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laowho

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About laowho

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    Star Forming

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    new jersey
  1. I've looked back over the original "challenge" to what I said, then my supporting evidence, then the following emphatic "challenge" from someone else, whereupon I asked for source material and for which I was chastised, both as a troublemaker and as an outsider. Message received. Best wishes everyone.
  2. It wasn't a challenge. It's a request for clarification. There are several factors that would play in personal observations and opinions, not the least of which would be the condition of the primary. People have the right to know where they might save money if they needed to. I fail to see how mischaracterizing my post helps anybody.
  3. Maybe Giordano Bruno too...just before he went to the stake for his many worlds assertions. Not that he would've needed it, but it wouldn't hurt (sorry--no pun intended).
  4. Go here: www.telescope-optics.net/diffraction_pattern_and_aberrations.htm Note that coma, astigmatism and pinched optics will look almost identical whether you test intra-focally or extra-focally. And turbulence will look similar but with a discernable difference. The other aberrations are all markedly different depending on whether you're intra-focus or extra-focus. Cheers
  5. OzDave, I checked out the link you're referencing but what you need are images. They're everywhere on the internet--same images as you'll find in Suiter. Various aberrations show differently from extra-focus to intra-focus, but there are some that look the same. And yes, it may be that it doesn't matter whether you're talking eyeball or CCD--I don't know--but make sure you're familiar with what you're describing and then determine it's aspect intra-focal and extra-focal.
  6. Yes, I understand Suiter's analysis and how he generated his images. What I'm suggesting, and what the OP is asking, is whether and how changing the placement of his CCD should change what he's seeing. This is his question, and I still fail to see how simply telling him to read Suiter's book will answer that IF there's anything about CCDs that ought to be known or taken into account, hence my qualification. Maybe just answer his question if you know? Cheers
  7. That was my thought too when I saw the thread title, but I don't remember seeing anything in there about AP/CCD. Maybe in a later edition?
  8. Yeah, it's tempting to wanna make the planets bigger, but I often can't get above this even for the moon (though this becomes more of a seeing issue). As Brantuk says, it takes special nights to pump up the mag much past 200x, no matter what size your scope. Most nights we're happy to use an 11mm at around 250x (if we can...sometimes we can't even get there. Living by the coast can have its drawbacks).
  9. Well, from here just off the top of my head, page 50, "Illustrated Guide to Astronomical Wonders: From Novice to Master Observer" "The good news, though, is that low power is more forgiving than high power, so if you need to economize, the finder eyepiece is the place to do it." As for spending more, it's for the added glass. But yeah, this is pretty common knowledge and is also born out by experience. Cheers,
  10. Yes Laurie, It does seem that way, doesn't it, almost a knee-jerk reaction out of fear that if someone gets a scope requiring a step stool they'll magically stop using it, thus confirming the inviolable principle "the best scope is the one you'll use." It's twisted, tortuous logic sometimes, or even a "dumbing down." If there are specific reasons to prefer fast, for AP or richest field use, that's one thing, but I don't see an absolutely mandatory convenience as rising to the level of real criteria upon which to make the whole determination. Maybe if you factor in mobility...but still...as you say, it's the lack of options and discussion of the relative merits that for myself is the most off-putting.
  11. Oops...sorry. I see the Delos doesn't quite reach.
  12. I'll just add, since you mentioned cost, that the longer focal length EPs are much more forgiving on the light cone, and that if someone were to look for a place in their magnification range to save money, the low power end is the place where they can do this. We were constrained in our choices here, but had we been able, we probably would have gone with the ES 82 or 100, but only because of the cost/benefit analysis. Also, you're only asking for about 1 degree TFOV, and you'd be able to accomplish that and your exit pupil range with a Delos, no? From everything I've read, it's the best of the bunch. I'd also be asking whether I'd mind a visible field stop.
  13. What's that sound...an angel just got its wings? Gotta love it.
  14. Interesting. Hadn't ever thought of this aspect of "regular collimation needs," and the cell would factor in for this as well. However, the primary axial error tolerance is TWICE as great for f/6 than it is for f/5, and so when collimation IS desired/warranted, it really is that much easier, and as a correlative, the need for collimation should therefore also arise less frequently.
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