Manufacturer: Lacerta
Product number: FFB20plus

EUR 179,90


incl. 19 % VAT (DE)  
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excl. 6.95 € shipping costs (DE)  
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rating: 5.0 of 5
  • Details..
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  • In the box..
  • Reviews..
Lacerta Flatfield Box in lightweight design with neutral white LED light
A Flatfield Box (FFB) is ised for creating Flats which are needed for exact calibration of astro images. With them, vignetting (darker edges) and also shadows of dust particles in the image (called donuts) can be removed. That is not only necessary for aesthetics, but only a perfectly "flat" image can be processed in a way that weak signals become visible. The contrast can be increased more, the background does not become blotchy and weakest extensions of the object become visible.

Use of the Flatfield Box:
With this flatfield box, so-called FLATs can be created. These flatfield exposures capture vignetting and "donuts" which are caused by dust particles on sensor, filter or corrector. They can be seen as unaesthetic dark rings or areas in the image.

In the course of image processing, these distracting phenomena are subtracted from the image. Almost all image processing software offers the possibility of subtracting a flat.

The result is a perfectly smoothed image. The contrast can be increased considerably more to show finest details of the objekt, and the background stays evenly smooth.

The advantages of the Lacerta FFB plus LED flatfield boxes:
The LED flatfield generators deliver a very colour-neutral light, so the colour channels are evenly strongly saturated. This is the ideal base for a successful flat even with narrowband filter, with DSLR or with color astro cameras.
The illumination of the LED Flatfield Box is extremly uniform, even better than with the EL films, which still have a weak variation over the surface (banding).
Unlike the EL film, the LEDs do not flicker with the line frequency, allowing significantly shorter exposure times like 1/500 seconds.
The LEDs can be controlled in the brightness (Dimm version). With this, for example cameras with mechanical shutters can be used which need a somewhat longer exposure time for a correct flat. A flat with an exposure time which is too short would be flawed by the shutter. We recommend a minimum exposure time of 2 seconds per flat.

Illumination:with LEDs
Clear aperture:240 mm
Current draw:1.73 A at 13.8 V
Power connection:12V - + is inside - 5.5/2.1 mm hollow plug
Material:Plastics for low weight
Dimensions flat field box:260 x 260 x 60 mm
:
LED flatfield box
12 V cable with cigarette lighter plug

How do I get a good flat field image?
A good flat compensates for edge shading (vignetting), but also for darkening caused by dust on the filter, sensor or corrector. The background becomes even, the contrast can be raised further to make finer details visible in faint nebulae. The following basic settings should be noted:
The ISO or gain setting must be the same as for the lights, i.e. the actual astrophotography.
Telescope, camera and accessories, such as filters, off-axis guider etc., must be the same as for the actual exposure, also the position of the focuser should be unchanged.
The exposure time should be so short that nothing is "burned out", i.e. overexposed. Only in this way can the flat unfold its full effect. We recommend an exposure of 30-50%. The flat should not be burned out, but it should also not have any unexposed areas.


How do I find the right exposure time with the shooting software, for example Maxim DL?

The ADU value (Analog Digital Units) helps here. Every capture program shows this value when you move the mouse over the image. In the center of the image, where the illumination is highest, the ADU value is highest. The longer you expose, the higher this value becomes. If the ADU value is higher than the maximum value of the camera, the image is overexposed. A camera with 16 bits has a max. ADU value of 65536, one with 14 bits has 16384, one with 12 bits only 4096.

The exposure time of the flat should be so short that in the middle of the flat the ADU value is at most 50% of the maximum value of the camera. Then the flat looks well exposed. We recommend to take at least 10 flats per exposure and to process them to a "master flat".

If the flatfield box is too bright, that means it always produces overexposed images, then a white paper, which is fixed in the flatfield box, helps. This will dim the light and allow for slightly longer exposure times.


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Reviews

Written by Gerhard Geipel
on 2023-07-26

"Perfekt für Flatfieldbilder an 8"" Teleskopen, Allerdings braucht man meist nicht die volle Lichtstärke. Läuft bei mir problemlos mit 9-10V am PrimaLuceLab-Astro-PC."

Written by Christian Vocks
on 2023-02-13

"Passt genau auf mein Celestron C8, erste Flat Aufnahmen sowohl mit LRGB- als auch Schmalband-Filtern sehen vielversprechend aus."

Written by Andreas Runge
on 2020-04-21

"tut was es soll"

Written by Andres Sanchez
on 2018-05-20

*****

Written by Thomas Militzer
on 2018-01-10

"Die Box funktioniert einwandfrei, wie beschrieben. Zur Stromversorgung verwende ich das 12 V- Netzteil meiner Skywatcher HEQ5-Montierung. "

Written by Wolfgang Heyne
on 2017-08-04

"Praktisch und einfach in der Handhabung. "

Written by Frederic Kappeller
on 2017-03-14

"Gegen über andere hersteller ist er stabiler.man braucht den teleskope nicht aufrecht zu richten um die flats zu machen.Man kann denn 12V kabel von der skywatcher montur für die stromversorgung benutzen.Ich hätte damals schon den lacerta bstellen sollen.billiger und bessere qualilät."

Written by Hanns Selig
on 2016-12-20

"Funktioniert wie beschrieben. Den 12V Stromaschluss kann man auch mit dem Kabel des Lacetra MGEN Autoguiders (falls vorhanden)versorgen und muss nicht unbedingt ein extra Kabel anschaffen."

Written by Henning Olsen
on 2016-12-06

"der produkt war 100% in ordnung"

Written by Stevan Klaas
on 2016-09-27

"Good flat field. Sturdy, allows to hang it on tube even when not vertical"

Written by Nikolaus Hanjohr-Popa
on 2016-05-23

Klasse!