Briones Mt Diablo Trail, Walnut Creek, CA 94598
Unified Muslim Community 
Bay Area Crescent Moon Sighting Site 



View of Mount Diablo from Concord; The main peak is at right, North Peak at left and Mount Z at center

When to Observe Thul Hijjah Waxing (NEW) Crescent ?
The geocentric conjunction (Geocentric New Moon) will occur Inshalla on (Sunday 13 September 2015) at 06:41 UT

Sighting the new crescent on (Sunday 13 September 2015) and (Monday 14 September 2015) is shown in the below graphs using the program Accurate Times by Mohammad Odeh according to Odeh criterion. Where:-

Mount Diablo is a mountain of the Diablo Range, in Contra Costa County of the eastern San Francisco Bay Area, in northern California. It is located south of Clayton and northeast of Danville.

It is an isolated upthrust peak of 3,849 feet (1,173 m), visible from most of the San Francisco Bay Area. Mount Diablo appears from many angles to be a double pyramid and includes many subsidiary peaks, the largest and closest of which is the other half of the double pyramid, North Peak, nearly as high in elevation at 3,557 feet (1,084 m) and about one mile northeast of the main summit.

Geography[edit]

The summit is accessible by foot, bicycle, or motor vehicle. Road access is via North Gate Road or South Gate Road. The record time by bicycle from The Athenian School in the town of Danville to the summit is 43:33 minutes.[4]

Mount Diablo State Park[edit]

The peak is the centerpiece of Mount Diablo State Park, a state park of about 20,000 acres (8,000 ha) in area. The park was the first public open space of a complex—according to Save Mount Diablo—now including 38 preserves, including nearby city open spaces, regional parks, watersheds, that are buffered in some areas with private lands protected with conservation easements. Preserved lands on and around Mount Diablo total more than 90,000 acres (36,000 ha). The day use fee for Mount Diablo State Park is $6 or $10 per vehicle depending on where you enter the park.[5]

Viewshed[edit]

On a clear day the Sierra Nevada is plainly visible. (The best views are after a winter storm; a snowy Sierra shows up better, and summer is likely to be hazy.) Lassen Peak, 181 miles (291 km) away, is occasionally visible.[6][7] Sentinel Dome in Yosemite National Park is visible,[8] but Half Dome is hidden by the 8000-foot ridge at 37.755N 119.6657W. Eight bridges are visible, from west to east; San Mateo; Bay; Golden Gate; San Rafael; Carquinez; Benicia; Antioch and Rio Vista.

Historic claims that the mountain's viewshed is the largest in the world—or second largest after Mount Kilimanjaro—are unfounded. It does boast one of the largest viewsheds in the Western United States and it played a key role in California history. Countless peaks in the state are taller, but Mount Diablo has a remarkable visual prominence for a mountain of such modest elevation. Its recognizable form and looming presence over so much of the baydelta, and Central Valley, and good visibility even from the Mother Lode, all key regions during the gold rush and early statehood, made it not just a well-known visual touchstone but an important landmark for mapping and navigation. The summit serves as the reference datum for land surveying in much of northern Californiaand Nevada.[citation needed]

The summit is accessible by foot, bicycle, or motor vehicle. Road access is via North Gate Road or South Gate Road. The record time by bicycle from The Athenian School in the town of Danville to the summit is 43:33 minutes.[4]

Mount Diablo State Park[edit]

The peak is the centerpiece of Mount Diablo State Park, a state park of about 20,000 acres (8,000 ha) in area. The park was the first public open space of a complex—according to Save Mount Diablo—now including 38 preserves, including nearby city open spaces, regional parks, watersheds, that are buffered in some areas with private lands protected with conservation easements. Preserved lands on and around Mount Diablo total more than 90,000 acres (36,000 ha). The day use fee for Mount Diablo State Park is $6 or $10 per vehicle depending on where you enter the park.[5]

Viewshed[edit]

On a clear day the Sierra Nevada is plainly visible. (The best views are after a winter storm; a snowy Sierra shows up better, and summer is likely to be hazy.) Lassen Peak, 181 miles (291 km) away, is occasionally visible.[6][7] Sentinel Dome in Yosemite National Park is visible,[8] but Half Dome is hidden by the 8000-foot ridge at 37.755N 119.6657W. Eight bridges are visible, from west to east; San Mateo; Bay; Golden Gate; San Rafael; Carquinez; Benicia; Antioch and Rio Vista.

Historic claims that the mountain's viewshed is the largest in the world—or second largest after Mount Kilimanjaro—are unfounded. It does boast one of the largest viewsheds in the Western United States and it played a key role in California history. Countless peaks in the state are taller, but Mount Diablo has a remarkable visual prominence for a mountain of such modest elevation. Its recognizable form and looming presence over so much of the baydelta, and Central Valley, and good visibility even from the Mother Lode, all key regions during the gold rush and early statehood, made it not just a well-known visual touchstone but an important landmark for mapping and navigation. The summit serves as the reference datum for land surveying in much of northern California

Earliest names[edit]
View of Mount Diablo's North Peak from the main peak

About 25 independent tribal groups with well-defined territories lived in the East Bay countryside surrounding the mountain. Their members spoke dialects of three distinct languages: OhloneBay Miwok, and Northern Valley Yokuts.[11] The Chochenyo-speaking Ohlone from Mission San Jose and the East Bay area, called the mountain Tuyshtak, meaning "at the dawn of time". Most of Mount Diablo, including its peak, was within the homeland of the early Volvon(sometimes spelled Wolwon, Bolbon or Bolgon), a Bay Miwok-speaking tribe, and as early as 1811, the mountain was called (in Spanish) "Cerro Alto de los Bolbones" (High Point of the Volvon) or sometimes "Sierra de los Bolgones".[12] The Nisenan of the Sacramento Valley called it Sukkú Jaman, or as Nisenan elder Dalbert Castro once explained, "the place where dogs came from in trade".[13]

A Southern Miwok name was Supemenenu. It has also been suggested that an early Indian name for the mountain is Kawukum or Kahwookum, but there is no evidence to confirm the assertion. According to Indian historian Bev Ortiz and "Save Mount Diablo":[14] "The name "Kahwookum" was made up in 1866—with no real Indian connection—referred to the California Legislature's Committee on Public Morals, and tabled. It resurfaced as a real estate gimmick in 1916 with a supposed new translation, "Laughing Mountain", attributed without documentation to Diablo area Volvon Indians.[15]

Current name[edit]

The conventional view is that the peak derives its name from the 1805 escape of several Chupcan Native Americans from the Spanish in a nearby willow thicket. The natives seemed to disappear, and the Spanish soldiers thus gave the area the name "Monte del Diablo", meaning "thicket of the devil." Monte was later misinterpreted by English speakers as mount or mountain.[16]

General Mariano G. Vallejo, in an 1850 report to the California State legislature, gave this much romanticized story of the derivation of the name of Mount Diablo from its Spanish to Anglo form, related to the mountain and an evil spirit. Vallejo's report could be interpreted to align with Gudde's account. (Kyle, and Ortiz)[9][17]

This name was later applied to Salvio Pacheco's Rancho Monte del Diablo, the present-day site of the city of Concord. The name's origin was misinterpreted by English-speaking newcomers to refer to the mountain rather than the settlement.[15]

The name Monte del Diablo (‘Mount of the Devil’) appears on the "Plano topográfico de la Misión de San José" about 1824, where there was an Indian settlement at the approximate site of the present town of Concord {Pacheco}. On August 24, 1828, the name was applied to the Monte del Diablo land grant for which Salvio Pacheco had petitioned in 1827.

One attribute that makes the name Mount Diablo appropriate is that the mountain glows red at sunset.[18]


Briones Mt Diablo Trail, Walnut Creek, CA 94598