Refractor vs. Reflector Telescopes

By Daniel Mounsey

These observations took place during the 2003 Mars opposition near Mt. Wilson California. I have tested dozens of really high end scopes, but there were a few that really caught everyone’s attention. On this particular night, there were about ten to fifteen of us. A buddy of mine named Henrik asked me if he could tag along on this run. This would be his first time to ever look through a telescope.

Seeing on this night was 8-10. In other words, a great night. Some important people were present. John Pons, probably one of the most experienced planetary observers in the world, Steve Kennedy of Kennedy Optics as well. There were two of his 24″ F-4.6 dobs at the site. This guy is an absolute fanatic with optical perfection. Both of these scopes literally punch out perfect looking star tests on both sides of focus after cooling. Ed Grissom would also be present with a 13.5″ F-6 housing another one of Kennedy’s mirrors. More about Grissom later.

Observations began at about 10pm. My friend Jorge had his 8″ F-9 TMB apochromat set up on a Losmandy HGM200 mount. Jorge uses an AP Maxbrite diagonal along with a Zeiss Badder bino and prefers the TMB monos. For my first observations, I must have spent a good 30 minutes viewing through the TMB. Let me start by telling you that the images in this scope are absolutely world class.

The sharpness and contrast of the globe of Mars were absolutely gorgous and the image were totally aesthetic. We were at about 400x. Jorge and I were studying a feature called Hellas Planitia which hangs just below Syrtis Major. I could make out all kinds of markings. My buddy June had his C9.25 set up next to it, but it was being overwhelmed by the images of the TMB. The C9.25 was really good but wasn’t quite as sharp and contrasty as the TMB.

At about this time, most of the group was crowded around the 24″ scopes. Body heat can sometimes be an issue but everyone understands this at Charlton and stays clear enough. I decided to step over and see what was going on.

Kennedy was using a Denk bino along with an ND filter and a pair of classic Clave’s which Pons loaned him for the evening. Kennedy had to be somewhere in the neighborhood of 600x. As I climbed up the ladder and peered into the eyepieces, the view of Mars nearly blew me off the ladder! It must have been about the apparent size of a nickel held up close.

The color and detail was absolutely staggering! What was even more incredible was that the actual contrast of the features themselves was unbelievable! Another friend of mine said he didn’t realize big dobs could produce images like this. I then understood why everyone was waiting to peer through the 24″. I still couldn’t get over it. I mean the color and detail just shot out at you like a picture in a book.

After climbing back down the ladder, Pons asked me what I thought about the images of each scope. Before I answered, I went back to see Jorge at the 8″ to regain my true thoughts. Here was Jorge with nearly a $30,000 rig in a corner all by himself. I mean anybody with experience in this area would have killed at the opportunity to look through an 8″ apo like this, especially on this night.

Pons came over and the three of us discussed the images. Pons told me that if you look real carefully in the TMB, you’ll see all the details you’re seeing in the 24″. I decided to compare the images again on this particular night. After going back and forth a couple of times, I agreed. The truth is, is that you can actually make out the same details, but your eyes had to be trained more to see it. The only difference is that it just doesn’t shoot out at you with as much color and authority as the 24″.

But which image did I actually like between the two? As far as detail and color, the 24″ outperformed the 8″ apo clearly, but it came at a cost. The reason for this is because it was not quite as sharp looking. There was some scintillation around the limbs of Mars and it was hard not to see the diffraction spikes bleeding off the limbs as well. So, even though the color and detail was there, I was still reminded that I was actually looking through a telescope. I guess you would call it quantity over quality. The apo gave a view that was more like you were looking out the window of a space ship. It was more pretty to look at.

Let me tell you, the 8″ was no slouch. I think most people just want instant gratification, but a skilled observer would be fine with the 8″ apo. My thought was that it would be really nice if the 8″ could produce the color, brightness, detail and image scale of the 24″ and retain it’s sharp, contrasty images. On the other hand, it would be nice if the 24″ could keep all its detail and color but have the sharp aesthetic looks seen in the apo. It was like each scope had something the other didn’t, but I’d still have to say the 24″ was the destroyer of worlds that night.

At this point, we had almost forgotten that Ed Grissom had his scope just about cooled down. He was a little late that night at setting up. To tell you the truth, I was not surprised people were not asking him for a look through his scope yet. I mean this thing looks like a piece of junk! It has an old, beat up looking sono tube, which sits on a big old German EQ mount.

Grissom uses an old Tuthill binoviewer and an old set of the original Televue plossls which are actually my favorite planetary eyepieces of all. Ed said his scope was ready if I was interested in having a look. He must have been somewhere around 500x. As I climbed up the stool an peered into the bino, nothing would prepare me for the mother load of all images that night. It would have such a profound impact on my memory, that I already knew within five seconds of seeing Mars, which scope clearly gave the most incredible views that night or any other.

It was the best view of Mars I had ever seen, even to this day. I mean it was just so unreal! The globe was literally etched like a piercing sabre! The color, definition, contrast and detail was absolutely incredible! Appearing like a steel ball-bearing from a pinball machine. My dreams had been answered and it was the real space ship effect. I would describe the image as combining all the things the other two scopes had all into one package. Ed is such a humble man, God bless his heart.

What I love so much about him is that he blows people away without even trying. It is so sad that he has never recieved the credit he truly deserves as an ATM. I believe he’s the best in the world with Newtonians. He misses nothing! It’s the way he does it and these curved spiders of his are just so beautiful to look through.

Later that night, my friend Henrik came over to me and said, I don’t know what kind of scope that is over there, but that one’s got the best images here. He was pointing at Ed’s scope. I’m telling you guys, don’t be fooled by bad looks. It’s what’s inside the eyepiece that counts. I asked Grissom, what the heck he does to these Newtonians and it’s very simple. If you’re interested to know, I’ll tell you, but the man’s a genious. Anyway, there you have it.