Albrecht Du rer's "Praying Hands" is among the world's best known and best loved drawings. The accurate and pious sheet, drawn in 1508, which entered the collection of the Hapsburg emperors three centuries ago, has never been displayed outside Vienna. But it is coming here this fall.

After 20 years of planning, Vienna's Albertina, once a royal palace and now a great museum, has agreed to send to Washington a significant collection of its best old master drawings. The exhibit -- which includes works by Michelangelo, Cranach, Rembrandt, Raphael, Rubens, Poussin and Fragonard, as well as the grand Du rer -- will open in October at the National Gallery of Art.

Rare old master drawings, even fine and famous ones, tend to have about them something admirably modest. So do most of the museum shows set to be displayed here in the season just beginning. A few, it's true, will be anchored by big names, and Edgar Degas is perhaps the biggest -- that 19th-century master was a nearly-perfect painter. "Degas: The Dancers," which marks the 150th anniversary of his birth, will open at the National Gallery in November. King Louis XIV, another famous Frenchman, will be the subject of "The Sun King: Louis XIV and the New World," which opens in December at the Corcoran Gallery of Art. But despite events such as these, there will not be many "blockbuster" exhibits in Washington this season. Most of the new shows will be scholarly and subtle rather than spectacular.

There is subtlety aplenty in the black paintings of Ad Reinhardt. And there is just as much in Dan Flavin's elegant sculptures of white light. Both those New York artists -- and painter Robert Motherwell, who gets a full-scale retrospective -- will have solo exhibitions at the Corcoran this month.

The Hirshhorn Museum and Sculpture Garden, 10 years old on Oct. 4, will celebrate that birthday with an ambitious exhibition designed to display what its scouts regard as the most important new art of the past decade. The Phillips Collection, closed for many months, will reopen with a show of recent paintings by England's Howard Hodgkin. Werner Drewes, once of Weimar's Bauhaus, currently of Reston, will have a one-man exhibition at the National Museum of American Art.

The artists of America have always had a fondness for closely observed fact. Four graphics exhibitions -- the first devoted to the bird painter J.J. Audubon, the second to the landscape painter Thomas Moran (who first visited Yellowstone in the 1870s), the third to naive drawings and watercolors from the Garbisch collection, and the fourth to folk art renderings from the Index of American Design -- will open at the National Gallery in October.

"Baseball Immortals: The Photographs of Charles Martin Conlon," a free-lancer who worked for The Sporting News between 1905 and 1935, will open in October at the National Portrait Gallery.

"Old Master Drawings from the Albertina" follows another first-rate drawing show, from Milan's Ambrosiania, which will remain on view through Oct. 7 in the Gallery's West Building.

More than 100 American pictures from the famous collection of Baron Hans Heinrich Thyssen-Bornemisza -- among them works by Copley, Homer, Sargent, Pollock and O'Keeffe -- go on public view today (through Oct. 28) at the Baltimore Museum of Art. September

On Sept. 12, the Walters Art Gallery, Baltimore, will open "The Grand Prix de Rome: Paintings from the E'cole des Beaux-Arts 1797-1863," an exhibit of 150 prize-winning paintings from Paris's most important annual competition (through Oct. 28). The Hirshhorn (Sept. 13) will open "European Modernism: Selections from the Museum's Collection" (through Jan. 13, 1985.) And the Corcoran (Sept. 15) will open "Robert Motherwell," a retrospective exhibition which includes 70 paintings and collages by one of the last of the "Old Masters" of the postwar New York School (through Nov. 4).

On Sept. 18, the Phillips Collection will stage a "Homecoming Celebration" to mark both the reopening of its renovated galleries and the return of those works from its collections which have been on tour for more than a year. "History as Content," an exhibit of work by contemporary artists from Washington, Baltimore and Richmond -- all of whom explore historical and topical themes -- will open Sept. 18 at the Washington Project for the Arts (through Oct. 20).

On Sept. 21, Washington sculptor Chris Gardner will unveil "Follow the Leader," an outdoor work at 7th and D streets NW commissioned by the WPA as part of its Washington Art Site Program (through November). A small exhibit of the paintings of Ad Reinhardt, one of minimalism's founders, opens at the Corcoran on Sept. 22. All 17 works displayed come from the collection of Washington's Gilbert Kinney, a former Corcoran director (through Nov. 16). On Sept. 29, the Corcoran will open "Monuments to V. Tatlin," an exhibit of the white fluorescent light sculptures of New York's Dan Flavin (through Nov. 25).

The last two weekends in September, some 200 area artists will open their studios for the WPA's annual Open Studio tour. Maryland studios will be open Sept. 22, Virginia's Sept. 23, downtown Washington studios on Sept. 29, and other Washington studios on the 30th. October

The Hirshhorn Museum and Sculpture Garden (Oct. 4) will open "Content: A Contemporary Focus, 1974-1984," a survey selected by Hirshhorn curators Howard Fox, Miranda McClintic and Phyllis Rosenzweig. The show, which will include 150 works in various media by 126 artists from many nations, will occupy the entire third floor of the round museum (through Jan. 6). On Oct. 5, "Werner Drewes: 65 Years of Printmaking," an exhibit of 110 works by the Reston artist, opens at the National Museum of American Art (through Dec. 24). "The Photography of Gordon Parks: A Retrospective View," opens Oct. 7 at the Baltimore Museum of Art (through Nov. 11); two days later, the Baltimore Museum opens "Old Gods and Young Heroes: The Pearlman Collection of Mayan Ceramics" (through Jan 20).

On Oct. 10, "Traditional Architecture of Saudi Arabia," 22 drawings by the architect Wahbi Al-Hariri-Rifai will open at the Smithsonian Institution's Castle on the Mall (through Nov. 7). The Phillips (Oct. 11) will open a show of 40 paintings by England's Howard Hodgkin, an artist whose intimate abstractions distantly recall the works of Vuillard and Bonnard (through Dec. 16). And on Oct. 14, four exhibits of American works on paper, all drawn with high accuracy, opens at the National Gallery. They are: "J.J. Audubon: Birds of America," an exhibit of 40 color engravings (through April 14); "American Naive Watercolors and Drawings from the Garbisch Collection" (through Jan. 13); "Thomas Moran: Drawings of Yellowstone Park" (through Jan. 27); and "Renderings of Colonial Era Folk Art from the Index of American Design" (through Jan. 27).

"Baseball Immortals: The Photographs of Charles Martin Conlon," a collection of portraits made between 1905 and 1935, all from the collection of The Sporting News, opens Oct. 20 at the National Portrait Gallery (through March 15). On Oct. 28, "Old Master Drawings from the Albertina" opens at the National Gallery (through Jan. 13). And "Praise Poems," an exhibit of 50 choice works of African art from the Katherine White Collection, will begin a national tour at the Smithsonian Institution's Museum of African Art on Oct. 31. November

"From Regency to Empire: French Prints and Illustrated Books from the Permanent Collection" goes on view Nov. 10 at the Baltimore Museum of Art (through Dec. 2). On Nov. 16, a pair of exhibitions, both suggestive of Manhattan, will open at the National Portrait Gallery. They are "Miguel Covarrubias: Caricatures," an exhibit devoted to the Mexican artists whose drawings appeared often in Vanity Fair and The New Yorker, and "The Metropolitan Opera Centennial: A Photographic Album" (both through Jan 13). "Contemporary Prints from Gemini," an exhibit of more than 100 works (by 31 artists among them Frank Stella, Claes Oldenburg, Sam Francis, Isamu Noguchi, Richard Diebenkorn and Jasper Johns), all of which were printed by Gemini Graphics Editions Limited, opens Nov. 18 at the National Gallery of Art (through Feb. 24).

The Baltimore Museum of Art on Nov. 18 opens "The World of Grandma Moses," an exhibit of 60 paintings and working drawings (through Jan. 6). On Nov. 22, the National Gallery will open "Degas: The Dancers," an exhibit of approximately 60 objects, paintings, sculptures, pastels, monoprints and drawings, all dealing with the ballet (through March 10). December

On Dec. 1, an exhibit of the paintings of Gladys Nelson Smith (1890-1980), a little-known Washington artist, opens at the Corcoran (through Jan 27). "Homage to Franz Kline," an exhibit of photographs by Chicago's Aaron Siskind, opens Dec. 7 at the National Museum of American Art (through March 3). Also Dec. 7, "Options '84," the third juried biennial exhibit of area art opens at the WPA (through Jan. 26).

"The James McLaughlin Memorial Staff Show," an exhibit by local artists employed at the Phillips, opens Dec. 8 at that museum (through Jan. 6). On Dec. 9, "50 Years of Babar," an exhibit of 214 original drawings portraying Celeste, Babar and the rest of their elephantine family, opens at the Baltimore Museum (through Jan. 27). And three quite different exhibits (one of them mouth-watering) open Dec. 15 at the Corcoran. They are "The Sun King: Louis XIV and the New World," which deals with the 17th-century monarch and the exploration of "his" Louisiana (through April 7); "The Pennsylvania School of Landscape Painting: An Original American Impressionism," an exhibit of the pictures of Edward Redfield, William Lathrop, Daniel Garber, Robert Spencer and other artists of the so-called New Hope School which flourished between 1850 and 1940 (through Jan. 20); and "Mouton Rothschild: Paintings for the Labels," a show of works by Henry Moore, Picasso, Motherwell, Chagall, Warhol and other painters, all done for the labels of that yummy red Bordeaux (through March 10). The New Year

On Jan. 15, "Sharing Traditions: Five Black Artists in 19th-Century America: Selections from the National Museum of American Art," will open at that museum. The painters are Joshua Johnson, Robert S. Duncanson, Edward M. Bannister, Henry O. Tanner and Edmonia Lewis (through April 7).

On Jan. 19, the Phillips will open "Kimura: A Retrospective," an exhibit of paintings by the Japanese-born artist who has lived in Paris for the past 30 years (through March 10).