For the past year or so, I have been using the t-shirt method with a photography set light panel to light up the t-shirt.
Turns out that this was too bright, and since I had to take such fast shots, I was getting different brightnesses due to the 60hz variation of brightness.
So, I started looking into the luminescent sheets, but the price for a 15 inch sheet and then the special power supply was rather high.
So I started looking around for different alternatives.
Here is what I discovered, and how I went about building it.
One day at the Home Depot, I saw a display for some round ceiling flush mount LED Light fixtures.
One of them was a 15 inch fixture with a very well and evenly lit panel.
Upon checking out the device, I found that the 'glass' turned out to be just a hair over the 12 inch tube for my 11 inch SCT.
Voila, it fit over my scope.
To prepare the mounting hardware, I cut out a piece of sheet metal to cover the back of the mounting hardware, painted it white, and fastened it with tiny bolts.
I drilled a hole to let the electrical wires exit so I could access them later.
Snapping the fixture together results in a nice flat lightbox about one inch thick.
The next challenge was to build a mechanism to hold the light fixture securely to the scope.
I came up with a scheme to make a holder that would allow the 'new light box' to securely fit over the scope.
I decided to cut two rings out of some 1/2" foam core craft board.
My Dremmel tool worked wonders on forming the cuts as seen here. First the large disk, then cut out the inner disk.
I glued the two rings together forming a one inch think ring.
I lined the inside of the rings with the fuzzy side of some Velcro rolls.
This will allow a snug fit around the telescope tube.
Verifying the snug fit... I had to calculate the inside diameter of the rings to account for the double thickness of the velcro.
I then glued the ring to the light fixture.
Since this light fixture is dimmable, I picked up a regular single pole light dimmer and connected it up to the lightbox.
Now, I can dim the lightbox to a level that will allow me to take properly timed flats so that I get the proper Brightness and Exposure for my setup.
Testing now shows that I can easily attain the characteristics for good flats as described to me by a fellow PixInsight Forum Member.
Here is the finished product snugly attached to the scope, and due to the materials and the black velcro, there is no light leaking out to interfere with fellow astronomers.
So now, I need to make an adapter to fit my 6" Newtonian tube. So I made an adapter ring to fit the 6".
Same construction as the larger ring above, with the velcro to fit snugly around the smaller tube.
Now, the adapter ring fits inside the larger, and now fits on the 6" Newtonian.
1 LED light fixture - 59.95
1 Dimmer control - 19.95
2 sheets 1/2" foam core board - 6.00
3 rolls of Velcro Strips - 9.00
1 can white spray paint - 8.00
1 roll double stick tape - 3.59 ( this is how I glued all pieces together )