First Light - at last - 16" Lightbridge (LB)

[albedo0.39]

Excuse the long report...

I've been on the forum for only a few weeks now and think it's brilliant. Lots of good advice and plenty of information to keep the creative juices flowing.

Anyhow, after nearly 3 weeks of owning a 16" LB, I gave the scope it's first outing yesterday - quite by accident.

Since getting the scope and inspired by good engineering practise, with what Mick and others have done with their LB, I modified as follows:-

• Completely flocked both upper and lower tubes
  
• fitted handy S-S carrying handles to upper and lower tubes
  
• modified the secondary collimation mechanism
  
• Added side stiffeners and additional bracing to bottom carcass
  
• Indexed the truss tubes
  
• added cork to strategic areas of truss brackets to aid stiffness when locked
  
• Replaced all fixings with stainless steel cap screws and deep section washers
  
• Indexed / centred spider in upper tube
  
• Mirrors were re-silvered by Galvoptics
  
• Bearings polished
  
• Touched up all paint with perfect match Revell Satin Black
  
• In addition, all truss tubes / rings had been painted black.
  

So yesterday evening (it was getting dark-ish) and I had just finished the putting the upper tube together and thought I'd see what it looked like built up on my patio.

I thought "why not - let's see what it's like to collimate" so I wound the primary adjustments until the mirror was fully compressed and then backed off 2 turns on each.

Getting nervous now...

Now remember, I've had 3 weeks to read almost every bit of wordage on collimation out there. Books, Magazines, the interweb...everthing. I stood there in shorts, a T shirt on, a collicap and a cheshire ready to take on an F4.5 - known to eat amatuers like me for breakfast.

No laser, no Catseye, nothing auto-whatsoever about this collimation. It was going to be rough and very ready.

With careful adjustment of the secondary mirror I got it central and aligned to the focuser tube. With my modified secondary mechanics, it literally took me a few moments to get it completely aligned. I then removed the dustbin lid from the primary and with a couple of tweeks of the primary had all the optical surfaces in line.

Surely... it can't be this simple ?

So, I started all over again and this time, with a collicap and the cheshire did it one more time from scratch. Again, in about 3 mins, I was back in alignment. Also, because the springs were nicely compressed there was no difference whatsoever between collimation at any angle.

Now, I'm getting really nervous / excited !

I'm sitting in front of a 'scope I could have but dreamt of about 2 months ago and all that stands between me and what I can imagine are the eyepieces in the house.

I quicky rush inside and grab the lot.

Right now, I have a 9mm Meade 5000 Super Plossl, 12mm Plossl, 17mm Plossl and Meade 26mm 2" QX" WA . All pretty average, nothing special anywhere (I'm expecting really poor views from what I have read, but hey ho..)

I plug in the Meade 5000 9mm, head for Polaris and try to kick off with an alignment of the Red Dot Finder. It's twilight and I can see about 10 stars - at most.

Mrs Steve comes out with a cuppa, a coat and some gloves (it was a bitter strong wind...) - I realise I'm now fully authorised to stay out as long as it takes.

I find a star in the eyepiece and focus and "presto" it focuses. I'm not studying, but WOW.. is that bright or what ! - I look up and can barely see that this canon is looking at.. After a few minutes, i spot it and align the RDF.

I then slew the scope to the next bright object. I think it's Procyon - nothing special. What else is in the sky ??

I know... Saturn ! - Gulp

Nervously, I swing the scope to the orange star in the sky. I'm sure it's Saturn because "Stars twinkle, planets don't" and of course I've been tracking in Stellarium for weeks now. I align the RDF over Saturn and then take in my first view of the planet.

"Oh my.. is that real ?"... I literally held my breath. It looked like a photograph had been taped to my eyes. It was simply breathtaking. The shadow of the rings on the planet, the cloud belts - the colours... I was simply not prepared.

But hang on... I've only got a cheap eyepiece in and the scope cannot possibly be collimated.. I must be mistaken. But no. For the next hour I start to split doubles, and see things that I was not prepared for. I tried a star test and all I got was a perfectly circular blob, with a shadow of the secondary and the spiders perfectly central to the image - no matter what I did, no airy disc. I've since learned that the previous owner has never seen an airy disc on any fast / large aperture dob in the UK.

So - apologies for the length of my report, but I'm just so excited about what I've seen.

I think I managed to collimate the scope pretty much first time. Sure, I know I'll improve in the daylight, but the star tests seems to be OK and moreoever, I know how I got to collimation.

The LB is so tweakable it's an engineers dream and I'm grateful to all those in SGL that have dropped me the odd advice. If you have any comments on my set up, I'd be only to pleased to hear them (and about my low-tech collimation)

But for me, that hour in the garden yesterday night between 9 and 10pm, and that first image of Saturn at 200x was the best free show on earth. I cannot wait for Kelling, trying out new eyepieces and all that goes with this superb hobby.

Thanks for reading !

[G4YVM]

Nice review! The excitement is palpable.

makes me in more of a hurry to get my own finished!!

David

[Beyond_Vision]

Great report Steve sounds like a fantastic set up you have there. I see you are in Cheltenham. I am a member of the Cotswold Astronomical Society we are holding a Cheltenham Science Festival Star Party on June 3rd would y0u be interested in bringing your scope along?

Regards

Kevin

[Lee]

Fantastic first light report.

You just can't beat a big dob. Could you add some pictures of it?

Lee.

[Doc]

What a fantastic first light report.

As you say the view from this monster is unbelievable. I've also only got average eyepieces but am saving up very slowly for a set of naglers so I expect the view with a MPCC to be something special.

I'm surprised your collimation went so easy, I struggled for a while but once you cracked it you find it's pretty easy from then on.

Does your collimation move a tad when you lock your primary mirror down with the locking screws?

Anyway post some pics please.

[calibos]

Nice review! The excitement is palpable.

makes me in more of a hurry to get my own finished!!

David

Ditto!!

I've read lots of First Light reports and observing reports in general. Doc's for instance are always a fabulous read and I look forward to them. There was something about your report Steve though that really got my juices flowing. Dunno whether it was the writing style or the content but like David said, "The excitement is palpable"

I've been working on my own LB16 for a week straight at this stage and was starting to lose motivation. I'm exhausted and was going to rest for a few days, but this post has fired me up again to get back into it without rest Would you believe, I've had my LB16 since before Christmas and it got about a 5 minute first light! I really need to get it finished soon and get it out under the stars like you and Mick(Doc).

[mdstuart]

I remember my first night out with the 10 inch dob and I was just blown away by the quality of the optics on the skywatchers. Lovely coloured dots and the pole star double was fine...

Mark

[acey]

Does your collimation move a tad when you lock your primary mirror down with the locking screws?

Mine does (on a 12" flextube) so I don't lock them down. The mirror should remain steady without them, if not then you want the barest touch necessary to stop any movement. They're designed to lock things hard during transport.

[albedo0.39]

Great report Steve sounds like a fantastic set up you have there. I see you are in Cheltenham. I am a member of the Cotswold Astronomical Society we are holding a Cheltenham Science Festival Star Party on June 3rd would y0u be interested in bringing your scope along?

Regards

Kevin

Hi Kevin - If I'm not racing the next day, then I'd be pleased to do that.

If you PM me with the details, I'll drop it into the diary. Of course, I had considered joining the CAS but It's on the "to do" list. Also, I've never been to a Star Party so if there is a defined protocol of do's and don't then I'd appreciate the heads up.

Cheers

Steve

[albedo0.39]

Does your collimation move a tad when you lock your primary mirror down with the locking screws?

Anyway post some pics please.

Hi Mick

I think I mentioned in another group (Yahoo LB) the collimation stayed on the nail between zenith and low down viewing (such that it was). I highly recommend the 2ndary mod (posted in SGL) and also to crank down the primary and then back off a couple of turns.

I then used just 2 adjustments to get primary in collimation - makes it a cinch (and that, as you can gather was not what I expected).

Trouble is.. it's now cloudy for the next few days so I'm still living from retinal memory !

Pictures are in my camera - will be posted shortly (regretfully with me in the frame as well)

I feel such a kid with this scope !

[albedo0.39]

Ditto!!

I've been working on my own LB16 for a week straight at this stage and was starting to lose motivation. I'm exhausted and was going to rest for a few days, but this post has fired me up again to get back into it without rest Would you believe, I've had my LB16 since before Christmas and it got about a 5 minute first light! I really need to get it finished soon and get it out under the stars like you and Mick(Doc).

Oh no... keep going !!!

You have plenty of time left to give it first light. I took mine down to it's constituent parts and was in fact thinking the other day:-

"will this ever work again ? - will I ever look through it instead of at it"

Never mind, the quest is not over yet and now I've seen it working, I'm off on another bunch of upgrades, most of which involve the ease of transportation.

Good luck - what is yours in dry dock for exactly ?

[John]

Mine does (on a 12" flextube) so I don't lock them down. The mirror should remain steady without them, if not then you want the barest touch necessary to stop any movement. They're designed to lock things hard during transport.

It's the same with my 12" Lightbridge as well. I don't use the locking screws on mine at all now.

Nice 1st light report albedo0.39

John

[calibos]

Hi Steve,

Planned a heap load of mods, Functional, Aesthetic and Whimsical. Ordered all the bits and pieces over the last few months. Received most of the bits and pieces over the last few months........Realised that the one mod that needed to be done before all the others could start.....was the last thing to arrive

Thats why its only now that I am able to do the bulk of the work in the last week or so. Should be finished in another week.

One clue as to what I am up to is the name I am giving my LB16. It had to be wordplay with an astronomy tie-in and something I could maybe 'Theme' the scope around.

I chose....'KnightRider'

[Eddie]

Super first light report. Makes me miss mine!!!

Eddie

[Doc]

It's the same with my 12" Lightbridge as well. I don't use the locking screws on mine at all now.

John

Yeah I don't lock mine down either now.

[albedo0.39]

OK, I finally managed to grab some images of the first light "test run" - excuse the shorts and the plastic bag deep sky filter over the secondary in the shot..

More to follow..

[Doc]

Very nice Steve I like the supporting braces (now where did I see them before ). My altitude break had been moved to the opposite side as I find you never use it anyway.

Looking good. Whats your next mod?

[irishbloke]

Hi Steve,

One clue as to what I am up to is the name I am giving my LB16. It had to be wordplay with an astronomy tie-in and something I could maybe 'Theme' the scope around.

I chose....'KnightRider'

Going to have the red leds and talking watch? actually the talking watch isn't such a bad idea cause I near blind myself when looking at mine a t night!!!

[calibos]

Going to have the red leds and talking watch? actually the talking watch isn't such a bad idea cause I near blind myself when looking at mine a t night!!!

Yep! That would be one of the whimsical mods to tie the scope to the Knightrider Theme. Its one of the few things I am doing to the scope that has no functional purpose whatsoever. Its just there to look cool!

(Needless to say it'll only ever get switched on before an observing session to give other amatuers a laugh before being switched straight back off. Will only ever be left on for public outreach events near streetlights where dark adaptation is a non issue. At those kind of sidewalk astronomy events, it'll be fairly eyecatching and attention grabbing and might help pull in passersby from a greater distance who come over to investigate the rolling LED they saw from a distance.)

[albedo0.39]

Looking good. Whats your next mod?

Well, I'm definately adding a Wixey, but the effort there is more about reaching for the credit card than anything manual... (PS where is the best place to get them from .. I have seen them on O-Bey for £25 ish)

After that, I'm now looking at Lower OTA weights, teflon bearing for altitude, transportation wheels and a mod to the AZ bearing. In all honesty, I do not find the movements "buttery" like all the literature suggest but perhaps it's because I work in precision engineering where 1 micron is a large unit.

Also as I head up the company that did the Drive and Motion control system for the Centre Court of the new Wimbledon Roof so I have many many ideas to add a very tasty movement to the axes... but... that would perhaps be against the spirit of what I see as my pleasure from a Dob - namely it's a "mop and bucket" set up rather than i-SCope (if you get my drift)

BTW - my bracing was in OAK and although it doesn't match the white, thought it something I wouldn't have to worry about the odd blemish and knock

Cheers

[Doc]

Get your wixey from FLO, mine was included in his SGL discount scheme.

IMO replacing your bearings for teflon and formica is no replacement for a properly balanced scope. Balancing is the key word here, get it right and the factory bearings are very good indeed.

[albedo0.39]

IMO replacing your bearings for teflon and formica is no replacement for a properly balanced scope.

As always.. you now have me wondering. I moved my mirror a little further down the tube (0.25") but in no way does it feel out of balance. It always stays where it is put, even without the alt brake.

How to check this ?

[Beyond_Vision]

Hi Kevin - If I'm not racing the next day, then I'd be pleased to do that.

If you PM me with the details, I'll drop it into the diary. Of course, I had considered joining the CAS but It's on the "to do" list. Also, I've never been to a Star Party so if there is a defined protocol of do's and don't then I'd appreciate the heads up.

Cheers

Steve

I will find out the details and PM them to you. The CAS meetings are on the second Saturday of every month at 7.45pm at Sherdington Village Hall.

Regards

Kevin

[legion48]

OK, I finally managed to grab some images of the first light "test run" - excuse the shorts and the plastic bag deep sky filter over the secondary in the shot..

More to follow..

Ok, because it was such a good first light report I'll forgive the shorts, but the tee shirt?........Never!

[Doc]

As always.. you now have me wondering. I moved my mirror a little further down the tube (0.25") but in no way does it feel out of balance. It always stays where it is put, even without the alt brake.

How to check this ?

Steve mine still have the felt bearings and it's very smooth. I see from your photo you are still to fit a finder or two. And depending on what size eyepieces you are using will depend on how much weight you will need to fit on the lowet OTA.

There's no special way of testing just makes sure when the scope is tilted to say 60 degrees it doesn't move up or down due to it's own weight distribution.