Dougie
member
Reged: 07/02/08
Posts: 11
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Ok so I've been reading up on DIY telescopes for years and I think I'm going to go for it. I would like to be able to see clear detailed views of things like Saturn, Mars and some of the other galaxies and nebula's. What size mirror would be needed for something like this? While this is my first DIY telescope I am quite crafty and build lots of other DIY things. I learn fast and I'm not afraid to take time and do things slowly and accurately. So I know you'll probably recommend something like a 6" because I'm a beginner but I would really rather do something bigger as I'm not going to rush it. I would also like to eventually build some sort of CCD module to mount to the scope and take pictures as well. Not sure if this has any effect on the size of mirror I would like?
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llanitedave
Humble Megalomaniac
Reged: 09/26/05
Posts: 9655
Loc: Amargosa Valley, NV, USA
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I'm a bit biased, but I'd recommend 10" as a maximum size for your first DYI scope, especially if it's your first scope overall. Beyond that, things start getting pretty involved.
Not to worry, though, a good 10" can give mighty impressive views.
Having imaging as a goal won't affect the size of your optics so much, but it will have a big impact on your mount design.
If you think you can do it -- you can. Go for it! 
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Homebuilt 10" dob, old Coulter mirror.
16" Royce conical mirror: Construction on S.O.E. (Sauron's Other Eye) has officially begun!
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MMICKELS
Aluminum Knight
Reged: 01/20/04
Posts: 24478
Loc: The Land of Shake and Bake
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Dougie, welcome to Cloudy Nights. I was told to take a class on telescope making and to not attempt a "Truss" type scope. I didn't take a class, and I built a three pole design. Everything fell into place and I wouldn't change most of it. I say Go For It! 
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Mark
"The only thing wrong with immortality is that it tends to go on forever."
Herb Caen
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Dougie
member
Reged: 07/02/08
Posts: 11
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I've owned some telescopes before. Granted nothing quite as large as what I'm considering now  . I don't have tons of cash so generally I try and do something I'm going to use a long time the first time. Thats one of the reasons for not doing a small one and then moving my way up. I would order a mirror which would make things MUCH easier but 800+ bucks for the ones I was looking at is a bit unfeasible and I'd get more pleasure knowing I ground out my own mirror . I would kind of like to keep the total length no more then probably 8' unless I make it able to disassemble somehow. The later option is probably the better one. Is it really that much harder to cut a FL or 4 or 5? If possible I'd really like to do something a bit bigger then 10" I'm not trying to sound cocky or anything but I think I can do it. I was originally thinking 18" but that might be rather huge. But something like 10-15" I think would probably do me lots of good until I move into a place where I can put up a little observatory and build a monster Or at least have a garage to store it in.
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llanitedave
Humble Megalomaniac
Reged: 09/26/05
Posts: 9655
Loc: Amargosa Valley, NV, USA
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Mechanically, you could certainly do a large scope on your first try if you're handy, experienced, and confident.
As far as making your own mirror, everyone I've read recommends going smaller first. Mirror making skills are not exactly like "mechanical" skills. You need to build them up from scratch, and polish them systematically (both your skills AND the mirrors).
If you'd rather grind than buy, great, but be aware that if your ultimate goal is the actual USE of the telescope, grinding a large mirror is going to take an awful long time.
So why don't you start with a couple of smaller ones: say an 8" first, then a 12", then the full-size mirror you ultimately want. The price of mirror and scope in the smaller sizes is trivial compared to an 18", so for each mirror build a full telescope to use it with.
That way you have a useable and satisfying instrument during each step of your learning effort.
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Homebuilt 10" dob, old Coulter mirror.
16" Royce conical mirror: Construction on S.O.E. (Sauron's Other Eye) has officially begun!
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Dougie
member
Reged: 07/02/08
Posts: 11
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Well do you think it would be horribly starting with something like a 10" or 12"? I know its going to be a slow process I figured at minimum 3 months to grind if I work on it everyday.
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HiggsBoson
professor emeritus
Reged: 02/21/07
Posts: 708
Loc: Kal-li-fornia
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Hello Dougie
My situation may be of interest to you. I started 2 years ago with the desire to purchase a 12.5” scope. I decided that I wanted to learn about mirrors and scopes by grinding my own mirror. I was disappointed to learn that the abandonment rate for first time mirror makers is a strong function of mirror diameter.
I made an embarrassingly small 6” to learn mirror making. I could have done an 8’ but what would be the point. I wanted 12.5” and would accept nothing less. The smaller the first one the sooner I would get the mirror I wanted. I finished the 6" with about 35 hours of work. The 6”, F/9 scope was too long to fit into my car so I developed a strut design that disassembles. Photos are available in the member gallery under my screen name.
The project came out very well and exceeded my highest expectations. As I was completing the mirror I ordered a 12.5” blank.
The 6” telescope taught me about observing, collimation, contorted viewing positions and thermal underwear. With no previous experience with building telescopes or actual observing I had a lot to learn.
My 12.5” design has changed many times in response to learning from using the 6” telescope. It has been very valuable as a test bed for my ideas. My 12.5” will be a far superior instrument due to the time and effort I have invested in the 6”. I am now figuring the 12.5” which is the final step in completing the mirror. The 12.5” is an F/4.5 and I will spend more time testing it than it took to grind, polish and test the 6”.
If you are truly committed to making a larger mirror, then you can not be concerned by the few hours that will be invested in knocking out that first 6” mirror. On the 12 you will find that you need to learn additional techniques to complete a larger, faster mirror. With this accomplished you are good to attack monster mirrors up to about 24”. Be advised scopes in this size range are more lifestyle choices rather than optical instruments.
My 6” remains more capable than its observer. Shortly I will have an even more capable instrument and my poor skills will remain the limiting factor for the foreseeable future.
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Michael
ATM: 6" F/9 Newtonian Travel Scope
ATM: 12.5" F/4.5 Real Soon Now...
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llanitedave
Humble Megalomaniac
Reged: 09/26/05
Posts: 9655
Loc: Amargosa Valley, NV, USA
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What Michael said. You could start with a larger mirror, but what would be the point? You wouldn't save any time (might even take you longer) and you would not be likely to save any money, either. Mistakes can be expensive.
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Homebuilt 10" dob, old Coulter mirror.
16" Royce conical mirror: Construction on S.O.E. (Sauron's Other Eye) has officially begun!
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mark cowan
Vendor (Obsidian Optics)
Reged: 06/03/05
Posts: 1221
Loc: salem, OR
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Welcome to CN!
If you only want to make one 'scope and you want decent aperture under 8' in length I'd suggest something like a 12.5" f/6-f/7. This will provide an incredible planetary telescope with lots of deep-sky ability and it can be supported on a bog-standard Dobsonian mount which can be tossed together in a weekend and a half made with stuff you can scrounge and/or buy at the hardware store. With a good portion of high-quality field available and no need for correcting it further, you can hang a webcam camera on it for "lucky imaging", or a DSLR for deep sky if you put it on an equatorial platform.
Parabolization isn't so time consuming that you couldn't stand the inevitable need to start again a time or two, which will happen if you're picky or you haven't got access to a class or somebody local who knows how to do it. Hands on is very helpful.
In the class I took years ago by John Dobson (maybe you've heard of him?) there were several people who did 12.5" as the first mirror, amongst a lot of 8s, 10s, and one 6". Those mirrors looked HUGE at the time, but they got along fine.
The point is the class ran twice a week for a month, and almost everybody had a finished telescope - mirror, mount, and all - built by the end of it. The mirror should take about 1 hr/inch to grind out and about the same to polish decently enough to make you happy.  Figuring, OTOH, always takes slightly longer than you can stand, but you can always quit once you think it's probably good enough...
After you get it sort of working you'll be hooked and that will provide the motivation for making a really good one - or improving the first. Home built telescopes are never really finished.
Best,
Mark
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Dougie
member
Reged: 07/02/08
Posts: 11
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Hmm anyone know if there are any sort of clubs or classes around Pittsburgh PA? It's not so much the time consumption I'm worried about. I was looking at prices though and didn't realize blanks were so expensive. A friend of mine that used to build telescopes shows me a place to get a 10" finished mirror for like 400 bucks. Makes me thinking about going that route although I do kind of somewhat want to grind my own mirror. If there was a class or something around here I'd be more then happy to attend. If I did build a 12.5" it would probably be a strut style that I could pull apart and an F6 or F8 since it would be able to be dismantled. I figure that should be around 10' long.
As for the camera thing I was thinking of pulling apart a DSLR and using the CCD out of it or something.
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Mitchell
member
Reged: 05/19/08
Posts: 71
Loc: USA
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I would say a 10" is doable as a first mirror, but its definitly a whole nother ball game once you go above that. I made enough mistakes on my first mirror (6") that if I had made them on a 10"+ it would have take many many many times longer to correct.
You seem like you want to put in the time and effort, and thats great, Try a small one and if you still want to make the bigger one, go for it! Everyone wants instant gratification, but you seem willing to put in the time which is a sure track to success. 
Good Luck, you can find plenty of help here. I have some trial and errors of various mirrors on my site:
www.freewebs.com/mitchsspacepics
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Clear Skies and Good Health, Mitchell.
ATM:
4.5" F/3.75 ~ 6" F/6.5 ~ 8" F/8.25 (Polishing) ~ 10" F/4.8
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Gary Fuchs
professor emeritus
Reged: 05/22/06
Posts: 548
Loc: Easton, PA, USA
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It's a bit of a hike but if you could get to this years Stellafane you could see demos of every stage of mirror making and get your hands on pretty much all of it as well. Check out the photos. It's a lot to take in but a great intro and you'd meet lots of people you could learn from.
The chance to really hog, fine grind, polish, and see how a mirror is tested (more than one way too) is pretty valuable. After that you'd likely know what you need and have an idea of how much work is involved. Also a chance to see a lot of really neat scopes you might otherwise only see in pictures and not get to examine close up and ask questions about.
Gary
A few more thoughts about Stellafane...
The mirror making demos are set up in a large pavilion. Some things, like making a pitch lap, are done at specific times, or just once, but there are several barrels and other supports with usually 8" or 10" mirrors at different stages. People wander around throughout the day and just sit down and grind. One of the Springfield Telescope Makers or even a passerby will guide you. There's usually a really thick 20" or so(?) blank if you want to try something really tiring. It's not a classroom situation but you can learn plenty from a variety of sources.
Stellafane is oriented towards the amateur and there's an implicit understanding that we often have to make do with what we can find. Because of that you can get a "feel" for what you can substitute and what you might do if you don't have exactly what a book lists.
Edited by Gary Fuchs (07/03/08 07:02 PM)
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Dougie
member
Reged: 07/02/08
Posts: 11
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Yeah thats a bit far I don't even drive haha. If someone locally was going that might be possible that thats about it. Would love to go though looks like fun.
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Almagne
member
Reged: 02/25/08
Posts: 23
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Quote:
Hmm anyone know if there are any sort of clubs or classes around Pittsburgh PA?
Pittsburgh has one of the oldest and largest clubs in the country. And IIRC they even have two amateur observatories - one south of the city in Washington County and one north of the city. (Of course, there is also the professional Allegheny Observatory on the North Side, too.)
The web site of the Amateur Astronomers Association of Pittsburgh is: http://www.3ap.org/
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Dougie
member
Reged: 07/02/08
Posts: 11
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Hmm not seeing much info as far as classes and what not I wonder if they do that stuff but I'll look into it more Thanks!
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Gary Fuchs
professor emeritus
Reged: 05/22/06
Posts: 548
Loc: Easton, PA, USA
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Here's another possibility, though still a hike and next spring: DelMarva Mirror Weekend
At the Delmarva weekend you aim to complete a mirror and there are some very talented people to teach you. If you could get to say Philadelphia or DC (bus, train?) you might be able to get a ride with another attendee. You'd work hard but it's worth it. Plus the location is comfortable and the food is good.
Gary
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wirenut
sage
Reged: 09/21/06
Posts: 416
Loc: m'dale Pa
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I checked with 3AP before about mirror making class last summer. they didnt know of any but gave me contact info of a member whose done a few. if you find one in the pittsburgh area let me know the closest I've found was in washington D.C.
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8"GSO dob
8,17 mm hyperions & FT rings
21mm stratus
25,15,9 mm plossls
ultima barlow
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Fiske
Carpal Tunnel
Reged: 03/14/04
Posts: 1931
Loc: Missouri / United States
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Dougie:
My first ATM project was a 22-inch truss-tube Dob. (Uh, I bought the mirror!) Some pictures on this thread . Don't be intimidated. Do what you want to do!
You have already found the most important resource for making your project a success -- the CN ATM forum. 
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Fiske Miles
Nikon 8x42 LX / 12x50 SE Binos
Mini Borg 60ED, TV-101, AT80Ach, XT-8, C11/CI-700, 22-Inch Dob
Way too many Nagler eyepieces
http://www.fiskemiles.blogspot.com/
www.fiskemiles.com
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Fiske
Carpal Tunnel
Reged: 03/14/04
Posts: 1931
Loc: Missouri / United States
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One tip on the mirror: check out AstroMart for a used mirror. You can get a 10-inch at a pretty good price. The advice above not to go larger than a 10-inch is on target. Especially considering your budget.
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Fiske Miles
Nikon 8x42 LX / 12x50 SE Binos
Mini Borg 60ED, TV-101, AT80Ach, XT-8, C11/CI-700, 22-Inch Dob
Way too many Nagler eyepieces
http://www.fiskemiles.blogspot.com/
www.fiskemiles.com
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Dougie
member
Reged: 07/02/08
Posts: 11
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Yeah not much listed there at the moment. There's a 20" but I'm guessing thats way beyond any budget I might have in mind. If I could do a larger scope I wouldn't mind a budget going into 1500-2000 but for a 10" I'd like to keep it around 500-750 if possible.
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