Baader DADOS Slit – Spectrograph 2458550
The first draft of the DADOS®-slit spectrograph was based on our simple Blaze grating, which we had made for schools for more than 20 years. When we unveiled the prototype of the DADOS® some years ago, we listened closely to the following online-discussions, which lead to several large changes in the design of the product.
So, many ideas and critics from active spectroscopists were incorporated in the design of the DADOS®. We are very grateful for all feedback, because we are sure that the final product has become much better because of this.
DADOS® is designed for telescopes with about f/10 or slower. Faster apertures will cause some vignetting. The spectral resolution is not affected by this in any way.
Note: The DADOS comes with a 200-line grating as standard. A grating with 900 lines or 1200 lines can be ordered for an extra charge. If you need additional gratings for your DADOS, these have to be ordered separately (and especially optically adjusted for this device). If you already own a DADOS, we must ask you to return your DADOS each time to us when you order another grating, apart from the standard 200 line grating. The initial calibration of the grating in relation to the mechanical body of the DADOS must be one here one time.
Nowadays, we use the following three reflection gratings (200 L/mm as standard, 900 L/mm and 1200 L/mm sold seperately) which are copies of special master gratings (they are no standard gratings from a catalogue!) - the Blaze angle of the gratings (as well as the optics, see below) is matched perfectly to the geometrical and optical properties of the DADOS®.
The desired wavelength range can be set with a micrometer gauge. A sturdy T-2 connector for large CCD-cameras (e.g. SBIG) or several adaptations of eyepiece holders (as well a much larger "Backfokus") is included.
Other gratings with the common size of 25x25x6mm with more or less resolution can also be used with the DADOS®.
The efficiency of the DADOS® slit-spectrograph is at least 60% at 550 nm.
|Grating||Dispersion at 550 nm||spectral resolution lambda/delta lambda|
at 550 nm with the 3 slit diameters
|spectral range covered|
|lines/mm||nm/mm||nm/ 9 µm Pixel||25 µm||35 µm||50 µm||ST-7/ST-402||ST-8/ST-1603|
The second core element besides the gratings is the reflecting slit element with a precisely manufactured triple slit (with gap widths of 25/35/50µm). You can see all three slits at the same time and easily choose the right one for each object at a glance.
Because of the forward-reflecting slit element with razor-sharp, perfectly smooth edges and an additional, sophisticated optical system of tilted mirror and projection lenses, you can focus – just as with larger spectrographs – directly onto the image of the star with affordable, common CCD-guiding cameras or webcams (not inluded) or even with a guiding eyepiece and easily guide the telescope!
Two reasonably-priced 1¼" DADOS Kellner eyepieces with 10mm (#1304110) and 20mm (#1304120) focal length are included. They can be used for finding objects and for manual guiding without a guiding camera. A slit illumination (included in the scope of delivery) made of a dimmable red LED helps you to focus the guiding star and the slit itself. It illuminates the slit from the back towards the guiding camera/eyepiece, so that the LED's light will not reach the lens of the collimator.
The collimator system in front of/behind the Blaze grating is made of an achromatic and a triplett system. These were specially designed for the best-possible resolution and are coated with the best available anti-reflection-coating. These are no standard lenses from a catalogue!
The collimator lens can be moved over a wide range with a 2" Helical focuser very precisely, so that (almost) all known CCD- and DSLR-cameras (as well as almost all standard eyepieces) can be focused.
On the telescope side, the DADOS® has got a black 2" nosepiece. You can attach an optionally available Neon-calibration lamp (#245 8590 - not included) with 2"-adaper and 220V cable to it.
If you remove the nosepiece, you can use the standard 2" SC female thread inside of the front part of the DADOS® for a variety of other adaptations. We have several adapters for a sturdy connection using this thread, e.g. a 2"/T-2 reducer (# 295 8242) to attach the DADOS® directly to optics with the standard T-2 photographic thread (M42x0.75).
You can also the female 2" thread of the front cube to screw the DADOS® without the nosepiese directly at a Schmidt-Cassegrain-telescope. Use our 2" Locking-Ring (#245 8270) to fix the DADOS® in any orientation - this way, you can even mount it between the fork arms of many Schmidt-Cassegrain with an alt-az mount. Both guiding and imaging camera are mounted in a 90°-angle towards the DADOS® to keep it as compact as possible.
To mount the DADOS® on a telescope or attach other accessories, a clamp with 3/8" and 1/4" thread (#245 8593) and 38mm diameter is available.
The two-piece clamp has got a 3/8" thread at the bottom side (a 1/4"-thread is included) and a 1/4" thread on top.
You can use it to mount the DADOS® on a ball-head or a tangent assembly as secondary unit. You absolutely need it in a classroom to mount the DADOS® on an optical bench or for any setup without a telescope.
There are plenty adapters available for all kinds of guiding cameras a well as for almost all imaging CCD-cameras – just take a look at our Astro T-2® accessories.
This user-friendly slit spectrograph, which was designed especially for use in schools or universities and for amateur observers, offers all features of a professional spectrograph. Especially remarkable are the following features:
Spectra of NGC 6543 and M57, taken by OStR Dipl.-Phys. Peter Stinner, Kopernikus-Gymnasium, Wissen
|USAGE||Perfect for visual and photographic use with or without a telescope. Suitable for amateur astronomers for private use and for spectroscopy education on schools and universities.|
|SPECTRAL RESOLUTION||with different reflection gratings: up to R = 5000|
|OPTIMIZED SPECTRAL RANGE||395-700nm tuneable (ca. 365 - 900nm with 200 L/mm reflection grating)|
|BREAK-EVEN VALUE||200 L/mm: m = 8 mag. vis | 900 L/mm: m = 6 mag. vis (30cm-telescope S/N=50, 20min. exposure – see instruction manual)|
|MECHANICAL DESIGN||Blaze Grating Spectrograph with moveable and exchangable reflection gratings|
|FIELD SIZE||optimized for sensor sizes: ca. 13x18mm, usable from 6.9 x 4.3 mm (ST-402, ST-1603, STF-8300M, DSLR, ...)|
|ÖFFNUNGSVERHÄLTNIS DES KOLLIMATORS||f/10|
|OPTIMIZED FOR FOCAL RATIO||f/10 telescopes|
|ADAPTABLE TO||DSLR-, CCD- and Video-cameras|
|SLIT SIZE||Multi-slit plat with three slits 25, 35 and 50μm|
|ILLUMINATION||manual red LED for Slit-Focusing|
|SPECIAL FEATURES||110-page tutorial. Flip-Mirror with callibration unit under preparation|
|GUIDING PORT||with 1¼"-connection for eyepieces, video- and guiding cameras|
|INCLUDED ACCESSORIES||DADOS, reflection grating 200 L/mm, 10mm and 20mm eyepiece|