Solar Projection Screen BAADER PLANETARIUM

It consists of a rear projection screen and a T-2 thread for connection to common eyepiece projection adapters. The screen was developed and tested with the Baader OPFA (I - VII) eyepiece projection adapter (available in various versions). When used with the corresponding Baader Classic Ortho eyepieces on refractors with focal lengths between 250 and 1200 mm, it produces a solar image that fills the 9 × 9 cm projection surface. Sunspots, the darkening of the Sun's limb and the progress of eclipses can be observed. The screen can also be used with other T-2 projection adapters instead of the Baader OPFA; however, in that case you will need to determine the required distances yourself. Unlike traditional open projection screens, there is no risk of someone reaching the light beam or even looking through the eyepiece. Rear projection allows for a closed system. The screen can be attached to any telescope suitable for solar and eyepiece projection.

When the telescope is mounted on a tracking mount, the Sun can be observed comfortably for several hours. If the mount is not perfectly aligned with the pole, the Sun will slowly drift out of the field of view. From the drift direction, you can see during the day in which direction the mount needs to be corrected and thus improve the alignment while observing. Detailed instructions for this can be found in the PDF of the operation manual. The projection screen is especially useful for public outreach, when many guests take turns to look through the eyepiece of a telescope equipped with its own solar filter: if the screen is connected to another small guide or finder telescope, you can check whether the Sun is still centered on the main telescope and at the same time show the waiting guests what they can expect.

Requirements

To use the Solar Projection Screen, you will also need:

A telescope suitable for solar projection with a stellar diagonal/prism - ideally a refractor with a focal length of 250-1200 mm. The projection screen has been tested on telescopes with f/5 (90/500) and f/4 (VarioFinder 61/250), as well as 150/1200 mm and 150/2250 mm refractors, each for several hours at full aperture. To reduce thermal stress on the star diagonal, we recommend using telescopes faster than f/6 and, if necessary, reducing the aperture of telescopes with larger diameters to about 80 mm. You can see the entire Sun in telescopes up to about 1200 mm focal length; larger telescopes produce higher magnification and show only part of it. A variable eyepiece projection adapter with T-2 thread. The Solar Projection Screen was developed for the Baader OPFA. The diameter of the solar image depends on the distance to the projection surface. The Eyepiece Projection Adapter OPFA I - with 1¼" eyepiece holder (#2458141, € 63,-) has a 1¼" connection;The Eyepiece Projection Adapter OPFA II - with 2" eyepiece holder (#2458142, € 80,-) fits star diagonals/prisms with a 2" eyepiece holder. If you use a Baader diagonal/prism with T-2 connection, you can screw the OPFA IV Eyepiece Projection Adapter - Basic Version with T-2i (#2458144, 55 €) directly into the housing and thus save focal length posterior.Tambi. You can also use other projection adapters, but this may result in different image sizes. The solar image should be at least 60 mm in diameter.

A heat resistant eyepiece. In addition to the Huygens eyepieces usually recommended for solar projection (which are hard to find in good quality these days), you can use the Baader Classic Ortho eyepieces with focal lengths of 6, 10 or 18 mm or the 32 mm Baader Classic Plössl.

Most telescopes that provide sufficient back focal length for eyepiece projection can also be used with the Solar Projection Screen. The Solar Projection Screen requires approximately 30 mm of back focus. Alternatively, the OPFA can also be screwed directly to a T-2 prism, such as the Baader Zenith Prism Diagonal T-2/90° with 32 mm prism (T-2 part #14) (#2456005K), via the T-2 thread for a very short adaptation. Explosive view of BSPS on Baader OPFA

Configuration and Use

The BSPS consists of the special projection screen, a T-2 thread adapter and a three-piece pre-cut cardboard kit with pre-assembled adhesive strips to assemble the housing. Alternatively, you can download STL files to produce a plastic protective cover housing on a 3D printer.Remove all optical finders from your telescope, or cover the lenses of any optics that may still be installed. Insert the eyepiece into the projection adapter, remove any T-2 extension tube if necessary as instructed to adjust the distance, and screw the projection adapter into the Secure Solar Box. Then, insert both into your telescope with a star diagonal (in a refractor), point it at the Sun, and focus. Using the sliding focuser on the OPFA (or other variable eyepiece projection adapters), you can slightly adjust the size of the projected solar image.

To center the Sun:

Telescope focal length OPFA with the following extension tubes (included with the OPFA) Classic Ortho Eyepiece

250 mm (Baader VarioFinder 10x60) 2x40 mm Classic Ortho Eyepiece 6mm, 1¼" (HT-MC) (#2954106 )

400 mm (Celestron PowerSeeker 80/400) 1x40 mm

500 mm (Bresser AR 90/500) 2x40 mm Classic Ortho Eyepiece 10mm, 1¼" (HT-MC) (#2954110 )

580 mm ( Baader APO 95/580 )

600 mm (Celestron ED 80/600) 1x40 mm

700 mm (Celestron Inspire 70/700 )

910 mm (Vixen 80/910 Mf) 2x40 mm Classic Ortho Eyepiece 18mm, 1¼" (HT-MC) (#2954118 )

1000 mm (Vixen 90/1000)

BSPS on Baader APO 95/580 CaF2 Travel Companion

Note: To achieve focus on telescopes with a 1.25" focus, the OPFA sometimes had to be screwed directly to the Baader Diagonal T-2/90° zenithal prism with 32mm prism (part T-2 #14).

Mechanical Specifications

Inside Diameter / Clear Aperture (mm) T-2 (M42)

Solar Filter with mount/thread Yes

Optical Specifications

Rear focus distance required 30mm

Solar wavelength White light (integral light)