occulting device

Build an occulting fixture for your telescope Mitch Cluck This device is designed to partially occult the objective of your telescope to block out extraneous light from the moon when you wish to observe a fainter object that is located next to the moon. My version is built to connect to my Meade ETX-90EC. You will have to build an appropriate version for any other type of telescope. Adding a layer of solar screen material to the bottom occulting ring structure will allow you to observe the area around the sun without the sun's glare obstructing the view. An alternative method is to use this device without the solar screen material early in the morning when the sun is just coming up over the horizon. Rotate the occulting section so that the sun is blocked from view and observe the surrounding area. Be very careful so that you do not run the risk of damaging your eyesight or telescope from accidental exposure to the sun's extreme light level. The occulting device consists of a 4" PVC pipe coupling with an extension that houses partial occulting disks. The light path of the occulting disks covers approximately 60% of the total aperature. The occulting disks are shaped so that the 60% is shaped in a little over 1/2 the disk diameter with an outside ring to reduce reflections and improve image contrast. The occulting disk are fastened to the outside tube extension with a set of internal blocking of dark paper placed between the various occulting disks to act as spacers and structural reinforcing. The occulting disks and the tube extension are built from black construction paper. This arrangement is fastened to each other and the PVC pipe coupling with white glue. There is a space of 1" between the occulting disks and the tube extension is 8" long. Tghe PVC pipe coupler has 4 "fuzzy" velcro pads fastened onto the coupling to securely mate the occulting fixture to the telescope face so that it does not slip off. To use, just aim the telescope at the moon. Align the fixture so that the occulting section covers the moon leaving the open area to cover the area of the object that you want to observe. this device will block out most of the glare. The occulting rings will trap extraneous light which will improve contrast. This device is very handy for observing faint objects and also planetary observing when the target is so close to the moon that image details are washed out by glare. I have found that CCD imaging in these circumstances are also improved in most respects. There is a problem that blocking approximately 60% of the telescope aperature greatly reduces the image quality. This is something to keep in mind when using this device. Occulting disk top view (very rough). 1 occulting disk every 1" oo o oooo o oooooo o ooooooo o oooooo o oooo oo Occulting fixture side view (very rough) PVC coupler paper tube (8" long) xxxxxxxxxxxxxxxxxx============================= #### 0 0 0 0 0 Fuzzy velcro pad 0 0 0 0 0 0000000000000000000000000 0 ^ 0 0 0 0 ### 0 ^ 0 0 0 0 xxxxxxxxxxxxxxxxxx===^=================^======= ^ ^ Occulting disks spacers (typ.) ^ ^ Occulting disks (typ.) spaced 1" apart.