Building a first telescope is there an easy choice?

[Jastronomy]

First off thanks in advance.

 

I've been around astronomy my entire life and used plenty of telescopes but never actually got around to building one.

I grew up spending a lot of time with John Dobson so I'm very familiar with the Dobsonian and the concept of grinding mirrors etc.

 

I'll likely be building two telescopes. The first as a proof of concept and to actually get it done then a much larger one that will take a lot longer and not be portable. 

I'm buying a farm and I may actually build an observatory to house it as well. The farm is at 9000ft and should provide amazing viewing. 

 

As I intend on building the much bigger telescope second should I build the first one in the same style mount and configuration or do you not see that as a big deal?

For the first telescope I was planing an 8" Dobsonian style. I could go bigger or smaller. I'm not concerned about length so I'd take the focal length that makes sense.

I could grind or buy a mirror. 

 

For the second telescope I have no idea. I'm skilled in construction but I don't want to build something massive just to have it. If there is a simple answer like "you can go up to X inches with this style" or "you'll see incredibly marginal returns after X inches"  or "after X inches it gets 10 times as expensive" let me know. My guess is there isn't a simple answer. 

 

I'm not afraid to take on too massive of a project and I've got a decent budget. I also have the time to hand grind mirrors etc. 

I'd assume the first one I'll keep under $1000 USD and the second one I'd be open to finding out what my options are. $10,000 USD isn't a problem but naturally I don't want to throw money away and if something really awesome can be done for more I'd entertain it. 

 

Thanks ahead of time and from what I've read in the past that this awesome community has produced.

 

Jastronomy

[Peter Drew]

For a DIY telescope build I think there is very little option outside that of the Dobsonian design. It is within the range of anyone that is reasonably handy, provides a stable easy to operate mount with minimal precision parts and easily available materials. IMO, its greatest advantage to suit your goals is that the system is successfully expandable to suit any potential increase in aperture.   

[Stub Mandrel]

50 minutes ago, Jastronomy said:

The farm is at 9000ft and should provide amazing viewing.

I didn't know you COULD farm 1 3/4 miles up! ... but google tells me high altitude coffee is very special!

But why do I suspect you are buying it for the viewing rather than the productivity :-)

[Putaendo Patrick]

Your options really are virtually endless and will largely depend on your skills (and patience to develop them), access to materials and technology. Amateur Telescope Making (ATM) began and flourished in the US in the 1920s and 30s. In part it was the result of the high prices of commercially made telescopes in that era. Many people made basic telescopes which met their immediate astronomical needs, but a few went on to construct very sophisticated telescopes indeed. In the 1960s John Dobson essentially simplified and cheapened the process of ATM. Supposedly he used the glass from ship's portholes for blanks, and his basic mount avoided the complexity and expense of other types.

I would suggest that today, the economic argument for making your own telescope is no longer valid. It will probably take a long time and quite a bit of trial and error to reach the levels of today's commercial offering, and what you spend in the process is likely to be more in the long run. However, assuming you know this, I would begin to look at the earlier literature on the subject, and then decide how much you can and want to do yourself, and how much you may want to buy in in terms of parts. Although there have been significant changes in material specifications, construction techniques have really changed very little.

Perhaps the original text which started ATM is William F. A. Ellison: The Amateur's Telescope. Ellison was director of the Armagh Observatory in Ireland, and the 1920 edition with his annotations can be downloaded from their site: http://star.arm.ac.uk/history/tat/

Next you may want to look at the fascinating three volumes edited by A. G. Ingalls: Amateur Telescope Making, published by the Scientific American magazine in the 1920s and 30s - although there are several more recent reprints. Russell W. Porter's contributions, especially to volume one, are notable as are his superb illustrations. This is probably the most complete compendium for the pre-Dobson era and all three volumes must weigh in at close to 2,000 pages! As the introduction says, it's a mine of information -  but it has to be mined!

There are several interesting books from the immediate post-World War 2 period which are still valuable. Jean Texereau - How to Make a Telescope was originally published in French, look for the expanded English second edition. G. Matthewson - Constructing an Astronomical Telescope came out in 1947 and was expanded in 1955. Neale E. Howard - Standard Handbook for Telescope Making came out in 1959, published in the US and reprinted in the 1980s.

More up-to-date is the collection of essays edited by Stephen F. Tonkin - Amateur Telescope Making in 1999, with some good ideas.

Three considerably more specialised books which are well worth a look are: R. N. Wilson - Reflecting Telescope Optics (two volumes); Harrie G. J. Rutten and Martin A. M. Van Venrooij - Telescope Optics, A Comprehensive Manual for Amateur Astronomers and Allan Mackintosh - Advanced Telescope Making Techniques (two volumes).

Finally, the consensus of opinion is that if you do decide to grind your own mirrors, start with 6 inches. You will save more time in the long-run practicing and perfecting your technique on this first!

Good luck.

 

[mapstar]

Sounds like a man with a plan.

Making your own mirror is a truly wonderful, enjoyable, frustrating, time consuming, educating, and mind boggling experience. You have to be dedicated though.

Think long and hard about it as you need the equipment to do it. Small is probably not worth it and large can drive you mental. It will give you huge satisfaction when complete though.

Getting someone else to make the mirror is probably the way to go if time is limited. 

Building a scope is totally different to working the glass. I guess you won't need to move the scope so a traditional style dob would be easiest but I would recommend the book by Albert High- Building large portable Newtonian telescopes as it is quite modern. 

Good luck we'll be here for the journey 

[Putaendo Patrick]

Thanks, Mapstar! Albert Highe's book looks very interesting. Here's a link to the publisher's site: http://www.willbell.com/tm/PortableNewtonianTelescopes.htm

Willmann-Bell also publish several other telescope making titles, including reprints of some earlier ones I mentioned.

[mapstar]

There are also plenty of lovely build threads on here to follow and cherry pick ideas from.

A great community and you'll receive as much help, encouragement and support as you need to see you to the end and beyond.

[Gina]

I considered building a telescope - I've built lots of things but not a scope.  I don't think I'd want to grind a large mirror but did wonder about buying the mirrors and taking it from there.  I already have a 190mm Mak-Newt so it would have to be something a lot bigger to be worthwhile.  So I too would be interested to know what's available as a pair of mirrors with primary at least 10" (250mm).

[Putaendo Patrick]

Gina, just to whet the appetite here are a couple of sources of mirrors in the UK:

Orion Optics UK at Newcastle under Lyme, Staffordshire http://www.orionoptics.co.uk/OPTICS/telescopemirrors.html who go up to a 500mm f4.

Oldham Optical UK at Scarborough, North Yorkshire http://www.oldhamoptical.com/#!price-list/cr8f who go up to 600mm or larger.

I'm sure there must be others. In the USA, there's the Zambuto Optical Company at Rainier, WA http://zambutomirrors.com/mirrors.html

 

[Gina]

Thank you   I've had a look at Orion Optics and looks promising   I'll check out the others...

[mapstar]

Nichol optic also another choice Gina 

[Physopto]

If you want someone who is dedicated and helpful talk to John.

Orion were a pain in the behind in all correspondence that I have tried. I will never attempt to buy from them again. (was not a mirror). Their customer service is almost non existent and I never go back to those who fail give good service.

Derek

[Jastronomy]

First off, thanks for all the amazing responses and support. You might not see anything for a little while possibly months but who knows I may get right on this. I do promise I'll put together a build log though.

A little additional information. I'm in Colombia and I've got skilled employees / 4' x 8' CNC so the options are pretty wide open. 

 

On 6/16/2016 at 08:47, Stub Mandrel said:

I didn't know you COULD farm 1 3/4 miles up! ... but google tells me high altitude coffee is very special!

But why do I suspect you are buying it for the viewing rather than the productivity :-)

I could possibly do some coffee and I've grown things this far up before. The main objective is to have a good time though. This is a recreational farm to drink beer and swim in the pool with friends. Hopefully look through the giant telescope as well soon enough. 

 

Thank you all for the sources your recommended. I'll take a long look at some build threads and price things out and go from there. Likely it will be a 6" or 8" Dobsonian first and then figuring out exactly what I want to go with after. 

 

 

[cassiewoofer]

Hey Peter, oops Jastronomy (not very clear who's posted on my computer) sounds like you're living the dream.... Farm at 9000ft Wow! Anyway, don't let anyone dissuade you from building your own!... It may not be financially worth it (if you consider the prices now AND you consider time working on a project as the same as time working at work (which I don't)) but some of us just like to make things and there's nothing more rewarding than making your own telescope.

 Your plan is just about what I would recommend to someone with experienced hands. (that's not experience in telescopes but other more regular stuff)

I started my first telescope 4 years ago. it was a 6 inch, and was initially in a cheap cardboard tube which meant I could just mess it up / play / make mistakes and not worry...... I changed the eyepiece hole position 3 times! But being scared of cutting means you progress slowly. I had the poly tube ready once I had perfected the dimensions of the Card one.

 Anyway the mirror is the hard bit! I went with 6 inch which was a bit cautious so your idea to go for 8 as a starter is a good one. An 8 inch scope is the most useable size here in Uk as it fits in the car and is easily lifted by one person.

 

 Good luck, you will probably get hooked,... I've had a break but did a 6" and 8" a 10" and a 12" and though her indoors might not know it yet but think I'm feeling the once planned 16" inch is creeping back into my mind.

 I might be better off though improving the mount on the 12". However I get more enjoyment out of making them and proving they work than actually using them on a regular basis!!! I mean the skies we've had for the past few years have been awful!

 

 Good luck with it!

 

 

[madjock72]

At 9000ft will Jastronomy not need some form of heating because of ice.? But cant wait to see the end results.