Prior to the market opening yesterday morning, analyst Shebly Seyrafi of Calyon Securities issued a research note to clients warning of circumstances for concern facing Apple.

In particular Seyrafi attacked Apple’s average selling price, “Apple’s premium-pricing model is vulnerable in today’s recessionary environment,” he wrote. Adding that Apple’s ASP of $1398 is over twice that of HP’s at $663.

Seyrafi also lowered estimates on Apple’s overall Mac revenue for the current quarter due to the general decline in PC sales, the analyst now estimates Apple’s quarterly Mac sales at $3 billion, down from an earlier estimate of $3.3 billion.

Citing investor concern over the health of Steve Jobs, Seyrafi also lowered estimates for the sales of iPhones from 3.2 million units to 3 millions units during the current quarter.

Finally Seyrafi also lowered his 2009 fiscal year earnings to $5.51 a share from $5.66 a share and cut his price target on the stock to $90 a share from $95.

Shebly Seyrafi isn’t the only analyst to be trimming estimates, Shaw Wu of Kaufman brothers also lowered his 2Q revenue estimate for Apple from $7.8 billion to $7.7 billion. The analyst maintained a “Buy” rating on Apple and also left his $1.06 a share earnings target in place.

Wu added that Apple’s Mac sales look weak during the current quarter and the analyst doesn’t expect the company to refresh the current line of iMacs until June at the earliest.

Earlier this week the iMac was pinned for an imminent update.

Despite these two analysts reports Apple’s stock price closed up four percent yesterday.