Jump to content

Banner.jpg.b83b14cd4142fe10848741bb2a14c66b.jpg

Converting a SW 16” Flextube Dobsonian to a Truss tube Dob.


tomato

Recommended Posts

57 minutes ago, LondonNeil said:

Nice clamps, nice build. 

How long do you think the scope will take you to set up when all finished?

Thanks, the fully assembled scope will live in my garage, my granddaughter as part of her A level Design project will design and make some wheel barrow handles to trundle it round to the back garden. A quick collimation and it should be good to go so I estimate about 10 minutes for this set up. 
For transport to a dark site it will strip down to the rocker and mirror box, the truss tubes and the secondary cage. This will take about 20 minutes to set up with two of us on the job, I reckon.

  • Like 1
Link to comment
Share on other sites

Posted (edited)

20 minutes isn't bad at all I reckon.  I am guessing it'll be heavy, but being able to dismantle and easily fit inside a car will be such a boon

Edited by LondonNeil
  • Like 1
Link to comment
Share on other sites

Yes, I don’t think any 16” scope can be classed as light weight, but I’m hoping it will be a distinct improvement on the original Skywatcher flextube, that design was just too much for me.

Link to comment
Share on other sites

We did a successful focus test last night, the cage had to be raised about 15mm to put the focuser tube at half its travel with the star focused. On to the altitude bearings next…

  • Like 2
Link to comment
Share on other sites

  • 2 weeks later...

I’ve been away on a short break but meanwhile Tomatobro has continued to progress the build. The altitude bearings have been made and fixed to the mirror box, and the rocker box constructed. I have some virgin ptfe and laminate sheet incoming for the Az bearing.

IMG_20240621_102753.thumb.jpeg.8962df0019a2aa298731444fbf4b87fe.jpegIMG_20240621_102803.thumb.jpeg.0d75039f5253d1009208abfd9a737dfd.jpegIMG_20240621_102811.thumb.jpeg.bbbac62594f1ab2810b63db4726fdb60.jpeg

  • Like 5
Link to comment
Share on other sites

Great build & conversion, if your into imaging and you clearly have the skills have you had any thoughts on making an equatorial fork mount for it?

I took a Light bridge 16" and have adapter it into a large fork mount. Admittedly the mount already existed however i did all the control myself using arduinos and steppers.

It now links into ascom, phd2 and nina and can goto and guide reliably at around 0.8 arc sec. It's now really starting to produce great results.

With modern guiding and plate solving I reckon it doesn't even need the big worm gears and would even work better with a friction drive or rigid pulley system.

However something like this does need a little obsy and it's not a project for the beginner, but if you ever have any thoughts that way let me know...

  • Thanks 1
Link to comment
Share on other sites

Thanks for the feedback. Seeing it in the flesh now so to speak, I did for one crazy moment think about bolting a hefty dovetail to the OTA and putting it on the Mesu, but I don’t think it would fit in the dome!

I fork mount would be quite an ambitious project but you never know, I suspect an equatorial platform might be the next thing.

  • Like 1
Link to comment
Share on other sites

7 minutes ago, tomato said:

Thanks for the feedback. Seeing it in the flesh now so to speak, I did for one crazy moment think about bolting a hefty dovetail to the OTA and putting it on the Mesu, but I don’t think it would fit in the dome!

I fork mount would be quite an ambitious project but you never know, I suspect an equatorial platform might be the next thing.

Not a problem

IMG_0800.jpeg.c29bc36de53761828682656e7511b070.jpeg

  • Haha 3
Link to comment
Share on other sites

It's good to see the project complete almost. Whet I think we need to know now is how it looks packed,  how long does it take you to assemble and ready for use,  and are there any drawbacks or unexpected advantages that are apparent now (when) it's in use?

Looks fab.  That's a big plus for a start!

  • Thanks 1
Link to comment
Share on other sites

FYI...(M51 with only 40mins of data - yes would be a lot of work but if you ever decide yes then happy to try and help)

image.thumb.jpeg.47c6cd1f6d6e842b087620dc1d46fff0.jpegimage.thumb.png.c8069f838625aa22a6800f4003d27300.png

Edited by Demon
  • Like 4
Link to comment
Share on other sites

p.s. I find mirror cool down time to be one of my greatest problems, I've mounted 4 big blowing fans to get it down to temp asap, then in theory its best to suck using a smaller fan (although mine still blow). I used this to help me modify the mirror cell as the initial Meade/GSO design was wrong Use of PLOP – SkyInspector.co.uk. Then theres collimation which particularly for imaging is another aspect which many underestimate - I use my own diy version of an OCAL every so often, then a collimated laser for checking for movement only (but mine is permanently in obsy so it doesnt get taken apart or moved - although I'm still less of a fan of truss tubes now...lol). Dont forget a nice light shroud (made mine from stretchy fabric). I also stick a rolled up camping mat on the end of mine when imaging as light shield and it also helps stop dewing. It looks like you're an experienced astronomer but hope this helps...p.s. mine likely uses the same factory GSO 16" mirror and when I spoke to an experienced commercial astro mirror manufacturer he wasn't dismissive about how it should perform if you get the cooling right and he was right. Enjoy, yours looks great.

Edited by Demon
  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Very impressive setup. It would have to be permanently set up with a roll off observatory like you have, but I think I would need to be under a darker sky to justify it, as I can get decent integration times with my existing dual Esprit 150 rig.

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.