Courtesy of Sharon Wang on the Astronomers Facebook Group: Here's a fairly exhaustive list for posting your meeting announcement, with submission links or instruction page
General Astronomy:
CADC:
http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/…/editMeetings.…
Astro Meetings twitter:
https://twitter.com/astromeetings
Astronomers Facebook group
Astronomy Facebook group
AAS events:
https://aas.org/node/add/event
NASA Exoplanet Program:
https://exoplanets.nasa.gov/exep/events/
Conference service.com:
http://www.conference-service.com/auxiliary/submit.html
ESA website:
http://eas.unige.ch/meetings.jsp
email to submit an entry to the list.
Canadian Astronomical Society:
http://casca.ca/?page_id=108
IAU newsletter:
http://www.iau.org/publications/e-newsletters/
SPIE newsroom:
http://spie.org/newsroom/information-for-advertisers
Exoplanet-Specific:
Exoplanets newsletter:
http://exoplanet.open.ac.uk/index.html
COOLNEWS:
http://casa.colorado.edu/~skinners/coolnews.html
exoplanet.eu:
http://exoplanet.eu/meetings/
Planetary and Life Sciences Community Meetings Calendar:
http://www.hou.usra.edu/meetings/calendar/postmeeting.cfm
DPS email newsletter:
https://dps.aas.org/newsletters/16-29
see end for submission instruction.
Planetary news:
http://www.lpi.usra.edu/planetary_news/submit/
AAS Divison of Dynamical Astronomy Newletter
Astrostat-Specific:
Astrostatistics & Astroinformatics Portal:
https://asaip.psu.edu/meetings
International Astrostatistics Association:
http://iaa.mi.oa-brera.inaf.it/adm_program/modules/announcements/announcements.php
International Society for Bayesian Analysis:
https://bayesian.org/node/add/date