Aperture fever , the Emperor's new clothes ?

[cotterless45]

This isn't a dig at the Dob Mob , hurrah ! Just a few things to think about, particularly for beginners with small scopes thinking of going big ,

I've given the hours searching for fuzzies and lugging around big apertures. I've seen lots of galaxies and from the edge of town they are mostly disappointing. I'd certainly agree that they are a different target from dark skies, where big aperture works.

I noticed a 16" Meade Starfinder on ebay, ideal ? http://www.scopereviews.com/page1r.html

The ota is about 100 lbs , eek.

Ok , if you're still keen get a truss, with a shroud , you'll not be pleased with the amount of muck that manages to find the primary. Solid tubes are the thing. Personally an 8" will do for your adventures.

In addition a bigger fast scope is going to hate your reasonably priced eps.

There are pitfalls in aperture fever, it's not for everyone.if you can , get to view using big aperture under skies that you'd normally use.

I can't see big aperture being of use at the edge of town. I had a comparison of 10" f5 Dob versus 6" achro. Under good seeing , the frac won outright. Even with the frac, a smaller 4" achro gives more contrast. In addition achros can produce views in poor seeing and transparency.

Forget about bigger aperture pulling in more light pollution. What will give you darker views is using more magnification up to a point, unfortunately you're going to blow away the faint diffuse targets .

Looking at it the other way, perhaps it's choice of targets if you have light pollution. Whatever you use, you're not going to get much joy with M51 or other diffuse galaxies.

I've so great deal of time for my 8" f6 Newt . There's plenty achievable targets, planets, planetary nebulae,lunar, stars, clusters and the brighter galaxies.

Have a good think if you've got a rich of aperture fever. It might not give you all you wish for.

Now bigger aperture is becoming more available , you might save yourself some hassle by getting a smaller aperture jab,

Nick.

[michael.h.f.wilkinson]

Don't really agree with this, although you are right that to get the most out of a big dob, dark skies help. The same is true for any scope. My C8 completely outclasses my 80mm achro (APM triplet at that) on almost any target, except the widest of wide field. This is from a suburban garden. Galaxies look faint, it is true, but the satisfaction of finding an elusive target is great nonetheless. It is true that the view of M51 using my C8 from a dark site beats the view through the university's 16" RC from a light polluted site. I am pondering going to a 12" or bigger scope but realise I really should get one that sets up easily, or it will just sit and gather dust. It should also be transportable to dark sites. Truss tube scopes are not a problem regarding dust, provided they have a dust cover for the mirror box.

[bomberbaz]

Interesting point of view Nick. Some of what you say strikes a chord, my mirror looks quite mucky but as i have nothing to compare it with, I can't say how mucky that actually is.

I do find the extra aperture on mine makes a not insignificant difference. i had a 8" sct and have to say my 12" flextube if far better than that was. I couldnt get the owl nebula in the sct but manage a fair view from my garden with the flex. Being a flex portability isnt an issue either, I think each part is less than 20KG so not too heavy and still takes less than 15 minutes to set up.

I also have a 4" frac and i love it too for giving great big wide filed views and I think everyone should have one for just this purpose. It also makes a great grab n go, 2 minutes from house to garden but when it comes to getting deep, the dob fills its boots.

Steve

[baggywrinkle]

I agree wiith much of what Mick says. For an absolute beginner it is a bewildering hobby, even for the experienced it can be problematical. I am not saying that all newbies should be restricted to 4'' refractors and a max of 8'' on a reflector, but there could be a bit well considered thinking when going for the biggest tube you can afford.

Big in some ways is not always better. However the market today is awash with big OTA's and of course the advertising to match the sizes...

I wonder how many folk buy a big tube abd due difficulties give up.

[swamp thing]

Good post Nick

But as Michael I don't quite agree....sorry 

Now, most know that I bang on about dark skies and that is where a big scope really can stretch its legs...........

However I will admit that even from LP ones aperture can and does help. 

Recently I observed with rusty split who had his lovely 14" home built Dob, and jamie with his shiny new 150ED frac. I had a van full of camping gear and my big scope, but didn't bother setting mine up as the site was LP, and I was off to Wales for some dark skies the next night

Gotta say Rusty's dob killed it for me.......by quite a way. The frac is a wonderful scope and gives some lovely views but the Dob's image scale and resolution just showed pretty much everything better. What detail there was available was seen better through the larger scope. 

Don't get me wrong I still wouldn't bother setting up my larger scope under LP skies as for me it just isn't worth it but I can understand a little bit why some do........ish.

Perhaps using a 14" against a 6" isn't really a fair comparison, but bearing in mind the cost of a 6" ED frac.......its not that unfair is it?

[Liquid360]

I'm a newbie but I have an opinion here. A couple years ago I shopped for my first "real" scope. I read through the forums and across the board the sentiment was get the biggest you can afford and handle. I ended with a 10in LX90 ACF. It was the biggest I could afford and I could lift it. It almost destroyed my interest in this hobby. It was just too large. Yes I said it. In hindsight I should've purchased an 8 or, dare I say it, a 6in. There are other factors at play in people's lives. Not everyone has a yard and a strong back. I'll even go so far as to say that a beginner is unlikely to see much if any difference between 2-4in. I echo the wisdom of the best scope is the one that gets used and 9/10 that's the scope requiring less effort to carry around. Now if you have a yard and a pier, by all means go big or go home, but if you'll need to carry your hardware anywhere, start with a small scope. My lx90 about stopped me in my tracks.

[Alien 13]

I kind of agree with Nick a scope isnt some sort of magical image intensifier all it does it change the image scale the limiting factor of how much light gets into your eyeball is the exit pupil various scopes will show different things but is a wide field view at a dark site with bino`s better or worse than a small scale detailed view with a big newt.

Alan

[ronin]

It tends to be difficult.

An apeture of double so 4x area does not show in many ways 4x as much.

M33, M42 and a few others come out better, clusters will as well but, I hate to say it, clusters generally are not "exciting".

More aperture will help on nebula like the Veil, N American, Pelican, Rosette etc, but they will still be faint. Afraid you are not going to be dazzled. Lets say the nebula will be more apparent, if the skies allow.

You will see numerically more galaxies in areas like the Virgo cluster, but they will not be bright detailed galaxies, they will still be small roundish disks bearing fair resemblance to slight coma on stars. Just instead of 20 you will see 30 maybe 40.

In effect more aperture will provide more detail if the detail is easily present to be extracted, and there are not overly many that fall into that catagory. Where noticable improvements will be seen is in the boarderline objects, ones that were "not bad" should now come out better. Will the Sombrero galaxy fall into this?

It is a bit like car engines, going from a 1.8 to a 3.6 will not get you from London to Edinburgh in half the time. You should however get a 20%-25% time improvement and you will be more relaxed when you arrive.

Scope wise I translate this to a nice improvement in what can be realistically seen and easier to see it.

Liking refractors means you do not have this problem, it is in general a reflector condition, reason is simple. Too darn expensive to go from a 100mm ED to a 200mm ED, and not even going to think of the cost of a good 200mm triplet. I have grown sort of attached to my kidneys and othjer organs.

[Paul73]

Good post Nick

Although the advice on this forum does tend to be pretty practical re size of scope. However, this is generally based on ease of lugging the things about, rather than realistic LP viewing. I'm always amazed at what you bag from your edge of town site. Little 10" wouldn't stay with you with even moderate LP.

The chap that I bought my scope from was selling because he had gone for the biggest that he could afford rather than a smaller GoTo effort which would have shown him far more from his LP back yard.

Paul

PS. I'm still going to get a bigger Dob one of these days. I've got Binos. That's like having two refractors isn't it?

[Moonshane]

I have scopes from 40mm to 400mm and they all have a place in my 'heart'. My largest scope is the least used and the most used are my 40mm PST (now converted to a stage 2 mod), and my 120mm f5 for white light. That said, at night i find refractors very uncomfortable to use and much prefer my dobs, especially my 12" f4 which provides beautiful views even from my light polluted garden. The one thing my dobs don't do is provide a rich wide field of view. The 120mm f5 with my 40mm Tv widefield and 26mm Nagler do this superbly. I probably have too many scopes (in a 70s carry on film voice) 'ask my wife' but I truly enjoy them all. Whilst the least used the 400mm f4 dob is spectacular at dark sites.

[happy-kat]

I will stick with what I can set up quick and easy. Star parties or local clubs can hopefully provide opportunites to see more. I guess observatories give great space to have that fever :-)

[SimonfromSussex]

There is beauty to be found in a clear sky what ever size scope you have.

I had a cracking night on holiday sitting on a balcony with a basic pair of binoculars picking over the wonders in Sagittarius.

However, having progressed up the apertures and tried lots of different scopes I have to say, for the targets I go after (nebula,galaxies,globs) bigger is better imo.

My current scope shows so much more detail. I'm picking globs out in the Andromeda galaxy, the veil looks like a mono ccd picture, galaxies are much clearer and easier to work detail.

That's not saying that you cannot have a great time with a smaller scope, you absolutely can and I would encourage everyone to just look with what ever you can get your hands on, but bigger does just show more.

[Bodkin]

There are a lot of personal preferences in choice of telescopes.  My own experience of buying and using telescopes tallies very well with Nick's points

• Don't fight the light pollution if you are a visual observer. The Moon, planets, double stars and a few deep space objects kept me very busy when I lived in London.
• Bigger is not always better.  I have pretty dark skies but almost always use the 10 inch rather than the 20 inch.  I try to enjoy what I can see.
• Longer focal ratios (F6 or so) are great for smaller newtonians, say less than about 12 inches.  You don't need the most expensive eyepieces, collimation is less fussy and the secondary mirror is smaller.

Moving up in aperture can be a great experience, particularly if you have really enjoyed using your current scope.  However, if you are not enjoying using your observing it is unlikely that buying a bigger one will solve the problem.   Just my view.

[Luke]

I had a case of aperture fever, going from 8 to 11 to 12 to 16 inches, and it has made me appreciate smaller scopes more. Of course, I get a real buzz when I have a good session with the dob, but on hols I used my 60mm frac and had a very nice session under dark skies. Our sky at home is okay (can just about make out the Milky Way), nothing special, and aperture certainly does make a big difference for us visually, our 16 inch at home beats a 12 inch at Kelling with considerably darker skies and no pesky lamp posts.

If I was starting out again and wanting to keep spending half sensible for DSO observing, I think I'd get me a 10 inch solid tube dob.

[swamp thing]

One thing I've noticed since switching to large apertures. I wonder if other large scope owners have notice it too?

I now see more detail than I used too when using smaller scopes. Its like the big glass some how teaches you to see......???

I see far more through my smaller scopes than I ever used to. weird. 

[Paul73]

One thing I've noticed since switching to large apertures. I wonder if other large scope owners have notice it too?

I now see more detail than I used too when using smaller scopes. Its like the big glass some how teaches you to see......???

I see far more through my smaller scopes than I ever used to. weird.

Practice? Or, does your mind fill in a few gaps from memory?

Paul

[Floater]

Enjoyable and interesting thread you started here, Nick.

And something running through it is discernible: personal choice. And that choice will always be based on different factors. For some, budget is paramount, for others it's portability, or the likely skies/seeing available, or a preference based on nothing really quantifiable.

My 150 Dob is what I describe as 'semi-portable' - just about as much as I'm able, or prepared, to cart about. My TV76 is a joy because it's just so easy to pick it up on the tripod with one hand and my EPs or stool in the other hand and get it outside or into the car. I pick up more of the fuzzies with the Dob but 'The Hole' causes problems. Horses for courses, I guess.

I now see more detail than I used too when using smaller scopes. Its like the big glass some how teaches you to see......???

I see far more through my smaller scopes than I ever used to. weird.

This is interesting in itself, Steve. I think you're right - there may be something else in play here, other than just aperture.

I'm a bit of a twitcher for birds and like to identify other beasties. I can spend ages with books trying to pinpoint which kind of bumblebee (just as an example) I've seen and may struggle. But when someone more knowledgeable highlights what I should be looking for, I get it nailed. Having seen these features once - whether birds, caterpillars, moths or bees, etc. - I seem to be able see them much more easily the next time I'm observing.

I like to describe it as the eye having been 'educated'.

Now if only the sun were visible, I'd be perfectly happy with my available 40mm of aperture in Ha ...

[John]

One thing I've noticed since switching to large apertures. I wonder if other large scope owners have notice it too?

I now see more detail than I used too when using smaller scopes. Its like the big glass some how teaches you to see......???

I see far more through my smaller scopes than I ever used to. weird. 

I certainly find that when I've managed to see something for the first time, it gets somewhat easier to make out on subsequent occasions and with smaller apertures.

Whether that is due to increased awareness, polished technique, lingering memories or a subtle combination of these things I'm not sure !

Big aperture that can be used regulary is a joy. Big aperture that lies idle much of the time becomes demotivating in due course I think.

[webboid]

There are pitfalls in aperture fever, it's not for everyone.if you can , get to view using big aperture under skies that you'd normally use.

I can't see big aperture being of use at the edge of town. I had a comparison of 10" f5 Dob versus 6" achro. Under good seeing , the frac won outright. Even with the frac, a smaller 4" achro gives more contrast. In addition achros can produce views in poor seeing and transparency.

Good point Nick

I suspect that those with larger scopes are more likely to use them under dark sky conditions & their hobby has evolved so that carting it all to such a location is part of their dedication. However, big sometimes is not better even from a dark sky location. I was observing with a friend recently from a very dark location but skies were not that good that night (SQM 21.1). Views in his 24" dob were good to my eyes when compared to my somewhat smaller 12" dob. He remarked that he had too much aperture that night.

On another occasion I was comparing views in my 12" vs an 18" dob from a dark sky on the Swan Nebula & significantly more detail was seen in the larger dob. Similarly on the Crescent Nebula.

Portability aside I believe you definitely see more detail once you get into the 16" plus inch size.  

When viewing at home with some LP I have been able to see more with the 12" compared to the 8" I had, but you have to work so much harder to make out the dim stuff anyway. The thrill for me is then looking at the same objects from a dark sky with the same equipment. I see more & get a somewhat brighter view. This often confirms my at home observation.

Having different scopes for different purposes helps add to the variety of observing experiences. That is why I now have a few to pick from but generally my 12" is my preferred option, even at home, if several hours of clear skies is likely.

[estwing]

"Too much aperture that night"....classic!

[PeterW]

Alien-13.. "Magic image intensifier..."? Yes, go buy one and couple it to some red glass or better a narrow h alpha filter and go " faint" nebula huntin under light pollution, of busting globulars. Not cheap, but fun watching people want to chuck their Ethoses away. Add it to the scope of your choice, fast fratio preferred fhough.

PEterW

[Daniel-K]

BIG SCOPES = BIG REWARDS  go as big as you can handle i say, you only live once!

[Liquid360]

The equation is a bit more complicated than that.

[Daniel-K]

The equation is a bit more complicated than that.

Ok

Buy a big scope + 1 keen astronomer + dark skies = Happy astronomer

[Moonshane]

No no no

you missed out top eyepieces :0)