Jump to content

Banner.jpg.b83b14cd4142fe10848741bb2a14c66b.jpg

16 inch Telescope

Corkeyno2

Recommended Posts

Corkeyno2

Corkeyno2

Posted
  • Author
Posted
49 minutes ago, niallk said:

Hi to the OP,

Best of luck with the 16" :thumbsup:

The only thing I'd strongly recommend is choosing a scope with easy tool-less assembly/ disembly in the dark, and that breaks down to manageable sections for transport. I think this is very important to ensure use ... if it is a chore you come to dread then it will fall out of favour.

You will just love how globs, general star colours, and planets (no 'zzzzz'! :grin: :grin:) look in the increased aperture.

With a transportable dob, getting out to dark skies around the new moon if the weather is good will be an amazing experience - unleashing the beast on DSOs and getting the benefit of increased image scale.

As for a 16" being the last scope you'll ever need to buy ... well after a week of getting my 15" (love it), I think I was already stealing glances at 20"-22" scopes on line :happy7: It's very important to have dreams!

May I ask what 'OP' means in this context.

Link to comment
Share on other sites
  • Replies 147
  • Created
  • Last Reply
ronin

ronin

Posted
Posted

I hope I am right but I suspect the point Tiny Small was trying to make was both f/5 scope, actually all f/5 scopes, produce an image of equal brightness. So 10", 16" or 3", any aperture if f/5, the prime image is the same unit brightness. What however differs is the actual image size, the 16" f/5 producing an image of equal unit brightness but a larger physical image size at the focal plane. Note this refers to the primary image plane only and once we start putting eyepieces in the way the result at the eye ball will change.

It is what comes of mixing photographic terms with visual observing ones I suppose.

 

Link to comment
Share on other sites
NigeB

NigeB

Posted
Posted
12 hours ago, swamp thing said:

Is worth the effort. That's why I do it. :)

 

Indeed, no argument - I've been there and done it. When I was a teenager (and to paraphrase Douglas Adams) in a terrible miscalculation of scale I bought a big Dob - a 14" Dark Star. My parents weren't thrilled to lose their dining room to it, and they named it Dusty Bin. But despite that, my dear old Dad would help me load it into his car on clear weekends and drive me up to the dark Northumberland village where my grandparents lived, set it up, then hunker down in the car and go to sleep while I soaked up ancient photons. It was spectacular - but quite an undertaking.

Link to comment
Share on other sites
jetstream

jetstream

Posted
Posted

I pick my scopes by focal length (mag) and aperture to get the f ratio I need. This in turn allows me to choose ( already picked) eyepieces right in the strike zone for exit pupil size... ie my 15" f4.8 1828fl

To the OP- a 16" scope is big, but if you like that and will use it- more power to you!!

Link to comment
Share on other sites
Timebandit

Timebandit

Posted
Posted
15 hours ago, Tiny Small said:

I think that people are getting a bit confused because it's a dob we're talking about. In a frac, it is literally a hole at the front of the scope, but with a dob, because the mirror is at the back and reflects the light, people are mistakenly referring to the mirror size as the aperture. The aperture is still the hole at the front.

We seem to be high jacking the thread so maybe getting back on to the OP's post. With a 16" dob and the right skies... you will see a hell of a lot.

 

14 hours ago, swamp thing said:

Not quite. According to my dictionary.

The aperture refers to the hole through which light passes. The aperture stop on a telescope is taken to be edge of the primary objective not the hole in the tube. So the aperture is the diameter of the primary mirror or lens. 

Sorry I did not explain this very well in my last post. :) 

 

Hurraaay. So the aperture is the diameter of the primary mirror or lens.?

 

I was just about to post a request for NASA contact details to get one of their chaps to confirm this matter in regards to a land based Dob(reflector, better keep it correct)?

Link to comment
Share on other sites
Timebandit

Timebandit

Posted
Posted
3 minutes ago, Peter Drew said:

A 3" F5 is the cause of aperture fever, not the cure!.   :icon_biggrin:

 

Totally agree, But Tiny was trying to convince me a 3" f5 and a 16" f5 had the same aperture??. My head was starting to hurt? as It went against  everything that I had ever read and seen when taking about a Dobby(reflector). I am sure now hopefully this item has been clarified 

Any how Corkey(I hope we have not bored you to death over aperture?) now we have confirmed it is a 16" aperture telescope you are interested in are you still going to go for it?. I have a 4" apo and love it's sharp views, But the 14" 1/10  Dobby will take it apart on faint DSO and high magnification planetary detail (especially at a dark site)

Go on buddy get yourself a 16" , some decent wide angle eyepieces ,a dark site and open up the space details others can only dream about☺

Link to comment
Share on other sites
swamp thing

swamp thing

Posted
Posted
41 minutes ago, Timebandit said:

 

Totally agree, But Tiny was trying to convince me a 3" f5 and a 16" f5 had the same aperture??.

Writing f5 like that you could easily get confused into thinking they were. Astronomers write 16" f/5 this shows that  the second figure is the focal ratio of the first figure (which is the diameter of the primary element or aperture), not the photographic speed (f stop or aperture :D) of a camera lens ;) which could be written 2030mm f5 

Confused yet :icon_eek: :icon_scratch:.....???? What a riot this is eh :D:D:D 

 

Link to comment
Share on other sites
Timebandit

Timebandit

Posted
Posted
8 minutes ago, swamp thing said:

Writing f5 like that you could easily get confused into thinking they were. Astronomers write 16" f/5 this shows that  the second figure is the focal ratio of the first figure (which is the diameter of the primary element or aperture), not the photographic speed (f stop or aperture :D) of a camera lens ;) which could be written 2030mm f5 

Confused yet :icon_eek: :icon_scratch:.....???? What a riot this is eh :D:D:D 

 

 

Hi Steve. I stand corrected 3" f/5 and 16 f/5 hopefully I am an astronomer now?. My head is going hurt again if divert from the dobby reflector aperture to the camera aperture ect ect for the sake of / ?

Link to comment
Share on other sites
brantuk

brantuk

Posted
Posted

" I'm going to wait until I have a bit more experience and then I will go for the 16". "

Nooooo..... get the 16" now lol - they're dead easy to use - it's just a Newtonian on a turntable/rocker box - only bigger - no further experience require. They're fabulous - you can get superb views now and your smaller scopes can start gathering dust like they're supposed to hehe! :wink2:

(Or ignore my addiction to dobs and tell me to go away lol) :grin:

Link to comment
Share on other sites
Timebandit

Timebandit

Posted
Posted
9 minutes ago, cloudsweeper said:

Kim, you're a bad influence!  BTW - I've my got sights set on a 12" Dob - plenty big enough, considering local light pollution!

Doug.

 

Kim has the right idea?. , Talking of a 12" on this post is just being a lightweight?. 

Link to comment
Share on other sites
N3ptune

N3ptune

Posted
Posted
4 hours ago, Corkeyno2 said:

I'm going to wait until I have a bit more experience and then I will go for the 16".

Oh? ok

I was thinking of the 16" this morning and I said to myself it must be really nice at some point own a 16" Newtonian (on a Dobson base), like this one from earlier:

QCr3l1Z.jpg?1

1000 x 1800 F4.4.

What's a bummer is the obligation to buy really expensive eyepieces for it..., and I have this question:

The Explore scientific 68d (28 - 34 - 40mm) series are they good enough for this kind of 16" telescope? with an average price 300$ each that's already expensive for the average Joe. What about the Xcel LX, with 60d, can they benefit from this light bucket too? (If one can tolerate 60 degrees AFOV)

 

 

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.