Comments for TelescopeEyePiece.org http://www.telescopeeyepiece.org Cool Telescope Eyepieces Fri, 30 Jul 2010 21:50:14 -0600 http://wordpress.org/?v=2.9.2 hourly 1 Comment on Meade Plössl 9mm 1.25-Inch Illuminated Wireless Reticle Eyepiece for Telescope by Victoria Miller http://www.telescopeeyepiece.org/meade-plossl-9mm-1-25-inch-illuminated-wireless-reticle-eyepiece-for-telescope/comment-page-1/#comment-3531 Victoria Miller Fri, 30 Jul 2010 21:50:14 +0000 #comment-3531 This might be a great item for the very well experienced, but the item is very difficult to recenter if you move any of the set screws the smallest amount. I inadvertently tightened a thumb screw when I replaced the batteries. I have never been able to accurately realign the center target, and $90 is going in the trash. I cannot see any reason to have such a wide range of adjustments possible on an eyepiece used to center for initial alignment to begin with. Additionally, there was so much lubricant on the recitile frame, a tiny amount smeared when moving the adjustment screws. There is now a distortion when illuminated. I am switching to an Orion with a fixed rectile. Rating: 2 / 5 This might be a great item for the very well experienced, but the item is very difficult to recenter if you move any of the set screws the smallest amount. I inadvertently tightened a thumb screw when I replaced the batteries. I have never been able to accurately realign the center target, and $90 is going in the trash. I cannot see any reason to have such a wide range of adjustments possible on an eyepiece used to center for initial alignment to begin with. Additionally, there was so much lubricant on the recitile frame, a tiny amount smeared when moving the adjustment screws. There is now a distortion when illuminated. I am switching to an Orion with a fixed rectile.
Rating: 2 / 5

]]> Comment on Meade Plössl 9mm 1.25-Inch Illuminated Wireless Reticle Eyepiece for Telescope by Markus Rosar http://www.telescopeeyepiece.org/meade-plossl-9mm-1-25-inch-illuminated-wireless-reticle-eyepiece-for-telescope/comment-page-1/#comment-3530 Markus Rosar Fri, 30 Jul 2010 21:20:21 +0000 #comment-3530 looks good at the first glance. I would have hoped for a somewhat nicer packaging as it only comes in a plastic bag without an ezecap on the side where you look in. probably good quality but would have excpected nicer packaging for 80$. Rating: 4 / 5 looks good at the first glance. I would have hoped for a somewhat nicer packaging as it only comes in a plastic bag without an ezecap on the side where you look in. probably good quality but would have excpected nicer packaging for 80$.
Rating: 4 / 5

]]> Comment on What is the magnification of a telescope with a focal length of 200 cm,with an eyepiece of focal length 35? by wallyrush http://www.telescopeeyepiece.org/what-is-the-magnification-of-a-telescope-with-a-focal-length-of-200-cmwith-an-eyepiece-of-focal-length-35/comment-page-1/#comment-3240 wallyrush Tue, 08 Jun 2010 06:34:08 +0000 #comment-3240 Your answer is here... http://www.skyandtelescope.com/equipment/basics/3303926.html?page=2&c=y Wally Your answer is here…
http://www.skyandtelescope.com/equipment/basics/3303926.html?page=2&c=y
Wally

]]> Comment on What is the magnification of a telescope with a focal length of 200 cm,with an eyepiece of focal length 35? by Search first before you ask it http://www.telescopeeyepiece.org/what-is-the-magnification-of-a-telescope-with-a-focal-length-of-200-cmwith-an-eyepiece-of-focal-length-35/comment-page-1/#comment-3239 Search first before you ask it Tue, 08 Jun 2010 06:21:09 +0000 #comment-3239 Divide the focal length (in millimeters) by the focal length of the eyepiece (which is always stated in millimeters). So 2000/35 = 57x. Your computer should have a calculator utility. Feel free to use it. If you are looking to purchase an eyepiece to maximize your field of view, I recommend that for any eyepiece longer than about 32mm the barrel should be 2" rather than 1.25" (yeah, barrel sizes are still stated in inches), otherwise you'd be better off with a 30-32mm eyepiece because a longer focal length in a 1.25" barrel will have the field of view cut-off and narrowed in spite of the lower magnification. In other words, without going to a larger barrel eyepiece there will be no gain in field of view going longer than 32mm. Eyepiece design has some bearing as well, but for our purposes we'll assume Plossl eyepieces. Divide the focal length (in millimeters) by the focal length of the eyepiece (which is always stated in millimeters). So 2000/35 = 57x.

Your computer should have a calculator utility. Feel free to use it.

If you are looking to purchase an eyepiece to maximize your field of view, I recommend that for any eyepiece longer than about 32mm the barrel should be 2″ rather than 1.25″ (yeah, barrel sizes are still stated in inches), otherwise you’d be better off with a 30-32mm eyepiece because a longer focal length in a 1.25″ barrel will have the field of view cut-off and narrowed in spite of the lower magnification.

In other words, without going to a larger barrel eyepiece there will be no gain in field of view going longer than 32mm. Eyepiece design has some bearing as well, but for our purposes we’ll assume Plossl eyepieces.

]]> Comment on What is the magnification of a telescope with a focal length of 200 cm,with an eyepiece of focal length 35? by Doc89891 http://www.telescopeeyepiece.org/what-is-the-magnification-of-a-telescope-with-a-focal-length-of-200-cmwith-an-eyepiece-of-focal-length-35/comment-page-1/#comment-3238 Doc89891 Tue, 08 Jun 2010 05:41:50 +0000 #comment-3238 200 cm or mm? 200 cm = 2000 mm - thats fairly long. Divide 2000 by 35mm - about 60 power? work it out with a calculator 200 cm or mm? 200 cm = 2000 mm – thats fairly long. Divide 2000 by 35mm – about 60 power? work it out with a calculator

]]> Comment on Why are objects tilted when I look through the eyepiece on my telescope? by Geoff G http://www.telescopeeyepiece.org/why-are-objects-tilted-when-i-look-through-the-eyepiece-on-my-telescope/comment-page-1/#comment-3226 Geoff G Sun, 06 Jun 2010 02:34:07 +0000 #comment-3226 Yours is a Dob, if I remember correctly. If the eyepiece were located on top of the tube or 90° away from that, on the side, the image would be exactly inverted. But since your eyepiece is probably around 45° away from the top, the image is rotated by that amount. Since there's no right way up in space, we all just get used to the orientation. At least with a Dob, the angle is always the same; on an equatorial mount, a Newtonian's eyepiece orientation is all over the place! Yours is a Dob, if I remember correctly. If the eyepiece were located on top of the tube or 90° away from that, on the side, the image would be exactly inverted. But since your eyepiece is probably around 45° away from the top, the image is rotated by that amount. Since there’s no right way up in space, we all just get used to the orientation. At least with a Dob, the angle is always the same; on an equatorial mount, a Newtonian’s eyepiece orientation is all over the place!

]]> Comment on Why are objects tilted when I look through the eyepiece on my telescope? by screaming monk http://www.telescopeeyepiece.org/why-are-objects-tilted-when-i-look-through-the-eyepiece-on-my-telescope/comment-page-1/#comment-3225 screaming monk Sun, 06 Jun 2010 02:21:39 +0000 #comment-3225 Is it possible that your diagonal is 'swung around' and oriented that way! It would be like if I lifted one side of my monitor. Is it possible that your diagonal is ’swung around’ and oriented that way! It would be like if I lifted one side of my monitor.

]]> Comment on Why are objects tilted when I look through the eyepiece on my telescope? by RickB http://www.telescopeeyepiece.org/why-are-objects-tilted-when-i-look-through-the-eyepiece-on-my-telescope/comment-page-1/#comment-3224 RickB Sun, 06 Jun 2010 01:27:20 +0000 #comment-3224 First, the objective element (which is either the lens in the front or the big mirror in the back, depending on what kind of telescope you have) will cause the image to rotate by 180° -- that's just the way lenses/mirrors work. Then, before it reaches your eye, the light is reflected at right angle by a mirror or prism (so it comes out perpendicular to the tube). This adds an additional tilt to it, whose angle depends on the angle of the mirror or prism (which tends to change as you re-orient the telescope to look at different parts of the sky). First, the objective element (which is either the lens in the front or the big mirror in the back, depending on what kind of telescope you have) will cause the image to rotate by 180° — that’s just the way lenses/mirrors work.

Then, before it reaches your eye, the light is reflected at right angle by a mirror or prism (so it comes out perpendicular to the tube). This adds an additional tilt to it, whose angle depends on the angle of the mirror or prism (which tends to change as you re-orient the telescope to look at different parts of the sky).

]]> Comment on Why are objects tilted when I look through the eyepiece on my telescope? by Simmi http://www.telescopeeyepiece.org/why-are-objects-tilted-when-i-look-through-the-eyepiece-on-my-telescope/comment-page-1/#comment-3223 Simmi Sun, 06 Jun 2010 00:49:14 +0000 #comment-3223 maybe it isnt alligned correct(and they look that way because of deffraction) maybe it isnt alligned correct(and they look that way because of deffraction)

]]> Comment on Why are objects tilted when I look through the eyepiece on my telescope? by onegater http://www.telescopeeyepiece.org/why-are-objects-tilted-when-i-look-through-the-eyepiece-on-my-telescope/comment-page-1/#comment-3222 onegater Sun, 06 Jun 2010 00:45:22 +0000 #comment-3222 Your head might be tilted when you look through the eyepiece. Your head might be tilted when you look through the eyepiece.

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