Dragon Astro 12" Dob

[Beulah]

1 hour ago, mapstar said:

The uppers are fixed with bike skewers so there's no rattle or movement on any of them. 

Yeah, hoping to upgrade to them, too Don't fancy losing wing nuts as they fly off into the ether after furtive attempts to tighten them with cold hands... 

[Dragon_Astro]

14 hours ago, Beulah said:

I used around 10swg (3.25mm thickness), just under an inch diameter (roughtly 22cm) tubes and they are pretty sturdy. If you are planning to connect the 8 truss tubes as one unit, make sure you don't overtighten the fixings as there needs to be some flexibility and movement when you construct the telescope. Once connected to the primary box and secondary cage (those fixings should be hand tight), the truss tubes are sturdy, trust me!.

The great thing is that parts can be replaced as you have made them and mods are never ending! I'm using metal wing nuts and have promised myself to replace with ergonomic plastic ones as soon as funds allow.

Pics, please!

10swg? Hmm maybe I need to look at thicker gauge tube...I'd originally thought 16swg

[mapstar]

8 hours ago, Dragon_Astro said:

10swg? Hmm maybe I need to look at thicker gauge tube...I'd originally thought 16swg

Plenty thick enough 

[Beulah]

10 hours ago, Dragon_Astro said:

10swg? Hmm maybe I need to look at thicker gauge tube...I'd originally thought 16swg

Yeah, I was just being uber cautious....

Heat shrink is also fab for cold aluminium tubes...if you have a hot air gun (hair dryers won't work) :https://www.ebay.co.uk/itm/BLACK-HEAT-SHRINK-TUBE-ELECTRICAL-SLEEVING-CAR-CABLE-WIRE-HEATSHRINK-TUBING-WRAP-/160809668245?var=&hash=item0

 

[Astrobits]

I had my ally tubes powder coated with a matte black finish. Not perfectly matte black but not shiny so less reflection than a shiny finish.

Nigel

[Dragon_Astro]

Sorry for lack of updates (and pics). Not exactly a master craftsman or anything, so don't want to show myself up lol

Currently waiting on delivery of the truss tubing and angle for various brackets/fittings.

The funds pot has also run a bit dry, so will have to build it up a bit before I can get more ply, knurled hand knobs, D nuts etc.

[Dragon_Astro]

The aluminium tube and angle was actually delivered yesterday, which will need minimal cutting as I had it custom cut to the lengths I wanted it. Ordered the tube a bit longer than I need, so will just be a case of trimming a small bit off if I need to

Holes have been drilled in 3 of the tubes, another 5 to go over the weekend.

[Dragon_Astro]

Update:

I've reached a stage with this now where last night I could put together the main Dob assembly and test the focus etc as it was a clear forecast.

Did a quick rough collimation with a laser, and went ahead with first light....with fingers crossed. Took a bit of tinkering with focus as I'd only set up a temporary "push/pull" focuser with tubes, but stars soon snapped into focus with my SW eyepieces (not the best, need to upgrade them).

As its a truss design and I'm yet to even paint it black, let alone sort out a shroud, there was obvious lack in contrast but that's easily remedied with better eyepieces and said shroud.

The assembly wasn't on the rocker box, so was mostly pointing to zenith, but I was able to roughly tip the dob to point at different parts of the sky.......Cygnus area was particularly mesmerising, the amount of stars visible was at times nauseating lol

Assembly was relatively easy to pick up, I'm not the biggest of build (10st when wet) but I was able to move it.

Left to do.....

Azimuth bearings, paint it all black, source a RDF (looking at the Baader Skysurfer), blackout shroud.

[Dragon_Astro]

Realise it’s been far too long since I updated this, a year in fact, but I got frustrated with it to the point where I wished I hadn’t started it lol

Even now it’s still not completed, almost but not quite. It’s collimated and just about usable to look at Jupiter and Saturn a few weeks ago. The details on Jupiter were amazing and the 4 moons looked “round” rather than star like which I’m used to in my smaller scopes.

[Stu]

Looks fabulous, very compact. Glad the views are up to expectations.

[Dragon_Astro]

11 minutes ago, Stu said:

Looks fabulous, very compact. Glad the views are up to expectations.

Cheers Stu

By no means tested it thoroughly yet, but it does look promising.

I think I went a bit too thick on the choice of ply, it’s a lot heavier than I’d like. In hindsight, if I could start again, I’d make the boxes and bearings out of aluminium.

That could still be on the cards if this dob starts giving me too much back ache lol.

[Alan White]

Wow, looks great, excellent job.

I had wondered how the build was going, now I know.

 

[Dragon_Astro]

21 hours ago, Alan White said:

Wow, looks great, excellent job.

I had wondered how the build was going, now I know.

 

Thanks Alan :)

I’m quite happy with it, like I’ve said I wished I’d gone for more aluminium rather than going for the thick Ply.

All in all though it works, and to say I have no shed/workshop so everything was cut and drilled on my dining table, I think it went quite well lol.

Personally aswell I’ve never built anything before and my DIY skills are not THAT good lol

It was worth the punt on buying the mirror set from AstroBoot though, and it worked out cheaper than buying a ready made Dob of its size.

[Alan White]

I think you are underestimate your wood skills, it looks great.

Built on the Dining Room table, if that was me i would have drilled a hole into it!

Enjoy using the fine looking instrument you have crafted.

[Dragon_Astro]

36 minutes ago, Alan White said:

I think you are underestimate your wood skills, it looks great.

Built on the Dining Room table, if that was me i would have drilled a hole into it!

Enjoy using the fine looking instrument you have crafted.

Many thanks Alan

Haha yes I did that a couple of times, accidentally went through the scrap wood I had underneath and into the table a tiny bit.

The wife covered the marks with a tablecloth lol

[Dragon_Astro]

Alan, I’m actually tempted to make another....ive got the bug! 😄

[Gina]

Holes are nothing - I have holes in mine plus a groove all the way across where I went a bit deep with my router!!  But this is no special table - just a cheapo thing chucked out by my mother decades ago.  Serves more as a workbench than a table for eating off.

[Dragon_Astro]

2 minutes ago, Gina said:

Holes are nothing - I have holes in mine plus a groove all the way across where I went a bit deep with my router!!  But this is no special table - just a cheapo thing chucked out by my mother decades ago.  Serves more as a workbench than a table for eating off.

Easily done isn’t it Gina lol

Ours is a cheap s/h table, mostly used as said workbench and my 5yo daughters craft table.

[Dragon_Astro]

Trying to decide on a finder....

Telrad...

Rigel Quikfinder....

or Baader SkySurfer 3?

🤔

[Alan White]

On 06/08/2019 at 12:44, Dragon_Astro said:

Trying to decide on a finder....

Telrad...

Rigel Quikfinder....

or Baader SkySurfer 3?

🤔

That is such a personal thing to decide upon,

I have both a Rigel and Telrad, of the two I prefer the Telrad in use,

but find the Rigel small footprint easier to locate on various scopes.

 

[Dragon_Astro]

I am swerving towards the Telrad, shame it’s so big. It’s having to find a good spot for it.

The Rigel has a much smaller footprint as you say......but is the sight any good Alan? I’ve heard it moves with head movements?

[mapstar]

On 14/08/2019 at 11:28, Dragon_Astro said:

I am swerving towards the Telrad, shame it’s so big. It’s having to find a good spot for it.

The Rigel has a much smaller footprint as you say......but is the sight any good Alan? I’ve heard it moves with head movements?

I some times find the rigel rings a bit difficult to get your head in the right place to find them. Telrads are easier to work with using the long body as a reference. 

Other than that they are small and light which helps with balance and also stands off the tube higher which can help. 

[MarsG76]

Good luck with the project....

[MarsG76]

On 02/08/2019 at 05:20, Dragon_Astro said:

Realise it’s been far too long since I updated this, a year in fact, but I got frustrated with it to the point where I wished I hadn’t started it lol

Even now it’s still not completed, almost but not quite. It’s collimated and just about usable to look at Jupiter and Saturn a few weeks ago. The details on Jupiter were amazing and the 4 moons looked “round” rather than star like which I’m used to in my smaller scopes.

That looks awesome..... great result, even if its not finished yet....

If the Gallilean moons were round instead of just point, than you must have had some awesome seeing.. I remember those nights.. rare here but when they happen, wow.

 

[Dragon_Astro]

Managed to get a good hour or so observing tonight, before the clouds rolled in.

Easily found M13, which was a generous peppering of stars right down to the core, more appeared the longer I looked.

Then it was on to M31 and it’s companion M110, M31 still just a very large bright smudge but the large Moon that was rising didn’t help.

Also looked at my favourite double, Albireo