reflector vs refractor?

[brianb]

In My Humble Opinion.

IMHO this version is generally used by people who consider their opinion is not so humble at all i.e. I know what I'm talking about and I'm telling you.... Isn't "internet etiquette" a great thing?

Back to the ithread: a refractor in the 3" to 4" range makes a great "wide field" instrument for both visual use and imaging. It's small enough to use as a "grab and go" on an altaz mount, or to sit happily on a basic imaging mount like the HEQ5 or EQ6. A refractor is also the best instrument for solar work, where light grasp is not an issue, the turbulent seeing usual when the sun is shining makes a large aperture a waste of money and the "clean" light path saves worries about what happens to all that heat concentrated onto the secondary mirror.

But, in sizes of 6" and above, IMHO reflectors rule, Newtonians if light grasp & optical performance at a low price is all important, SCTs if money is available and portability is a serious consideration. Maks? well, those around 5" or 6" are nice for moon & planets, but the larger ones never seem to cool down properly, and the long focal ratio is not well suited to deep sky work.

Just my 2c worth ... I know that not everyone agrees with me, but I assure you that my prejudices are based on experience rather more than my experiences were coloured by prejudice.

[arad85]

For novices like myself it is not always clear what an abbreviation means. Where the first instance of an abbreviation is used, its full meaning should be stated: In My Humble Opinion (IMHO) etc...

A little thought would make it so much easier for newcomers.

Slightly OT (Off Topic ) but I think I'd agree for astronomy related things, but things like IMHO, AFAIK, FWIW, LOL etc... are general abbreviations used on the net. Given the net is so prevalent, I don't think we should assume this is peoples first visit to the net.

Google is but a click away and, IMHO, people should learn to use that for things they don't understand... It's a lot quicker for them, and a lot less frustrating for people who use the terminology on a daily basis.

Sorry if I sound harsh but it's up to users to fit in with the net, not the other way around, just as it is up to users of this forum fitting in here and not the other way around....

[haitch]

I assure you that my prejudices are based on experience rather more than my experiences were coloured by prejudice.

I Like your perspective on life. I shall try to remember that.

[Eyeball]

Slightly OT (Off Topic ) but I think I'd agree for astronomy related things, but things like IMHO, AFAIK, FWIW, LOL etc... are general abbreviations used on the net. Given the net is so prevalent, I don't think we should assume this is peoples first visit to the net.

Google is but a click away and, IMHO, people should learn to use that for things they don't understand... It's a lot quicker for them, and a lot less frustrating for people who use the terminology on a daily basis.

Sorry if I sound harsh but it's up to users to fit in with the net, not the other way around, just as it is up to users of this forum fitting in here and not the other way around....

I have just completed building a website for a local authority - it is built to the Web Accessibility Initiative (WAI) Triple-A Standard for accessibility. It is mouse and keyboard accessible, and caters for the blind and those with a range of other disabilities.

It is easy for a person who can use a mouse to go to Google. The Internet is not for the young and able bodied alone!

[arad85]

I have just completed building a website for a local authority - it is built to the Web Accessibility Initiative (WAI) Triple-A Standard for accessibility. It is mouse and keyboard accessible, and caters for the blind and those with a range of other disabilities.

It is easy for a person who can use a mouse to go to Google. The Internet is not for the young and able bodied alone!

And I have helped define the user interface and then project managed one of the digital switchover Help scheme set-top boxes that will be used by the blind and over 75s (and anyone else that wants it for £40!).... What of it

The issue here is not about disability access, but of crediting other users here with some understanding of the Internet, until they ask. I have, and will continue to help people where I can (including defining IMHO for someone on this forum a week or so back ), but it should be done when we are asked, not up front. That's all I'm saying....

Oh, and to me an acceptable answer to "but what does <insert acronym> mean" could be "Google is your friend my friend". After all, they do say give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime don't they

[lostinspace]

a great deal to mull over there peeps, thanks to all for your advise. lostinspace praying for clear skys.

[MishMich]

There you go - I've been thinking IMHO was 'In My Honest Opinion' for ten years now. That is because I have no humility I guess. My only prejudice is people, being a dedicated misanthropist. Common abbreviations like these tend to be taken for granted.

M.

[arad85]

There you go - I've been thinking IMHO was 'In My Honest Opinion' for ten years now.

It can mean either humble or honest - generally depending on the authority you carry on the subject being talked about

[nightspace]

Here's my take on this. Ideally, for visual use, you want two scopes: one for deep sky, one for planets. However, if you are starting out and you are not sure whether your interest in astronomy will last, it wouldn't be wise to spend too much.

So my advice would be to get a dobsonian 8" - 12" and use this for a year or so. It will show you all you need to see when starting out but it will be particularly good for deep sky objects.

Then, if you find you are getting enough cloud free nights, and if you want to take the interest further in astronomy further, purchase an apochromatic refractor (80mm) for i) grab and go, ii) very wide fields of view, iii) imaging. Of course, you'll also need to purchase a good mount as well.

I purchased a 12" Revelation dobsonian just before Xmas and I have only had it outside once. I caught a brief glimpse of the Pleiades a few weeks ago before the clouds blew over. The scope cost me £499. The way things are looking at the moment, I am glad I didn't spend any money on more expensive equipment. Still, if we get a long run of clear nights, my views might change!

One final thing: if the sky in your area is heavily light polluted, you won’t be able to realise the full potential of the dobsonian’s light gathering potential. I might then start with the refractor and forget about DSOs.

[lostinspace]

a great responce, a lot to digest, thanks everyone.. and for clearing IMHO up, i thought it was just me!

[Eyeball]

And I have helped define the user interface and then project managed one of the digital switchover Help scheme set-top boxes that will be used by the blind and over 75s (and anyone else that wants it for £40!).... What of it

The issue here is not about disability access, but of crediting other users here with some understanding of the Internet, until they ask. I have, and will continue to help people where I can (including defining IMHO for someone on this forum a week or so back ), but it should be done when we are asked, not up front. That's all I'm saying....

Oh, and to me an acceptable answer to "but what does <insert acronym> mean" could be "Google is your friend my friend". After all, they do say give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime don't they

I see you use a abbreviation/acronym tooltip for AFAIK, but as you know it is only mouse activated, unless you have taken the trouble to also make such tags keyboard accessible, as I have.

I provide the means for a user to access information - people do not have to ask someone else! You should show consideration for all users, and not assume they know the meaning of abbreviations/acronyms and other Internet terminology or should know the meaning.

Don't bother me go ask Google - what a mantra!

[arad85]

I see you use a abbreviation/acronym tooltip for AFAIK, but as you know it is only mouse activated, unless you have taken the trouble to also make such tags keyboard accessible, as I have.

No, I don't use it, the forum software automagically inserts it.... If we're worrying about abbreviations, should we also worry about defining other acronyms like LASER (light amplification by stimulated emission of radiation)

I provide the means for a user to access information - people do not have to ask someone else!

No, you are providing people with the information, not the method of accessing it. The method of accessing it is to show them how to use google.

Don't bother me go ask Google - what a mantra!

Yup. Worked for me for the last I don't know how many years. Been thanked a number of times for it too

[Eyeball]

No, I don't use it, the forum software automagically inserts it.... If we're worrying about abbreviations, should we also worry about defining other acronyms like LASER (light amplification by stimulated emission of radiation)

No, you are providing people with the information, not the method of accessing it. The method of accessing it is to show them how to use google.

Yup. Worked for me for the last I don't know how many years. Been thanked a number of times for it too

If a disabled user was forced to log on to Google because information could not be sourced locally and Google opened in a new window, that user loses the ability to use the browser's back button in order to return to the site. They become disoriented.

This conversation is off topic and I will not comment further, only to add that it is little wonder that the Internet is inaccessible to such a large percentage of people because of attitudes like yours. As I said before, it is not the sole domain of the young and abled bodied.

[kniclander]

@ Arad - FWIW I'm with you m8

[arad85]

If a disabled user was forced to log on to Google because information could not be sourced locally and Google opened in a new window, that user loses the ability to use the browser's back button in order to return to the site. They become disoriented.

Given what you've said about what you have recently implemented I'm amazed by this comment Why is it likely that a disabled user will become disoriented You are linking two completely different things (physical ability to use a keyboard/mouse vs ability to understand multiple windows) to try and justify your position! I'm really amazed....

A pc-competent physically disabled person who can't use their mouse will have their PC setup so that they can access everything off the keyboard (assuming they have full use of that) - the operating system has features designed into it to help people with disability use and navigate the windows system (alt-tab and MouseKeys for example). If they can't use the keyboard shortcuts, they will probably have something in place to enable them to switch these modes on/off at will.

The people who are likely confused by a new window opening are likely to be those who are not familiar with a PC - old, young, able bodied, disabled - it can be anyone. The way to deal with that is to educate them with what the internet can do, rather than wrap them in cotton wool and insulate them from it.

This conversation is off topic and I will not comment further, only to add that it is little wonder that the Internet is inaccessible to such a large percentage of people because of attitudes like yours. As I said before, it is not the sole domain of the young and abled bodied.

You should see some of the mail lists I'm on. Top posting (google it ) is always jumped on, sometimes in the rudest of ways, and although I don't particularly like the style of the mailing list, or the tone that some people use on it but I get useful information from it, so I abide by the rules on there. Just as I abide by the rules and conventions in place here. If I don't understand something, I'll ask, but I'm equally as likely to google something (actually probably more likely to) rather than ask. I can't remember how many times I've looked up peoples 'scope specs on google to help them with something like an eyepiece purchase.

What this and other boards are is a community. Those communities abide by certain rules (as evidenced by the recent MishMich thread about what was acceptable and the thread asking about whether other optical passions such as microscopy should be catered for with a separate forum). I've never been part of one where the up front rule was to spell everything out as you need to assume everyone is a complete Internet newbie and I've also never been part of one that is so rude that simple questions which can be referred to google are just jumped on and the person made to feel an idiot (although they do exist!!). I'm here often enough that I don't want to see this place go to either of these extremes either...

[MishMich]

Pointless discussion. The internet works the way it works because that is the way it is and that is how it has developed. How did people ever manage to surf the web before Windows? We didn't have browsers and buttons and fluff to get us around. We had a black screen with text on it. Many of the abbreviations were there way before we had fluffy Windows browsers, primarily because everything was done as command type, and when you spend most of your time at the console typing, you want quick abbreviations to save typing.

If people don't like the way the internet works, nobody is forcing them to use it, they can leave it any time they like. I suspect that the interfaces have become much more accommodating of people with disabilities since those days. The acronyms and abbreviations are a fact of life, like SPAM, and other things we might wish were not the case on the internet. The problem is it started out as a techie's tool/toy, and now anybody can log on, even people who are semi-literate. At one time only adults used it, now it is seen as a playground for children, and adults are expected to conform to standards determined by what is appropriate for children. By all means, use the internet - but please don't try and make us stop using it the way some have been using it for a long time.

M.

M.

[Ogri]

I've been building and supplying computers for over 20 years, to able bodied and disabled people.

I make it perfectly clear to whoever they may be, that I encourage them to experiment, I encourage them to take the sides off and look inside, and if they mess up, just tell me what they have done and I can put it right.

They understand, whenever I leave their premises, that the only way they can really hurt their machine, is to chuck a bucket of water over it, and otherwise, 'do as the kids do, press the buttons, click the mouse, play the card games to get familiar with the actions necessary, and have fun with it' and 'If you ain't sweating, you ain't learning'.

I haven't had to do a support call for other than repairs to virus damage, for more years than you might believe. People get on with it and manage to do it (and I haven't made any enemies yet, customers tell me to pop in for a cuppa and a chat whenever I am near, and they will phone me for advice on computer stuff prior to them upgrading, so I sort components for them to have a look at and link them to customer reviews so they know exactly what they are getting).

There are many options that can be customised cheaply for disabled people, such as the Nostromo N51 which can be programmed for many convenient functions. Some get on well with it (though I can't say I do myself, but if you have difficulties, they don't cost the earth, and are worth a try).

Given the chance and the peace and quiet without people fussing in their face all the time, to get on with sorting things out for themselves, disabled people usually do a darned fine job of coping all on their own (and get the sense of achievement out of it that they deserve to be able to experience).

I say that as someone that is also disabled.

[ombos]

Well, what a Palaver, I now understand why the so called 'Nanny State' exists. If every time you wrote an abbreviation we had to write it in full why the heck would we be using abbreviations for in the first place. Now IMHO 'IN MY HUMBLE OPINION' if you use forums any forums its YOUR yes YOUR responsibility to find out what the abbreviation mean, do you think the rest of us were born with the capability to know what they all stand for? NO we find out for ourselves, oh yes it can be done so just find out yourself and stop moaning about it, in the time it takes you to write about not understanding abbreviations you could have found out what it means 100 times! And I'm 50 and still feel young and yes I have only one eye am I disabled? NO I'm not, for goodness sake lets all just get a life, and at the end of the day if you dont like what people have to say in reply to your comments dont blog my friend, its the nature of the beast and in fact life its self, oh a bit deep there hey, so come on blog away and respect each others views even when you dont agree with them.

[arad85]

Have you missed the followon thread http://stargazerslounge.com/lounge/95467-online-social-responsibility.html

He threw his toys out of the pram and asked to be removed from the user list.

[ombos]

Cheers for that yes I did miss it, I find that really sad, but we live in world where we all have different views and some must feel that they are victims and hard done by, but its still sad that someone left for whatever reason.

[MishMich]

Anyway, seeing we got trolled right off the subject. My own view is quite simple. Refractors are much better that reflectors - because I like them.

M.

[Mikea]

Anyway, seeing we got trolled right off the subject. My own view is quite simple. Refractors are much better that reflectors - because I like them.

M.

Good enough! Can we have the next question please?

[Krys]

From a newbie perspective, I'm glad I went with a refractor, as they are very easy to maintain, are durable and portable. If you have to travel to get to your observing site, that matters a lot. If I had a large, dark garden with an open horizon, I'd probably go for a Newtonian As it is, when I upgrade it'll probably be a Mak-Cas, and I do feel these types offer the best of both worlds in terms of aperture per £, without being unwieldy to move and set up.

[englishmike]

How about some practical points, heres something I found that worked for me :

"OK so if you are new and, completely confused about what telescope is best, Newtonian or reflector, I don't blame you.  I was just the same so I decided to buy a few telescopes trying them and sell them on until I got to the one that suited me most. I found refractors were great but I didn't like having the tripod up at nearly full extension to get a comfortable viewing angle. Yes you can use a diagonal which helps , making the image  the right way up but left and right is still swapped and now it will not match some of the star charts which are all up side down and left to right ! The tripod being  high  gives more shake and needs a longer time to settle. The Newtonians are great, they don't suffer as much shake, you can sit comfortable, easily adjust the eyepiece to suit your height and that works well for me. The newts do need time to cool down to minimise that “boiling” image but I leave mine out in the shed which helps a lot. Always buy a branded scope like TAL MEADE HELIOS , sky watcher stay away from the cheap china made ones they really are not that good. Ask me how I know ! But actually you wouldn't know unless you compared them against a known good scope. A telescope with a parabolic mirror , usually indicated by a P in the model number, should give better sharper images as its mirror focus point is a single point (called diffraction limited) where a Newtonian the focal point is more spread. Having said  that a Newtonian with an F8 mirror is on the verge of it being as sharp as a parabolic where say f4/f6 isn’t and could be a bit fuzzy. That’s why I suppose the  Chinese unbranded short tube telescopes didn’t seem as sharp. Also a lot of talk about better contrast in refractors, after trying out lots of different types I really never noticed it that much."

[ronin]

Krys, Mike, you are replying to a post that was Jan 22, 2010.

4 years is a bit old to resurrect.

Checking a few user names many have not posted on SGL for 3 years.