Jump to content

SkySurveyBanner.jpg.21855908fce40597655603b6c9af720d.jpg

6" f5 suitcase dobsonian project

Moonshane

By Moonshane
in DIY Astronomer

Recommended Posts

Moonshane

Moonshane

Posted
  • Author
Posted
Looks great pal.

Not easy to see where your gonna shave a few pounds off there.:D

Maybe some hole saws rather than a router, quicker way to get surplus wood out.?

That looks like how Sumerian does it, a few different hole saw sizes.

Regards Steve

cheers Steve, I could always cut strategic yet shapely holes like I did with my 16" http://stargazerslounge.com/2255001-post21.html

Sorry Shane but I am having none of it!!! There is no way you are not a carpenter by trade :( School teacher of wood work I'm thinking :) Another fine jod you have done there chippy!

cheers mate - not at all- previously in Banks and now in a primary school! to be fair though, I had a lot of help from my father in law on this one and he is a good joiner (retired) so has taught me well and most importantly has all the right tools.

That is looking superb Shane, excellent work. Really looking forward to seeing the completed job.

cheers Damo - looking forward to my truss tubes arriving but have some I can use to test it and gauge the length accurately.

Hi Shane. Been following this thread. Looking good. Hopefully I can take a good look thru it, maybe in the near future.

John

hi John

the views will no doubt be the same as when you looked at it the other night on the Giro. We'll get together soon I'm sure and hopefully this time no spotlight!

Link to comment
Share on other sites
  • Replies 127
  • Created
  • Last Reply
Moonshane

Moonshane

Posted
  • Author
Posted

Did a bit of metalwork today, making some small brackets for the upper, inner corners of the mirror box. These will be fixed in place and have tapped holes to enable me to fit the trusses via thumbscrews. I used 50mm x 50mm x 5mm ali angle cut into slices (I REALLY wish I had an ali blade for the chop saw - might invest in one eventually).

I'll also be making some fittings for the top of the trusses to fit to the UTA, and which will be small triangular section (out of 50mm x 3mm flat bar) and will permanently hold two truss tubes together at the top end and the other hole being used for fitting to the UTA threaded holes. Pics will follow when I have finished them but waiting for my tubes (5/8" x 16swg) and flat bar which has been ordered.

Link to comment
Share on other sites
Orionis

Orionis

Posted
Posted
Sorry Shane but I am having none of it!!! There is no way you are not a carpenter by trade :) School teacher of wood work I'm thinking :( Another fine jod you have done there chippy!

I would agree!

That is very well constructed and is looking great! :confused:

Link to comment
Share on other sites
swamp thing

swamp thing

Posted
Posted

Are you going to be using the spider/secondary housing out of the original donor scope Shane?

Wasn't that a two vane one if I remember correctly?

Will the fixings for that be on the upper tube struts, or are you planning a different fixing technique?

Interested Steve

Link to comment
Share on other sites
Moonshane

Moonshane

Posted
  • Author
Posted

hi Steve

I actually bought a different donor scope to the one you were thinking of (which I sold to fund the purchase). The one being used had a dual speed focuser and better optics (1/8PV).

Here's some pics showing what I planned and did - I used standard M6 rod connectors to join a 25mm cap head nut to the stock threaded rod ends. This allowed me to use the secondary and spider as it is originally and it can therefore easily be put back together if needed.

I plan to cover from the secondary blade to the end of the threaded rod with black heat shrink once I have got the dimensions sorted. It's roughly collimated now but I'll do a proper job when all together.

I have some black ABS plastic (0.8mm) on order and it will also be flocked in due course. I wish I had done the struts in ali pipe as that would have allowed a little adjustment. I may possibly plug and redrill one of the holes which is slightly cockeyed but there's enough leeway in the system to adjust it out.

Surprising how much weight the focuser and secondary add!

post-17776-133877763734_thumb.jpg

post-17776-13387776374_thumb.jpg

post-17776-133877763745_thumb.jpg

post-17776-133877763751_thumb.jpg

post-17776-133877763758_thumb.jpg

Link to comment
Share on other sites
Moonshane

Moonshane

Posted
  • Author
Posted

The dimensions are 250mm tall x about 330mm square so it's within the majority of airlines as far as I could tell? This can be reduced if required to some extent, especially if I use the helical focuser - I could easily make another specifically for airline travel in due course - it will be a while before I am on a 'plane!

In terms of weight, I'd prefer the current format for general use in the UK as this will be a lot more sturdy as it is. I am still working on various ideas to get the weight down though so watch this space.

Re the balancing, I am very confident this will not be an issue. Mainly as the bearings have a larger than normal (for this mirror size) radius and the mirror box will be heavier than the UTA. The balance point on this dob is not that far from the balance point on the original OTA / GIRO so I don't this it will be an issue, especially as in the main I'll be using 1.25" eyepieces. Also, there's always the option of a little counterweight / spring system.

The main reason I was keen to have a 2" focuser (which weighs 600g - much less than e.g. a Synta dual speed) is that this prevents me having to re-buy filters as I only use 2" ones currently. One of the points of a scope like this as Alan said is getting to dark places to see faint nebs where filters will help.

I have made a few assumptions with this but that's what a prototype/first go is about I suppose :)

Link to comment
Share on other sites
Moonshane

Moonshane

Posted
  • Author
Posted

cheers Angus, that's what I'd worked to. I am hoping if I put a handle on it and make it seem light with my strong arm (it's not THAT heavy) then I'll be OK. As I say though, I'll be working on ways to reduce weight in due course.

Link to comment
Share on other sites
Moonshane

Moonshane

Posted
  • Author
Posted

my tubing, flat bar and round rod have all arrived rather quickly today from Aluminium Warehouse - great service albeit with high delivery charges. that said, I got more product for less money than if I'd have walked into any of about 10 local firms I tried.

I'll hopefully be in a position this weekend to get it all put together for a test run if things go well.

Link to comment
Share on other sites
swamp thing

swamp thing

Posted
Posted
my tubing, flat bar and round rod have all arrived rather quickly today from Aluminium Warehouse - great service albeit with high delivery charges. that said, I got more product for less money than if I'd have walked into any of about 10 local firms I tried.

I'll hopefully be in a position this weekend to get it all put together for a test run if things go well.

Glad to hear your delivery came okay. It's always a worry that when you recommend a company the person you recommended them too will get nothing but trouble.:)

Look forward to reading your test report.:rolleyes:

Steve

Link to comment
Share on other sites
Moonshane

Moonshane

Posted
  • Author
Posted
That looks absolutely brilliant. I must make something like that one day. Have you drawn up detailed plans or do you design as you go along (as I tend to do, got away with it so far :eek:)

cheers Michael

each component determines the size of the next so you really have to play it by ear!

Glad to hear your delivery came okay. It's always a worry that when you recommend a company the person you recommended them too will get nothing but trouble.:)

Look forward to reading your test report.:rolleyes:

Steve

no probs Steve, i always take a view that a recommendation can go either way but been really impressed with them too.

Link to comment
Share on other sites
Moonshane

Moonshane

Posted
  • Author
Posted

It's alive, IT'S ALIVE!!!!

well, maybe not but did most of the metal work yesterday to created fittings for the trusses and made some temporary adjustable trusses to allow me to gauge the length of the final versions. I'll be putting black heat shrink on the poles eventually once done. It all sees to fit together nicely.

remaining jobs are to add formica and teflon pads to the rocker box and alt bearings, cut the final poles and drill the holes, fit the UTA baffle and add flocking, make a dew shield and then paint etc.

I am happy I made it so that with the construction of a different UTA I could use an 8" mirror too.

Here's a pic.

post-17776-133877766257_thumb.jpg

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • 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.