Aperture Fever.

[Guest]

I wondered why I was not feeling myself these last few weeks. I thought that it was the evenings drawing in. But no, I am having thoughts of how good my eight inch Orion Optics UK Newtonian is. But how could I better the view. A twelve or fourteen inch Newtonian came the thought. But then how to store and the enormous weight. Also not being able to transport this large telescope easily. 

What to do. I might get my flu jab, but does the chemist give an aperture fever jab? Don't be silly. But these are the nonsense thoughts that visit me when the fever has taken hold. 

Then, a new thought. A Celestron C11 with an F6. 3 focal reducer. Yes there is an increase in weight. But quite manageable. Nice wide field F6. 3 views. 

A two foot tube length. Also a much increase light gathering power over my eight inch. I would only use such an instrument at a dark sky site. 

Are there any of you out there who own Celestron C11 telescopes and use them for observing? 

Would you be kind enough to share your views and experiences with The C11. 

[DirkSteele]

I have owned a C11 for almost 16 years.  It is a great scope, and packs a lot of aperture into a fairly manageable package (though mine is on a Fork Mount which adds to the bulk and weight).  However, I rarely use it because I prefer the views offered by refractors and they are smaller and easier to lug around.  With the C11, the scope is going deeper, but the view does not sparkle the way it does in the fracs.  Also the field of view is a bit restrictive.  I cannot quite fit the Double Cluster in the max field, and forget about M45 or M31. 

 

I only use mine at f/10 so cannot comment on using the f/6.3 reducer.  Does it permit full un-vignetted views with 2" eyepieces or if it is not permitting the full use of a maximum field stop of a 2" EP, thereby really reducing (pun intended!) its utility for visual wide field views?

[johninderby]

Did a head to head comparison once between a C11 without a focal reducer and an 8” f/6 OO newt with a 1/10 pv mirror.. Result was pretty much a tie overall with for quality of views and detail seen. I was expecting the newt to be sharper but lose out to the C11 for resolution due to the greater aperture but found there wasn’t much difference really. Overall preferred the newt for general visual observing. 

So the C11 will be a much shorter OTA but may not deliver better views depending on the spec of your OO newt.

 

[Skyline]

Grumpy, you cant go wrong with the scope you've got. 

[Stu]

Why not consider something like this Martin?

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F302896214285

I agree with Matthew, the C11 is never going to be a widefield scope, perhaps 1.3 degrees max maybe with some vignetting. The grass isn’t always greener! A C11 is quite a big lump, although compact for the aperture.

The Intes Micro 7” f15 Mak I have got recently is great for small DSOs and lunar/planetary etc, but certainly feels restrictive versus shorter focal length scopes.

The 14” Sumerian Alkaid I’ve also recently got is perhaps the only larger aperture scope I am likely to use frequently and to get to dark sites because it is so compact. It has its compromises such as having to remove the secondary to pack it away, but I can live with those.

[fireballxl5]

I 'upgraded' from a 1993 vintage OO GX250 f4.8 to a 10" f10 LX200 'classic' for it's compact format and GOTO function. Although I loved the LX200 for it's many practical benefits, when I did do side by side comparisons the Newt always won, albeit there wasn't so much difference. I no longer own either scope but have fond memories of both.

[scarp15]

Its good to have options, I enjoy using my 8" OOUK VX F6 Dob, I equally enjoy the aperture gain using a VX14 dob. For some it may be too much of an effort perhaps, if so an OOUK VX12 either F4 or F5.3 would also make a manageable consideration. 

[Stu]

1 hour ago, scarp15 said:

if so an OOUK VX12 either F4

I think a 12” f4 would be a pretty handy option. Coma might be challenging, but it would be a fairly compact option for the aperture and at about 1200mm focal length more able to give wider fields.

[nightfisher]

I have a magic cure for aperture fever.......

 

 

 

 

 

 

 

Just be content with the scope or scopes you already own, remember taking a scope to a dark site is like adding 50mm to what it already has.

The only way to benefit from aperture is to go big, like from 8" newt to 16" newt.

As some other members will testify, i have gone through a large number of scopes, and now i have found what works for me....not some huge light bucket, not some fancy pants Apo ED, but a humble 127 Maksutov and a nice 90mm F5.6 achro frac

 

 

 

 

 

 

 

 

 

 

 

 

 

[johninderby]

Or a 40” dob and a villa in Tenerife to observe from. 

I think that’s called Fantasy Island or something.  ?

[mark81]

Aperture fever got me about six months ago and I still haven't shaken it off.  I have an ST80 with a 15mm BST...... that's it.... seriously.   My phone is full of screen shots of scopes that 'i'm going to get' they range from 102/1000 refractors to 20 inch Dobs.  To get back to reality I go online and read blogs about small scopes and the great fun people have with them.  I go outside, use my scope and the fever goes down.  An 8 inch Dob aint all that bad.... in fact, I would kill ( well, not kill... but sort of) for one of those.  Maybe if you get something bigger you will still get the fever.... where will it all end....

[John]

I eventually found my way to a pre-owned 12" F/5.3 Orion Optics tube assembly and then a kind SGL'er who made me a fine dobsonian mount for it. For under £500 (my least expensive scope apart from the little TV Ranger 70) I had a relatively portable, easy to setup and operate scope with great observing potential under my back garden skies and the convenience of it fitting in my car to be driven to darker ones.

I rarely get bouts of aperture fever now because I know that the 12" is the largest that I can handle easily and on my own. I do like to look through larger aperture from time to time though, but I just don't feel that I need to actually own it

With all the feedback on the www these days it's easy to find yourself in an almost constant state of "the other mans grass looks greener" but I think in many cases something you already have and are familliar with will do the job just as well 

 

 

[johninderby]

12” dob is an ideal size. Not to big to move around fairly easily.

Pity these were discontinued although not sure if any were actually sold.

 

[John]

I wonder if they ever made it out of the brochure ?

[scarp15]

Yeah that applies to me to, I feel as though in my own personal aperture journey, I have reached a full stop. This is partly because the 14" solid tube that I currently choose to use, is as much in this format, as I would wish to handle and feel that I have evolved to enjoy a broader range of scope or binocular. Complementing for wider field as mentioned is a good approach as is (as had been referred to) gaining a dark sky as often as able. It continues to be enjoyable to read observers reports regarding 18" plus scopes and potentially gain opportunities to look through larger aperture equipment at star parties, will be at this autumns Kielder star-camp, maybe there will be someone with something 16 - 20" there.

[johninderby]

They did have some mirrors made including the 50” but fell out with the man producing them which was the reason Orion cancelled the project. Think the mirrors turned out more expensive than anticipated.

[John]

5 minutes ago, scarp15 said:

Yeah that applies to me to, I feel as though in my own personal aperture journey, I have reached a full stop. This is partly because the 14" solid tube that I currently choose to use, is as much in this format, as I would wish to handle and feel that I have evolved to enjoy a broader range of scope or binocular. Complementing for wider field as mentioned is a good approach as is (as had been referred to) gaining a dark sky as often as able. It continues to be enjoyable to read observers reports regarding 18" plus scopes and potentially gain opportunities to look through larger aperture equipment at star parties, will be at this autumns Kielder star-camp, maybe there will be someone with something 16 - 20" there.

My astro society has an 18 inch newt which I'm hoping to spend some time with this Autumn and Winter. It's under a roll-off shed at our observatory site about 5 miles from where I live so relatively easy to deploy. I spent a happy couple of hours cleaning a few cobwebs off it and collimating the scope when I was last there a few weeks back.

 

[Guest]

10 hours ago, Stu said:

Why not consider something like this Martin?

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F302896214285

I agree with Matthew, the C11 is never going to be a widefield scope, perhaps 1.3 degrees max maybe with some vignetting. The grass isn’t always greener! A C11 is quite a big lump, although compact for the aperture.

The Intes Micro 7” f15 Mak I have got recently is great for small DSOs and lunar/planetary etc, but certainly feels restrictive versus shorter focal length scopes.

The 14” Sumerian Alkaid I’ve also recently got is perhaps the only larger aperture scope I am likely to use frequently and to get to dark sites because it is so compact. It has its compromises such as having to remove the secondary to pack it away, but I can live with those.

Thanks Stu. I will consider that type of telescope. 

[Guest]

Thankyou all for your insights. It is true that what I have is largish (8 inch). Also portable. I must admit that I once owned a twelve inch f6 Dobsonian. I very rarely used it as it was cumbersome to move around. I will keep thinking about this one. SGL is great for being able to get this advice. Thanks. 

[Stu]

Martin, I think it is often easy to keep chasing after something that may or may not exist. I'm a fine one to talk before you say anything ? ?

The 8" is a highly useable scope which hopefully sees plenty of action. I do most of my observing still with a 4". I know I miss out on plenty, but at least I'm observing.

I have had both 10" f6.3 and 12" f6 Orion Optics dobs. I found a significant weight difference between them; the 10" being much easier to move around and so it saw more use, whilst still being a highly capable scope.

There is no perfect scope, we know that, but having a couple or three that cover the bases is often where you can end up being most satisfied.

[Peter Drew]

19 hours ago, johninderby said:

Or a 40” dob and a villa in Tenerife to observe from. 

I think that’s called Fantasy Island or something.  ?

I have a 30" Dob and a place in Tenerife, unfortunately n'er the twain will meet. @Johns comment, brushing the cobwebs from a large telescope pretty much sums up the use rate of such apertures. Our least used usable telescopes are the 30", a 12" binoscope and a 8.5" refractor.???  "Go figure", as they say.   ?

[bish]

My aperture fever is kept under control when i look at my bank balance and feel the pain of a knackered elbow lifting a fairly light 250px. An observatory at a dark site and a load of money would be good.

[Saganite]

I had aperture fever with my 8" Dob, but a 12"OO VX f5.3 with a very high quality mirror came my way and I never think about owning a larger aperture anymore. It is by far the lightest 12" I have had which helps, but I am happy. 

[niallk]

8 hours ago, Peter Drew said:

 "Go figure", as they say.   ?

Why, what's wrong with their optics?

 

[estwing]

I've had ap fever for a few years now....really want a 24" ...my cure?..Keep taking the 18" to pristine dark skies.