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Equipment Discussions >> Reflectors

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Bill Weir
Carpal Tunnel
*****

Reged: 06/01/04

Loc: Metchosin (Victoria), Canada
Re: Let's talk about the Hubble Optics UL16 new [Re: nirvanix]
      #5566505 - 12/11/12 07:48 PM

Quote:

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


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bhuloka
super member


Reged: 03/06/12

Loc: Maryland, USA
Re: Let's talk about the Hubble Optics UL16 new [Re: Bill Weir]
      #5566619 - 12/11/12 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.


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nirvanix
Carpal Tunnel


Reged: 06/07/07

Loc: Saskatoon, SK
Re: Let's talk about the Hubble Optics UL16 new [Re: bhuloka]
      #5566650 - 12/11/12 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.

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bhuloka
super member


Reged: 03/06/12

Loc: Maryland, USA
Re: Let's talk about the Hubble Optics UL16 new [Re: nirvanix]
      #5566684 - 12/11/12 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.


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bhuloka
super member


Reged: 03/06/12

Loc: Maryland, USA
Re: Let's talk about the Hubble Optics UL16 new [Re: bhuloka]
      #5566688 - 12/11/12 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.

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Sean Wood
super member


Reged: 04/19/11

Loc: North Carolina
Re: Let's talk about the Hubble Optics UL16 new [Re: bhuloka]
      #5577489 - 12/18/12 03:30 PM

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

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


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lamplight
Carpal Tunnel
*****

Reged: 09/18/12

Loc: western MA, U.S.
Re: Let's talk about the Hubble Optics UL16 new [Re: Sean Wood]
      #5598987 - 01/01/13 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)


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dtripz
member
*****

Reged: 04/01/08

Loc: Brooklyn NY
Re: Let's talk about the Hubble Optics UL16 new [Re: lamplight]
      #5599638 - 01/01/13 01:32 PM

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

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c.bernardino
member


Reged: 04/20/11

Loc: Lisbon, Portugal
Re: Let's talk about the Hubble Optics UL16 new [Re: dtripz]
      #5724407 - 03/10/13 06:06 PM

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

thanks in advance,

Carlos


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Symui
super member


Reged: 03/29/08

Loc: 37.9,-121.9 - Northern Califor...
Re: Let's talk about the Hubble Optics UL16 new [Re: dtripz]
      #5724459 - 03/10/13 06:33 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


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dtripz
member
*****

Reged: 04/01/08

Loc: Brooklyn NY
Re: Let's talk about the Hubble Optics UL16 new [Re: Symui]
      #5724864 - 03/10/13 10:40 PM

Still waiting for the 18 to come.

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bhuloka
super member


Reged: 03/06/12

Loc: Maryland, USA
Re: Let's talk about the Hubble Optics UL16 new [Re: dtripz]
      #5725574 - 03/11/13 10:53 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


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Adonfff
journeyman


Reged: 10/13/12

Loc: Europe
Re: Let's talk about the Hubble Optics UL16 new [Re: bhuloka]
      #5732900 - 03/14/13 08:15 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...?


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dr.who
scholastic sledgehammer
*****

Reged: 01/05/12

Re: Let's talk about the Hubble Optics UL16 new [Re: Adonfff]
      #5757299 - 03/26/13 12:27 AM

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...

Edited by dr.who (03/26/13 12:30 AM)


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dr.who
scholastic sledgehammer
*****

Reged: 01/05/12

Re: Let's talk about the Hubble Optics UL16 new [Re: dr.who]
      #5758156 - 03/26/13 12:43 PM

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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bhuloka
super member


Reged: 03/06/12

Loc: Maryland, USA
Re: Let's talk about the Hubble Optics UL16 new [Re: dr.who]
      #5758771 - 03/26/13 06:01 PM

I ordered the push-to DSC's (skyhub) last week.
When I get it, I'll test and report here.
Tong says he is also sending me a spring-loaded brake for the azimuth bearing. I hadn't heard that he improved the altitude bearing to get rid of the bump. I'd like to know what the improvement was, exactly, and if I can do it to my scope.
Meanwhile, I expect the DSC's to arrive in a couple of weeks.


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dr.who
scholastic sledgehammer
*****

Reged: 01/05/12

Re: Let's talk about the Hubble Optics UL16 new [Re: bhuloka]
      #5758786 - 03/26/13 06:13 PM

Excellent! I am not quite half way towards the total price and need to decide between this and that CCD I was looking at. Any updated thoughts on the scope overall?

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alexvh
sage


Reged: 07/29/07

Loc: South Africa
Re: Let's talk about the Hubble Optics UL16 new [Re: dr.who]
      #5785351 - 04/08/13 07:24 AM

dr. who
from around the web, there seem to be mostly good impressions on the UL16. the only serious issue is the collimation shift that seems toget somebut not others. I am waiting on my order to arrive, but when it does, I will give a full review...I have the f4.5 with GOTO on the way.
I went for this instead of the obsession 15"UC. I hope I made the right choice!
looking at your signature, the 16" will be a nice addition to your stable!

Edited by alexvh (04/08/13 07:29 AM)


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dr.who
scholastic sledgehammer
*****

Reged: 01/05/12

Re: Let's talk about the Hubble Optics UL16 new [Re: alexvh]
      #5786389 - 04/08/13 04:51 PM

Cheers Alex! I actually am angling towards a Sumerian Optics. I have relatives and friends in the EU so he is willing to ship to them and they can then ship it to me. However I am thinking about one of the HO 14" mirrors for it...

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bhuloka
super member


Reged: 03/06/12

Loc: Maryland, USA
Re: Let's talk about the Hubble Optics UL16 new [Re: dr.who]
      #5786785 - 04/08/13 08:28 PM

Hi Alex, Dr Who;
From my experience with my UL16 over the last 8 months, collimation shift is not much of a problem at all. I do slight tweaks once or twice during a long night. Using a Glatter laser and tuBlug, this takes only about 1 to 2 minutes. Now that I'm used to it, I find that I can keep the scope collimated, and I can quickly sense when it has drifted a little. This seems to happen more when the air is cooling down quickly. Cooling all parts of the scope ahead of time seems to help. This includes the truss tubes and upper cage, not just the mirror box.

What IS a problem is ...
1. Movements aren't so smooth, (stiction), there's a bump in the altitude bearing, and the azimuth is far too loose.

2. Vibration and general shaking when the scope is pointed below 45 degrees. This is the biggest problem for me, when viewing Saturn, which is currently at only 38 degrees here in Maryland, USA. I have to wait after focusing, and avoid letting my eyes bump the binoviewers. Nudging the scope in this case just causes more vibration, so tracking becomes a real pain. I expect my soon-to-arrive Eq platform to make the scope quite useable at low altitude targets, as I won't have to touch it at all. I can just focus, let vibrations settle, then gaze through my high eye-relief Siebert eyepieces (which I love), as the platform does all the tracking work.

The scope is quite pleasant to use above 50 degrees.
I have ordered a Gregg Blandin Equatorial platform so that I can have tracking, and don't have to worry about stiction.


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