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reflector vs. refractor

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#126 erik

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Posted 12 February 2004 - 08:55 PM

hi john, no offense taken. i could use some more time under the stars as well(but the weather doesn't seem to think so).i'm sure beginners could find a better source than any of us as well, but someone considering a scope purchase may like hearing what other people use and their preferences(i know i do). and in contradiction to what pete said, i'm not trying to get the last word in, i just think that this is an interesting thread, as are most of the threads on cloudy nights.i don't know, maybe my sense of humour is too blunt(and maybe pete's comments were just that famous east coast jersey humour coming through!).anyway, i certainly don't want to offend anybody either.so if somebody else wants to have the last word, it's all yours.(unless you say something that i can't resist responding to.) !#?#@!, there goes my sense of humour again!

#127 Stacy

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Posted 12 February 2004 - 09:12 PM


Refractors are better. :roflmao:

#128 pete

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Posted 12 February 2004 - 09:21 PM

John / Erik
I am hardly offended. For me it’s more along the lines of grateful to have the pleasure of this dialog. John I grabbed that quote from something you had posted on a different thread, it was my way of conveying to you that I have read many of your posts. I surfed, this Forum many months before I registered and posted comments. I feel from reading various posts I have some sense of familiar, it sounds bizarre but I view the forum as my “cyber buddy’s in astronomy”. Having friends and family look through my scope over the years, among them only one that has emerged a follow amateur astronomer willing to stay out until 3-4 in the morning in the cold. I built my first scope from scratch without any prior knowledge of optics. I accomplished this by reading what people had to say on the topic, on the net. I built the scope dragged it outside having absolutely no knowledge of the sky .I set the scope on one bright object after another until I came to one that revealed it self as a disc. I also observed several stars next to it. Definitely a planet I thought to my self. I examined it more closely and noticed two diagonal bands. What a rush... VVVeeeenuuss, it’s Venus I shouted aloud. Loud enough to wake my wife, it was 2am. I went on to rediscover countless other object, even a comet (IZ) on my own without the use of star charts. Seek the thrill others before my time had experienced. I did this for a good year. Contaminated by all the reading I was doing, and decided to go back and identify the objects I viewed. All were Messier objects with the exception of the 5 naked eye planets and comet I Z. Anyway having a place to share the experiences and what I have learned is as important to me as the astronomy itself. I would like to extend a word of appreciation to all that participate and those directly responsible for this site.

Sorry Erik, this thread may have to go on until the sun goes red giant. I was out to SF CA several times, the water is to cold for my blood and it’s so bright. I had to walk around with my hands cupped around my eyes until I found a suitable pair of sunglasses. Does this condition effect your night vision? Is this a contributing factor when considering your partiality towards the light gathering properties of a reflector vs. refractor? Pete


#129 john-AZ

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Posted 12 February 2004 - 09:54 PM

For what it is worth, I found this to be an interesting perspective on the reflector vs. refractor debate in spite of some price point issues:
http://www.weatherman.com/york.htm
John




#130 pete

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Posted 12 February 2004 - 10:15 PM

John
The reflector smoked the views of his refractor like a cheap cigar. I guess that’s one way to put it…Pete


#131 imjeffp

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Posted 13 February 2004 - 10:03 AM

VVVeeeenuuss, it’s Venus I shouted aloud. Loud enough to wake my wife, it was 2am.

Not at 2:00 a.m. was it Venus. Sounds like Jupiter to me. Even better!

#132 pete

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Posted 13 February 2004 - 11:06 PM

That's right it was Jupiter and the stars next to it were moons. The diagonal lines were Jupiter’s cloud belts. Three years ago with the exception of the moon and Saturn, I would have identified all the plants as Venus. The Knowledge that Venus is visible in the winter at dusk and sets a shortly after the sun, came later. It took me a while to realize the planets followed the same path along the sky as the Sun. Even longer yet the Earth was rotating around a point in the sky behind my head. My time leading up to first light dealt with reflector design and assembly gathered from the telescope making ring on the net. Using the instrument was a different journey. I have strayed far off the topic with story telling and concerns of who is offending whom. I have serious questions and would like to get back to the subject.

We have discussed central obstruction in reflectors as a limiting factor when compared to a reflector. My question is… does the light loss and scatter because of multiple lenses becomes a factor to consider in high end Refractors. I understand some MFG are using optical oil between lens, does this oil absorb light, and does light transmission through the oil, degrade over time? I s better to send light through a lens or bounce it off a mirrored surface? When considering design superiority I believe this is important to discuss. Pete
:question:

#133 wilash

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Posted 14 February 2004 - 02:11 AM

That's right it was Jupiter and the stars next to it were moons. The diagonal lines were Jupiter’s cloud belts. Three years ago with the exception of the moon and Saturn, I would have identified all the plants as Venus. The Knowledge that Venus is visible in the winter at dusk and sets a shortly after the sun, came later. It took me a while to realize the planets followed the same path along the sky as the Sun. Even longer yet the Earth was rotating around a point in the sky behind my head. My time leading up to first light dealt with reflector design and assembly gathered from the telescope making ring on the net. Using the instrument was a different journey. I have strayed far off the topic with story telling and concerns of who is offending whom. I have serious questions and would like to get back to the subject.

We have discussed central obstruction in reflectors as a limiting factor when compared to a reflector. My question is… does the light loss and scatter because of multiple lenses becomes a factor to consider in high end Refractors. I understand some MFG are using optical oil between lens, does this oil absorb light, and does light transmission through the oil, degrade over time? I s better to send light through a lens or bounce it off a mirrored surface? When considering design superiority I believe this is important to discuss. Pete
:question:


Yes, light is absorbed and scattered when it hits an optical surface - whether a mirror or lens. A single element has two surfaces. Two elements in one group have three surfaces. An air or oil spaced double has four surfaces. Then the eyepiece adds to the problem. As you can see, the simplicity of the reflector MAY have some advantages. The more money you pay for the optics, the better the transmission is or should be. The medium of the optics is not a problem - oil or glass. The oil should last the life-time of the scope - it is not corn oil. :winky:

#134 Guest_**DONOTDELETE**_*

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Posted 17 February 2004 - 06:53 PM

I have an 8" dobsonian, and a 70mm refractor, both pretty decent quality. I am wondering how the 8"sct would compare with the 8"dob. I took the moon pic with the logitech webcam pro 3000 and a scoptronix adapter through the 8" Hardin Optical dob.

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