The Long Beach City College Planetarium
Also see: What is a Planetarium? / Visiting the Planetarium / Astronomy Open Houses
The Seligman Star Theater
 The Seligman Star Theater is the name I used to describe the planetarium shows I gave from 2006 through 2012. As shown above the actual name of the facility is the Long Beach City College Planetarium. I retired in May of 2012, so I no longer give planetarium shows, and "The Seligman Star Theater" is only a pleasant memory.

Introduction to the LBCC Planetarium
 Thanks to the former and ongoing generosity of the Long Beach City College Foundation and its donors, the planetarium projection system planned for more than a decade was finally installed in Room D326 on the Lakewood Avenue Campus, in August 2006. Images can now be projected onto a thirty-five foot diameter dome by a 1.5 megapixel full-dome full-color digital-projection system, the Evans and Sutherland Digistar 3 SP2 (This projection system is equivalent to using two superbright DLP full-HDTV projectors, one for the front half of the dome, and the other for the rear half). A supplementary LCD projector is mounted on the springline at the "rear" of the dome (near the entrance) for PowerPoint and Web-based presentations, and an additional BluRay-resolution projector was mounted next to it for presentation of widescreen science-related documentaries. Unlike traditional opto-mechanical projectors, which only display stars and constellations in their current positions, our digital projection system can display anything the human mind can conceive and a graphics processor can construct, transporting students and visitors on journeys through space and time that have no limitations, save for the time, effort and funds required to create or purchase such presentations.
 Unfortunately, time and funds only allowed for installation of the basic projection system prior to the start of the Fall 2006 semester, but a Bowen Technovation multi-kilowatt 5.1 surround-sound system was installed in early September 2006, allowing public open houses to begin in October 2006, albeit using relatively uncomfortable student-desk style seating (see second image, below). Irwin Galaxy 2 theater-style seating was installed in late February 2008 (see third image, below), providing a far more comfortable viewing experience for our students and visitors. Automation systems have also been added to the instructor/console area, so that much of the lighting, audio, and subsidiary systems which formerly had to be handled manually can now be remotely controlled from the instructor console.
 Upgrades and improvements to the system have been made on a continuing basis. The walls below the hemispherical dome were carpeted to provide additional sound control. Work also continued behind the scenes: air conditioning the computer room so that the main room does not have to kept as cold, and a long-term goal (though perhaps more than a lifetime in the future) is to paint the walls and ceiling behind the dome a deep black to enhance the contrast and apparent brightness of the projected images (light passing through the holes in the dome currently reflects off bright surfaces behind the dome, reducing the "dark" contrast). Over time, as newer versions of the hardware and software become available, minor (or if funds permit major) upgrades will be made, to ensure that our students and visitors continue to enjoy a state-of-the-art planetarium experience.

Planetarium Shows and Presentations
 Since Professors Seligman and Sholle were handling a teaching load more appropriate to three full-time instructors, they had very little time for non-classroom presentations. Professor Seligman presented once-a-month Astronomy Open Houses which included not only a live planetarium show, but also (weather permitting) telescope viewing on the roof of the D building, and did a limited number of private showings for large groups (by special arrangement). Professor Sholle also did several presentations to faculty members and for Foundation fundraisers, and very capably presented the February 2008 public open house when Professor Seligman could not be present. However, both have now retired, as well as their would-be replacement, and whether any public shows will be given in the future, let alone the near future, is very much up in the air.

Images of the Planetarium
The new theater-type seating, viewed from above The new theater-type seating, viewed from the left side of room
(photos by Professor Sholle)
 Two images of the newly installed theater-style seating. In the left photo, taken from above, the overall layout is shown, with the digital projector (inside its fenced support) near the center of the image. In the right photo, taken from the "left" side of the room (as seen by students and visitors), the partially completed operator/instructor console is shown at the left, and the projector/support is just above image center.
 The aisles between the theater seats are a bit wider than usual for such installations, to provide comfortable, easy access, and to allow for tilting the seat backs. Near the front of the room, the seats are tilted back at a considerable angle, to allow comfortable viewing of images high above the observer, while at the back of the room, the seats are tilted only a little, since less effort is required to look at the top of the dome.
 Although it may not be obvious in these images, each seat has, on its right side, a "tablet" which can be raised, airplane-style, to provide a writing surface for notes or exams.

Outside view of planetarium pyramid and dome
 Rooftop view of the planetarium classroom. Two immense steel rings beneath the pyramid provide primary support for the thirty-five-foot diameter hemispherical dome which serves as the projection screen. The bronze dome atop the pyramid merely advertises the location of the planetarium, and has nothing to do with the actual structure of the classroom.

View of planetarium classroom as of late August, 2006, prior to the installation of theater-type seating
 View of the planetarium classroom in late August, 2006. The partially completed operator's console is shown on the left, while the planetarium projector is inside the fenced structure in the center of the room. The student desk-chairs shown in this image were in use through February 2008, when they were replaced by the theater-style seating shown above and below. The dome consists of more than a hundred curved aluminum panels, heat-bonded to a white epoxy powder, which are perforated with innumerable small holes. The holes eliminate the echoing associated with a solid dome, and allowed installation of the sound system behind the dome, freeing space inside the room for extra seating. Cove lighting is concealed inside the base of the dome (the "springline"), which is not noticeable in this image, because it blends into the dark background of the acoustic ceiling tiles and walls. Please note that flash photography is strictly forbidden during planetarium shows. Not only is it distracting to the rest of the audience, but it is pointless, as all that would be seen in the resulting image is the blank white dome shown in the picture above.

Closer overhead view of projector area
(photo by Professor Sholle)
 A close overhead view of the projector and its support structure, showing the adjustable tablets to the right of each seat. The projector and its innards are shown in more detail in the images below.

The Digistar projector View of the inside of the Digistar projector, showing the two separate optical controller system boxes, and the vertical fisheye projection lens
(Photos by Professor Sholle)
 On the left, an image of the Digistar 3 SP2 projector inside its protective fence and metal container, with the lens cap on. On the right, an image of the Digistar 3 SP2 projector with its top off, showing the two projection system controllers (inside the silver boxes at left and right), and the fish-eye lens that projects a 1.5 megapixel image onto the thirty-five foot diameter hemispherical dome. Hidden beneath the lens is the optical column which combines the two separately calculated images into a single, full-dome image.

A diagram of the planetarium theater / astronomy classroom layout
 A(n early version of the) seating plan (by Professor Sholle) for the planetarium classroom. Eighty-four theater-style seats, up to four wheelchairs, and if needed half a dozen armless plastic chairs can be placed more or less inside the dome footprint (the circular outline is the springline, or base of the hemispherical dome; the dome itself is two feet wider). The arcs represent the baseline used for bolting down the seats. The seats extend backwards a bit, because of their size and tilt; for instance, the back of row A almost touches the front of the projector enclosure. For full-dome presentations, requiring a view of the top of the room as well as the front, the best seating is toward the back of the room but inside the circular footprint of the dome, near the central aisle. For non-full-dome presentations such as classroom lectures, sitting a bit to the side allows a better view of the lecturer.

Sample Images from the Digistar Projection System
(Photos by Professor Sholle)
A projected image of the northern circumpolar region, with a superimposed coordinate grid
Northern stars, and a coordinate grid.

A projected image of the Zodiacal and southern stars and constellations, with traditional figures representing the constellations
Zodiacal and southern stars and constellations (shown by traditional figures).

A projected image of volcanoes on Io, as visualized in an Evans & Sutherland demonstration clip
Volcanoes on Io, from an Evans and Sutherland demonstration clip.

A projected image of the rings of Saturn, as viewed from inside the rings, from an Evans and Sutherland demonstration clip
The rings of Saturn, from an Evans and Sutherland demonstration clip.

A projected image of a sunrise on Saturn, as visualized in an Evans and Sutherland demonstration clip
Sunrise on Saturn, from an Evans and Sutherland demonstration clip.