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Equipment Discussions >> Reflectors

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robininni
scholastic sledgehammer


Reged: 04/18/11

Loc: Stephenville, TX
Big dob for objects with structure and detail?
      #5910329 - 06/08/13 08:21 PM

I know from the start that some or even many may argue that most all DSOs have discernable structure and detail and that is part of what is so neato about astronomy--staring long enough and hard enough and using averted vision to discern those details!

But my point of view is that a faint smudge of a galaxy that is literally a bluish smear does not qualify and even brighter little smudges (blue snowball) don't get me excited. I am interested in a list of objects with **magnificent** detail such as the whirlpool galaxy, the sombrero galaxy, many globular clusters, and of course the orion nebula--these sorts objects--that one can readily detect much structure and intricacy with a large size reflector (say 10" and up). I also like many open clusters because I think they are beautiful.

Does anyone have such a list?

My reasoning is #1, I would like to have such a list, if already available, for my own enjoyment as these are the objects I like to view.


#2, I am debating about my future in visual astronomy and what telescope I want to have. I currently have a 10" Orion and and 25" Obsession. I am considering getting a 24" or even 20" Starmaster and selling the Obsession. Both would be shorter and I would just go with the 20" for not needing a ladder at all, it fitting through doorways, it being easy for one person to mess with the mirror, etc., but I know the difference in views between a 20" and 24" can be pretty big and so I don't know if I want to downsize from the 25" to a 20".

However, I use my larger aperture reflector to try to see more of already very visible objects and not to find tiny smudges that can't be seen in smaller reflectors. All I care about is seeing more detail in already detailed structures like m51. So I'm wondering if 25" of aperture is overkill for me because I'm just not hardcore and like looking a 'pretty things'?

I'm pretty new to astronomy, so I don't have a great knowledge of the heavens, but if out of the 1000s of objects amateur astronomers look at there really aren't but a handful of m51-like objects, and most use big apertures to resolve super faint objects rather than look at the already interesting objects available at smaller apertures, I think I would feel okay with downsizing for comfort as I am only going to view that handful of objects I am interested in, and 25" is a lot of scope to mess with for that. Does this make sense?

Any advice here on the objects I like or the benefit (or lack of benefit) of huge aperture for what I am doing?

Thanks,

Rob


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GlennLeDrew
Postmaster
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Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Big dob for objects with structure and detail? new [Re: robininni]
      #5910374 - 06/08/13 08:49 PM

Much of what facilitates the detection of detail in extended objects is surface brightness. For example, compare 0.7 arcminute Jupiter with a common 10 arcminute galaxy. Even though the latter has 200 times the surface area of the former, it presents but a *fraction* of the detail. In spite of the fact that the galaxy has much detail to similar contrast and scale. If we could magically bring the galaxy up to the surface brightness of Jupiter, the detail seen would be simply staggering!

It's our lousy resolving power at low light levels which is the hindrance. And no telescope can present an image having surface brightness higher than delivered by a smaller scope--and even the unaided eye. The bigger scope merely allows to magnify detail while preserving surface brightness.


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Jon Isaacs
Postmaster
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: Big dob for objects with structure and detail? new [Re: robininni]
      #5910376 - 06/08/13 08:50 PM

Quote:

But my point of view is that a faint smudge of a galaxy that is literally a bluish smear does not qualify and even brighter little smudges (blue snowball) don't get me excited. I am interested in a list of objects with **magnificent** detail such as the whirlpool galaxy, the sombrero galaxy, many globular clusters, and of course the orion nebula--these sorts objects--that one can readily detect much structure and intricacy with a large size reflector (say 10" and up). I also like many open clusters because I think they are beautiful...

...
I'm pretty new to astronomy, so I don't have a great knowledge of the heavens, but if out of the 1000s of objects amateur astronomers look at there really aren't but a handful of m51-like objects, and most use big apertures to resolve super faint objects rather than look at the already interesting objects available at smaller apertures, I think I would feel okay with downsizing for comfort as I am only going to view that handful of objects I am interested in, and 25" is a lot of scope to mess with for that. Does this make sense?




Rob:

Such a list is short.. there are only so many showcase objects...

But objects like the Blue Snowball, the Eskimo Nebula, for me, I consider these to be relatively bright and with magnification can put on quite a show. At 100x, there is not so much to be seen but at 500x, really idling along for a 25 inch, the reveal their treasures. Of course, they also reveal their secrets in smaller scopes... a 25 inch scope is not needed for most objects I observe...

In my mind, downsizing makes a lot of sense. I have scopes ranging from 60mm to 25 inches, I enjoy them all. When you asked about upsizing to the 25 inch, I thought you would be wiser to spend more time learning and developing your skills before taking on a very large scope. Bigger scopes show more but what has made the the biggest difference for me is simply that over the years, even as my eyes have gotten worse, I have gotten better.. I see more now at 65 than I did at 45 because I have those years under my belt.

If I had one wish for you, it would be to slow down and just spend some time patiently enjoy the night sky with a telescope, any telescope, any size.. any quality.

There are nights when I do use my 25 inch, probably more nights when I use my 16 inch but there are also nights when I break out my Celestron Powerseeker 70 and just enjoy what it can show me...

Jon


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Jason D
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Reged: 10/21/06

Loc: California
Re: Big dob for objects with structure and detail? new [Re: robininni]
      #5910382 - 06/08/13 08:54 PM

Rob, how does the view of M51 in your 25" Obsession compares to your 10" Orion reflector?
Jason


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nevy
professor emeritus
*****

Reged: 02/07/12

Loc: UK
Re: Big dob for objects with structure and detail? new [Re: robininni]
      #5910384 - 06/08/13 08:57 PM

NGC 891 is a nice one when it gets in a nice viewing position, it's very nice in my 16" at a dark site.
[image]http://[/image]
[image]http://[/image]
[image]http://[/image]


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robininni
scholastic sledgehammer


Reged: 04/18/11

Loc: Stephenville, TX
Re: Big dob for objects with structure and detail? new [Re: Jason D]
      #5910422 - 06/08/13 09:20 PM

Quote:

Rob, how does the view of M51 in your 25" Obsession compares to your 10" Orion reflector?
Jason




M51 looks better in the Obsession than it does in the Orion. I can see more detail. Arms and dust lanes are plainly visible (although still faint and sort of hazy) in the 25" and, while there, I wouldn't call them 'plainly' visible in the 10" from what I recall from last time I used the 10" a couple of months ago.

I definitely 'get' the larger aperture making the objects I like to view look better. But I'm just thinking if there are only 30 objects that really fit the bill for me(I really have no idea how many there are, just a guess), is the big scope worth the hassle factor? I guess that is a question only I can answer. What I was really hoping for is for some one to tell me how many of these sort of targets there are: 20, 30, 50, 100, 200?

Adding to my troubles is I like to 'try' everything out. I have a 10" reflector and I wanted to know what a big boy was like so I got the 25" Obsession. We all know the story of my mirror and while it's okay, I still want to know what a superb mirror would be like in the same aperture and what sort of difference that makes (or doesn't). I'm then curious as well if a smaller aperture (20") scope with superb optics would be as good or close to as good as a larger aperture (24-25") with okay optics and, if so, I wouldn't give up good views and then I get the benefit of no ladder, lighter telescope components, movement through doorways, etc.

I may not find the 'magic' for me, I may just end up trying various things. The problem is its a hassle and expensive to "try" large dobs out (I know that a star party would allow me to look into different scopes but I've yet to attend one--I'm a loner astronomer Yes... I know... part of the problem you say.).

Maybe I should go for the smaller scope (well 20" really isn't too small is it) with superb optics and if I don't use it a ton because I don't look at but a handful of objects I'll still sleep well at night knowing I have an awesome scope that I can fit through door ways that doesn't take up the space of a small car and which I can remove the mirror from without asking my wife for help .

Rob


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GeneT
Ely Kid
*****

Reged: 11/07/08

Loc: South Texas
Re: Big dob for objects with structure and detail? new [Re: robininni]
      #5910456 - 06/08/13 09:31 PM

Quote:

I still want to know what a superb mirror would be like in the same aperture and what sort of difference that makes




Whatever telescope you decide on, I recommend moving up to premium optics, and good quality eyepieces.


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GeneT
Ely Kid
*****

Reged: 11/07/08

Loc: South Texas
Re: Big dob for objects with structure and detail? new [Re: robininni]
      #5910473 - 06/08/13 09:38 PM

Quote:

I know from the start that some or even many may argue that most all DSOs have discernable structure and detail and that is part of what is so neato about astronomy--staring long enough and hard enough and using averted vision to discern those details!




No matter what size telescope you have, there will always be objects that appear as dim smudges. Its just that a dim smudge in a four incher will show detail in a 20 incher. I have owned a 20 and 18 inch Obsession, a 13.1 inch Coulter, a 12.5 inch Portaball, and a couple of 8 inch SCTs. I sold them all--except the 12.5 inch Portaball. For me, it is the perfect sized telescope. It is as easy to haul, set up, and take down as an 8 inch SCT. However, there is an additional wrinkle in the question you posed--dark skies. I have found that it does not matter much how large was my telescope if I was viewing in light polluted skies. Finding a good dark sky site is just as important in your quest as settling on what size telescope you should buy.


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bunyon
Post Laureate
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Reged: 10/23/10

Loc: Winston-Salem, NC
Re: Big dob for objects with structure and detail? new [Re: GeneT]
      #5910499 - 06/08/13 10:08 PM

It depends what you mean by "magnificent" detail. If you mean M42 or M51. No, there aren't many objects like that. A dozen? Two at most.

But there is detail in many DSOs. It won't be knock your socks off but with an experienced eye, you will see it. That includes hundreds of objects in a 25 inch scope. But even the couple dozen blow you away objects aren't walk up to the scope from your living room, take a peek and see it all. Visual observing through a telescope requires dark skies, dark adapted eyes, a good scope, and, most important, experience and training and an appreciation for subtlety. No two ways about it, visual astronomy is a subtle art. The biggest, brightest most awesome object isn't going to blind you and you'll have to poke and prod with averted vision, nudging the scope, etc. to see everything there is to see. It takes patience and time to learn how to see.

I'm not trying to be self-righteous. I started observing when I was 12, many years ago. As Jon says, I see a lot more now with worse eyes (and skies). For me, for many visual observers, I think, it is that slow reveal that is appealing. It is seeing some small new thing every year, teasing out just a little more information from an object that to a newcomer looks like a grey smudge. That is, at its essence, what visual observing is: seeing just a tiny bit of the universe that you haven't seen before each time out. If you take the time, the universe will show herself to you. If you don't take the time, it won't matter how big or premium your scope is, she won't.

Again, I'm not trying to talk you out of visual astronomy at all. I would caution, as others have, to move slow, take your time and gain some experience. I would also add, don't imagine money can overcome the need for experience. Anyone will see more in a big premium scope but one who hasn't learned to observe won't see all that can be seen in any scope.


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Jason D
Postmaster
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Reged: 10/21/06

Loc: California
Re: Big dob for objects with structure and detail? new [Re: bunyon]
      #5910515 - 06/08/13 10:24 PM

Quote:

Again, I'm not trying to talk you out of visual astronomy at all. I would caution, as others have, to move slow, take your time and gain some experience. I would also add, don't imagine money can overcome the need for experience. Anyone will see more in a big premium scope but one who hasn't learned to observe won't see all that can be seen in any scope.




I completely agree.
Rob, take it easy. Do not sell or buy scopes. Get more mileage of what you already have first.
Jason


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Fred1
Carpal Tunnel
*****

Reged: 09/19/07

Loc: Somewhere in the Orion Spur
Re: Big dob for objects with structure and detail? new [Re: Jason D]
      #5910528 - 06/08/13 10:34 PM

Rob, one of the founders of my club puts together these videos every month. You'll find most of the galaxies you asked about as you move through the continuing series.
Galaxy Log After accessing the site click on Galaxy Log Videos on the right side.

Edited by Fred1 (06/08/13 10:39 PM)


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omahaastro
sage


Reged: 08/30/06

Loc: Omaha, NE
Re: Big dob for objects with structure and detail? new [Re: Jason D]
      #5910532 - 06/08/13 10:37 PM

There's a faction of amateurs who will never find what they're looking for... ie, the beautiful, even color, views of galaxies, nebulae, etc... they see in astrophotos. I think those people may need to simply pursue astrophotography to get their fix... that, or consider a video imaging system, like a Mallincam. Then, there are those of us who will continue to be thrilled, hunting down and looking for subtle details in these faint fuzzies.

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omahaastro
sage


Reged: 08/30/06

Loc: Omaha, NE
Re: Big dob for objects with structure and detail? new [Re: omahaastro]
      #5910556 - 06/08/13 10:53 PM

Yikes... reviewing the 'new to astronomy' gentleman's equipment list... it would seem he's already explored nearly every facet of the hobby, lol.

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robininni
scholastic sledgehammer


Reged: 04/18/11

Loc: Stephenville, TX
Re: Big dob for objects with structure and detail? new [Re: omahaastro]
      #5910577 - 06/08/13 11:09 PM

Quote:

Yikes... reviewing the 'new to astronomy' gentleman's equipment list... it would seem he's already explored nearly every facet of the hobby, lol.




Yes, I've started my adventure in astrophotography but still find something very special with visual. I get frustrated at the lack of 'wow' factor with many targets looked at visually, and so I'm looking for 'the list' of wonder targets that really scream awesome at you when you center them in the EP!

Rob

Edited by robininni (06/09/13 12:08 AM)


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robininni
scholastic sledgehammer


Reged: 04/18/11

Loc: Stephenville, TX
Re: Big dob for objects with structure and detail? new [Re: Fred1]
      #5910580 - 06/08/13 11:10 PM

Quote:

Rob, one of the founders of my club puts together these videos every month. You'll find most of the galaxies you asked about as you move through the continuing series.
Galaxy Log After accessing the site click on Galaxy Log Videos on the right side.




Thanks so much, i'm checking them out!

Rob


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auriga
Pooh-Bah


Reged: 03/02/06

Re: Big dob for objects with structure and detail? new [Re: robininni]
      #5910643 - 06/08/13 11:55 PM

Quote:

I know from the start that some or even many may argue that most all DSOs have discernable structure and detail and that is part of what is so neato about astronomy--staring long enough and hard enough and using averted vision to discern those details!

But my point of view is that a faint smudge of a galaxy that is literally a bluish smear does not qualify and even brighter little smudges (blue snowball) don't get me excited. I am interested in a list of objects with **magnificent** detail such as the whirlpool galaxy, the sombrero galaxy, many globular clusters, and of course the orion nebula--these sorts objects--that one can readily detect much structure and intricacy with a large size reflector (say 10" and up). I also like many open clusters because I think they are beautiful.

Does anyone have such a list?

My reasoning is #1, I would like to have such a list, if already available, for my own enjoyment as these are the objects I like to view.


#2, I am debating about my future in visual astronomy and what telescope I want to have. I currently have a 10" Orion and and 25" Obsession. I am considering getting a 24" or even 20" Starmaster and selling the Obsession. Both would be shorter and I would just go with the 20" for not needing a ladder at all, it fitting through doorways, it being easy for one person to mess with the mirror, etc., but I know the difference in views between a 20" and 24" can be pretty big and so I don't know if I want to downsize from the 25" to a 20".

However, I use my larger aperture reflector to try to see more of already very visible objects and not to find tiny smudges that can't be seen in smaller reflectors. All I care about is seeing more detail in already detailed structures like m51. So I'm wondering if 25" of aperture is overkill for me because I'm just not hardcore and like looking a 'pretty things'?

I'm pretty new to astronomy, so I don't have a great knowledge of the heavens, but if out of the 1000s of objects amateur astronomers look at there really aren't but a handful of m51-like objects, and most use big apertures to resolve super faint objects rather than look at the already interesting objects available at smaller apertures, I think I would feel okay with downsizing for comfort as I am only going to view that handful of objects I am interested in, and 25" is a lot of scope to mess with for that. Does this make sense?

Any advice here on the objects I like or the benefit (or lack of benefit) of huge aperture for what I am doing?

Thanks,

Rob




Rob,

I don't think you are misguided at all and I don't think you need more experience to make your decision.

If your 25 inch is f/5, or f4.5, I think you will find a Starmaster 20" f3.3 very much smaller and much more convenient to use. Get it with a Lockwood mirror. You can sit down to observe. It will fit through doorways much more easily. Much easier to transport in a car or van.

Or you could get a jpastrocraft 16" f/4, which I have, with a Lockwood mirror. Extremely convenient and fun to use. Easy to set up and take down, integral wheels, which is a great help, seated observing for all objects.

A great many objects will be beautiful in either of these scopes. i too am a fan of showcase objects rather than dim hardly visible objects. Among my favorites are The Leo Trio, and the Veil. I estimate that there are at least 50 spectacular objects in large telescopes. All the bright globulars, for example, there are about 15 really bright ones, all the showpiece objects in Coma-Virgo, there are at least 20 of those, the Ring, The Helix, the Dumbell, the the Eskimo, the Blue Snowball, and M 8, 20, 43 among the bright nebulae, and lots of open star clusters, among them the Wild Duck and the three big clusters in Auriga.

With either of these scopes, you won't see quite as much detail but you will still see plenty of detail, you will see it a lot more often, and you will enjoy it more.

And Rick Singmaster, John Pratte, and Mike Lockwood are class acts, very good people to deal with.

Hope this helps,
Bill


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astrokwang2
sage


Reged: 05/06/04

Loc: Arizona
Re: Big dob for objects with structure and detail? new [Re: omahaastro]
      #5910716 - 06/09/13 01:00 AM

Quote:

... Then, there are those of us who will continue to be thrilled, hunting down and looking for subtle details in these faint fuzzies.




Yep.


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GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Big dob for objects with structure and detail? new [Re: auriga]
      #5910721 - 06/09/13 01:01 AM

Fundamentally, the realization that the visual impression of any low surface brightness 'fuzzy' can *never* come close to its photographic aspect must be hammered home.

One way to get there? Walk around your home at night when only exterior lights are illuminating the indoors. Compare the detail seen when doing the same during the daytime. Small body fonts in a newspaper article in the day are usually very much better seen than much larger headlines in a darkened room. The detail is there; it's just that under conditions of low light our resolving power sucks.


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derangedhermit
Pooh-Bah


Reged: 10/07/09

Loc: USA
Re: Big dob for objects with structure and detail? new [Re: GlennLeDrew]
      #5910777 - 06/09/13 02:03 AM

It seems you are well-funded. I think you are tired of the 25". If I were you, given what you have said, I would get a more recent (very fast focal ratio), more portable Dob in the 18"-20" range with Go-to drive built in from the maker. It's still going to require effort to use it, compared to your 10" or your CPC 1100.

If you need to sell the 25" to get the new one, then sell it. Otherwise, just hang onto it for a bit - put it in proper storage and let things develop. You may want to come back to it, either as is, or with new optics, or with a modified structure, or just to try again after you have some more experience before you sell it.

Then, given your other listed equipment, you can try the whole range of amateur astronomy at a high level and find what parts of it you want to pursue further, to focus on.

I don't remember if you listed any software. Skytools 3 won't show you images immediately like those at Hubble Heritage, but you can use its database to plug in what you know you like, and use the search filters to see how many similar objects there are in the entire sky.

I have a 12.5" Obsession. There are easily over 100 objects I find visually pleasing, just to look at them. Not all of them make me gasp, but I want to see them again and again. It sounds like you may be more selective, but with 18"-20", I think you can find 100 things too, but you're going to have to like (at least one type of) globular clusters, bright nebulae, and planetary nebulae. Maybe that's enough for you, maybe not.

I live in Burleson, not very far from you, and am not much of a joiner myself. Send me a PM if you care to.

Lee


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acochran
professor emeritus


Reged: 06/19/08

Loc: So. CA
Re: Big dob for objects with structure and detail? new [Re: derangedhermit]
      #5910860 - 06/09/13 04:11 AM

I'm a little the same way, wanting to see more than faint fuzzies. When I look at M51 I wish I had a brightness knob on my scope I could turn up, like on an old TV. All I can do is look for darker skies.
Google "galaxies" on the Internet, you'll find a list of the ten brightest. Plus other lists of galaxies. Look for the ones with the highest surface brightness.
There's one I want to see, low in the south about 9PM here right now, just above the giant globular cluster Omega Centauri. I think it's NGC 5128 a mag. 7 galaxy. Those are rare.
Check out all the nebulas in Sagittarius, they are magnificent!
Andy

Edited by acochran (06/09/13 05:34 PM)


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