In an open letter to supporters, David Southern, the club's managing director, cautioned against hesitation as the Foundation of Hearts prepare to step up their fund-raising in the coming days.
The future of the Edinburgh club is still in doubt after their descent into administration in June with debts of £28.4m, despite the fans' group having been given preferred bidder status. More than 7000 supporters have pledged monthly contributions to the club's running costs if the Foundation are able to succeed with a planned Company Voluntary Arrangement, and Southern has urged fans against the alternative.
He said: "As managing director of Heart of Midlothian Football Club, I believe that we, as supporters, now have a golden opportunity to secure the future of the club for many generations to come. We are on the verge of creating another defining moment in the history of the club. Every one of us has enjoyed the highs of the Scottish Cup wins, Champions League qualification, regular European competition, the associated big nights at Tynecastle, and the record-equalling league win run."
That particular chapter of the club's history is now closed, Southern warned, but instead it is time to write a new one. "The departure of the former owner and board presents an opportunity to establish certainty and stabilise the club for future generations," he said. "There is a 'cost' but it is negligible when compared to the cost of not securing the club now. This is our moment. If we hesitate, it may not just be the moment that is gone."
Fans have ploughed money into the club through fund-raisers and by buying season-tickets, merchandise and match-day briefs. The home end was also sold-out for the recent Edinburgh derby and close to capacity again for Saturday's 2-1 victory over Aberdeen. With money due to start coming out of pledger's bank accounts on Monday, though, Southern praised the part played by supporters in trying to rescue the club following the damage done by Vladimir Romanov's reign.
"Hearts is a club of the people," he said. "It always has been. If anyone ever needed proof of that it has been demonstrated time and time again, and not simply in financial terms.