Aurora Flatfield Panel

[deskman]

Hi,

I've just received my panel from Gerd (very efficient service) and am wondering:

Gerd's website talks of it emitting a uniform buish-white light. I have the AC adapter 305mm version and plugged mine in to a household power supply and the panel has a definite pinkish hue to it (stronger around the edges) as well as a couple of whitish blobs (as if the panel is not illuminating at those points) about the size of a thumb-print.

In case my eyes were playing tricks I asked my wife to have a look and without any prompting she saw exactly the same effects.

I've not tried actually taking a flat field photo yet (there'll no doubt be a whole new learning curve there for me to get it right!), but the colour is certainly not bluish-white, nor a uniform illuminance.

Can someone with a similar panel please let me know if their's functions the same as mine?

Thanks,

Brian

[andrew s]

Brian - Mine looks a uniform white to my eyes with no blobs. I have put it through my spectrograph and it has a a very broad double peeked but continuous spectrum. Sounds like your may have a problem unit. Regards Andrew

[deskman]

Hi Andrew,

Thanks for that.

Is yours pure white even when no power is applied?

Mine definitely has a off-white pinkish look to it even with no power on. The backing board on the other hand is very white by comparison - no I'm not trying to use it the wrong way 'round

The attached photo was taken with no flash, and with a piece of white A4 paper for comparison purposes as I realise internal lighting can make colours look different:

Regards,

Brian

[andrew s]

I will have a look tomorrow. No good trying to check under artificial light. Regards Andrew

[deskman]

Thanks Andrew.

[Freddie]

Just checked mine and it looks as yours does in the photo. Very pink when not powered up. Produces a perfectly fine flat field image when in use though. I don't have any of the "blobs" you mention.

[deskman]

Hi Freddie,

Thanks for taking the trouble to check that.

Does yours still look pink of different intensities across the surface when illuminated (mine does) as I believe per Andrew above, that it should be an even bluish-white.

Regards,

Brian

[deskman]

The below photo is with the panel illuminated.

Hopefully if you download it you will see the two "white / non-illuminated" looking blobs (arrowed).

The pink is not quite so obvious in the photo but much more obvious with the eye - the main thing is it is not an even illumination.

Brian

[ollypenrice]

A very simple test would be to take a flat, turn the panel on the scope and take another one. Does anything in the flat images turn with the panel? If not, forget about it. If yes, send it back.

We have two here and they don't look perfectly even but they work very well.

Olly

[deskman]

Good idea Olly.

When it stops raining I'll be able to give it a try as I can't use my scope without the shed roof rolled back.

Hopefully as you indicate it will be nothing - just surprises me that the description of an evenly illuminated bluish white light doesn't match with the reality.

Thanks for everyone's help. No one told me this hobby would involve so much to learn!

Regards,

Brian

[andrew s]

Brian - Just looked at mine and yes you could say it has a pink hew off but look uniformly white when on. I had to add some sheets of white paper to mine to get it dim enough to take a flat field with a reasonable length exposure (2-3 secs) to avoid a shodow due to the mechanical shutter on my CCD.

Andrew

[deskman]

Thanks Andrew,

I will give it a go as Olly suggests above and see what happens. Hopefully I'm panicking over nothing.

Thanks for the help.

Cheers,

Brian

[ianaiken]

Hmm can't say mine is like that. Mine does not omit a circular light source it's square (makes me wonder if it is an Aurora version and not something older). But mine does omit a uniform light source and it doesn't have any blobs or a hint of pink.

[deskman]

Finally had a chance to test this out:

Gerd replied to an email I'd sent him before I posted on this site (he'd been at a show in Paris and was unable to respond any sooner, fair enough).

He suggested a variation on Olly's approach:

Take flat field images, create a master flat, rotate the panel 90 degrees and do the same again. Then divide one image by the other. Any problems should be obvious in his words.

Having done this, the result was a "pure black" image with pixel values of only 1 or 2 across the whole image. I assume black was the desired outcome - and values of 1 or 2 across the image sure as beans looks "uniform" to me, so I guess that must be success!

Gerd reckons he tests every panel before he despatches it, so problems should not exist. He also said that my query was the number one question he gets asked all the time. In fairness to me, the expectation of an even buish-white light was set by Gerd's own website text. Gerd says he is working on updating the text. He's a busy man.

Final result is the panel looks like it should do a perfect job. Gerd's been very helpful with his after sales service.

Thanks also for everyone's help.

Regards,

Brian

[Fred_76]

Hi

I noticed that EL panels are very sensitive to heat. I made an experiment by pressing my hand on a panel for about 30s. When I switched it on, the ghost of my hand appeared slightly lighter than the rest of the panel :

Therefore, be carefull to store your panel in a uniform temperature place.

Fred