An ordinary start to David Vandyke's week has taken an upturn with the win of Astronomos at Randwick, a horse the trainer believes has a Group One future.

Vandyke was fined $12,000 on Monday for a positive swab returned by a horse previously in his care after veterinary staff admitted they had missed notice of the published withdrawal period.

The filly was part of the band Vandyke formerly trained for Segenhoe Thoroughbreds.

Vandyke admitted he found it hard to run his stable at Warwick Farm and control the Segenhoe operation at Randwick and parted company with Segenhoe last month.

Randwick trainer John Sargent took over those horses and Vandyke is concentrating on his Warwick Farm team including Astronomos who is one of three horses Vandyke has for Paul Fudge's Waratah Thoroughbreds.

And Astronomos proved to Vandyke he was on the right path towards the Group One Metropolitan in the spring when he burst through the pack to win the Benchmark 80 (2000m).

"He is a quality horse and the Metropolitan is the race we have in mind for him," Vandyke said.

"He will have a couple of weeks off and come back and make his way through the grades.

"The way he raced today he's looking for 2400 metres and it was great to see the way he won.

"It was an ordinary start to the week but it's picked up."

Ridden by Jason Collett, Astronomos ($2.60 fav) travelled midfield under a cold ride and produced the goods when it mattered to beat Dure ($15) by a short neck with Campania ($14) another half head away third.

A rising five-year-old, Astronomos has now won five of his seven starts and although he is still an entire, Vandyke says he shows no signs of aggression.

"He is one of the best-mannered colts I've ever had anything to do with," Vandyke said.

"He is laid-back and quite a lazy track worker but he might be the most exciting stayer I've trained."