Astrozap 15-inch long Aluminum Dew Shield
for the Explore Scientific AR152 Refractor
MSRP: $80.00 from Astrozap
Reviewed by Jeff Harman
Figure 1. The AR152 with its short 6.5” dew shield.
My only real complaint about the Explore Scientific AR152 Refractor is that its dew shield is short... terribly short. With a diameter of 8” and a length of only 6.5”, the supplied dew shield with the Explore Scientific AR152 Refractor (hereafter referred to as the AR152) quite often fails to keep dew from forming on the objective lens. It has been suggested by several amateur astronomers on the internet that Explore Scientific opted for a short dew shield so that the telescope could fit in the included case with the dew shield being attached, not stored separately. After searching all over the internet, I finally found that Astrozap made a replacement dew shield that just might fit my AR152.
Astrozap is known for making many high-quality dew shields in flexible and aluminum configuration. Although they had none listed for the AR152, they had one listed for the Meade AR-6 LXD55. After researching the two telescopes, I began to have a hunch that they were both made by the same manufacturer in China. Taking a chance, I bought the 15-inch long aluminum dew shield that was made to fit the Meade AR-6.
Figure 2. The AR152 with the Astrozap 15” dew shield.
The Astrozap dew shield is well made and powder-coated in white just like the AR152 and is fully lined with black felt to absorb any stray light that might harm the image seen through the telescope. It is made of welded aluminum which means that it starts out being cut from sheet material, is rolled to the proper circumference and the two ends are welded together to make it tubular. It weighs more than twice as much as the dew shield supplied with the AR152 because it is more than twice as long and is fully lined with felt; the original one that comes with the telescope is only sprayed internally with a light coating of flat black paint.
Figure 3. The blackest of felt.
Figure 4. Another view of the AR152 and Astrozap.
Testing the Astrozap dew shield was exceedingly easy in my part of the world because I live in the Blue Ridge mountains of southwestern Virginia and we'uns is alwayz hav'n mountain dew 'round these here parts! The “proof of the pudding” was done at my favorite dark site which is the Cahas Mountain Overlook at milepost 139 on the Blue Ridge Parkway. It had been raining for two days and the sky cleared nicely in the morning as a cold front moved in. I packed up the AR152, my Orion Sirius EQ-G mount, Celestron Power Tank plus all my eyepieces then took off to the parkway!
I arrived at the Cahas Mountain Overlook about 2-hours before sunset so that I could get all set up in a relaxed mode and have plenty of time to spare. As I pulled off the original 6-1/2 inch long dew shield that came with the AR152, I was thinking how the Astrozap dew shield (8.5 inches longer) would keep moisture from forming on the objective lens: the original one usually would start to fail in an hour or so once the dew began to settle on everything else. I pulled the Astrozap dew shield out of the box and went to put it on but found myself really struggling to fit it over the three raised rails on the lens cell where the dew shield was supposed to fit. Was it made too small?
Figure 5. The collimation screws on the cell.
After just as much difficulty taking it back off, I realized what the problem was. Not only did the Astrozap dew shield have felt but the three rails on the lens cell were covered with felt as well. These strips of felt on the rails of the lens cell, just behind the collimation screws, were to keep the AR152's dew shield on snugly but not permanently. The two layers of felt (on the rails and the lining inside the Astrozap dew shield) were what kept the two from fitting together properly. After pondering a while, I decided to carefully remove three strips of felt from the lining of the Astrozap dew shield. If I were to remove the felt from the rails on the lens cell, then the original dew shield that came with the AR152 would never fit snugly again and always fall off from that moment on. Luckily I had a sharp pocket knife and the surgery was a complete success! I went ahead and installed the Astrozap dew shield and waited for darkness to come. The mount was alligned, eyepiece installed in the diagonal and everything ready for an evening of looking at the sky.
As soon as everything was nice and dark, I slewed the scope to M-42 and drooled all over this wonderful nebula for almost an hour. Then off to that wonderful whirl-pool known as M-51. Now off to Saturn. The problem with Saturn is that it hypnotizes me and I loose all track of time! As I reached for my brand new eyepiece sitting in the tray, I found that it was fogged and realized that the dew was starting to settle. Just a quick blow from the heater in my truck cleared the dew off the eyepiece. When I changed the eyepieces, everything on the scope was moist from dew! Well, I continued my observing until I really began to get uncomfortably cool and found that everything was wet from the telescope to the grass: everything except the objective lens of the AR152. The Astrozap dew shield had done its job perfectly!
Figure 6. The Astrozap dew shield on the AR152 in all its glory!
To sum it all up, the Astrozap 15-inch long dew shield is an excellent replacement for the supplied dew shield that comes with the AR152. It is a good bit heavier than the original dew shield and you will have to adjust the balance of the telescope once it is installed. However, in my opinion, the $80.00 spent on the Astrozap is well worth it!
Jeff Harman is an amateur astronomer who lives in the Blue Ridge mountains of southwestern Virginia. He has been observing the night sky for 18-years and has several telescopes and a couple of binocular sets as well. He is known as “Cheap Scope Jeff” at Cloudy Nights.