Thoughts on the 16" Lightbridge from any owners

[peterbat (Peter)]

I've been using an LB16 for a couple of years now, and am still impressed by the views every time I get it out. Collimation can be a bit of a problem, but adding a set of Bob's knobs to the secondary made it a lot easier to tweak from time to time in an evening, and a laser collimation tool speeds up the process as well.
Using the fan to cool the primary for at least 30 minutes improves results quite a bit.
I took the tubes apart and had the rings and trusses powder coated mat black, and as I'm in inner suburban Melbourne I have a shroud, and a padded extension to the secondary cage - this helps block stray light, and also cuts down dew problems.
To make it easier to fit through doorways, and in the back of my car, I've cut down the circular plate on the base.
The eyepiece that comes with it, (QX 26mm) can give good views, but coma is obvious around the edges. I bought a 13mm Teleview Ethos, and the views are spectacular! This is the eyepiece that I use most of the time.
Now that I've added an Argo Navis I am in 7th heaven. Given the constraints of a very polluted sky, I'm seeing much more than I ever did with my 10 inch.
As Astronut says, every scope is a work in progress...
Would I buy this telescope again, given all the tinkering I've done to get it to just the way I want it? Absolutely.
I'm going to be up at the Border Stargaze. If you happened to be coming also I'd be happy for you to see just what this scope can do.

Peter

[garin (Garin)]

I've had my 16" Lightbridge for around year and I love it. Apart from being a bit large to move around (I still use my 10" around home).
We had a mini Messier marathon here in Perth a while ago and it really worked well, in fact the problem that slowed me down was I could see so many galaxies in the Virgo & Coma clusters, picking the correct object was the problem.

I didn't particularly like the included red-dot finder and have replace dthis with a Telrad (which I swap between scopes) and I couldn't really use it until I fitted a shroud - this wasn't due to stray light but due to my paranoia of dropping an eyepiece onto the main mirror will changing eyepieces.

The Altitude brake is mediocre and you need to make some kind of counterbalance weight arrangement to balance the scope, particulary when using heavier eyepieces.

I do get a bit of collimation shift from horizontal to upright position which I'm trying to nail the cause - I hear this is not uncommon. I have purchased a laser collimator that will allow me to easily check/fix the collimation during the viewing session.

I have also heard a number of people stating that the optics aren't upto the Obsession standards, this may well be true but taking into account that I paid AU$2195 brand new there is a massive difference in price.
I have fitted an Argo Navis now and have found this great and certainly optimises my observing time.

All in all it's not perfect but with few inexpensive modifications you can have a large apeture scope that's a joy to use.

Let me know if there are any more specific questions you would like answered.

[Don Pensack]

After collimating a friend's with Catseye collimation tools, I went back during the evening to look at the scope. Truly excellent optics--the equal of some premium scopes I'd looked through.
Add a Paracorr, and his scope was good enough to justify rebuilding with first class materials. It owed nothing to the premium mirror crowd.
I was, to say the least, surprised.
I don't know if it was typical, but I would expect a primary mirror of that quality to cost more than his complete scope.
A true bargain, I think.
Now the mechanicals? Well, let's just say the telescope is made to a price.

[stephenb (Stephen)]

Thanks to you all, as I said, I'm not interested in the mechanical side of the scope, but more regarding what I can expect to see with a 16" aperture, given this will be the largest aperture I have owned. I now have on order an SDM 16" and I'm looking forward to collecting it in the coming weeks. First light will be a hoot!

[JimmyH155]

I have a 12" LB and am thrilled with it. Remember, guys, the 16" has 218 square inches of aperture, whereas the 12" has 113 square inches - thats nearly twice more light gathering in the 16" THATS why youses will see that flag on the Moon
For me, an old codger, the 12" is the limit for carrying. I would find the 16" just too heavy and probably do myself a mischief with it

[Satchmo]

There's not much difference between a 12" and 16" until you take them out to a dark sky.

[stephenb (Stephen)]

Originally Posted by Satchmo

There's not much difference between a 12" and 16" until you take them out to a dark sky.

Are you referring to the weight, Mark?

[Satchmo]

With a bright suburban background, the view don't look too much different between a 12" and 16" . For example If the spiral arms or faint outer extensions of a galaxy are fainter than the local sky background, no amount of aperture will make them more visible. Larger apertures drag in sky glow as well as star light: the old adage `garbage in , garbage out' holds with telescopes too. If the seeing is very good the larger scope with good optics can reveal more planetary datail.

[Starkler (Geoff)]

One time at the club site, I wanted to do a side-by-side between the views in my 15" and a 16" LB. I was getting excellent high power views of saturn in good seeing at around midnight, some 4 hrs after set up.. I wandered over to the LB for a peek and saturn was a boiling bubbling mess.

These scopes with their 2" thick mirrors housed in such a way theres no airflow around the mirror could really benefit from forced air cooling. I'd say its mandatory or it will never perform like it should.

[Calibos (Keith)]

Couldn't agree more Geoff. I'll be implementing an innovative boundary layer fan system in mine to complement the main cooling fan at the rear. Also insulating the inside of the tube to prevent tube currents.

As you can imagine its a much more difficult proposition on a round metal mirror tub with only 1" to spare around the mirror especially if you don't want to be drilling lots of holes in your tube, than it is on a Premium or ATM with a big square Mirror box.

Thats why I had to get all innovative on the Lightbridges @ss

[Satchmo]

Originally Posted by Starkler

These scopes with their 2" thick mirrors housed in such a way theres no airflow around the mirror could really benefit from forced air cooling. I'd say its mandatory or it will never perform like it should.

Issues of the high expansion material aside , the `commercial' grade annealing on the cheap mirrors does not guarantee any stability of the figure , in the present or the future. But I think the market understands that you get what you pay for. There are no 'free lunches' in optics. They do a job at a price point and are very successful.

[Archy (George)]

Originally Posted by garin

I've had my 16" Lightbridge for around year and I love it. A

I do get a bit of collimation shift from horizontal to upright position which I'm trying to nail the cause - I hear this is not uncommon. I have purchased a laser collimator that will allow me to easily check/fix the collimation during the viewing session.

I also get collimation shift from horizontal to upright position. The cause on my scope is a shift of a truss in the lower truss clamp.