hey i have a question, im considering getting an 8 inch Dobsonian reflector and im just wondering what the lens size (6mm, 8mm, 10mm, 17mm and so on...) effects the image. like, what size lens is best for viewing planets, stars and so on.
@Universound57 - My 8" SCT is an f/10 scope. The dob will be about f/5 - or half the magnification per eyepiece, but twice as bright because you will see twice as much of the sky with the same eyepiece as you would in an f/10 scope. My favorite eyepieces with the 8" f/10 SCT have 15mm - 30mm focal lengths.The equivalent magnification in an 8" f/5 Dob will require 7.5mm - 15mm focal length eyepieces or, and what can save you money and is easier on the eyes, a 2x barlow, and 15mm-30mm eyepieces.
I definitely agree with you Jason. Jupiter and the other gas planets are like brroms and dust mops, picking up so much of the stray comets and no telling how many asteroids that are on route toward the sun. Even the moon has helped us out enormously. On its dark side is an impact crater 2250 km wide and 12 km deep. If that object had struck the earth, would we be here today?
@jdastro Did you know Jupiter actually puts us in danger too, with its gravity pulling asteroids on the other side of us towards jupiter but they might it us!
In the description you point out that this reminds us how vulnerable we are. I completely agree with you for sure. An impact is a very serious threat, and one of the only natural disasters we have the technology to stop right now (if we figured out exactly how to implement our current technology). BUT... The gas giants actually run interference for us terrestrial planets. They work as a cosmic vacuum, picking up all the rocks headed are way. Just an interesting fact. This should be scary tho hah
F/10 SCT - Celestron Nexstar 8i. I add a barlow plus 32mm eyepiece. Then record video with 10x on a camcorder. Not always get good imaging. Need the planet to be very high for seeing to be good.
good things about telescopes is if say there is a impact on say jupiter,mars you dont have to look on tv you can just point your telescope and have a look for yourself.
Hi Joe - Will try yo answer that. I have actually wondered about that myself and , depending on the power, the apparent size is variable from a pecan to an orange on the ground from a standing position. What I did was keep both eyes open and projected the scope view onto the ground near the foot of my tripod. Trick with camcorder video is I can zoom in about 5x more than what the eye sees. I made this video at about 140x.
Wonderful view. I have a question. When you view Jupiter through an 8 inch, how big does the planet appear? If you were to hold any object two feet in front of your face, what would be most comparable to the the size of the image?
Hope I make sense to you. I'm looking into buying a telescope. I mean, even if the image was the size of a penny, if I can make out the red dot and some bands, I'll be satisfied.
@JokinJoe The aperature actually wont affect how big the object is just the amount of detail but the focal length of the scope and eyepiece will make the object apear smaller or larger. Also a barlow can amke an image look 2 times as big.
@JokinJoe i can make out it pretty good during a new moon phase with my 8 inch dob reflector. 25mm with a barlow 2x's works pretty good. it's about the same size as a pencil erazer on mine. looks beautiful though, it's four moons included
hey i have a question, im considering getting an 8 inch Dobsonian reflector and im just wondering what the lens size (6mm, 8mm, 10mm, 17mm and so on...) effects the image. like, what size lens is best for viewing planets, stars and so on.
Universound57 4 months ago
@Universound57 - My 8" SCT is an f/10 scope. The dob will be about f/5 - or half the magnification per eyepiece, but twice as bright because you will see twice as much of the sky with the same eyepiece as you would in an f/10 scope. My favorite eyepieces with the 8" f/10 SCT have 15mm - 30mm focal lengths.The equivalent magnification in an 8" f/5 Dob will require 7.5mm - 15mm focal length eyepieces or, and what can save you money and is easier on the eyes, a 2x barlow, and 15mm-30mm eyepieces.
jdastro 4 months ago
the initial shoemaker-levy explosion was bigger than the earth.
italicslob 1 year ago
I definitely agree with you Jason. Jupiter and the other gas planets are like brroms and dust mops, picking up so much of the stray comets and no telling how many asteroids that are on route toward the sun. Even the moon has helped us out enormously. On its dark side is an impact crater 2250 km wide and 12 km deep. If that object had struck the earth, would we be here today?
jdastro 1 year ago
@jdastro Did you know Jupiter actually puts us in danger too, with its gravity pulling asteroids on the other side of us towards jupiter but they might it us!
shamthemanSMBMG 10 months ago
In the description you point out that this reminds us how vulnerable we are. I completely agree with you for sure. An impact is a very serious threat, and one of the only natural disasters we have the technology to stop right now (if we figured out exactly how to implement our current technology). BUT... The gas giants actually run interference for us terrestrial planets. They work as a cosmic vacuum, picking up all the rocks headed are way. Just an interesting fact. This should be scary tho hah
jasonroxorz 1 year ago
F/10 SCT - Celestron Nexstar 8i. I add a barlow plus 32mm eyepiece. Then record video with 10x on a camcorder. Not always get good imaging. Need the planet to be very high for seeing to be good.
jdastro 1 year ago
this is amazing! i have an 8 inch dob. and cannot get this view. what are your optics?
patrickchand666 1 year ago
omg ! :D
BeBoACfan 1 year ago
good things about telescopes is if say there is a impact on say jupiter,mars you dont have to look on tv you can just point your telescope and have a look for yourself.
gara9100 1 year ago
cool stuff 8 inch seems a decent scope
markuslebt 2 years ago
Hi Joe - Will try yo answer that. I have actually wondered about that myself and , depending on the power, the apparent size is variable from a pecan to an orange on the ground from a standing position. What I did was keep both eyes open and projected the scope view onto the ground near the foot of my tripod. Trick with camcorder video is I can zoom in about 5x more than what the eye sees. I made this video at about 140x.
jdastro 2 years ago
Wonderful view. I have a question. When you view Jupiter through an 8 inch, how big does the planet appear? If you were to hold any object two feet in front of your face, what would be most comparable to the the size of the image?
Hope I make sense to you. I'm looking into buying a telescope. I mean, even if the image was the size of a penny, if I can make out the red dot and some bands, I'll be satisfied.
JokinJoe 2 years ago
@JokinJoe The aperature actually wont affect how big the object is just the amount of detail but the focal length of the scope and eyepiece will make the object apear smaller or larger. Also a barlow can amke an image look 2 times as big.
hiian123 1 year ago
@JokinJoe i can make out it pretty good during a new moon phase with my 8 inch dob reflector. 25mm with a barlow 2x's works pretty good. it's about the same size as a pencil erazer on mine. looks beautiful though, it's four moons included
casper191985 1 year ago