A collection of personal items belonging to Sharon Tate, the actor murdered by Charles Manson’s followers in 1969, is to go on display ahead of an auction of her items.

An ivory silk moiré wedding dress, mini dresses by Ossie Clark and others, peep toe shoes and a black floral lace Dior gown with satin bow that she wore for the London premiere of her husband Roman Polanski’s cult film Cul-de-Sac are among the items in an exhibition at the Museum of Style Icons in Newbridge, Co Kildare, Ireland.Among the many items of clothing there are more intimate possessions including photographs collected from her bedroom dresser, books that were on her nightstand as well as her false eyelashes with used tubes of adhesive and mascara and a bar of Erno Laszlo soap preserved in its plastic case.

The items are being sold by Tate’s sister Debra, who was 15 at the time of the murder, because, she said, the pieces were becoming tougher to care for.

“Of course I told [Roman] what I was doing out of courtesy, but every time he sees these things it’s painful for him to this day,” she said.

“I wanted to give a flavour of the person behind the scenes and that is why I put in almost everything,” she said.

The items were collected from Tate’s home in Cielo Drive in Los Angeles by her father, who took two weeks to collect the possessions and take them to his family home after her murder. Tate said her mother wanted to keep everything.

“My father was in the military, in G-2, which was intelligence and counter-intelligence, so as he was going through the house and packing things up he was also looking for evidence that may have been left behind by the police,” said Tate. She has been looking after them since 2000, following the deaths of her mother and younger sister; first in her home and since 2011 at a storage facility after a robbery.

The location remains a secret as, she said: “I still get death threats from crazy people.”

The exhibition comes ahead of the sale of over 100 lots at Julien’s Auctions in Los Angeles on 17 November and online at JuliensLive.com.

“We’ve had more catalogue orders for this auction than any other auction we’ve done outside Michael Jackson,” said the auction house’s executive director, Martin Nolan.

Additional lots in the sale and not in the exhibition include wedding gifts such as a portable chess set with cut crystal pieces. “Sharon was being taught by Roman,” said Tate.

Prices range from an estimated $150 (£115) for copper kettles and a kerosene lantern from their kitchen to her wedding dress, which is estimated to fetch from $25,000.

Most of the pieces were worn regularly, like the vintage chiffon top that, said Tate, she wore around town or at Joshua Tree National Park – either with jeans or bathing suit bottoms.Tate has kept a few items, like a black Chanel leather shoulder bag “where I can feel Sharon the most”, she said.

With the 50th anniversary of Sharon Tate’s death next August, there has been increasing interest in her – with three biopics scheduled for release next year including Quentin Tarantino’s Once Upon a Time in Hollywood with Margot Robbie as Sharon.

As a 26-year-old rising Hollywood star and at the centre of the decade’s in-crowd, with friends like Warren Beatty and Peter Sellers, she was the epitome of a 60s style icon. “She was beautiful inside and out,” said Tate.

Tate has plans to keep her sister’s memory alive. Over the last two years she has had a pattern made “for every single thing” so she can recreate her wardrobe as a Sharon Tate clothing line “so it’s not lost forever”.

• The exhibition runs from 8-25 October 2018.