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Let's talk about the Hubble Optics UL16

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#151 starman345

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Posted 11 November 2012 - 04:04 PM

Great report, I much enjoyed reading it. This gives me hope that my 14 HO mirror will deliver good views when I get the scope finished.

#152 sniperpride

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Posted 11 November 2012 - 09:28 PM

No offense, but tell me you are not honestly comparing an 8 inch to a 16 inch scope....If the 16 does not beat it out on fainter objects you have a problem.

#153 bhuloka

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Posted 12 November 2012 - 12:24 AM

"No offense, but tell me you are not honestly comparing an 8 inch to a 16 inch scope....If the 16 does not beat it out on fainter objects you have a problem. "

It was a test of general optical quality, not quantity, you might say. For its size, the 8" Edge HD is really sharp, with absolutely no collimation issues. The Hubble, however, was an unknown, and my first Dob. Until now, it has been definitely fuzzy, and very UN-satisfying in the planetary viewing department. The 8" was very obviously kicking its rear in that regard. But on faint objects, yes, the 16" was always vastly superior right from the start. But I feared that I had gotten a very poor 16" mirror that would never do well with high-power views. So I compared it side-by-side with a known sharp performer, not for brightness,(which would be ridiculous, as you point out) but for sharpness and pinpoint stars, which, until now, I hadn't seen in the 16" because of my poor collimation skills. That was the point, and I'm now satisfied that the 16" mirror is almost in the same league with some very nice premium mirrors I have looked through(an 18" Webster and a 20" Midnight), and better than a 16" Lightbridge which I spent an evening with back in May.

#154 Sean Wood

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Posted 11 December 2012 - 09:02 AM

Hubble has added some products to their line...
A 14" f4.6 UL($1895), 18" f4.0 UL($3695) and a set of Bluetooth adapted digital setting circles they are touting for use with an Android tablet and Sky Safari... U do a single or double alignment and the tablet image follows you. From how they're making it sound. $149 if you get it when you order the scope or $249(+$40 s+h) outright.
Pretty nice additions I'd say.

#155 nirvanix

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Posted 11 December 2012 - 12:26 PM

Yes, I'm now strongly considering taking the Hubble plunge. It's a lotta scope for da money and people seem quite satisfied with performance except for some tweeks. Not sure where I fit in on the size scale. Would the 14" f4.6 need a paracorr? Likely the 18" f4 would.

#156 starman345

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Posted 11 December 2012 - 12:35 PM

I have a 14" f4.48 and haven't finished the build yet, from what I've read it seems some people aren't bothered by the coma while others are, I'm going to try without then see. Like you say, probably at f4.0 coma would be a bit more evident. But, that 18" f4.0 would keep your feet on the ground, a big plus right there. These new additions to the Hubble line make for some nice competition for the other makers.

#157 Sean Wood

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Posted 11 December 2012 - 01:42 PM

I'm considering one of these and I'm coming off of a 10" Light Bridge... The 16 is still looking to be my best bang for the buck... Don't know if I could justify $1200 for another 2" of apature... Or would there be enough difference in views to make it worth my while to save another few months for the big boy?

#158 bhuloka

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Posted 11 December 2012 - 02:24 PM

Well, Sean, the eyepiece height is the same for the 16" f/4.5 and the 18" f/4.0
Therefore I have also wondered if the 18" would have been a better choice. But I am happy with my UL16", as it is lighter and more portable than an 18". The difference in light gathering is 200 sq. in. compared to 254 sq. in. , so a 25% increase. But a big jump in price. So, yeah, brighter, but not $1200 worth, to my thinking.

Regarding paracorr; I'll be binoviewing this scope (Siebert Black Nights arriving next week). The optical corrector that comes with the scope is basically a paracorr for the binos, so I won't be getting a separate paracorr.
I used to think this scope had lots of come, but it was mostly just poor collimation. Since I've gotten better at collimating the scope, the coma has not bothered me much. It's there, but not such a big deal at f/4.5
I find that poor seeing is more of a problem than coma.
When seeing is good, things look pretty crisp, given proper collimation. So I'm glad I didn't buy a paracorr.

The mechanical issues remain unsolved; too much stiction in altitude movements, and too loose in azimuth. These problems ARE solveable, though, if one has some time to spend on them. Next year, I plan to solve them just by getting Hubble's goto system, and letting the motors move the scope.

#159 bhuloka

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Posted 11 December 2012 - 02:27 PM

Sorry; the optical corrector comes with the black night binos, not with the scope.

#160 nirvanix

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Posted 11 December 2012 - 06:38 PM

Thanks starman and bhuloka for answering my question about the paracorr. Nice to hear that the 14" may not have heinous coma.

So much choice in scopes these days. Feels like the kid in a candy store metaphor. :jump:

#161 Bill Weir

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Posted 11 December 2012 - 07:48 PM

Nice to hear that the 14" may not have heinous coma.


It will have the same amount of coma as any other f/4.5 mirror. To many it will be bothersome and to the others who don't care what the edge of the FOV looks like it will be tolerable. To be sure though a f/4.5 mirror has a fair deal of coma. All it will require to clean it all up would be a type 1 Paracorr and there are more than a few out there in the second hand market for a reasonable price. I even have one that I just haven't put on the market since getting the type 2 to go with my f/3.3 mirror.

Bill

#162 bhuloka

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Posted 11 December 2012 - 09:41 PM

Yes, there is definitely some noticeable coma. I didn't mean to imply that it is insignificant; just that it doesn't bother me at the moment, knowing that my coma-corrected binoviewers will be arriving shortly. The coma does intrude on high-power Jupiter viewing, as I have to constantly nudge the scope to try and keep Jove in the coma-free center. I do lose some detail when I let the globe drift to the margin of the field at 389x.
Regarding wide-field views; They seem OK. Well, I haven't used a Paracorr yet, so I guess I don't know what I'm missing. :p

#163 nirvanix

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Posted 11 December 2012 - 10:04 PM

Thanks Bill and bhuloka. I'll just have to wait and see what I feel about the view. Have an f5 now and don't notice the coma at all.

#164 bhuloka

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Posted 11 December 2012 - 10:28 PM

There is also an issue with vibration in this scope. The lightweight build means that the scope will bounce and jitter when it is aimed near the horizon; anywhere below 40 degrees, really. It's not bad at low power, but it's a real deal-breaker at high magnification (over 125x, I'd say).

The GSO focuser that came with my scope was defective. I sent it back to Tong, and he sent me a new one, which works fine. But I replaced it with a Moonlite CR2, which is MUCH lighter, and far lower profile, as well as smoother turning.

#165 bhuloka

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Posted 11 December 2012 - 10:32 PM

At high viewing altitudes, the scope is stable, as long as there's no wind blowing on the spider, which is prone to vibration. One nice point is that this scope handles Dobson's hole really well. This is because the azimuth bearing is so loose that it's still easy to turn when pointed up high. A silver lining to that cloud, I'd say.

#166 Sean Wood

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Posted 18 December 2012 - 03:30 PM

Now they're offering a 16" f5 for $1995.. Wow!!!

Any disadvantages outside of the hassle of a ladder at zenith?

#167 lamplight

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Posted 01 January 2013 - 12:48 AM

pulled the trigger on the 16 myself last week. thank you so much for all the info bhuloka !

Sean, from heir website: Eyepiece height at zenith: 1690mm / 66.5" (f/4.5), 1890mm / 74.5" (f/5)

#168 dtripz

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Posted 01 January 2013 - 01:32 PM

I ordered the UL 18, can't wait to test it out. Quite anxious about the mirror being good however..

#169 c.bernardino

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Posted 10 March 2013 - 05:06 PM

dtripz,
any news now? please keep us posted...
Bhuloka, have you done more obs sessions?

thanks in advance,

Carlos

#170 Symui

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Posted 10 March 2013 - 05:33 PM

Anyone receiver theirs yet? A few folks in the local Astronomy club are interested in learning more about this scope and mirror.
TIA, Rick

#171 dtripz

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Posted 10 March 2013 - 09:40 PM

Still waiting for the 18 to come.

#172 bhuloka

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Posted 11 March 2013 - 09:53 AM

My binoviewers arrived in January, and I have had the scope out several times since then. I did some viewing tests this Saturday night in good seeing. I stayed up all night, in fact, and had some great views; faint fuzzies, open clusters, globular clusters, and Jupiter/Saturn.

The more I use this scope, the more I understand it's strengths and weaknesses.

My overall feelings are:
-The optics are fine, but require collimation to be VERY precise, especially for planetary or double star viewing.
The collimation tends to drift, at least when the temperature is dropping, so, when it's cold, recollimating is an absolute necessity.
-I LOVE the lightweight portability. The scope takes me 30 minutes to carry from the car, set up, collimate, and begin viewing.
-I love the fact that, at f/4.5, I can sit in my Stardust viewing chair comfortably, even at full zenith. (I'm only 5'6", so standing requires a 3" step at full zenith.)
-Movements are not as good as other scopes, but I think this will get better with minor changes: I got some real ebony star bearing material, and some Sailkote spray lubricant. I'll install the ebony star when I get some time.
I think that will make altitude movements smoother, but not perfect. Why not? Because the bearing is only 1/2" wide. I suspect that 3/4" is needed to support this weight smoothly, without stiction. Even as the scope is now, though, Sailkote does seem to help better than other stuff I've tried, like powdered graphite.

Saturday night, I set up next to a 12" Zhummel dob, with excellent optics. At first, I felt that the Zhummel optics were doing much better than mine. But then I realized the cause; I'd just brought the mirror out of my HOT car. Usually I remember to set the scope out to cool for an hour or two, but this time I didn't. What a huge difference that made! Jupiter had a double image, was fuzzy, and shimmering with mirror thermals. Yecchh! The Zhummel was already cooled, had a nice clean, stable image.

So I concentrated on faint fuzzies for a couple of hours.
This scope is great for the FF's!
After the mirror cooled, I checked collimation; it had drifted a lot. Recollimated, then started with Globs, Open Clusters, and Saturn. The mirror was cool and collimated, atmospheric seeing was better, and the binoviewers were rocking! Everything was sharp. I looked at M3 (185x); super resolved!
Then Saturn; so beautiful! Cassini's division was steady, complete 360*, sharp. No crepe ring or Encke minimum, though. The B ring was a darker color than A. I saw3 moons; Rhea, Dione, and Titan. Enceladus was hidden in the planet's glare. (3:15 a.m. Sunday morning)
Then to M57; faint blue-green color. No central star, but I could see the little 13th mag star next to it. A very good view.
Then the real test; epsilon lyrae, the double double.
Darn it, I could not get a clean split! I had only a messy split, still at 185x. There were little comatic spikes on the stars. So I checked collimation. Sure enough it was off, but only by a little bit. Surely such a small deviation couldn't be so bad!?
The barlowed Glatter laser was only off by half a diameter of the Catseye center hotspot hole. I fine tuned it.
Wow, what an improvement! There were now 4 neat little stars in epsilon lyrae, with a tiny bit of clean separation between the airy discs.

The conclusion is that yes, there is coma, and collimation has to be absolutely perfect. (When you get this scope, you must check the center spot placement; mine was off by 2mm!) I wonder if it will be more stable in the summer, when temperatures don't fall so much.
I don't have a paracorr, but I feel that it's not needed, since I use binoviewers almost 99% of the time. The Siebert multi-magnification optical corrector seems to work well enough with the Black Night Binos. Also, I am now planning to get Jim Fry's Catseye collimation tools for even more precise adjustment. I already have his combo sight tube/cheshire, but haven't used it. I will get an autocollimator, and learn how to use these tools (in the dark!). I'm looking forward to the next star party, when I'll be able to set up next to a good premium dob, and have a real optics showdown. I expect the Hubble Optics mirror to finish in a respectable 2nd place.

-Lawson

#173 Adonfff

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Posted 14 March 2013 - 07:15 PM

Hi guys,

I got my 16" at the end of the last year.
I only tested it once because of bad weather with winter but enought to see what tweaks was required.

First test was ok despite the weather was not and according to what I used to see in my LB16 (homemade structure).
Expect for contrast and stability !

For contrast, add foam at the top just like most ppl does and the bottom, when observing from home, even the ground is "shiny", not required when in the real spot.

For stability...brakes, cause without it was a good tool to find the wind direction !
I use one of the hole on the side of the rocker to push a thin plate with a screw, which brake the alt direction just like needed since can be ajusted.
And one hole above the ring to do the same for the az direction.
Will post pics later about them.
And for altitude again, must add a solid iron bar on alt bearings, there are even holes for it since this is an feature of the 18"...but bearings bends without them on both side.

Had to find a correct position for the eyepiece holder to avoid tilting with heavy eyepieces.

And thats it...clouds and heavy wind for months...need some more testing now !

Didnt check for center spot on mirror...just cant believe this happen, how the hell can they place it at the wrong place...?

#174 dr.who

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Posted 25 March 2013 - 11:27 PM

As a way to subconsciously delay myself from buying the mono CCD I am planning I am thinking about getting the 16. Anyone know if the bump and too loose problems are fixed or do I need to prepare to roll my own fix ? I am serious about buying one by the way CCD aside.

I have always had a large Dob in the back of my mind but was always put off by the huge weight, high cost of a ul, and lack of decent goto/push to because of the LP I observe in but with digital setting circles I think I can handle the push to part and with a UL I can cover the weight but I can't justify the expense of an Obsession or the like so this is in the wheel house but I want to make sure it's not a big mistake...

#175 dr.who

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Posted 26 March 2013 - 11:43 AM

Folks-

As an FYI here is the response I got from Tong regarding questions I had:

Hi Carson,

Thank you so mcuh for your interest in our products.

1) We have improved the ALT bearing, so there will be much less chance for the ALT bearing to bump during the movement. However with even with the previous design, the bump is a setup (adjustment) issue, you can always adjust it more carefully, so there will be no bump felt during movement.

2) The looseness in the azimuth bearing have been resolved by adding a very effective adjustable spring load friction brake.

3) I will recommend the SkyHub over GoTo, it is almost working like a GoTo at only 10% of the cost! It literally takes minutes to install. You are right, it is only a Push To and no tracking.

4) Yes, we do offer an advanaced GoTo system at a very reasonable price. http://hubbleoptics.com/GoTo.html.



5) We will offer a light shield option soon.



Thank you and best regards,
Tong






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