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Coronado Personal Solar Telescope (PST)
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I have no undisclosed interest in Coronado or its products
and I purchased this item via normal channels. All included pictures are my
My first view of the sun through a hydrogen alpha filter probably occurred during a science education conference held annually in New York. A Celestron C8 with a Daystar filter was setup on a sidewalk so passers by could take a peek at the sun. I was awed by the views and at the time could only dream of being able to afford the equipment to view the sun in that way.
In April of this year I attended the Northeast Astronomy Forum in Suffern, NY and had an opportunity to view the sun through several different hydrogen alpha telescopes including the Coronado PST. Each scope had a line of people waiting to enjoy the view. The line for the PST at that time was the longest and I debated about standing in line to look through such a small scope. When I got a chance to look through the PST I was surprised by the view. I only looked through it for a few moments but the view of a few solar prominences was impressive. I thought to myself that the view was great for the small scope.
After the show I thought about getting a PST from time to time but the long waiting lists were a bit of a turn off. I eventually decided just to go for it and get on a waiting list hoping that the scope would be a nice Christmas present. Another factor in my decision was the seemingly constant string of cloudy nights we have had in New York for months. My opportunities to observe had night had become few and far between.
One day just by chance I decided to check the Orion website to see what items they had in their clearance section and I noticed that they were now selling Coronado PSTs and that they were in stock. I called and they were indeed in stock. I ordered one right away. They told me that it would ship out in a couple of days when their order came in from Coronado. I eventually got an email that told me the scope had not come in on time. My heart sank. I called and they told me they did not receive their order but that I was close to the top of their waiting list. I would definitely get one when their order came in. As I was told the order came in and I received my PST on a two day delivery.
The PST was well packed. The foam insert was custom made for the scope. It came with a 12.5mm kellner eyepiece in a plastic bolt case. It has a nice metal screw on lens cap. The scope is well built and seems sturdy weighing about three pounds. It has a 40mm aperture and a 400mm focal length. The bandwidth is <1.0Å - <0.6Å. As I understand it the bandwidth is optimized for viewing solar prominences.
At first I tried mounting it on a light weight Vivitar photo tripod. That setup seemed a bit flimsy. My Telepod/Bogen tripod provided a much more stable mount for the scope. The scope has two mounting hole in its bottom. I mounted in on the Telepod using one of the holes.
The next day I was able to try the scope out. I used the supplied kellner eyepiece. The set screw for the eyepiece is plastic. Metal would have been nice but not necessary. The scope has a built in sun finder called a Sol Ranger. I pointed the scope toward the sun and found its image easily in the finder. I found the image needed to be a bit off center for the sun to be centered in the eyepiece. The focus knob is located on the bottom end of the scope. It has a smooth feel and it was easy to achieve focus. On the tube of the scope there is adjustable tuner. The function of the tuner is to give the ability to adjust the performance of the solar filter. Once focus is obtained by using the focus knob the tuner can be adjusted to bring out surface detail and prominences. I discovered if I move the image around in the field of view different areas of the sun came into focus better. I was awed by the views the little scope gave. I knew that it would show prominences very well but I was surprised by the surface detail that I saw. Filaments showed nice detail as well as plage areas. I even witnessed an M class solar flare. Throughout the day I was able to see distinct changes in the sun.
That day I tried a variety of eyepieces with the scope. The 12.5mm kellner that came with it does a decent job. I tried the following eyepieces with the scope: 32mm and 20mm Meade Super Plossls, a 12.5mm Celestron Ultima, and 25mm, 9mm, 6mm, and 5mm University Optics Orthoscopics. All the eyepieces I tried came to focus in the scope. I found that the 12.5mm Ultima and 9mm orthoscopic gave the best views. It seems that some people who have purchased PSTs lucked out and got a 12mm Coronado Cemax eyepiece instead of a 12.5 mm kellner. The Cemax eyepiece has special coatings that enhance contrast for solar viewing. I also heard that some people received a plastic lens cap instead of a metal one.
I took the image above afocally with an Olympus D-550 digital zoom camera through a 20mm Meade Super Plossl in my PST. It came out better than I expected, in particular the large area of prominences on the lower left. The view through the scope is much better than the image shows.
I eventually came up with the idea of piggybacking the PST on top of another scope that would be used for white light observing. My Stellarvue AT1010 could serve in this role. That scope has a tube ring that has a couple of mounting holes in it. I used a threaded stud to attach a photographic ball head. I attached the PST to the ball head. I can adjust the position of the PST so that the views through both scopes are the same. This setup allows me to view the sun in hydrogen alpha and white light at the same time side by side. The Telepod/Bogen tripod I use holds the setup well. I can move the AT1010 in its ring so that the setup is fairly well balanced.
I was fortunate enough to be able to observe with another person who has a Solarmax 40 on a Takahashi 60mm refractor and another PST. We were able to compare one PST to another as well as compare the PST to the Solarmax 40. We also took the opportunity to double stack the Solarmax on the PST and compare his Cemax 12mm eyepiece to other eyepieces.
When we compared the Solarmax 40 to the PST we found that there was greater surface detail of the sun as seen through the Solarmax but the view was darker. The PST seemed to show prominences better. The comparison of one PST to another showed us that the views were similar but there was variation between the two. His scope showed a distinct ghost image that did not go away with changing focus, tuning, or eyepieces. The tuner in that scope seemed looser and had grinding feel to its motion. The double stacked view through the PST was stunning. The level of surface detail was greatly enhanced even though the view was darker. Prominences did not show up as well with the double stacked setup. His Cemax eyepiece was compared to my 12.5mm kellner and Ultima. Both the Ultima and Cemax gave better views than the kellner. To my eye the Cemax and the Ultima gave similar views with a slight edge to the Cemax. I think I would need more time to compare to two to see which works better.
Overall I am extremely pleased with this telescope. It is an
amazing value at $499. The views it gives are impressive. It has opened up
a whole new aspect of astronomy for me. At this point in time many vendors
have a waiting list for these scopes. If you are on one it is well worth the