum.
@ 114 deg

Important note

*Absolute time accuracy is essential**

to connect all the observations
together after the fact. Check the time of your computer with many sources (phone talked hour, different internet sites, ideally with a GPS). Its advised to check the registered time right after and right before the integrations, so if there is a drift, we can correct it by having the difference.

Beware of the dead time between the images: if you manage an exposure time of 1 sec (for example), but have your camera takes 2 sec to read the image, then there is a 67% chance that you miss the dis(re)-appearance of the star. So it's better to have, for example, a 4 sec integration, so you have 67% chance to get the occultation in one of your exposures.

Finding charts from DSS:
  05 x 05 arcmin FOV (North is up, East is left)

x 20 arcmin FOV (North is up, East is left)

Prediction Updates

Prediction from Lucky Star web page (i).


With observations on the begining of March, from Sirra Nevada Observatory, J.L. Ortiz obtained the following last-minute prediction

KMZ file


New NIMA version taking into account Huya's positions form Pico dos Dias and Sierra Nevada Observatories (ii).

Please, see the observation tips at the top!