Less is OK, but more is better . . . much better

January 30-31 - Another "double" night - double stars, and observing on both the pm and am sides, but there was also some time for some more images through the AT66 with MallinCam video. My main focus was to test simple (and inexpensive) eyepieces against their glass-weary cousins. I won't keep you guessing. With me the modern, wide field, large eye-relief eyepieces are simply better in many ways. But I was also surprised at how much you could get out of the humblest of eyepieces - a Kellner design.

I'll do a separate post ont he video experiences - with images. But here's my experience with simple eyepiece designs.

There are lots of good arguments for and against the simple eyepieces, but what was driving me was a small irritation with the charming little AT66 I've been raving about of late. When pointed high with a heavy eyepiece like the Hyperion in it, the focuser can slip. You can adjust the tension, but I found this tricky to the point of irritation - especially on a cold night. One of the keys to getting the most out of a good refractor is precise focus. So even if the focuser slips a tiny amount, it's a huge problem. So I asked myself - what if you could get away with using just light-weight eyepieces in this little dude? That would be simpler all around - and for a while last night I had myself convinced it was a pretty good idea, especially if your main prey is double stars.

The second part of this equation is the inexpensive "SmartStar Cube" mount I have on order. It's rated for 7-11 pounds. The last thing I want to do is stress it. I believe it will handle 7 pounds fine - but I'm leary about adding much more. The ED80 - which is the main scope I intend to use the new little "go to" mount with, weighs about 6 pounds. Add a 2-inch diagonal with 1.25-inch adapter and you're up to nearly 7.5 pounds. Now put in the typical Hyperion eyepiece and you're up over 8 pounds. Should handle it, but less makes me more comfortable. (Incidentally, the shipping weight on this new mount with tripod is a bit under 12 pounds. I'm used to putting scopes on a mount where the scope is only about half - or one-third - as heavy as the mount. In this case they're going to be closer to equal.)

The 3.5mm Hyperion, delivering 114X on the AT66 weighs14.7 ounces. An excellent Televue 2X Barlow and 6mm Plossl weigh less than half that amount together - and deliver a tad more power - 133X, which is at the theoretical limit of what this little refractor should use. Bottom line - even witht he Barlow plus an eyepiece, you;re putting less stress on the AT66 focusing mechanism than with a Hyperion alone. A 10mm Kellner eyepiece weighs in1.25 ounces - practically nothing. So . . .

When I started shortly after 6 pm last night it was clear and very windy and the CSC gave the seeing for that time as rock bottom - terrible. But it wasn't. It was darned good and I don;t know why - or good for the the tiny aperture of the AT66. My test object was a favorite double, Almach. This is an easy split, but the two stars are close enough so under bad seeing they interfere with one another.

I immediately learned something new about eye relief and double stars - it doesn't matter! Should be obvious. I've only been doing this stuff off and on for half a century. But with the a 10 mm Kellner alone - or with 2X Barlow - you don;t have to get near to the eyepiece. You can be an inch or three away and wearing glasses. Why? Because tou can see just fine fro that distance and all you need to see is the center of the field. Double stars take up very little room, even at 80X, which is what the Kellner-Barlow combination delivered. Another key here is, of course, to be using amount that tracks. Sitting back that far from the eyepiece and dealing with a moving target would be more problematic.

So much for the two main advantages of the modern, premium eyepieces - wide field and large eye relief. But was there a quality difference? Maybe - but Ican't detect it. Maybe I'm just not a demanding enough observer. Honest. I'll give you that. But really, comparing the quality of the image between a 5mm Hyperion and the Barlow/Kelnner combination left me with nothing to choose between. OK - there was an edge to the Hyperion in easy of use - and there is a subjective advantage to the larger field. I find it more pleasing to see stars in the larger conttext. But when you;re focused in on a double - or on aplanet, or some other small, fairly bright object, I think a decent Kellner or Plossl can do the job despite the small fov and lack of eye relief.

After an hour of trying various combinations I was telling myself that well, the Hyperion will be better on other scopes. I didn;t waste my money. This changed, however, quite abruptly in my morning session. During that time I focused on the globular clusters M13 and M3, plus the galaxy pair of M81-82, and the "Whirlpoo," galaxy M51. Og, and I also went looking for M101. Now here I really don;t expect much out of the 66mm scope, but again Iwas surprised. M51? well, you detect it. I'm not sure I would call that observing. M81-82 are very nice, however. they were a bit tight in 5mm Hyperion, a bit loose in the 13mm. I have an 8mm on order and I suspect they'll look great in it. At 5 am theyw ere high in the sky and made a wonderful sight. No, you don;t see much detail, but you're looking at something 8 million light years away. Don;t expect miracles.

M101 was much better than I expected, though again,y ou are looking at the ghost of a galaxy and not much more. Even looked decent in the 10mm Kellner. The two globular clusters were fine - but they suffered from the low resolution of the 66 and it's low light grasp. No comparison to the stunning visual appearance of these objects in the 15-inch Obsession. But on all these objects the wide field, high-contrast, long eye relief of the Hyperion were all a distinct advantage. Unlike with doubles, the wider field is not simply a matter of aesthetics, but of practical value. In tyring to separate the faint, spiral wisps of M101 from the background sky it simply helps to have lots of dark background around the subject. So the Hyperions are what I want to use on this scope and on my other scopes as well. Good to know there are some other choices that can do an acceptable job at much less weight and cost, but I'm in the camp with the modern eyepieces. If i were ana ccomplished planetary or lunar observer, I may feel differently. I'm not. When it comes to the planets and moon and I'm just another space tourist ;-)

OK - some could argue that Ramsden are even humbler. Those are the eyepieces I started with as a child - a mixture of Kellner's and Ramsdens with Orthoscopics a dream too rich for my pocket. Kellner's still show up from time to time. They used to be - maybe still are - packed with the Coronado PST. Well, there's good reason. They do a fine job on bright objects and with a just a few glass-to-air surfaces, they require fewer fancy coatings and less alignment. But when I started out the night I included these justbecause I have ahandful from various sources. I really was going to test a few high-powered Plossls - the standard low-priced eyepiece of today. At the same time, in thebaclk of my mind, was whether or not to order a couple high-powered orthoscopics that are popular with demanding planetary observers.

The advantage of these simple eyepieces is just that - they're simple. They have three or four pieces of glass, whereas a modern, wide-field, large eye-relief eyepiece like the Hyperions I'm fond of, have 7-to-8 lenses in various coplex arrangements. The disadvantage of the simple lenses are two - small field of view and short eye relief so that to see the entire field you need to get your eye right against them and then you're frequently looking through a peep hole. The disadvantage of the wide field eyepieces is with so many internal surfaces they can develop internal reflections that are anoying, and scatter light so they don't have good contrast.

But first, let me share the view of M45 - the Pleiades, as well as M31,32, and 110, M33, and the elusive - but catchable - Horsehead. The Pleiades shot was the most difficult difficult to come by. I needed two 10 mm extentions on the MallinCam ahead of the with the MFR-3 focal reducer. To get this to come to focus in the AT66 I had use a SCT-style "visual back" and run the camera straight through. (I'm still not confidence this is the only way - but it is what worked for me last night. ) On the NexStar mount this combination limits how high you can point the scope before the camera hits the base.

In any event, it was enough to give me the whole cluster, which was my goals, and it did it very nicely. Again, I took several snap shots and the 12-second integration showed the nebulosity, especiallya round Merope.

More images in a moment, but the first order of business was to test some simple eyepieces I have that have been gathering dusts. These are Kellner's and Plossls - time-tested opticalo design that