Bored enough to make a lightbox

[MikeP]

Here's my Mark II light box. (Don't ask about the Mark I).

It is just one of the EL sheets under some perspex fitted into a slim box. The top part slides in so that I can use the same box for three different scopes.

All made with scraps of wood and MDF.

Mike

[barkis]

Quite ingenius that Mike. How deep is it,? sufficient to stay on the scope obviously.

Ron.

[jgs001]

Looks good Mike... the EL panels is another thing on the very long list of things to get...

[MikeP]

Its only an inch or so deep - enough for it feel secure on the dew shield.

Mike

[barkis]

Are these Panels just like a flourescent tube, only flat.?

And the light is uniform across the whole area I take it.

Ron.

[Kerrp30]

Okay what is this for and what are the materials needed?

Regards

Paul

[yesyes]

It's used to make flat frames. These are calibration images that are loaded into the stacking software along with the light frames containing the object (and other calibration frames like dark frames). Flat frames are meant to cancel out irregularities in the telescope's optical path (internal reflections, vignetting, ...).

The illumination from the light box should be as even as possible. It is mounted in front of the scope and then pictures are taken through the telescope with the camera set to automatic exposure. This needs to be done with the camera in the same orientation as when the light frames have been taken and at the same temperature; ideally during the same imaging session.

[MikeP]

Hi Paul,

Here's a link that explains it - ccdastrophotography.com resources

In simple terms, when you take an image of something in the night sky, the effect of any bits of gunge show up in the image. After taking the image(s) you plonk the light box on the end of the scope and take another image. That second image reveals only the effect of the gunge and its effect can then be "subtracted" from the first image using suitable software.

A light box just provides an evenly illuminated field - some people just put a white tee shirt over the end of the scope and shine a light on it.

The light is provided by an EL Panel - EL Panels - the rest of the box can be made of anything you like to support the panel. I have three scopes that an A4 panel is large enough for so I made it reusable by having three different sized holes to fit over the end of the scopes.

Bet you wish you hadn't asked.

Mike

[Kerrp30]

Thanks YesYes and Mike P, very interesting my mum and dad have an old 15" laptop, looks like the screen is coming out!!

Then it just a case of mounting it in a box. Just out of interest how much did you sell your 8" ones for YesYes?

Paul

[yesyes]

From what you say it sounds like you've already seen my acrylic version. But just in case, here's how I've done it:

yesyes astro blog Lightbox

I would be able to make them for £80 - £100 depending on size and design. Currently making one for an SGL member similar to Mike's design with replaceable front plates for 2 scope sizes (80 and 100mm refractors).

(before anyone asks, I'm authorised to sell these on SGL under my reseller user yesyes_diy) :-)

[Kerrp30]

Right got laptop and stripped the inverter card out along with the Screen. Not got down to the splitting the screen and the backlight out yet.

The laptop is a HP pavillion dv8000.

The screen is a LG Phillips LP171WX2(A4)(K9) which is fine and I can find a datasheet for my issue is the Inverter, SPS-403831-001 IN/B

. Going to take the input cable to the inverter out the laptop as well. The only thing being i do not know what to connect the other end to?

Anyone any ideas?

[yesyes]

That's the tricky part... You need to find out what the pinout is and what "enable" voltage you need. It's usually 12V supply for the lamp and then either 5V or 2V for enable and set the brightness to max.

Do you have any part number on the inverter board?

[Kerrp30]

Might just power it up and use a dvm to measure what is on the pcb. Need a power supply for it now!!

1&2, 6&7 are joined together. Suspect that is 12v and ground. 5 is n/c 3 and 4 are signal pins as thin tracks.

Will look for more numbers on the pcb tonight.

[yesyes]

Most inverters I used had the 12V supply on the outer pins. So that sounds about right for your one. Usually they have an electrolytic capacitor across that voltage somewhere near the plug. With that you can see which one is +12V and which is Ground. Then I would try putting 2V on the other 2 pins with the panel lamp plugged in. If nothing happens, try with 5V.

[Kerrp30]

The only other things I can see on the PCB are YEO YNV-C03, E131735 & 6001720L-B

Here are a couple of pictures

[yesyes]

That looks quite similar to one I have at home. I'll have a look when I get home. This is nice as you can use the copper pads to solder the wires on and don't need to fiddle with the tiny contacts on the connector and try soldering some wires on that.

But I get the feeling we are hijacking this thread...

Might want to PM me or start a new thread if others are interested?

[astrovirus]

...start a new thread if others are interested?

Yes please keep posting, I have a spare laptop that is just waiting to be dismanteled for a project like this. Nice to have this info at forehand to know what to expect. But a new topic is more appropiate as we are hijacking this thread indeed.

Regards Tim

[Kerrp30]

New thread started.

Sorry MikeP for the Hijack