Posts Made By: William Paolini

At the US Naval Observatory in DC they have 2 Clark refractors. The smaller 12" is used for visual during tours on Monday evenings. They primarily seem to use either XWs or Naglers. In their small box of choices are things like:

40 XW, 35 Pan, a 9 or 13 T1 I believe, some Celestron Ultimas of varying long FLs, then some Claves (very long FL 2" ones), and even some Meade RG Orthos! They of course also have some Clark supplied Huygens but they are in the display case

I've not had the T6s and any Explore 82s at the same time, and I did recently get a 6.7mm Explore 82. This particular FL of the Explore showed as follows:

- softness off-axis around 10% from the field stop due to astigmatism in an f/6 APO. Moving it to a 10" f/4.7 Dob with no Paracorr thing began to get less than optimal at the 50% mark and then rather moderately aberrated at 20% or so from field stop. so not near how a T6 performs. From memory, the T6 had a touch more rectilinear distortion and a touch more lateral color off axis than the Explore, but has no astigmatism from my recollection or notes so overall a substantially sharper off-axis.

- on-axis was quite crisp and really excellent focus snap, better than my T6s used to perform.

- tone was very slightly warm.

- light control/baffling is better in the T6. the bright Moon just outside the field stop showed some reflections in the opposite side of the FOV. These vanished once the Moon was in the FOV.

- contrast and transmission were probably on-par, and judged quite good in the Explore.

Basically, if you have an f/6 or longer focal length refractor it's a very nice eyepiece for the price as the on-axis for planetary is quite nice, better than I recall on the T6 line as their on-axis planetary performance was a nit for me. For faster scopes, especially Dobs would not recommend it.

Whether the other focal lengths perform the same don't know. The 6.7 Meade 5000 UWA performed differently off-axis and was sharp to the edge, overall on-par or a touch better in some respects than I recall my T6 had (RD and lateral color for example). I also noted that the Smyth group in teh barrel was a different arrangement in the MEade 5000 UWA vs the Explore for the 6.7mm units. So their design is slightly different there. Baffling/light control was same in Meade as was in Explore, so not up to the TV standard there.

If you are looking for a less expensive alternative to the T6 line, then would look to the Meade 5000 UWA's over the Explore's based on what I saw in the 6.7mm units of both lines. I actually prefer the overall picture the UWA gives to the T6's and have since acquired the 8.8 and 4.7 as well as a result. Don't know how the units longer that 8.8mm perform though.

Hope this helps.

As Jon mentioned, you don't need top tier glass since your scope has a very eyepiece forgiving f/10 focal ratio. However, if one enjoys premium for premium's sake, that's OK as well. Only you can answer that though.

If you have no eyepieces and need a set to get going, then I would say think of it from a basics rule such as th 50x, 100x, 150x rule. These three magnifications and a Barlow can get you just about anywhere very effectively. I take this rule and adjust it some, so I pick 2 anchor eyepieces to give me widest true field of view (TFOV), one in 2" format and the other in 1.25". I usually only like one 2" eyepiece as for me, switching between 2" and 1.25" is a bit of a hassle (it's just me).

For the 2" widest TFOV you can get a 70 deg wide field like a 41 Pan, 40 Paragon, or 40 Pentax XW or XL, or even things like the 82 deg 31 Nagler T5 or 28mm UWAN, 30 Meade 5000 UWA, etc. All pricey of course. Or you can take a bit more practical route and go with something like the TV 55mm Plossl or the Meade 4000 56mm Plossl (the latter being a very reasonable $99 and works great). If you think you will only be in this wide field scanning mode only infrequently or for finding stuff, then I would choose the Meade 4000 56mm Plossl myself and save some bucks. I use to use on with my C8 and loved it in that role. It has a 50-52 deg AFOV. btw, these 55mm/56mm eyepieces will give you about 45x, so near the "rule's" lowest setting.

Next is the widest TFOV 1.25" which can mean something like a 24 Pan (68 deg) or 32mm Plossl (50 deg). Your choice as either will produce a nice smallish exit pupil for you and keep the background sky looking rich and black. Persoanlly I would spend some money here and get the 24 Pan (104x in your scope). Why? Well this is a "magic" eyepiece in the market place as far as I'm concerned. No other 24-25mm out there produces as nice and clean of an image as this and it works in any scope, regardless of how fast the focal ratio is. One of the few out there IMO that is worth every pennie of its cost and is a lifetime keeper eyepiece.

OK, done with 50x and 100x, time to find a 150x eyepiece, so around 17mm. Again, to same some cash but still not sacrifice much of anything, would probably go the 17mm Hyperion (68 deg AFOV). Very comfortable and great performance and around $120 I believe new (although I'd get everything used from here on AMart, 99% if not 100% as good as new). Of course, if you want to go premium then a 16T5 Nagler or a 17T4 for the more pricey premium level.

If you want to go a step higher and get a 200x also, then the 13mm Hyperion fits that spot nicely. Again, if you want the premium level then could go with a 13T6 Nagler with 82 deg AFOV.

So to sum it, at premium levels:
1 - 41 Pan (need to ask others if the 41 Pan will vigneete in yoru scope -- if so then the 35 Pan) or 31 Nagler
2 - 24 Pan
3 - 16T5 or 17T4 Nagler
4 - 13T6 Nagler

Bringing it down a few notches in price but still great performance:
1 - 55 TV Plossl
2 - 24 Pan
3 - 17 Hyperion
4 - 13 Hyperion

Bringing it down further, but still great performance although smaller AFOV for the shorter FLs:
1 - 56 Meade 4000 Plossl
2 - 25mm TV Plossl (or Sterling Plossl with as it has a little larger AFOV of 55 deg)
3 - 20mm TV Plossl (or 17mm Sterling)
4 - 15mm TV Plossl (or 12.5 Sterling)
5 - 2x Barlow

Tons of choices out there for your scope that work great, not just these.

The obvious answer IMO is that for it to be "worth it" is completely subjective and depends entirely on the perceptions and feelings of the person.

Specifically for me it is not worth it on several levels (and yes I have viewed thru them).
- - only 1 22% increase in angular size from an 82 deg Ep so simply not significant enough perceptually for me and I much prefer the percent increase to be around 40% (for comparison, going Plossl to Nagler is a 64% jump and dramatic).
- - Size and bulk of current implementations is simply too bulky and user unfriendly for me. If they ever get them down to the T6 sizing then perhaps.
- - Cost is too high. For the 22% angular gain I personally don't feel the 220% gain in price (or thereabouts) acceptable for me.
- - Any slight background darkness and magnitude depth improvement from the small change in exit pupil / magnification I may get replacing an existing 82 with a shorter FL 100 deg is too small of a visual gain considering all other factors.
- - Any additional TFOV I can get from the 100 deg over the 82 deg I can as effectively obtain by just using a slightly longer FL. A 16T5 and 13E have about the same FS, a 3mm difference in FL is not a deal breaker in any view with any of my scopes.

Again though, all these are unique to me (and perhaps others). There are plenty of people for whom small incremental changes are significant things which they enjoy. Nothing wrong with that. Plenty of play room for everyone as long as new lines get added and not at the expense of other lines.

I think the article you reference is quite correct, a basic battery would be:
-Center Fire Rifle
-Shotgun
-Medium to High Power Pistol
-22 Rifle and Pistol

I think "optionals" would be an assault type firearm and a black powder firearm as well (either pistol or rifle, simply for days when you want to relive what it was like in the past).

Now the choices as to exact caliber of the center fire rifle and more powerful pistol, and shotgun would be different for each person, depending on the primary application.

FWIW, when I had the T6 line (5mm thru 13mm), the 5mm I had had more lateral color than any of the others in the line. Going back re-reading my observing notes on eyepieces it was clearly lacking in that respect. I wouldn't think that would cause a run of selling though. Probably just a random spike.

FYI, of the sale ads still on the system for "T6" in the ad, since late Nov 2009 here's the tally:

03 - 2.5mm
02 - 3.5mm
10 - 5mm
08 - 7mm
03 - 9mm
08 - 11mm
06 - 13mm

Gary,

Exactly what are you looking for in a planetary eyepiece? Do you have any preferences or requirements relative to AFOV, ER, tonal qualities? Also, do you have tracking with your Tak FCT-100?

-Bill

Steve Hollenbach said:
... what on Earth would they be in fear of?

The places (i.e, situations really) that angels would fear to tread, and where often fools rush into or go to, are those places and situations where by virtue of them making the decision to go there they have put themselves into opposition with God or with God's will. So really, just a different way of saying that fools often rush into sin.

My understanding is that it is more or less a translation problem as in context, it should have been respect and not fear. This like provides a very short answer, but there are many more. So translators used the incorrect English word many times evidently.

http://answers.yahoo.com/question/index?qid=20090117121047AADPKUB

Steve,

How about these reasons....

Q: OK, why fear God?
A: If you accept the premise that God exists and He is God over you, then obviously He has lots of power and capability, so while fear would not be the way to always be in His presense, sure could think of lots of situations that if I got myself into them, then fear would be appropriate. So in the end, it's really context driven. Just like with police, most of the time don't fear but respect their authority, then of course if I did something I know I should not have, that respect would turn into into fearing.

Q: Certainly if God created me and knows me better than I know myself, I have no reason to fear.
A: True as stated. However, how would this question change if God set you free to make your own decisions...and take the consequences with them? So like becoming 18 and subject to adult rules. So sure, I know my son better than he knows himself, but still I have to let him grow up, make his failures, and let him take the consequences. So free will...a definite double edged sword.

Q: I hardly think the creator of the Universe would be so offended by an inferior being that he'd behave like a spoiled child and smoke the whole planet over my inability to cope with challenges he has purposefully provided.
A: A lttle story for this one...you know, I really like bamboo. Planted some in the back yard. Tended to it for a while then let it do its own think...I gave it free will (smile). Now can't tell you what a p.i.t.a. it is! I would love to "smoke" all of it!

Q: Certainly God has more maturity, peace of mind and patience than my Dad. I offended him quite a bit and he never banished me to an eternity of torture.
A: Tricky one this one. Is everone in creation a "child" of God? Plenty of verses to indicate that this is not true...and why the whole concept of being born again...or more accurately put to have one's "old man" die. So would think perfectly reasonalble to be banned if you were never the child to begin with. So then what if you are a child? Well, don;t think you will be banned...unless you commit the one transgression where He stated there is no forgiveness...denying the Holy Spirit. Now what does denying the Holy Spirit mean? That's another thread I'm sure