Light Box

[RobertM]

I don't think it would matter, even for OSC's as the important thing is to get flat field frames with all the optical defects (dust bunnies/field illumination etc).  The situation is more complex for mono chipped cameras as you will have to take one set for each filter position - that's 4 positions for LRGB + another for Ha.  OSC's and Digital SLR's just need the one set with the LP filter in place.  As long as your optical train does not move they should be valid for a number of months.

Don't forget that flat field images are scaled by your imaging software and that would be valid for DSLR's to.

Flat field frames should be as evenly lit as possible, Mikes design looks good to me.  Some people have more than two screens but that's probably over the top for us.  I've heard of the rounded lens end of LED's being filed off and can imagine that would help a lot.

Hope that helps
Robert

[JohnP]

I am going to use an old wine box or something

Fay - make sure you drink the wine first or you could end up damaging your optics....  Probably also best to make sure that the white surface is not too shiny as you may end up with strange reflections etc.

John

[Fay]

John,

I have got a bag of tricks from Maplins, it will be like that cookery programme where they throw a few items on the table & the chef has to make of it what he can!!!!!!!!

I will probably blow something up anyway. Does the mount cable, when clipped onto the 12v battery, need a 3 or 5 amp fuse? I got both in case.

Fay

[JohnP]

I think you should be OK with 3A - I think spec is something like 2A max - give it a go... If the mount is cold (depths of winter) & is fully loaded then I guess it may get close to 3....????

John

[Ian]

you might find the fuse blows if the mount gets jammed against something. Probably not a problem for you Fay, but with my newt, the mount was always trying to put the mirror where one of the tripod legs was 

Note, this is not necessarily a bad thing, but just make sure you've got several spares in your box of bits. That'll make your box a little less light. That bit was a joke... 

[Fay]

Ok, thanks for that.
I have got these LEDS which have their own cables coming out of each one. Do these go into the cigarette connector or is there something in between?

I'm on a mission now.

If all else fails, like a free box in Tesco's, I saw sheets of white sided hardboard in B & Q. Do you think this is too heavy? I have also bought a sheet of white sturdy card, but may not be man enough.

[JohnP]

Fay - what is the PN of the LEDS you got from Maplin's. LED's have a MAX current you can supply to them (something like 20mAmps) if you just connect them to 12V without a current limiting resistor you can watch them smoke...!!!! Also LEDS have polarity - you need to make sure they are connected the right way around...

John

[Fay]

Whoops, stumbling block No.1

I was going to say, do you want a photo before it blows up & after!!!!!!!

All I can see is 12volt. the ref is:A27FJ. 

[mickw]

According to Maplin FAQs for these LEDs, they can be connected directly to the battery so should have internal resistor - Can't find their spec. though.
Presumably they have red and black wires ?
If so, red to positive (+ve) and black to negative (-ve)

I have got these LEDS which have their own cables coming out of each one. Do these go into the cigarette connector or is there something in between?

If they're long enough yes, but don't forget a fuse 

[Mike]

It has 4 lights inside, one on each corner.

[Fay]

Thanks for that Mick. Do you think I should put a switch on or just let them either come on, or blow, up when I connect to battery?

Mike where did you get the foam board?

[mickw]

Don't bother with a switch, you'll only be connecting it when you want to use it anyway.
Besides, you'll be a little further away when it goes BANG

[Mike]

Mike where did you get the foam board?/quote]

Hobbycraft at Crayford.

[Fay]

I rang them & they only do one that is plastic both sides. They don't seem to do the boarded sides now then. Thanks for that Mike

[Mike]

The one I used IS the one with plastic both sides. I never mentioned them having cardboard sides