Astro


Named for its American creators Allinger, Stern and Rosler, Astro is a defensive convention for use
against an opponent's 1NT opening. Over an enemy 1NT,

2C: Hearts and a minor, 12+ points
2D: Spades and another suit, 12+ points

Double and all other overcalls are natural.

Advancer's rebids to 2C are:

Pass: Long club suit, signoff
2D: An artificial relay denying 3 cards in the anchor suit (hearts)
2H: Signoff
2S: Long spade suit, signoff
2NT: 10+ points, one-round force, asking overcaller to bid his second suit
3H: Invitational

Advancer's rebids to 2D are:

Pass: Long diamond suit, signoff
2H: An artificial relay denying 3 cards in the anchor suit (spades)
2S: Signoff
2NT: 10+ points, signoff, asking overcaller to bid his second suit
3C: Long club suit, signoff
3S: Invitational

If advancer gives the relay response (2D to 2C and 2H to 2D), overcaller's rebids are:

Pass: The relay response happened to be overcaller's second suit
Two of the anchor suit: A good five-card suit or better. Opener should bid his good
anchor suit first before showing a good second suit.
Cheapest second suit: A good five-card suit or better

If overcaller rebids two of the anchor suit, advancer may rebid 2NT to ask for his second suit.

Pinpoint Astro 

Pinpoint Astro uses the following overcalls of 1NT:

2C: Clubs and hearts
2D: Diamonds and hearts
2H: Hearts and spades
2S: Spades and a minor