+ Reply to Thread
Page 2 of 9 FirstFirst 1 2 3 4 ... LastLast
Results 21 to 40 of 170

Thread: Backyard Astronomy     submit to reddit submit to twitter submit to tumblr

  1. #21
    CoP Dynamis
    Join Date
    Oct 2007
    Posts
    283
    BG Level
    4
    FFXI Server
    Shiva

    It isnt as big of a deal as the site shows, http://www.celestron.com/browse-shop...14eq-telescope shows its retail price as $249.95 but compared to other places that sell this model it seems to be the cheapest. Amazon has it for 187. Have been debating getting into this as well, had a bad experience with one bought from costco, had to return it after the first use. Was a motorized tracking telescope, its battery connection inside broke while setting it up and couldn't turn at all. So said F buying a automatic one again.

  2. #22
    RNGesus
    Sweaty Dick Punching Enthusiast

    Join Date
    Jan 2005
    Posts
    24,383
    BG Level
    10
    FFXIV Character
    Lenette Valkyr
    FFXIV Server
    Gilgamesh

    It's still pretty cheap for the specs. I wasn't able to find anything else for that price that were close to those numbers.

    And personally, like I said, as a beginner half the fun to me seems to be finding things for myself. Maybe if I were to get really into it and did lots of photography or whatever I'd get a motorized one someday. But for now a regular one with good focus and plenty of magnification seems good to me.

  3. #23

    As I read reviews, I see a lot of people recommending the Celestron 130EQ over the 114EQ. It's currently about $250, but one of the forums I found says it goes on sale around $199. Since I'm not making a decision today, I might watch for that one to go on sale again, it could be worth the extra $40. And it gives me time to read more and determine what I really want. I think you have a good point, as a beginner I would like to learn to find things on my own. Then I have a few years to save up $1000 or so and go crazy lol.

  4. #24
    RNGesus
    Sweaty Dick Punching Enthusiast

    Join Date
    Jan 2005
    Posts
    24,383
    BG Level
    10
    FFXIV Character
    Lenette Valkyr
    FFXIV Server
    Gilgamesh

    The 114 has a highest useful magnification of 269. The 130 only has 150. What it has going for it is that it has a "fast" focal ratio whereas the 114 only has a "medium." It has a bigger aperture (130 vs 114), but smaller focal length which might be what results in the lesser magnification power. But hey, those images will come out brighter and sharper.

    Fast f/4 to f/5 focal ratios are generally best for lower power wide field observing and deep space photography. Slow f/11 to f/15 focal ratios are usually better suited to higher power lunar, planetary, and binary star observing and high power photography. Medium f/6 to f/10 focal ratios work well with either.

    An f/5 system can photograph a nebula or other faint extended deep space object in one-fourth the time of an f/10 system, but the image will be only one-half as large. Point sources, such as stars, are recorded based on the aperture, however, rather than the focal ratio – so that the larger the aperture, the fainter the star you can see or photograph, no matter what the focal ratio.
    So as a beginner I stick by my original choice since it seems the best for delving both into near objects and deeper space things.

    Based on the above quote I'd be careful about buying a low F ratio telescope unless you're looking specifically for deep space images only.

  5. #25
    Who's driving? Oh my God Bear is driving! How can that be??
    Join Date
    Sep 2008
    Posts
    3,970
    BG Level
    7
    FFXI Server
    Lakshmi

    Quote Originally Posted by Obiron View Post

    How important is focal length? I notice the Orion StarSeeker III has 500mm, whereas the 130 SLT has 650, and for a little more money the Celestron NexStar 4 SE has a whopping 1325 (but slightly smaller aperture). Is there a good range to stay in to get enough magnification without losing quality?
    Focal Length is the length in mm from the primary mirror/lens in the tube to the eyepiece. This includes any distance light needs to bounce off any secondary mirrors. The focal length number can be used to help determine your magnification power and the aperture gives you what's called the limiting magnification. The limiting magnification is the maximum magnification you can get before the image starts to lose image quality.

    Taking a look at the Orion StarSeeker III 114mm GoTo, it has a 114mm aperture and 500mm focal length. The limiting magnification is found by taking the aperture size and multiplying by 2, so in this case the limiting magnification is 228x. Now, as you use the telescope, you switch through different eyepieces to increase your magnification. The standard eyepiece is 25mm, so to find your magnification with that eyepiece you take the focal length/eyepiece, in this case with a 25mm eyepiece you are looking at 500/25=20x magnification. Eyepieces get down to about 6mm in size but the hole to look through is very small, but if we took at 7mm eyepiece you are looking at 500/7=71. In order to get close to your limiting magnification, you'd have to use a 3x Barlow lens which would triple your magnification to 213.

    The NexStar 4SE is a Cassegrain type telescope. What's great about these is you can get high focal lengths with a short tube because the light has to bounce from the back end of the tube, to the front, and then back again. This particular scope has a 102mm aperture so that means 204x limiting magnification but boasts a 1325mm focal length. With a high power eyepiece of 6mm you easily exceed the limiting magnification (1325/6=220x), so you can use lower power eyepieces instead.

    tl:dr version:

    Bigger Focal Length=higher magnification with eyepices
    Aperture size x2 = highest magnification before you start to lose detail

  6. #26
    RNGesus
    Sweaty Dick Punching Enthusiast

    Join Date
    Jan 2005
    Posts
    24,383
    BG Level
    10
    FFXIV Character
    Lenette Valkyr
    FFXIV Server
    Gilgamesh

    How come the 114 says its highest usable maginification is 269 when its aperture is 114? 114x2 = 228 ;x

  7. #27
    Who's driving? Oh my God Bear is driving! How can that be??
    Join Date
    Sep 2008
    Posts
    3,970
    BG Level
    7
    FFXI Server
    Lakshmi

    Quote Originally Posted by Tyrath View Post
    Based on the above quote I'd be careful about buying a low F ratio telescope unless you're looking specifically for deep space images only.
    Yeah Low F ratios can be considered mostly for wide field astophotography. Objects such as the Andromeda Galaxy, Pleiades, and the Orion Nebula benefit from lower F ratios because they easily fit in the field of view. The larger F ratio telescopes won't be able to fit these objects easily into their field of view. However, there are accessories that you can purchase called Focal Reducers that bring the focal length down. I have an f10 scope and I cannot fit all of the Moon in the field of view when taking photos, so I have to use a focal reducer which brings my ratio down to f6.3 allowing the Moon to fit perfectly in the frame.

    Quote Originally Posted by Tyrath View Post
    How come the 114 says its highest usable magnification is 269 when its aperture is 114? 114x2 = 228 ;x
    Manufacturers are using a different formula which is Aperture in Inches x 60 and rounding up.

    114mm=4.48 inches x 60 = 268.8 rounded up to 269.

    The difference in the numbers really is that Aperture in mm x 2 is a safer number to go by. Each night will have different atmospheric seeing conditions and getting up to 269x magnification would probably require a very still upper atmosphere or at least one with minimum turbulence.

  8. #28
    Who's driving? Oh my God Bear is driving! How can that be??
    Join Date
    Sep 2008
    Posts
    3,970
    BG Level
    7
    FFXI Server
    Lakshmi

    Went and dug up some old photos from two years ago when I started with Astrophotography.

    If anyone wants to get into imaging planets, it is better to use video mode on a DSLR or a CCD camera/webcam. I went out and bought a cheap 0.3 MP webcam and removed the focusing lens from it and attached and old eyepiece barrel with duct tape where the lens was. This allowed me to slide the webcam directly into the eyepiece slot on my telescope. Here is a comparison between a single shot taken from my DSLR versus 1 frame of video taken from a webcam video recording.

    My 350D's sensor has a diagonal size of about 26.5mm so it is the equivalent of a 26mm eyepiece. When connected to my telescope it gives me 76x magnification (2032mm focal length of scope/26mm). However, my DSLR cannot take video so I am limited to single shots. This one was at 1/800 and I don't remember the ISO:

    Saturn 76x Magnification 350D DSLR


    My 0.3MP webcam has a sensor size of about 38mm so it gives me less magnification (53x) however, recording videos of the planets gives better images that can be stacked together for more detail. This is a non stacked frame from a video of Saturn I took in 2012:

    Saturn 53x Magnification 0.3MP Webcam

  9. #29
    BG Medical's Student of Medicine
    Join Date
    Oct 2006
    Posts
    19,366
    BG Level
    9

    Fuck me this is so amazing to contemplate.

  10. #30

    So because of this thread, I've spent the last couple days doing nothing but looking into telescopes. After reading a lot of reviews on the Celestrons, while they have their strong points, I'm now leaning more towards the Orion StarBlast 4.5. Reviewers tend to paint it as having a higher build quality. Also, it's Newtonian and has a parabolic mirror, which I didn't even know were considerations for a scope.

    I want to look into some refractors too, but I may pull the trigger on the Orion this weekend and hope it gets here quick enough I can see Saturn in opposition next week.

  11. #31
    Who's driving? Oh my God Bear is driving! How can that be??
    Join Date
    Sep 2008
    Posts
    3,970
    BG Level
    7
    FFXI Server
    Lakshmi

    Quote Originally Posted by Obiron View Post
    . Also, it's Newtonian and has a parabolic mirror, which I didn't even know were considerations for a scope.
    Yeah there are different types with sub types with each having their own strengths and weaknesses.

  12. #32
    RNGesus
    Sweaty Dick Punching Enthusiast

    Join Date
    Jan 2005
    Posts
    24,383
    BG Level
    10
    FFXIV Character
    Lenette Valkyr
    FFXIV Server
    Gilgamesh

    I decided to go with the 114 I originally posted and it just got here today. Excited to put it together later tonight and play around with it. Will have to learn everything as I go xD

  13. #33
    Who's driving? Oh my God Bear is driving! How can that be??
    Join Date
    Sep 2008
    Posts
    3,970
    BG Level
    7
    FFXI Server
    Lakshmi

    Congrats on your purchase. The second telescope I ever owned was pretty much the exact same setup/type so I can tell you from previous experience it will give you some pretty awesome views. What size eyepieces did it come with?

  14. #34
    RNGesus
    Sweaty Dick Punching Enthusiast

    Join Date
    Jan 2005
    Posts
    24,383
    BG Level
    10
    FFXIV Character
    Lenette Valkyr
    FFXIV Server
    Gilgamesh

    20mm and 10mm based on the specs. I haven't had a chance to sit down and look around quite yet, things getting in the way >_< If I had my way I'd have been not working today and just playing around with it all day lol

  15. #35
    CoP Dynamis
    Join Date
    Oct 2007
    Posts
    283
    BG Level
    4
    FFXI Server
    Shiva

    Pulled the trigger as well on it, arrived today and put it together after work. I don't like the slow motion cables it has on it, feels very cheap and it came missing a screw for one but hell I dont think I'll ever use them. Kinda opened up the 20mm erecting eyepiece, all the lenses fell out and had to look up how to put it back together correctly. So here is to clear skies tonight even with tons of like pollution from Baltimore. It was shipped hella fast for free shipping.

  16. #36
    Shimmy shimmy ya shimmy yam shimmy ya
    Sweaty Dick Punching Enthusiast

    Join Date
    Nov 2007
    Posts
    20,490
    BG Level
    10

    The wifey recently bought me an Orion StarBlast 4.5 Equatorial Reflector Telescope. Haven't had a chance to take it out yet though and I'm completely ignorant of telescopes in general. Any comments or advice for this kind of telescope and what will I be able to see?

  17. #37
    Who's driving? Oh my God Bear is driving! How can that be??
    Join Date
    Sep 2008
    Posts
    3,970
    BG Level
    7
    FFXI Server
    Lakshmi

    Quote Originally Posted by Tyrath View Post
    20mm and 10mm based on the specs. I haven't had a chance to sit down and look around quite yet, things getting in the way >_< If I had my way I'd have been not working today and just playing around with it all day lol
    So 45x and 90x magnification. That's awesome that they included the 10mm eyepiece.

  18. #38
    RNGesus
    Sweaty Dick Punching Enthusiast

    Join Date
    Jan 2005
    Posts
    24,383
    BG Level
    10
    FFXIV Character
    Lenette Valkyr
    FFXIV Server
    Gilgamesh

    How do you get the magnification number from the mm again? :3 On the site it says 50x and 100x.

  19. #39
    Who's driving? Oh my God Bear is driving! How can that be??
    Join Date
    Sep 2008
    Posts
    3,970
    BG Level
    7
    FFXI Server
    Lakshmi

    Quote Originally Posted by Tyrath View Post
    How do you get the magnification number from the mm again? :3 On the site it says 50x and 100x.
    Celesteon 114 EQ with 900 focal length right? Should be focal length/eyepiece

  20. #40
    RNGesus
    Sweaty Dick Punching Enthusiast

    Join Date
    Jan 2005
    Posts
    24,383
    BG Level
    10
    FFXIV Character
    Lenette Valkyr
    FFXIV Server
    Gilgamesh

    Ah I see. It's 1000mm.

Quick Reply Quick Reply

  • Decrease Size
    Increase Size
  • Remove Text Formatting
  • Insert Link Insert Image Insert Video
  • Wrap [QUOTE] tags around selected text
  • Insert NSFW Tag
  • Insert Spoiler Tag

Similar Threads

  1. Help on an astronomy question.
    By Xno Kappa in forum General Discussion
    Replies: 26
    Last Post: 2009-06-02, 02:39
  2. Astronomy Buffs [contest]
    By xerodok in forum General Discussion
    Replies: 34
    Last Post: 2009-04-03, 11:58