Author Topic: Buying big dob, xx14g or xx16g (Another one...)  (Read 155 times)

gatawestwall

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #15 on: January 17, 2018, 12:21:50 AM »
Muddman97,

Remember, the larger the scope the more important it is to be under dark skies to truly see the benefits of the increased aperture.

Here is a map that shows how dark your skies are...it's not perfect but can give you a good idea of what you can expect of your location. Anything in from blue to grey is considered "dark".

Clear skies!

Saul Zhang

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #16 on: January 18, 2018, 09:13:31 AM »
Quote
"(I want to see structure on the larger/brighter DSOs, such as the arms of m33, or good detail on m31 etc..)"
Not sure you will get that with a 14 - 16". Good detail on galaxies is hard to get. See the below simulator:
http://www.stelvisio...scope-simulator
On the other hand, nebulas and globs, at a dark site, will really pop! And, hopefully, the optics will be good enough for planets?
The issue I have with those scopes is weight. But if you don't move them much, maybe a nonissue?

I've mostly watched sketches made through 14" or 16" scopes to get an idea of what galaxies will look like. It's really a shame that I can't find a club with a 14"+ scope nearby...

So what you are saying is that galaxies will look like smudges even when viewing through a 16"? :/

faubloginac

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #17 on: January 20, 2018, 07:14:15 PM »
Quote
So what you are saying is that galaxies will look like smudges even when viewing through a 16"? :/

Well, *most* galaxies look like smudges through any instrument. And, visually speaking, vivid high-contrast detail just isn't a feature of galaxies, with a handful of arguable examples.As tough as galaxies are, I've spent a lot of time on galaxy hunting in 4"-8" scopes. Most of the time, in that range, the only "detail" is the degree of round vs. oval shaped, and how concentrated the nucleus is.

"Good" detail is open to interpretation. The best galaxies will show substantial detail (by my standards) in a 16 inch scope from at least reasonably dark skies. Something like the mottling of M82 or the arms of a relatively bright and highly organized face-on spiral like M51 can be seen in considerably smaller scopes (some detail in M82 is easy in my 8 inch scope; the arms of M51 can be visible but are more difficult in the same scope). The range of galaxies that show at least some detail starts to increase a good deal somewhere around the 12 inch range, and the best galaxies will show more detail (or the same detail more easily) with increases in aperture from there.

memeforvi

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #18 on: January 21, 2018, 01:45:43 PM »
Coming from 70mm, I would say go for the 14". Cheaper, lighter, more managable and with a performance not far behind the 16". I find this comparison on M13 very clear:http://www.obsession...m/m13/index.php.

Rob Freeman

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #19 on: January 23, 2018, 04:16:56 AM »
Quote
"(I want to see structure on the larger/brighter DSOs, such as the arms of m33, or good detail on m31 etc..)"
Not sure you will get that with a 14 - 16". Good detail on galaxies is hard to get. See the below simulator:
http://www.stelvisio...scope-simulator
On the other hand, nebulas and globs, at a dark site, will really pop! And, hopefully, the optics will be good enough for planets?
The issue I have with those scopes is weight. But if you don't move them much, maybe a nonissue?

I agree with Jim Nelson above.
I think the simulator is pretty accurate when it comes to M31 and M51. Too bad it doesn't simulate more galaxies. Many galaxies are low on surface brightness.
And with regards to sketches, sketchers are really studying an object closely, for a long period of time.
Andy

Bill Godschalk

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #20 on: January 23, 2018, 05:59:05 AM »
Quote
Quote

"(I want to see structure on the larger/brighter DSOs, such as the arms of m33, or good detail on m31 etc..)"
Not sure you will get that with a 14 - 16". Good detail on galaxies is hard to get. See the below simulator:
http://www.stelvisio...scope-simulator
On the other hand, nebulas and globs, at a dark site, will really pop! And, hopefully, the optics will be good enough for planets?
The issue I have with those scopes is weight. But if you don't move them much, maybe a nonissue?

I agree with Jim Nelson above.
I think the simulator is pretty accurate when it comes to M31 and M51. Too bad it doesn't simulate more galaxies. Many galaxies are low on surface brightness.
And with regards to sketches, sketchers are really studying an object closely, for a long period of time.
Andy

So would you say this sketch:http://www.asod.info...12-inverted.jpg is way off compared what you actually observe (this seems way to bright)?

or these:http://skytour.homes.../files/M51X.jpg,http://www.asod.info...-m-32-m-110.jpg

in a 14"/16"?

Max Sandell

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #21 on: January 25, 2018, 07:59:03 PM »
Quote
Quote

Quote

"(I want to see structure on the larger/brighter DSOs, such as the arms of m33, or good detail on m31 etc..)"
Not sure you will get that with a 14 - 16". Good detail on galaxies is hard to get. See the below simulator:
http://www.stelvisio...scope-simulator
On the other hand, nebulas and globs, at a dark site, will really pop! And, hopefully, the optics will be good enough for planets?
The issue I have with those scopes is weight. But if you don't move them much, maybe a nonissue?

I agree with Jim Nelson above.
I think the simulator is pretty accurate when it comes to M31 and M51. Too bad it doesn't simulate more galaxies. Many galaxies are low on surface brightness.
And with regards to sketches, sketchers are really studying an object closely, for a long period of time.
Andy

So would you say this sketch:http://www.asod.info...12-inverted.jpg is way off compared what you actually observe (this seems way to bright)?

or these:http://skytour.homes.../files/M51X.jpg,http://www.asod.info...-m-32-m-110.jpg

in a 14"/16"?
Yes the first is way too bright. The second two are reasonable expectations in a 14/16". A lot depends on sky conditions obviously.

But M31 and M51 are exceptions to the rule - most galaxies do not show so much detail. Again - it depends on sky conditions. In most typical sky conditions (green/yellow sites) - there are maybe a dozen galaxies that show meaningful detail in a 16".  The rest are still mostly amorphous blobs. At very dark sites with great transparency, however, that number will increase quite a bit. 

As to your more general question - I would say a few things. First, I would generally say you are a good candidate for a larger scope since you will be using it from home and are young / physically able to handle it. The ladder thing can be annoying for your wife - but a single step on a step stool isn't too bad. Second, I would recommend you try out a larger scope if possible before buying - so you can get a sense of what bothers you. Third, consider how often youmight want to go to a darker spot. In all likelihood, Bortle 4/5 skies simply aren't going to show the "wow" views you are looking for. A 10 or 12" scope is going to show more from Bortle 2 skies than your 16" will from your Bortle 4/5 back yard. But if you are almost certainly going to stay in your yard - I'd say go bigger if you can handle it.

Rodrigo Page

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #22 on: January 29, 2018, 11:36:44 PM »
The second linked image is about what my 12 produces for me. Maybe slightly dimmer. With my 16 the image is just as bright but more detail/contrast than image 2. All from blue zone dark sites. Really depends on the skies that night. My 16 and 12 are very good custom mirrors. I also own both a 12 and 10 inch gso mirror and have compared them against the custom 12 and there is a noticeable difference. Especially planetary viewing. Just more detail to pick out.

With that said my 10 inch gso is very good and better than my 12 gso.

The thing about sketching "which I do frequently". Is that it is through someone else's eye and artistic skill. So just take that into account.  But sky conditions, experience, the target, size of the optic, observers vision health and optical quality all play a role in what someone Interprets. Which is really just an opinion.

I have made sketches of the same targets as above and they have been more detailed and sometimes less.

These are a couple of mine.

 bbcodeImage-js (do not remove or edit this tag)


16 inch dark skies, ngc4565

 bbcodeImage-js (do not remove or edit this tag)
12 inch gso mirror M51 dark skies bbcodeImage-js (do not remove or edit this tag)


12 inch gso mirrror suburban skies bbcodeImage-js (do not remove or edit this tag)
12 inch gso mirror M99 dark skies

 bbcodeImage-js (do not remove or edit this tag)


16 inch TO mirror from suburban skies. M104

coepupinsynch

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #23 on: January 31, 2018, 07:55:59 AM »
I have a Terry O mirror 14 inch that I just completed, but have not done any serious observing with yet. So I can't give a comparison of this size optic.

Tyler King

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #24 on: January 31, 2018, 12:44:30 PM »
I am slightly leaning towards the 14", I will definetly take it to bortle class 3 or 2 skies during winter. I have a Volkswagen van, so no trouble carrying either of the scopes, but it looks like the 14" might be the wisest choice for taking it with me to darker skies.

taccihalmo

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #25 on: January 31, 2018, 12:55:36 PM »
since i don't get out to observe much, except lately to a couple star parties
a year i think i would have been better off getting a 16inch. before i purchased
my 12" Intelliscope i thought the 82lb mirror box weight of a 16" Skywatcher
dob would be too great, but after seeing all these veterans at Okie-tex with
their monster dobs function okay i have changed my mind. so if you get out
much i would go with the smaller choice, otherwise Aperture Rules!!
jim

Robert Garcia

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #26 on: February 08, 2018, 09:55:52 PM »
Quote
Well, this thread just sold me on getting a 14" instead of a 16" to replace my 10".

Whats that we say? The best scope is the one that gets used? Yeah, I don't want to get into a 16" and be overwhelmed by setup.
If a 14" will give just as good a view as a 16" and give the WOW factor over the 10", then I am sold on the 14".

Thank you all.


A 14 inch will not give just as good as view as the 16 inch but it will still give a good view..

My take on the 16 inch Orion: it's nearly 200 lbs and tall enough to need a ladder. That's too much for a 16 inch.. my 16 inch weighs half that and doesn't need a ladder.. if one is going to go with a scope that weighs 200 lbs, get one with the performance that goes with it...

In terms of the 14-16 inch question, they're more alike than their different, both are very capable. When upgrading, forget about being WOWd.. that wears off soon enough.. figure you're looking for added capabilities.

Jon

Jeremiah Greer

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Re: Buying big dob, xx14g or xx16g (Another one...)
« Reply #27 on: February 09, 2018, 11:11:19 AM »
Quote
So would you say this sketch:http://www.asod.info...12-inverted.jpg is way off compared what you actually observe (this seems way to bright)?
or these:http://skytour.homes.../files/M51X.jpg,http://www.asod.info...-m-32-m-110.jpg

in a 14"/16"?
I have little doubt that with careful observation, perhaps at a variety of magnifications, and good skies, you can see all the detail in the first sketch with a 12.5" instrument. That doesn't mean it accurately and closely recreates the experience at the eyepiece. It certainly is showing too much contrast to be truly realistic.
Sketches that truly represent the eyepiece view are very difficult to produce (although they're more representative than most photographs). A sketch may represent the detail you pull out of observing over, let's say, 30 minutes of careful observation. A sketch that truly represents the eyepiece view would *also* take 30 minutes of careful observation to pull out the same detail! Even if you have the means and skill to produce such a representation, is that really the goal of the sketch? Probably not.
The 2nd M51 sketch is a little closer to the immediate experience at the eyepiece of a large-ish scope The last sketch of M31 is representative of the detail if you have very dark skies - seeing that second dark lane isn't easy.