Photo: Prince Harry and Meghan Markle on Christmas Day 2017; By Mark Jones [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
If you haven't, you may want to check out the natal horoscopes of Rachel Meghan Markle and that of Henry Charles Albert David--Prince Harry -- hers, Rodden Rating AA (BC/BR in hand), his, RR A (from news reports).
For royal wedding details try the BBC.
A few planetary basics of their natal charts include:
Actress Meghan born August 4, 1982 4:46 am PDT Canoga Park, CA with Sun 12Leo00, Moon 4Lib54 (sextile), ASC 24Can17; Moon in Libra rules; Prince Harry born September 15, 1984 4:20 pm GDT Paddington, UK with Sun 22Vir57, Moon 21Tau20 (trine), ASC 11Cap21; Saturn rules (which is appropriate for a royal expected to behave a certain proscribed way). Personality-wise she is an exciting Fire-Air combo of energies while he is a practical double Earth blend.
The royal wedding ceremony is to begin on May 19, 2018 at precisely 12:00 GMT in St. George's Chapel, Windsor Castle with the Sun (husband) in late Taurus and the Moon (wife) around 22-23 Cancer. The two signs are sextile, a beneficial relationship which should make for a comfortable and well-supplied home. (Personal note: my parents had this exact Sun combo! He gardened, she baked). Yet all marriages require adjustments to be made, even royal ones and we see this on May 19, 2018 for the romantic love bird duo, Mars and Venus, are inconjunct which suggests such adjustments will be needed and concessions required. Resentment and victimization can be involved with a Venus-Mars inconjunct relationship but hopefully the couple have previously worked out such potentials for one partner cannot always be the one who concedes and 'does the favor' and this is where resentment may interfere with harmony.
Note that their May 19th ceremony occurs with the Sun in Taurus, Harry's Moon sign, and Moon in Cancer conjoining Meghan's Ascendant. Jupiter in Scorpio leads a Locomotive shape of all the planets on that day so much success and good fortune are to be expected. Plus, their marriage begins under the auspices of the 1 South February 15, 2018 Solar Eclipse @27Aquarius with its themes of 'flooded with ideas and options' (Brady); humanitarian work (AQ) is certain be a focus of the couple.
As for the Wedding Day blend of Sun Taurus-Moon Cancer with its gentle Venus-Moon vibes, we see a romantic partnership that nurtures and likes to be thought well of. Family and childhood are very important to this pair and I suspect such matters will be in the news quite soon after May (if not before! Cancer = the mother). It appears that Meghan may be on the sentimental side while Harry is more common-sense-oriented and down-to-earth. Together strongly domestic, this is a great 'nest-building' combination! Creative and imaginative, the two will have a diplomatic approach to others and each will be a reliable and loyal partner for the other although a strain of stubborn prejudice may turn up now and then.
All in all this is a very caring combination so let's close with three 'Images for Integration' from the Harveys' book Sun Sign Moon Sign for they illustrate the Sun Taurus-Moon Cancer partnership of Prince Harry and his soon-to-be-bride Meghan Markle well:
"A baker undertakes to feed an orphanage...Dr. Spock teaching mothers how to bring up their children...Tchaikovsky's Swan Lake."
Sending them wishes for their lasting happiness!