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Saturninus

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About Saturninus

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    Nebula

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    Honolulu
  1. Thanks for explanations! Sometimes I do feel as if the Airy Disk is some kind of 15th magnitude planetary nebula that everyone else has been able to find except for me... But if I need to get above 250x to see it, then that explains why I never have. Too much atmospheric blurring at that magnification to make out something as delicate as an airy disk. I am usually limited to 225x or below. Occasionally, I can get above 300x on Saturn specifically, but gather that planets behave very differently than point sources of light such as stars. To be clear, most stars are pinpoint sharp. It just the really bright ones, like Arcturus or Sirius, that look like asterisks. Come to think of it, I'm not even sure how those stars are supposed to look at 400x under perfect conditions in an 8" SCT
  2. Hey thanks very much for your comments. Very very helpful. I'm glad to know that I don't have to go to extremes to get a really good view. Well, actually I will be putting my wallet through some extremes... If the forum gods are not too offended, I'll post this question in solar observation forum. It would be interested to hear the topic of best seeing conditions debated. Yes, the same rules apply to Hawaii. Except that in Hawaii, everything is 30% more expensive. We refer to it as the sunshine tax. So I figured I should make the most of it and get a closer look at what I am paying for.
  3. I've had my 8" SCT for awhile now, and I have been generally satisfied with it. But I have a secret that I have been keeping to myself this whole time...I don't think I have ever really seen the airy disk with it. I've seen it with a 127mm mak-cas, and in a 110mm refractor, but I never quite get there in my 200mm SCT. I know that the larger the aperture of the telescope, the smaller the airy disk. Is it the case that at 200mm aperture, atmospheric blurring will prevent me from ever getting to a high enough magnification to see the airy disk under normal conditions? How else can I evaluate the optics of my telescope? Planetary and lunar details seem sharp to me, globular clusters resolve pretty well, but the bright stars are always a bit fuzzy...
  4. I don't have any solar observation equipment yet - I'm still trying to learn as much as possible before making the plunge - but it will eventually happen! But first I'd like to try to understand solar seeing conditions so I can get an idea of what to expect where I live. I understand that due to atmospheric conditions, I am unlikely to ever exceed magnification around 60x on a regular basis no matter how big of a scope I use. But where can I go to get the best possible conditions? I know that a concrete parking lot would be bad. Heat radiates off the ground. Am I better off in a grassy field? Or how about near the beach observing out over the ocean? Or how about the edge of a balcony on a tall building far above the ground? What time of day is best? Earlier in the morning when the sun hasn't had much time to heat up the ground, but the sun is at a low angle? Or am I better off when the sun is high overhead even if the ground is hotter? And how about altitude? If I go up a mountain and observe at high altitude, would I be able to achieve higher magnification? If so, how much higher could I get versus sea level? Or are the atmospheric limitations just as bad at high altitudes as they are at low altitudes during the day? Thanks for any advice. I've tried searching online for this, but can't seem to find a good resource that explains it all
  5. Thanks for sharing that link. Where I live in Honolulu, the light pollution is pretty bad. I think I'll need to go higher mag.
  6. For a given aperture, should I go for exit pupil or magnification? If I were set on getting a 42mm binocular, am I better off getting an 8x to maximize the exit pupil, or going 10x to see deeper? I know that 10x50 is often cited as the ideal, but I think 50mm is going to be too big, and while I am sure the extra 8mm helps, I’m hoping that it is not going to make too much of difference because I don’t want to pay the penalty in size and weight. So then it is either 8x42 with the bigger exit pupil, or 10x42 with the higher mag. Is there an answer that most people lean towards?
  7. Oh ok thanks. Easy answer. So then the only thing affected is the backfocus required?
  8. I've got a 8" f10 SCT that has a 1.25" prism diagonal. I like to use a 10mm BCO ortho to observe planets 200X. The problem is, the BCO is such a small eyepiece, that I literally can't get my head in close enough to look through it close enough without bumping my forehead against the rear of the OTA. I can get a 1.25" nosepiece that I can basically use as a sort extension tube. It extends the eyepiece out just far enough so that I can use it comfortably. But how will this affect magnification? Is there a formula for determining how much magnification is added per milimeter of extension tube? I don't want to raise the magnification by too much because 200x is perfect as it is. Thanks for any help
  9. No I never got a handle, but lots of good ideas here. I think I'll try a drum bag
  10. Yes I experienced this last night. I was looking at jupiter, and every time I tried to go past 250x it got sloppy. Then after a short nap i woke up again and Saturn...maybe the atmosphere was much better at 2am, maybe it was much higher in the sky, or maybe I was just seeing things, but I was getting up beyond 400x and it seemed like Saturn was getting better and better!
  11. I often hear the optimal power for viewing certain objects as expressed in magnification per inch of aperture. For instance, I hear that Jupiter is best observed at 35x per inch of aperture. I guess this equates to an exit pupil of 0.7 Is this advice true no matter what size scope you use? For instance, in a 6 inch refractor, that is 210x. In a 4 inch refractor, that is 140x. I would have thought that as long as seeing conditions permit, something like Jupiter would look best at 200x no matter if it is a 6 inch or 4 inch scope. So if I have a 4 inch scope and I want to do planetary viewing, and seeing conditions generally permit 200x on a regular basis, should I be clustering my EP collection around 200x magnification, or would I get better views at 35x per inch of aperture (140x total magnification) even though the image would be smaller?
  12. all sounds very reasonable. and I know where this will lead: Get both! One day... I guess the larger exit pupil at any given magnification for the larger scope overwhelms the glass quality, assuming that the larger scope is of reasonably good quality. What about on objects where surface brightness is not an issue - such as Jupiter? Or a more extreme example - for solar observation? Sometimes, when viewing jupiter, a thin cloud will pass over head and darken the image slightly, and it seems like I can see even more detail!?
  13. In the 110m ED doublet, i would be using a 5mm EP to get to 157x, at about 37x per inch of aperture.<br /> <br /> In the 80mm apo triplet, I would be using a 3mm EP to get to 160x at 50x per inch of aperture. <br /> <br /> All other things being equal, which image has better contrast and resolution? Assume the ED is corrected well enough that chromatic aberration is not bothersome. Does the bigger scope operating below it's maximum outperform the smaller, superior scope that is being pushed to it's limit?
  14. Thanks for all the moral support folks. I just wanted to be sure I wasnt overreacting. This was my biggest astronomical purchase to date and I was really looking forward to years of fun with this scope. You can imagine my disappointment in getting this particular sample. I dont really blame the retailer, since it was drop-shipped directly from the manufacturer. But I will have to return it to them and let them deal with the manufacturer. As for the manufacturer, I'm never buying a product from them again. This is the second time I've had to deal with a dirty product sample. I just don't like their business model. They seem to rely on post-purchase customer service to make up for cost-cutting quality control shortcuts. I'd rather buy from a small shop that takes pride in every product they put out the door.
  15. This was drop-shipped directly from the manufacturer to me. Would you be happy with this? Those specks you see are not on the outside surface of the element. All of that is on the inside elements, where I can not clean them without taking the thing apart. I am not inclined to take it apart to clean it, and I don't even know if I could. For all I know, the dust is in-between the elements. This is photo was taken with direct sunlight on the objective - so the sunlight is lighting up the dust pretty good. Perhaps the dust has no practical effect on the image - but then again the dust is clearly noticeable to anyone doing a QC check...unless it is the case that this kind of dust is always present in brand new scopes and people just generally live with it. But this is not a cheap scope...its a 102mm carbon fiber triplet apo!!! What tier of manufacturers should I buy from if I would prefer not to get a brand new scope with this kind of dust in it?
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