first light on 16" lightbridge report

[sejanus (Gavin)]

thought I'd post a bit here for anyone considering one.

The scope moves very freely and smoothly, albeit a bit noisily. You can literally move it with a finger, which is good for the wife as she's keen to use it.

It's actually not as hard to move around as i thought it would be - you just lift it out by the truss poles and whilst it's heavy, it's manageable to move it short distances. I wouldnt want to carry it down stairs though.

As indicated on a previous thread the focuser was a bit temperemental but with the tips in there I have it working reasonably now, though it's still a bit "loose"

Collimating it never really worked. I've never had a prob collimating my previous scopes, but for the life of me I can't get the laser pointer to hit the center of the mirror. It's about 2-3cm off. Will have a further look today

Even not collimated, the detail on the moon was pretty darn cool. Better than I've seen before.

I then tried to put the argo navis on it but just wasn't sure of a couple of steps and so held off until today to email gary.

So then I tried some sight seeing. Orion was very low in the horizon, and looked about the same as old C11 used to when it was right overhead. I'm afraid I was a bit too tired to wait until 3am for it to rise to a decent height.

I then decided to put the telrad on as I was having problems finding stuff with the 1800 odd mm focal length. This is where I got a bit annoyed - just with a 2" eyepiece, and the telrad - the scope is now unbalanced and top heavy. if you don't hold it, it just goes down all the way to it's lowest point

So apparently meade only want you to use very light eyepieces, and their included garbage red dot finder

So I guess I need to figure out a way to put some weights on the base of the scope to balance it better. I went to bed deciding to look at it in morning and maybe go to hardware store.

So basically ;

good points ;

- optics seem promising despite dodgy collimation
- very smooth effortless moving of scope

bad points

- needs some home brew mods to make it usable long term

and the obligatory piccy ;

http://www.gavincato.com/tmp/lb16.jpg

[xelasnave]

Neat..do you plan to dress it with a cover over the trusses?
The weight problem will be found with most dobs I expect but that is not a worry.
I have a shock cord in place to stop my dob falling down when you add a heavier ep (ep with barlow saw it tip and I just caught it in time) probably would have caused no damage but the potential was scary.

when I started in the game all I ever wanted was a 16 but now they are here I can not get motivated mainly cause there are too many scopes laying around.

Thanks for the write up and impressions. The photo was great.
alex

[astronut (John)]

Hi Gavin,
Great report. Out of the box the LB's are a good scope, but as you've found out they do need some personal touches to make them work even better.
As Alex mentioned a shroud is a must. I also recommend a dew/light shield for the end of the tube. Since installing mine I haven't lost one night to dew (even at the wettest times)
The alt brake is a good idea, but..............it should only be used to steady the scope it will not balance it.
The scope needs to be balanced with weights first. On my 12" LB I use 2.5kg on the upper part of the lower tube and 1.25kg on the lower part of the same tube. This allows the scope to be balanced from horizontal to zenith, I then use the alt brake to steady it.
If you would like some images, I'll be happy to supply them or just go into the Lightbridge Mods thread.
There are other mods to carry out, stiffer springs, hand operated secondary & primary knobs and also blackening the inside of the end rings.
Or just powder coat (black) all the rings, $40.
But in the meantime, enjoy that big light bucket on the sky.

[DaveM]

For collimation of my 16LB I use an Orion collimating eyepiece, and then get to get things really close use a Catseye autocollimator. With the autocollimator you can get the best view possible, and I really noticed the difference when viewing Jupiter after I got it. I don't use my laser collimator at all now, because I can't be stuffed trying to collimate it, and it isn't that precise anyway. I try to do set up before it gets dark when possible, because everything is much easier to see.

For a counterweight I have used a couple of barbell weights in a money pouch, which I wrapped around the base. Not elegant, but it works until I come up with something else. This allows for a shroud, Paracorr and 31 Nagler to be used without any dramas.

Cheers,
David

[sejanus (Gavin)]

thanks guys

astronut - how do you attach the weights to yours? I have tons of lead from scuba diving but not sure if I should use it!

[astronut (John)]

Hi Gavin,
Here are some images of the counter weights.
It's two 1.25kg round weights in a dvd holder on the top and one 1.25kg round weight in a dvd holder on the bottom. It's all held in place with self wrap velcro, solid as a rock and will only come off if you want it too.
You will have to adjust the amount of weight according to your accessories.
The lead should be ok as long as your not constantly handling it.

[astronut (John)]

Here is a dearer, but more aethstetically pleasing solution.

[CoombellKid]

Top heavy with premium ep's. That's the reason I wont be buying one. I've
heard this complaint quite a bit. So I decided to build my own.

It wouldn't surprise me either if Meade put out a counter weight system to
fix this problem and try to sell it to you as an accsessory lol

regards,CS

[sejanus (Gavin)]

Question - anyone know anywhere locally to get a shroud from?

[Rodstar (Rod)]

Any half decent seamstress could knock one up for you for a pittance.

Not sure about local vendors. JMI advertise them a lot in the US.

[JethroB76 (Jeff)]

If you're going to go the US route for shrouds, Astrozap are said to be very nice, I think they've had a 16" LB one for a while now.