What's the average aperture these days?

[Volans]

G'day All,

The boss and I were discussing mirror sizes the other day and he was telling me stories about grinding his own 6" when he was a kid. The question came up: What is the average size of aperture these days? Back in the 60's a 6" was the norm or maybe an 8" and there was only one 12" in Queensland and the Bundaberg 19" was colossal beyond belief (or so the boss claims).

Peter.

[matt]

Appears to be be around the 10" mark...

Although that might all be about to change with quite affordable larger apertures coming on the market.

But you still have the issue of portability for most people who don't want a scope that breaks down into individual components.

[wavelandscott]

I think that average will fall in the 8-10 in...depending on how you calculate "average"...remember there are lots of relatively "little" refractors that will bring the average down...

[janoskiss]

Peter, I think a better poll question would have been: "What is the aperture of the scope you use most often?" and then taking the average of all asnwers. :P Mine is an 8". But the average amongst those who are taking the hobby at least semi-seriously is probably 10". Although like Scott says the refractor faithfuls might bring that figure down. :shrug: ... and if you include all the wobbly department store 60mm refractors around, then the average is probably around 60.02 mm. :P

[stinky]

I wouldn't call an 8" refractor "little" - I doubt there are too many represented at IIS.

Perhaps the results are best interpreted in relation to newtonians as there is no option for smaller than 8"?

[iceman]

You can get 6" GSO dobs, and smaller 4.5" newts as well (tasco and others).

But with the price of an 8" so cheap ($399), it's almost a no-brainer.

[Starkler]

Well my next scope purchase is very likely to be a 130mm newt on a Vixen porta mount, so go figure :P
:lol:

[asimov]

I remember your boss's era quite clearly Peter.

Yep, average size back then was 6" but if you had an 8" you were classed as 1 rung up the ladder from the norm. If you had a 10-14" Well! you were in a league of your own almost.

I dreamt of having an 8" when I was 12 & by the time I was 13 I ended up grinding an 8" & building the rest between me & my dad.

Those were great times back then, flipping thru Sky & telescope & Astro Optical Supplies Celestron catalogs & the likes, & seeing those HUGE 8 & 10" SCT's etc. :)

I reckon today the norm, or average size is 10"

[Muddy Diver]

Hey....where do I vote?:shrug:

[asimov]

Right up the top of the page Muddy.

[g__day]

You don't seem to have a spot for 11" scopes!

Also its kinda specific to your type of scope, a solar scope is likely to be tiny compared to a apo-refractor, which in turn is bound to be generally smaller then reflectors or Schmit Cassegrains, which will likely be smaller than dobsonians. All these scopes have differnet purposes, so to lump them all together in such a general question doesn't achieve much does it?

Too if you're drifiting into astro-photography your buget could easily be spread 50% mount and controller, 25% OTA and 25% CCD. So purpose can easily skew your results downwards towards quality over aperature.

The only thing you can say about an average is 50% are below it and 50% are above - that's what defines and average, A standard deviation or distribution curve/s focuses alot more useful attention.

[matt]

just have a bit of fun and vote, eh?:thumbsup:

[Striker]

Dam...looks like My C11 has missed out.

[asimov]

:thumbsup: @ Matt

[Volans]

G'day All,

Well it seems this poll has illicited a responce that I had not anticipated. Maybe if I give some background to the reason for my question then it will become clearer as to why I asked it.

The store room at the planetarium was in need of a huge clean up and in this process we came across the ex-curator's 6" Newtonian. The primary needs to be re-coated, the rack and pinoin is stiff, the spider is bent and the focuser can only hold the old 0.96" eyepieces. The ex-curator did not want it and this all started the reminicing that I mentioned in my original posting for this thread.

Earlier in the day the boss and I were putting the final touches on to the 4 week astronomy course we intend to run in May. The boss came up with the idea of bringing his 8" mirror in and I replied that I would bring my 13.1" in as well. We also found two discs of wood, 22" and 30" respectively, in the clean out. So we decided to make a small display for the students in the astronomy course that would dramatically show the difference in light gathering capacity between the 6, 8, 13.1, 22 and 30.

This then prompted the question I asked for the poll. Becuase it was just my boss and I discussing the matter, I decided to ask a wider audience, i.e, the members of IIS.

If, in my first attempt at a poll, I have failed to phrase the question properly, missed out on a specific aperture, seemed to favour reflectors over refractors and offered a poll that is statistically inept - then I do apologise.

Clear and steady skies to you all,

Peter.

[Muddy Diver]

Hey Peter and Asi

I was just kidding. If you notice my signature my 4" Celestron doesn't even qualify me to vote! :rofl:

Barry

[matt]

Don't worry about it, Peter.

I thought it was a good general question and the reference to your boss "grinding" his own 6" clearly suggested to me you were talking about reflectors.

If folks want something more technically involved and more specific perhaps they should put up their own survey/post rather than seeking to modify one that's already up and running (IMO).

Funny how things go... sometimes:thumbsup:

[g__day]

Good luck Peter, personally I think your question was far too general if you wanted to seriously sample a distribution. Other people might value this spectrum of data.

The only poor question is the one not asked.

[Robert_T]

Hey Asi, I could have written this about myself, but was lagging you in the ATM department by a few years :D

Hi Peter,I was in BBerg recently, the dome of that collossus is still there and I expect so is the scope (I only drove by with screaming kids in the back from a swim at Woodgate). Your boss is right though, 20-30 years ago Queenslanders used to talk in hushed tones of this mythical goliath telescope up north in the canefields!

cheers,

[seeker372011]

I happened to be speaking to Lee Andrews at Andrews Communications yesterday and his view was that 8 inches reflectors are declining in sale worldwide

[mickoking]

There are probably lots of smallish scopes out there so I believe the average size is probably between 100mm and 150mm. Larger 'scopes seem to get more attention so that probably skews the perception on telescope aperture.

[g__day]

It would also vary not just by use or purpose but very significantly by age, as scope prices per aperature have absolutely crashed over the last 4 years. So if your budget was say $5,000 you'd be in a very different aperature category if you bought today vs a few years back.

Even within this budget, with say a SCT, if you had a buget and weren't interested in astrophotography you definitely have shifted your budget towards larger aperature and lesser mount, but the converse also applies!

Also it would be very different result if you counted by numbers of scopes or percentage of total dollars spent. I mean how many cheap 3" or smaller department store toys are there? Tens of millions probably, this would totally skew your average, mean and median. Do you include observatory class scopes in this number too, or just serious amateur scopes by volume (not cost) and ignore all sub $800 scopes and all scopes over $25,000 as being outliers to your study?

[ving]

well with recent price drops the 10" has become the starting point i guess... its not that the 8" is bad, but more to do with pricing vs aperture. my 8" was nearly $600 when i got it, now you can just about get a 10" for that i think.

i picked 8"-10" because although alot of scopes over 10" are sold, i'd say the department store (and ebay) 70mm-78mm reflectors out sell everything. :)

of course the highest selling refractor size would be 60mm :)

[Volans]

G'day All,
Many thanks for your replies :thumbsup:( keep 'em coming!) I'm glad I conducted this opinion poll becuase it appears that I am in the minority and I honestly thought the average size would have been a bit larger, maybe getting up into the 12" area but I'm happy to change my view and revise it downwards.



g__day, this opinion poll was thought up with only amateur 'scopes in mind hence the posting to an amateur community. At the planetarium we have an observatory class telescope that is 6" in size. It is a very fine Zeiss Coude refractor that I use regulary to show guests the wonders of the sky over light polluted Brisbane :rolleyes: . That 'scope was installed by Zeiss 28 years ago when the planetarium was built. Would I count that 'scope in with amateur 'scopes? No, because it is a very odd beast and weighs just under 800kg...not exaclty your normal amateur setup. As to ignoring 'scopes below $800 and those above $25,000 in the study...the answer to that is simple.

It was never meant to be a concerted mathematical study in the first place.

Averages, means and medians, bell curves and distrubution plots, the number of 'scopes per capita divided by eyepiece size multiplied by the size of the Airy disk and subtracted from the colour of your eyes last birthday plotted against Galileo’s shoe size....all of that (well some of it :P) has to do with statistics and this opinion poll has nothing to do with that at all. It was never meant to be a serious, mathematically laid out, number crunching poll.

All I ever wanted from people was their opinion.

Peter.

[asimov]

And your getting their opinions Peter, your getting them! ;)

Should start a thread about the 'good ol' days' then Robert & I can ramble on to our hearts content! :D

[g__day]

Can't you tell I'm just having fun!?!

Personally I think you do have to break it down by class of scope and even if its someones first, second or third scope.

If you only sold one 100" and one hundred 1" scopes what's your average (by value, aperature size/total sales, # of scopes, etc). It's kinda vague.

Personally folk buying their first goto scopes today can consider 10" to 12" scopes within a reasonable budget. But if you're buying a no GoTo scope for the same budget you could buy 12" - 16" Dob's for less than half this price.

Simply put I don't think their is a meaningful average to the question asked, because the range (standard deviation) would totally swamp your average.

And lets say I have 4 scopes, how do I answer your question and how do you know my unit to average my single response is the same as anyone else here who also have multiple, different purpose scopes? What if I framed a single response by dividing my total aperature set by 4 but someone else added their collective aperatures (or the aggregated surface area and then turned this wierd number back into a virtual diammeter?)

I have well over 120" of screens, 12 GHz of CPU power at home, more than 6GB of RAM, Terabytes of data and alot of GPU grunt - I'd have no sensible way of giving you an "average" of my gear - it would be meaningless.

BTW Zeiss make very nice lens so I'm not suprised that a 6" refractor is a treat; but I am floored that it is mounted on a 800kg mount!

Personally may I suggest one day we construct a matrix that has a few rows asking what you wish to look at (and is it naked eye viewing, short duration astro-photography, or long duration astro photography), and columns that relate to what your budget is. Then your matrix cells could give you your optimal choices and likely price points and suggested configuration of equipment.

Kinda if I'm looking at DSOs with naked eye only -> get a large DOB, if its planets for short duration piccys - get a apo on a decent mount, if its planets on a longer duration get an apo on a brilliant mount, if its everything for short durations and very limited piccys, get a large, cheap SCT (eg Meade LX90), if its long duration for very varied objects etc...

Hope this helps!

PS

Anyone capable want to make such a chart or matrix?

[JoeBlow]

The way I interpreted the question was that it was asking about the average size of telescopes used by serious amateur astronomers of today such as most of the members of this forum. This wouldn't include a little boy who gets a 60mm refractor for his ninth birthday from his grandma and only has the slightest interest in Astronomy.

The Poll also seemed to suggest to me it was mostly talking about the average size of reflector telescopes. Personally refractors are in a class of their own, a 6 inch reflector to me is leaning more towards the small end of telescopes, while a 6 inch refractor is a more of a large telescope.

Anyway I voted for the 8 inch to 10 inch range as being the average today. Even thought the price of telescopes has dramatically dropped, however people especially those living in suburbia are still limited by size and weight. This is especially a problem for those of us that need to pack their telescopes into their car to travel to a dark spot.

I think for most suburban people a 10 inch telescope is the best compromise between size and aperture. A 10 inch today is just as easy to transport in most vehicles as is an 8 inch. So I would believe 10 inch will soon be the average for reflectors, if its not already.

[Adrian-H]

i believe it is 8 to 10, cause it rather dose get rather large and expensive onwards and that isnt all (nessicary), you can stay compact and still get as great views as the others, sure the big ones are affforable these days allso. but i think sometimes they gather to much light that ppl dont like, so many ppl in cities with scopes.

my spelling is horrible, thats ok tho cause i make up with my knowledge.

[Bassnut]

Its too broad a question, youd have to ask for "observing or imaging". Observing must be 8" or well over (eg dob) surely. Imaging, up to 6" refractor (and at 6" fairly rare and expensive) for widefield , or 8" and over (to 12 or 20") for SCT DSO. Id say 8-12" for SCT DSO imaging anyway.

[Ric]

Hi Peter, I have a small 20 page booklet dated circa 1969 entitled "Build your own 6" reflector".

It's a bit short on technical detail but explain grinding your own mirror with a lot of references to research. I also describes a basic timber mount to get started with.

Cheers

[Ian Robinson]

I think most amateurs have telescopes (reflectors) in the range 6-10".

Those who have refractors will average 80-100mm.

The SCT and Mak mob are probably in the range 8-11".

Now if you are talking serious cashed up amateurs (with money to burn) , it's anyone's guess - but they probably have Newts or dobs averaging 16-20" , or the APO crowd are probably 6-8" , and the SCT and Mak mob 14-16".

I voted 8-10"

[AlexN]

8" of DOB power!

[lknowlen]

8" F/10 Meade or Celestron S.C.T.
5" F/8 Refracting telescope
8" F/4 Dobsonian telescope

Most members of our astronomy club use these systems because they are popular.:)