Flocking Focuser draw tube
Posted: Sun Sep 29, 2019 11:01 pm
The draw tubes on my fracs are 2" and 2.5".
On my AR152f/ 6.5, which has a 2" focuser, I notice some dull light circle coming from the inside of the draw tube when viewed through the diagonal without an EP in place.
I used a smooth sided plastic soda drink bottle, photo mount adhesive, and thin wool felt to flock this tube interior.
I cut the top and bottom from a plastic soda bottle forming a cylinder. I split the cylinder and rolled it to fit in the draw tube. I cut this piece to size so that the rolled plastic expands to fill the inside diameter of the focus draw tube.
I cut a piece of black felt and mounted it to the split plastic cylinder from the soda bottle.
I rolled this mounted black felt, felt to the inside, and installed it through the back of the draw tube with needle nose pliers. Upon releasing the rolled plastic/felt sheet it expanded to the walls of the interior of the focuser draw tube.
I used no adhesive to attach the felt backed cylinder to the tube interior. This device can be removed if I don't find it useful.
Bingo!
Now there is no ring of light in the draw tube when I view through theEP collar on my diagonal.
You may not benefit from this flocking, but in my case it has improved the view.
I tested this in daylight on tree leaves in the back ward. Contrast has been improved.
Testing in daylight I observed that it was easier to come to focus on bright leaves backgrounded by even brighter unfocused distant leaves.
In prior daylight testing in my woods there was some struggle to find best focus between already bright leaves with a bright background.
I do not know the technical details of this difference, but the experience is enough for me.
I am now looking forward to a clear night.
I have attached an image of the ingredients for this project.
PS :
I forgot to mention that the felt sheet is cut 3mm long so that I could fold it back over the edge of the plastic cylinder.
The photo mount adhesive is applied to the felt.
On my AR152
I used a smooth sided plastic soda drink bottle, photo mount adhesive, and thin wool felt to flock this tube interior.
I cut the top and bottom from a plastic soda bottle forming a cylinder. I split the cylinder and rolled it to fit in the draw tube. I cut this piece to size so that the rolled plastic expands to fill the inside diameter of the focus draw tube.
I cut a piece of black felt and mounted it to the split plastic cylinder from the soda bottle.
I rolled this mounted black felt, felt to the inside, and installed it through the back of the draw tube with needle nose pliers. Upon releasing the rolled plastic/felt sheet it expanded to the walls of the interior of the focuser draw tube.
I used no adhesive to attach the felt backed cylinder to the tube interior. This device can be removed if I don't find it useful.
Bingo!
Now there is no ring of light in the draw tube when I view through the
You may not benefit from this flocking, but in my case it has improved the view.
I tested this in daylight on tree leaves in the back ward. Contrast has been improved.
Testing in daylight I observed that it was easier to come to focus on bright leaves backgrounded by even brighter unfocused distant leaves.
In prior daylight testing in my woods there was some struggle to find best focus between already bright leaves with a bright background.
I do not know the technical details of this difference, but the experience is enough for me.
I am now looking forward to a clear night.
I have attached an image of the ingredients for this project.
I forgot to mention that the felt sheet is cut 3mm long so that I could fold it back over the edge of the plastic cylinder.
The photo mount adhesive is applied to the felt.
