Glider pilot reported an near midair collision with a corporate jet in the vicinity of bdu airport.

Narrative:

Boulder airport is depicted on sectional charts as being high intensity glider environment. I was flying today at boulder airport and had just finished a short climb over foothills blvd from 7000 back up to 8300 so we headed east; level flight; to lose some altitude for a return into the pattern. Not a minute had gone by when a blur appeared directly overhead crossing from our 8 o'clock to our 1 o'clock and continued high speed descending flight towards metro (bjc). A small jet with winglets. Too close.since I had my handheld with me with a pre-set channeled to metro; I tuned to metro tower and heard them call a cessna advising of a learjet doing a straight-in to runway 12. So I called tower; [and reported I was] at 8000 feet over boulder airport and I just had a learjet fly directly over me with 100 feet separation. The learjet pilot replied 'the 100 feet is accurate'. Not much more to say except that I stated to the learjet pilot to be aware of the charted high density glider traffic over bdu.my take - since the learjet showed no signs of maneuvering during the pass; I doubt that they saw me until it was too late to do anything if at all. Possibly heads down looking at charts for metro prior to the near miss? Or looking above and beyond my aircraft for the runways visual at bjc? Or just missed us in their 275 mph (webtrack) descent into bjc. [These] gliders are not equipped with transponders.

Original NASA ASRS Text

Title: Glider pilot reported an NMAC with a corporate jet in the vicinity of BDU airport.

Narrative: Boulder Airport is depicted on Sectional charts as being high intensity glider environment. I was flying today at Boulder airport and had just finished a short climb over Foothills Blvd from 7000 back up to 8300 so we headed east; level flight; to lose some altitude for a return into the pattern. Not a minute had gone by when a blur appeared directly overhead crossing from our 8 o'clock to our 1 o'clock and continued high speed descending flight towards Metro (BJC). A small jet with winglets. TOO CLOSE.Since I had my handheld with me with a pre-set channeled to Metro; I tuned to Metro tower and heard them call a Cessna advising of a LearJet doing a straight-in to runway 12. So I called Tower; [and reported I was] at 8000 feet over Boulder airport and I just had a Learjet fly directly over me with 100 feet separation. The LearJet pilot replied 'the 100 feet is accurate'. Not much more to say except that I stated to the LearJet pilot to be aware of the charted high density glider traffic over BDU.My take - since the LearJet showed no signs of maneuvering during the pass; I doubt that they saw me until it was too late to do anything if at all. Possibly heads down looking at charts for Metro prior to the near miss? Or looking above and beyond my aircraft for the runways visual at BJC? Or just missed us in their 275 mph (webtrack) descent into BJC. [These] gliders are not equipped with transponders.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1383603
Time
Date	201608
Local Time Of Day	1201-1800
Place
Locale Reference	BDU.Airport
State Reference	CO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Sail Plane
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	None
Flight Plan	None
Aircraft 2
Make Model Name	Learjet 60
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Flight Plan	IFR
Person 1
Function	Instructor Pilot Flying
Qualification	Flight Crew Flight Instructor Flight Crew Glider Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 1600 Flight Crew Type 800
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 0 Vertical 100