Posts Made By: Mike Hosea

I think Gary finds surplus eyepieces of whatever types, machines casings, and at most combines an eyepiece with a Barlow. Some of them obviously came off surplus binoculars. The quality of the optics is, therefore, quite variable and highly dependent on the model. In some cases I didn't think Gary had the focal length right. I had an 18mm with "XL" lenses once. The coatings looked absolutely beautiful, but I somehow got the impression from using it that the transmission was not good at all. I don't really remember any specific tests, though, since it was some time ago. YMMV, I guess, although I have to admit I've always thought his eyepieces were fun to try and generally worth the price of admission. Not until today have I ever even thought to compare one to a Pentax XW, though.
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Mike

If you're utilitarian about it, you can just remove them and wrap some 3m Temflex Rubber Splicing Tape (probably about $2 or $3 a roll from Home Depot) around until you build up to whatever thickness you want. If you never used this stuff, just remove the cloth backing and stretch it thin as you apply it. It fuses into a solid piece of rubber. The rubber has a good texture for gripping.
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Mike

Rod Kaufman said:
3. Will Mike Hosea buy another 4mm eyepiece in time for Mars, and, if so, WHAT will he buy and WHEN will he buy it?(credit or debit?)

I got the bright idea yesterday to order an Antares 1.6x Barlow to use with my 6mm ZAO-II instead, but I don't have the Barlow yet. That's slightly shorter than 4mm, but still larger than a 0.5mm exit pupil in my scope.
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Mike

I don't know. The 13mm Ethos is my favorite eyepiece of all time, out of a few hundreds by the time I lost count. But I have to admit that it's a good focal length for my scope (2mm exit pupil).

The "take it in" argument is based on an entirely personal premise--that the wider field has no value if you can't soak it all in while staring at the center of the field. I reject that premise completely. Limiting yourself to staring down the center of the view with a widefield, not rolling the eye, is a waste. Sure, if that's the way you observe, don't buy the widefield, but it sounds weird to me. I think of it this way. I'm going to want to roll my eyeball a little bit, and what's the AFoV that represents the size peripheral field I'd like to maintain at all times? I argue that it's about 50 degrees, i.e. 25 degrees of peripheral field in all directions. Now to get this with a Plossl, I do have to stare straight down the center because if I roll my eye to the side, the peripheral field drops below 25 degrees to one side. If I go to a 60 degree eyepiece, I can roll my eye around the central 10 degrees and maintain a Plossl-size peripheral field. If a 70 degree eyepiece, I can use the central 20 degrees for direct vision. If an 82 degree eyepiece, the central 32 degrees can be used. Now with a 100 degree eyepiece, I can look anywhere in the central 50 degrees and maintain at least 50 degrees of peripheral field, i.e. at least 25 degrees in every direction. That sounds perfect to me.

I haven't looked at the latest ones, but the construction of the originals consisted of several things threaded together. There is a retaining ring in the barrel that holds the lens there. In the upper part, removing the rubber eyeguard reveals a retaining ring for the adjustable eyeguard. The eye lens itself is surrounded by a metal lip that can be grasped and unscrewed, removing a lens cell holding the upper optics. It, too, has a retaining ring. It's all pretty straightforward. For safety's sake the rule is to figure out which way gravity will hold the lenses in if something were to come apart unexpectedly and hold the eyepiece that way while unscrewing anything to get to something else. As long as you don't unscrew the retaining ring on either of the two lens cells (barrel cell and upper cell) the lenses should stay safe and sound.

A few months ago I bought a 17mm Celestron Nexstar Plossl new for $16 shipped. I also bought the 32mm. They were for my little grab-n-go Newt, and I also figured if I ever sold it, I'd need to provide some eyepieces with it (since it was sort of designed to be a beginner instrument, anyway, except my kids weren't that interested--go figure).

Anyway, the 32mm is everything I was afraid it would be (no need to comment), but the 17mm is really quite wonderful as far as I can tell. I've always liked this simple symmetrical design when the lenses are good. I don't care for the silver top next to the lens, but it really doesn't seem to matter. I was actually a little bit stunned at how good the image was in every respect when I put it in my 2x Meade TeleXtender.

I thought I'd just developed the same problem, but it turned out that the image was opening up behind the window I was clicking in. Once I brought brought the image window back to the front and then closed it, it was healed--the next image popped up in front normally.

The designation of "planet" is a linguistic, social, even political matter of little or no scientific importance, which is precisely why so many people care. If it were a useful scientific designation there would be little basis for debate. But I was happy to see Pluto reclassified because otherwise it would eventually be necessary to admit dozens of other objects as planets, which I think would be more socially disruptive. I reject the idea of grandfathering. Scientists have no business arbitrarily "grandfathering" Pluto whilest excluding larger, equally qualified objects as planets. Unfortunately, I found the earlier efforts to contrive a definition which supported Pluto's inclusion transparent. On the other hand, the definition chosen was even more contrived and disappointing.
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Mike

What you have to ask yourself is where Lakisha's support will go.

(Guess it went to Jordin!)

I find myself agreeing (somewhat uncharacteristically) with today's NY Times article

"Experts See a Need for Punitive Action in Bailout"

Even though we have to (try to) prevent a collapse, it doesn't mean we have to give free gifts to guys with 8-figure salaries.