PST Eyepiece Shield
I recently picked up a Coronado PST - what a great addition to my Astro Gear! Enjoying Astronomy during the day - effectively doubling my opportunity to observe - What's not to like? I have had a lot of fun watching the changes in prominences that happen in such a relatively short period of time. With the exception of Jupiter, we seldom get to see such dynamic changes happen so quickly.
Solar Prominence 8-31-07, 19:24 UT,
Coronado PST, Orion Explorer Zoom Eyepiece @ ~15mm
Canon Powershot A610, Afocal.
While it is a very simple and easy to use instrument, there is one issue that I struggled with. In using the PST, I found that like others, I am bothered by the sun's glare entering the eyepiece, reducing the contrast. As a result, I spent most of the time observing with my hands cupped around the eyepiece and observing eye to get the best view. Not a particularly comfortable position for extended viewing.
I looked around at some of the commercial solutions offered like the shields that attach to the tube, or between the scope and mount. It seemed to me that they would address just part of the issue by shading the eyepiece. I was also experiencing intrusion of light from the periphery of my vision from the area beneath the scope.
I got to thinking that the best solution would be an extended eyecup - something on the order of a few inches across.
I was walking the aisle of the local GlobalDominationMart when I saw this....
In the auto section, and made by Case Logic, the Catch-All it is a small
soft bag made from a firm neoprene material that is intended to attach to
the vent in your car and be a place to store your phone, pda, mp3 player,
etc. In addition to local stores, It is widely available on the net, just
Google "case logic catch-all" for a number of sources.
The top of the bag is held open by a hard ring covered by the neoprene.
I took it off the shelf and held the ring up to my eye, and sure enough it was wide enough to block all extraneous light. I was thrilled, but the lady that saw me do that was wondering was so exciting....
I rushed home with it and got out the PST. I took a razor and cut about an inch or so of the bottom seam stitches. I then slipped the eyepiece holder of the PST through the slit.
up the rig and headed out into the sun. It worked!! It blocked all of the extraneous
light and the contrast was fantastic.
The bag was soft and comfortable against my face. I pulled it up so that its top was just slightly above the top of the eyepiece and compressed it slightly with my face as I moved into the eyepiece. Perfect!
are the advantages:
1. Cheap - just $3.88
2. Easy - just cut a few stitches with a razor knife, slide it on. Done.
3. Will not mark the scope - very soft.
4. Light - Will not throw off the balance of the scope.
5. Folds flat and stores easily in the PST case.
Now that it is fit properly, I will add a couple of stitches on each end of the slit to prevent the the seam from opening further and making the hole any bigger. That should do it - total time invested, less than 10 minutes.
If you do any solar observing, or for that matter night observing in places where light intrudes, this is a good fix. It makes a huge difference with my PST, the additional detail visible with the eyepiece shielded is substantial.
In all, it is Simple, Inexpensive and Works Great - my kind of project.
Please feel free to contact me with questions or comments at
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© 2006 Rod Nabholz