Building a telescope, is it worthwhile.

[sammyff]

I probably should post this in the DIY forum, but since I'm a beginner, I'll put it here. Santa gave the kids a family present last December a telescope. Apparently his budget was low at the time so he bought them a 4" Newt, in case they didn't appreciate it. To his amazement, one look at Saturn they were hooked. But now they want to go bigger. But since Santa has a wedding to pay for soon, and petrol costs a lot, he has a small budget again. So....I thinks the way to go, building one may be fun. But..............
I have a few questions for you who may have been down that road before me.

1. What size should I go for,,,being the first one I've attempted.
2. How much should it cost, coming from someone who has build one recently.
3. Where do I get the plans, what good websites etc.
4. Anything you did when you built yours that you would never do again.
5. Where do I start (I know, the beginning, right)
6. Any other good advice you can give me.

Thanks,

Jimbo;)

[Blue Skies]

I get this question asked of me a lot, and the first thing I ask is "Are you doing this to save money?" Because if that's your reason for trying to make one, you're in for a shock - it's now cheaper to buy a new one that put one together from separately bought pieces.

Seriously, do your homework. Here's your shopping list: Primary mirror, secondary mirror, focuser, finderscope, at least two eyepieces, wood, tube (range of choices so depends) screws and bolts. The purchase of the mirror cells, both primary and secondary, and the spider, is optional, as it's not all that hard to make them, if you're handy.

Take this shopping list and browse the various online stores and write their prices down. Compare them to the ready made units. Hmmm....

It always amazes me how many screws and bolts you need. Whenever I take a scope apart I seem to end up with half the scope being these things!

I love building scopes, but I've been through too many people who rush into this without really considering the current state of play in the market. Too mnay people have said to me "Why didn't you tell me it was going to be like this! If I knew it was going to be this much work, and cheaper, I would have just bought one!" so I don't hesitate to lay it out bold and bare.

However if others are reading this also considering making a scope, and perhaps money is not the issue for them and they would like the experience, then go ahead! It's also a great way to customise a scope to the way you like it.

Another option not often discussed is buying a second hand one and refurbishing it. Sometimes there are some beauties out there languishing in back yards that people don't know what to do with anymore and you can get a bargin. But you need to know what to look for to see past the muck, unfortunately, and that only comes with experience.

To answer your questions directly:
1. Size - and 8" or 10".

2. Cost - already talked about that, but the dob I own now I made in 1997 and in the end it cost me $1050 once I'd paid custom fees importing stuff (hey, it was harder to do back then!) which in those days was just $50 more than an off the shelf 8" (yep, things sure have changed in ten years...)

3. Plans...ummm I'm bad and don't work that way and when I teach other people I tend to focus more on the principles of what you have to do to make it work rather than what exactly to do. When you build your scope you can solve the issues at hand in a number of different ways (more than one way to skin a cat, as they often say in the atm circles) and it just depends on what you like and what skills you have to acheive them.

4. Things I did that I wouldn't repeat - dont buy a cheap focuser!!! Buy a good one, pay the bit extra, you wont regret it.

5. Where to start - the primary mirror, and it's focal length. Everything else will flow on from those two parameters.

6. Advice - I think I've already given it. ;)

[xelasnave]

I have built a couple:D.
First two very bad third good but I liked one already built in China (12inch)better... but if I had not built them I would not be prepared to pay big bucks for good ones now.. I appreciate the effort and the time and the stuff you must learn..

These days I think it would be cheaper all things considered to buy one already made... a dob is a great choice and they are cheap.. 6 inch to 12 inch and 16 inches are here or soon will be.

I use from 50mm and 80mm binos, and two 6 inch scopes for photos and a 12 inch dob for visual... in a dark site and there is little difference in many respects so dont think something can be too small... I can not believe the views thru 80mm binos are so good.. I reckon you get a better view of Orion..other will disagree but there is my view.

A dark site is the key...do not underestimate that in your consideration..if you have to travell to a dark site get a scope that will transport with ease.. this may mean the 4 inch is it...and there is nothing wrong with a 4 inch if you point it at the right object:eyepop:.

Still if you are set on building one give yourself about 6 months to read the stuff out there;).. you can melt and mold your own glass if you want:whistle:..grind a lens for a refractor, make your own mirror and even silver it:).. just goggle ATM or the like you will be busy

...I have seen such sites.. they tell you how to do everything:eyepop: do you really want to or do you think it may be cheaper? it can be but you need to be cunning...

It is satisfying but time is more valuable than cash when you have small children.. the time taken by anything that means less times with them should be regarded with suspicion for they grow old far to fast as do all of us.


Buy a DOB and start grinding a 20 inch mirror:lol::lol::lol:
alex

[Blue Skies]

And that is also really good advice - making the scope is going to take you longer to make than you think it is! Especially the first time around. I know that always happens to me.

[xelasnave]

As to cost I built one from scrap entirely..old chip heaters cut down for a truss dob style, poles from a caravan annex, old form ply that had been used as such, but just the nuts and bolts and fibre glass and resin just kept adding up, cutting the rings and just sanding them..seems simple and it is but it takes so dam long... and so even though it was junk the cost of the hardware to put it together was unbelievable...I had a mirror and a secondary but they had to be "silvered" and that was not cheap... buy one built and enjoy it.
alex

[xelasnave]

Would you believe having said all this that I spent most of today all yesterday designing a new ota for my 12 inch:lol::lol::lol:

But only in an effort to reduce the weight of the ota and camera settup so maybe I can use the 12 inch on the eq6 mount for photos.. I know folk put 12 inch GSO's on eq6's but I would like less weight..can I build a light non flexible ota? can not help thinking about it:lol::lol::lol:. so there you go ... I can not deny the attraction to build a better mouse trap... but hopefully it will pass.
alex

[sammyff]

Good advice already. The majority vote seems to be that I'd be best to buy one and save the headaches. When I really think about it,.....I'd probably get frustrated building one because it would still be in pieces when we want to use it. Ok, I'll buy one, probably a used one.

Thanks again
Jimbo

[Jupiter]

I recently purchased Kriege and Berry's book, 'The Dobsonian Telescope' a how to manual. I would love to build one but it won't be for a while, but reading the book is teaching me so much about 'scopes that I didn't know.
I think you are making the right choice in buying one, and on the trade section here I am amazed how often good second hand scopes come up for sale.

[leon]

Although all the advice you have been given is true and correct, wouldn't it be nice though to stand back and say, yep, i made that. ;)

A long long time ago, about thirty years ago to be exact, i built my first 8 inch reflector from the mirror grinding, to the finished product.

It was hugely to heavy, but that is me, I like to make it strong, and it saw many upgrades, had been about 20 different colours in it's life time, but i built it and was proud of it. :D :D

I only sold it about a year ago, but that is me.

Leon :thumbsup:

[sammyff]

Well I've pondered on this all night. It was cloudy so I went to bed early. I've made my decision, thanks to your advice. I'll buy a second hand one for the quick solution. And I'll slowly build one as a long, long, long term project. Should have it finished in about 5 years the amount of time I have off. It will be slow but I imagine it will be quite a rewarding achievement. Good luck to me.

Jimbo:D:thumbsup:

[Blue Skies]

Sounds excellent. I hope you enjoy the journey!

[gary]

Hi Jimbo,

For many, building their own telescope is an end unto itself.
Just as there are people that restore vintage cars or aeroplanes
for the joy of it and driving or flying them might be a secondary consideration
there are actually many Amteur Telescope Makers (ATMs) who simply revel in the
joy of making something. Many of them like to observe as well, but for some
the building of the scope actually becomes the primary source of enjoyment.

For a small investment, grab yourself a copy of "The Dobsonian Telescope"
by Berry & Kriege and published by Willmann-Bell. This the bible for building
large aperture truss pole Dobsonians and even if you never build one,
the book itself is still an excellent read as you will see that there is very solid
engineering considerations that go into the design of these instruments.

Before you make your next purchase, consider joining a club. Observing
events are an excellent opportunity to get to look at and look through other
people's scopes. This can often then help you consolidate some future goal
for what your next telescope (and possibly the one beyond that), might be.

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
[url]http://www.wildcard-innovations.com.au[/url

[rmcpb]

Good descision!! You will never build one as cheap as a secondhand Chinese dob but, as a project, building one is a learning curve that is well worth following at your leisure. Especially when you have a servicable one for use in the meantime.

Cheers