has anyone seen/used this lightbox from astronomikHAS

[steve51450]

i have put some stuff of gerd Neumann's site below & a price list below but my German is useless but to me this seems a great cheap way of doing flats.

pricelist

EF Flatfield Foils

Until now taking flatfields was annoying with bulky flatfield-boxes, searching for the right spot in the sky or something like this. Lots of people skipped taking flats because of this!

The EF foils are offer you a new, comfortable and reliable way to capture flatfield data with your imaging system. There is no need for bulky flatfield boxes or getting the correct timeslot for skyflats: Simply place your EF Foil in front of your instrument, switch the inverter on an start getting flatfield data! The EF foil is lightweight, easy to handle and gives you a perfect even illuminated surface.

Benefits of EF foils:

• perfectly even illuminated surface!
  
• broad, continuous spectrum, may be used with emission line filters!
  
• Lightweight and easy to handle
  
• Inverter for 12V and 110/240V available. Perfect for stationary and mobile use!
  
• Easy to cut to the desired size
  

Color

The light from the foil looks blueish/white. Most foils from other sources seem to be white to the human eye, but the light is made of discrete emission lines. -Due to this the foils from most other sources at not suitable for narrowband emission line filters! I tested the products of all manufacturers worlwide and selected these foils because they are best for astronomical applications!

The spectrum of the EF is not made of some emission lines (like most foils do!). It has a very broad, continuous emission across the whole spectrum. This fact makes the foils great for narrowband emission line filters.

The two spectra below illustrate the difference between our continuous spectrum foils and typical foils with light generated with discrete emission lines.

Spectrum of a bad foil

(but still looks white the the human eye!)

Spectrum of a good foil

(You get this one here :-) )

Brightness

The brightness of the EF foil can not be controlled electronically. If the foil is too bright for your setup (very fast instruments), you should place one or more sheets of paper or a piece of white plexiglass between the foil and your telescope. The brightness is very even across the whole surface. It works well for the most critical observations, even photometry or spectroscopy.

Power

The foil is illuminated by an external high voltage, which is produced by the "inverter" you have also received. The high voltage is produced at a very low amperage, so there is no danger to you! A normal Wall-Transformer does not work!

Please use the foil only with the supplied matching inverter. Connecting a foil to a inverter of the wrong size reduces the livetime very much!

Exposure Time for Flatfields

There is no universal rule for the exposure time. Due to the focal ratio of your instrument, the camera and the filters the exposure time may vary between 1/100 of a second and 30 seconds. Please look at histogram of the images: You should have the peak at about 50% of the dynamic range of the camera, and no part should reach saturation! If you use special Astronomical cooled slow-scan cameras (SBIG, QSI, FLI, Atik etc...), you should avoid very short exposures, as the moving shutter might cause some gradients.

Look and feel

The EF foils look like a laminated piece of thick paper, with a cable on one side. They are very lightweight but very sturdy! You may use your EF foil directly at your scope: The easiest way is to point your instrument to the zenith and put the EF foil on top of the instrument. (You may also install the foil at the wall of your observatory of course.)

We do recommend that you secure a cable to the foil in a way that there is no force on it. A very nice way is to stick the EF foil to a thin piece of wood with double-sided adhesive tape. Mounted this way the EF foil is very sturdy and will serve you for many years even with mobile use!

Sizes

The EF foils are available in sizes from A7 (74mm) up to A1 (594mm) The EF foils are shipped in a rectangular size (from DIN A7 up to DIN A1). You may cut the foil to square size with normal scissors. Protect the new edge with a piece of tape to ensure that no moisture enters the foil layers. (It is not possible to cut the foil round, as the electrode on the upper side of the foil may not be cut.)

Size

active area

for instruments up to

A1

594mm × 841mm

594mm (23")

A2

420mm × 594mm

420mm (16")

A3

297mm × 420mm

297mm (11,5")

A4

210mm × 297mm

210mm (8")

A5

148mm × 210mm

148mm (5,8")

A6

105mm × 148mm

105mm (4")

A7

74mm × 105mm

74mm (2,9")

[centroid]

It does seem a very innovative approach to a flat-field lighting source.

As it references an inverter and high voltage, I guess its some sort of plasma film.

Dave

[Reggie]

Looks like the EL-Panels I saw a few months back and had thought about their use as flats panels,they should be able to run from 12v batteries too http://earlsmann.co.uk/ELPanels.htm

and heres the Gerd Neumann site in english

http://www.gerdneumann.net/v2/english/eng_flatfield_foil.html

interesting to see the difference in the spectrum of the light emitted on the neumann site, so please note in the webpage I posted the panels are not premium quality if anyone thinks about trying them. Thanks for the heads up Steve51450

Not sure if anyone else has seen them recently but in last month I think KFC have been running animated poster adverts at bus stops in Eastbourne and Brighton using EL-panels, I had a look and there didn't appear to be anything special about the unit it was in, looked like normal posters both sides, I pushed in the plexiglass and the poster moved like paper so I'm guessing its the same stuff.

[Ben Ritchie]

Very interesting Steve, looks exactly what i want!

[mcrossley]

Not sure if anyone else has seen them recently but in last month I think KFC have been running animated poster adverts at bus stops in Eastbourne and Brighton using EL-panels, I had a look and there didn't appear to be anything special about the unit it was in, looked like normal posters both sides, I pushed in the plexiglass and the poster moved like paper so I'm guessing its the same stuff.

Hmm, wonder what they are doing with them after the campaign....

Mark

[Psychobilly]

Reusing them I woulkd have thought as the graphic is printed as a transparency on film...

I was promised an A3 sheet of the material and a driver module for it from one of the UK companies producing the advertising materials in return for some images.. I sent of the images but the film never turned up and that was a year ago

Billy...

[ribuck]

Hi all,

I've just ordered the 210mm foil. Does anyone know what power supply is needed e.g. 12v 1amp etc.

You can get them direct from the supplier but i think £44 seems a bit steep (Half the cost of the foil).

Rich.

[anthony]

The power supply steps things up a bit. From memory (so totally unreliable) the Volts go up and up and up but the amperage stays low. Does not mean much to me but I am told that it is unlikely to hurt you! and that a normal power supply wont work.

[roundycat]

I am using one, have a look at this.

progressiveastroimaging.com • Login

and

progressiveastroimaging.com • Login

Dennis

[Whippy]

Links not working?

Tony..

[ribuck]

So that's another £44 for a power supply. I swear that this hobby is literally a black hole when it comes to making your cash vanish.

If i was married i could get divorced for less......lol, infact when i used to fly planes as a hobby that was blooming cheaper....ok rant over, i'm off my soap box.....lol.

[MartinB]

I have an A3 panel from Earlsman. It cost around £70 complete transformer which I plug into a 12V supply. I've sandwiched it in 3mm polar white perspex although 2mm may have been better. I also reinforced the wiring going into the panel with gaffer tape.

Produces brilliant reliable flats. Works with my 10" SCT and my FSQ 106. Occn I get some internal reflections but these are fixed by a sheet of white paper. You can pay a lot more for premium grade EL sheet but my experience with the Earlsman stuff is that this just isn't necessary (and I'm very fussy about flats).

[Psychobilly]

Was that just for the power supply or was it for the inverter thats needed to drive the panel. The panels get driven with an AC waveform about 100V p-p and at a couple of kHz... the panels themselves do not get driven from DC!!!! the drivers need to be matched to the panel size...

[ribuck]

Thanks Psychobilly, I figured that the foils would need a special power supply.

I've ordered the Gerd Neumann Flat Field Foil from IanKingImaging as apparently they work a lot better with narrowband filters but i'm starting to wonder as the cost if escalating in comparison £84 (210mm Foil) & (£44 power supply) = £128 total in compared to martins £70.

[MartinB]

The Earlsman comes with an inverter for use with a 12v dc supply. A mains adaptor is available as an optional extra.

[ribuck]

Martin it says on their website that the mains inverter is included on the A3 size, and the A4 Size is only £56, so much cheaper.

Think i'll be cancelling my ianking order and getting one of these.

[Psychobilly]

The panel life will be shortened if the inverter is driven from a 13.8V supply and not a 12V DC one.... so if you have an 13.8V obs DC bus dont drive the inverter off that...

[MartinB]

Mine comes off a 13.8v supply and is then regulated to 12v. Having said that, it isn't switched on a lot so probably isn't a huge issue

[ribuck]

Well I cancelled my Ianking order and placed one with earlmans, as i can get an A3 version complete with power supply £30 cheaper than I can get the Gerd Neumann A4 premium one with power supply so it's a no brainer for me and i really can't see there being that much of a difference.

Martin have you tried any flats with narrowband filters ?

[simon84]

I'm thinking of getting the A6 one from Earlsman, I think I read somewhere that it can be cut to size so does this mean that I could make one that would sit inside a self contained unit that would sit on the scope much like the lens cover so that no light escaped annoying anyone else doing any visual work?

[SteveL]

The earlsmann panels are laminated to be water tight... if you break that seal, mositure will get in and shorten the life of the panel. Plus you really dont want to get anything wet inside there, with several hundred volts flying around (those few people who saw the aftermath of my first EL sheet lightbox will know what I am talking about... burning foamboad and melted perspex makes a mighty impressive sound and smell with AC voltage arcing around it)

[simon84]

Thanks for the tip Steve, I'll build the light box around the full panel then so I dont have to cut it.

[Psychobilly]

Mine comes off a 13.8v supply and is then regulated to 12v. Having said that, it isn't switched on a lot so probably isn't a huge issue

That will be fine....

[MartinB]

Martin have you tried any flats with narrowband filters ?

Yes, quite a lot. Through the 3mm perspex I have in front of the sheet and my set up narrow band exposures vary between 5 and 15 secs to get around 16000 ADUs. I actually take some darks to match and leave Maxim to sort everything out.