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 Post subject: I'm getting itchy...
PostPosted: Tue Aug 26, 2014 6:11 pm 
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Velocepedist
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I'm starting to dream of that truss dob build again. And I'm scheming on how to get my hands on a mirror larger than the 12" I already have. Definitely suffering from summer Milky-way inspiration. Probably not going to happen anytime soon, but it is fun to dream...

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 Post subject: Re: I'm getting itchy...
PostPosted: Wed Aug 27, 2014 3:42 pm 
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Hubble Optics!

But then if you do that, you might as well just buy the whole scope from them. For $2K, those travel truss dobs are hard to beat.

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Homebuilt 16" Truss Dob
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Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


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Evolution is both fact and theory. Creationism is neither. -Anonymous


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 Post subject: Re: I'm getting itchy...
PostPosted: Wed Aug 27, 2014 6:16 pm 
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Building the scope is part of the fun. Actually, most of the fun. But I will admit, those prices are great if the mirrors are honest. $2100 for an 18" plate glass mirror seems like a terrific starting point. Maybe I'll just keep scouring astromart.

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 Post subject: Re: I'm getting itchy...
PostPosted: Wed Aug 27, 2014 8:32 pm 
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Yeah, I know what you mean. And you're handy with metal work too so you could probably build smnething better than what they offer, and for less $$. But I look at my homebuilt 16" dob, which is great, but the ones from Hubble sure do collapse down a lot smaller. But you're right- a lot of it comes down to the mirror. I wonder how good they are.

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-Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman

Evolution is both fact and theory. Creationism is neither. -Anonymous


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 Post subject: Re: I'm getting itchy...
PostPosted: Thu Aug 28, 2014 4:23 pm 
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Hey, I appreciate the recommendation, so don't take my comment too hard. Even a 1/2 wave 18" is an 18", and that means bright DSOs no matter how you slice it. I've read some forums that give mixed reviews, so probably akin to GSO mirrors. Some are solid 1/6 wave performers. Others struggle to break the 1/3 barrier. And let's not forget about pinched optics. My 12" GSO is mediocre, so I'd be hesitant to spend upwards of $2k for something less than clean.

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 Post subject: Re: I'm getting itchy...
PostPosted: Thu Sep 04, 2014 2:09 pm 
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Chopin wrote:
I'm getting itchy...


There are antibiotics for that bro......................... :mrgreen:

I've seen quite a few criticisms in the reviews of Hubble Optics mirrors, and it seems like it's a crap shoot to get a good one. OTOH if you do happen to get a good one you've got a light-weight sandwich mirror at a great price that should cool quickly. Tough one.......caveat emptor and all that. Let us know what you decide.

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Oh, yeah. The Stifmeister's coming back to Grand Harbor. Deck the halls. Bye-bye, Great Falls. Wipe my a$$ and lick my ba!!s It's Stifler time, baby. Whoo-hoo-hoo. Whoo-hoo-hoo. ~Steve Stifler-American Pie 2 :lol: :lol: :lol:


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 Post subject: Re: I'm getting itchy...
PostPosted: Thu Sep 04, 2014 5:53 pm 
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I'm not in a position to pull the trigger at this point anyway. A better bet would probably be to contract a reputable mirror maker to grind and coat a 20" to my specs. Then I can build the rest around it. Besides, Kerry, in the time it took you to post I've already started down the other dream route, a Borg Binoscope. I've actually become quite smitten with these...

Lunt 100mm ED Binoculars

Still, it's a big chunk of change.

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 Post subject: Re: I'm getting itchy...
PostPosted: Fri Sep 05, 2014 10:31 am 
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Those binos are gorgeous. I'd love to get some nice big color-free binos.

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-Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman

Evolution is both fact and theory. Creationism is neither. -Anonymous


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 Post subject: Re: I'm getting itchy...
PostPosted: Fri Sep 05, 2014 6:30 pm 
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They would definitely be a lot cheaper than the binoscope. But the idea of having a modular design works better in the long run for someone like me, since you can upgrade the scopes at any time. I'm tempted to pounce on the first pair of used Matsumoto mirror diagonals I see. It's a long shot, though. The last pair I'm aware of to hit astromart was like four or five years ago, they were the 1.25" models, and located in China. I won't lie, I'm a little nervous that it won't be long before they stop making them. And I'm just frugal enough to reject paying full price for a new pair.

But yeah, big color free binos with 1.25" collets...how awesome would that be!?!

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 Post subject: Re: I'm getting itchy...
PostPosted: Sat Sep 06, 2014 9:55 pm 
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Pretty awesome! :cool:

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-Erik Wilcox
Homebuilt 16" Truss Dob
8" Antares f/5 Newt
SV 80mm ED Nighthawk NG on M1 ALT/AZ
Nikon Prostaff 65mm spotter on Trekpod
Konusvue 20x80 binos/Peterson PipeMount


"Newt Gingrich is what stupid people think smart people sound like."
-The Great Paul Krugman

Evolution is both fact and theory. Creationism is neither. -Anonymous


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 Post subject: Re: I'm getting itchy...
PostPosted: Tue Sep 09, 2014 5:50 pm 
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Oh yeah - a true, binoscope would be wicked cool. (No, I'm not from Boston, but it certainly fits in this case). I've looked at those for a long time but never pulled the trigger. A binoscope and a 20" truss dob? Yeah that works!!

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Kerry

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Oh, yeah. The Stifmeister's coming back to Grand Harbor. Deck the halls. Bye-bye, Great Falls. Wipe my a$$ and lick my ba!!s It's Stifler time, baby. Whoo-hoo-hoo. Whoo-hoo-hoo. ~Steve Stifler-American Pie 2 :lol: :lol: :lol:


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 Post subject: Re: I'm getting itchy...
PostPosted: Wed Sep 10, 2014 2:40 am 
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Like the Koolaid Man says, "Ohhhh, yeahhhh."

Been watching AM like a hawk. I've seen a few nice mirrors lately from Swayze and Pegasus in the 15-20" range. I don't think 15" would keep me happy for long, but a mirror of that calibre is tempting.

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 Post subject: Re: I'm getting itchy...
PostPosted: Wed Sep 10, 2014 12:35 pm 
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Chopin wrote:
I don't think 15" would keep me happy for long, but a mirror of that calibre is tempting.


The contrast on the high-end mirrors is usually outstanding. You would notice a difference going from 12" to 15", but the logical jump would be an 18" minimum if you are looking for a Wow-factor. 20" would get you a full magnitude deeper over the 12, which is quite significant at that aperture.

Keep in mind a few things before taking the plunge. How are your nighttime temps? Fairly stable or dynamic? In our desert, temps are in a constant state of flux most nights, dropping steadily from dusk until dawn. It can be tough for a 20" mirror to keep up. 16" is about the max for us without having to really dig into the thermal management both on the scope, and time-wise for reaching equilibrium. Of course if you can get that dialed-in, then it's worth it.

Do you have room to leave it assembled for roll-out? It would be nice not to have to put the beast together every time you want to observe from home. If not, will the 20" rocker and mirror boxes fit through your internal doorways, or would you need to leave it in a living area, risking the Wrath of SWMBO (She Who Must Be Obeyed) :lol:

Are you going to transport it, and if so can you get the 20" in the vehicle with all your other gear? With a passenger?

As you no doubt know there are a bunch of other things to consider when owning a scope of this size, but these are the ones that tend to slip to the back of my mind when I get excited and start considering / re-considering getting a 20".

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Kerry

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Oh, yeah. The Stifmeister's coming back to Grand Harbor. Deck the halls. Bye-bye, Great Falls. Wipe my a$$ and lick my ba!!s It's Stifler time, baby. Whoo-hoo-hoo. Whoo-hoo-hoo. ~Steve Stifler-American Pie 2 :lol: :lol: :lol:


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 Post subject: Re: I'm getting itchy...
PostPosted: Wed Sep 10, 2014 4:30 pm 
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Ha ha. All very good points. Of course I know all of this already. But I will give you credit for reminding me. I genuinely don't tend to recall those issues when getting aperture greedy (in my dreams of course). Fact is $4000 (minimum) for a quality mirror of that size can instead get that APM/Lunt binocular telescope plus two premium low power eyepieces and a heavy duty fork mount. A "binoscope" isn't small when mounted, but certainly smaller than the GEM mounted 10" newt that resides in my garage between the push mower and the garden tractor. Better still is that temperature equilibrium is essentially a non issue with 4" objectives, and less so with refractors. I won't lie, a binoscope has been at the absolute top of my dream list since getting into astronomy some ten or so years ago. And this image is one of the main culprits...

Image

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 Post subject: Re: I'm getting itchy...
PostPosted: Wed Sep 10, 2014 4:40 pm 
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But then I see something like this and the gears start turning again... :cheesygrin:

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Single ride personal records: Distance-76.7miles, Max Speed-50.4mph, Max sustained speed (20miles) 19.5mph
“Life is like riding a bicycle. To keep your balance, you must keep moving.” ― Albert Einstein


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