My oldest scope is an Edmund Palomar Jr (Pal Jr). It’s a 4.25 inch (108mm) Newtonian reflector on a German equatorial mount. It’s been in regular use ever since I got it in 1973. These days I use it primarily for solar observing using a Baader AstroSolar Safety Film aperture filter. I also use it to compare views with my Zhumell 10 inch (250mm) Dobsonian (Z-10) and to verify what a smaller aperture can show under washed-out skies.

The optics on the Pal Jr are surprisingly good, consistently showing picture-perfect diffraction patterns. It gives great views of the planets and splits η Orionis whenever the seeing is decent. In dark skies, it’s shown me most of the Messier objects and plenty of NGCs. In washed-out skies it still gives good views of double stars, open clusters, the brighter globular clusters (without any hints of resolution), and the brighter nebulas (M27, M42, M57), but apart from M31 it is exceptionally hard to see any galaxies with it. I’ve made a point of including observations with the Pal Jr throughout Washed-out Astronomy to balance the Z-10 view with a smaller aperture view.

The most interesting thing about the Pal Jr is that it was hit by lightening some years ago….

Lightening 1, Telescope 0

In 1991 I kept the Pal Jr in a light-weight shed, the kind commonly used to keep lawnmowers and gardening tools. During a particularly ferocious thunderstorm that summer, lightening scored a direct hit on the shed. Amazingly, nothing caught fire although the roof and one wall of the shed were heavily damaged. My immediate concern was water damage, but the Pal Jr was kept at the opposite side of the shed and was tightly capped, so the inside of the scope stayed dry. The outside of the tube had a small scorch mark near the bottom (mirror end) of the tube, but I didn’t worry about it, until I looked down the telescope at the mirror. The mirror was covered with a “lightening pattern” across most of its face. It looked as if static electricity had danced across the aluminum layer, melting the aluminum into a beautiful pattern—beautiful but unfortunately useless for astronomy.

So I sent the mirror off to be re-coated (I wish I had taken pictures of it, but I didn’t think to do it at the time). But the re-coater called me to report that the pattern was actually melted into the surface of the glass, and the mirror would have to be re-ground. And so I paid to have that done (I’m not an ATM-kind-of-person) and a month later had my mirror back. The new figure was just as good as the old one, except the focus was shorter, about 1004 mm (instead of the original 1080 mm).

Modifications

While the Pal Jr is now considered a “classic” telescope, I’ve always treated it as a working telescope and have never hesitated to improve it. The modifications I’ve made so far are:

• The original f/10 mirror has been re-ground (courtesy of the lightening strike) to f/9.3. This also forced me to move the primary mirror mount about 3 inches forward in the tube. I also center-marked the primary (the original primary was not marked).
• The original focuser (which had pressure-tabs to hold the eyepieces in place) has been replaced with a focuser that uses a set screw to lock the eyepieces in place. This allows me to change eyepieces without throwing off the telescope’s aim.
• The original rectangular secondary mounted on a single-stalk has been replaced with an elliptical secondary mounted on a three-vane spider. I needed to do this because the new focuser couldn’t hold the original the single-stalk diagonal.
• I flocked the upper end of the telescope tube with Protostar flocking material.

These modifications are all visible in the photo above.

Overall Review

The optics on the Pal Jr are top-notch, as shown by the consistently clean Airy disk it shows during star-tests and its consistent ability to split doubles near its Dawes’ limit (1.1 arcsecs). The long focal length makes the views coma-free. Unfortunately the mount is nowhere near as good as the telescope. It vibrates a lot and the motion on both axes doesn’t have enough stiction, so when the scope is perfectly balanced a slight breeze is enough to move it around. The mount has screw-knob friction brakes on both axes, but tightening them even a little bit makes the vibration significantly worse. I plan to one day re-mount the Pal Jr as a Dobsonian, which I think would make it a great telescope.

Despite these complaints, the Pal Jr has shown me many sights and it is still a good performer. The mount legs disassemble and assemble quickly, making it easy to throw in the car and set up. The silly straps used to attach the tube to the mount actually work pretty well, and make it easy to rotate the focuser to a convenient viewing angle. The Pal Jr still wows both kids and adults when they see Jupiter, Saturn, the double cluster or the Orion nebula through it. It provides great views of the Sun using the Baader filter, and most importantly, I still enjoying looking at the skies through it, even washed-out skies.