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View Full Version : OT. DIY telescope question (Evan, Macona ?)



Mr Fixit
01-24-2016, 03:39 PM
Hello Group,
I have been asked by my 9yr old grandson if we could build a telescope. Google search gave lots to filter through. The grandson has spent time in the shop, run the lathe and seen the other equipment used so I'm comfortable having him working with the machine's (supervised) to do a project.

The Dobsonian looks really cool to build (machinist stuff) but I'm clueless about this topic and felt this would be the place for some direction.

So, my background is an electrician, HVAC Tech and home hobbist, machine work knowlege is highschool 35yrs ago1class, self taught since I acquired my equipment 2010. I have a SB9A tool room lathe, Bridgeport clone mill, welding forms, stick, mig,tig, gas, and a few sheet metal tools.

Question is does anyone have a design to recommend, a web site to visit, a forum to join, an opinion about the whole idea of doing this.
I'd like to honor his request but I also know failure or never completed projects are no fun, so I'm looking for your guidance on this one!:confused:

TX
Mr fixit for the family
Chris :)

P.S. Evan, Macona, you came up in searches here for old topic's that's why I called out your name's.
TX Chris

The Artful Bodger
01-24-2016, 04:27 PM
Chris, there is a heap of information at http://www.cloudynights.com/index

I have very little experience and have restricted my amateur telescope making to building mount or two.

This is a great project to have with a young person.

boslab
01-24-2016, 04:34 PM
Actually it's not that difficult, ok if you start making mirrors it gets more involved, I helped make one but never did one for me, it had to be sent for aluminising, unless your macona that would be normal!
Don't build a skeleton telescope if you have any light pollution!, found that out quick
A dobsonian would be a good place to start, sheet ply is adequate, amazingly.
https://stellafane.org/tm/dob/
Evan knows just about all there is about astrophotography, he's put up some stunning photos.
I suppose that's the advantage of the BC night sky.
I've never taken a photo so I know nothing about that.
I know a few guys into thier own build, I get ti make some bits and bobs for them, mostly bits of tube, the last one was a length of 6" PVC sewer pipe with nylon rings to hold the optics, crude but effective.
(I have a book about telescope building by Patrick Moore somewhere, I had 2 off him, one about the moon, he signed that one, nice guy, was not happy with his next door neighbours chestnut trees, most annoyed, http://www.amazon.co.uk/Amateur-Telescope-Patrick-Practical-Astronomy/dp/1852330007)
Mark

Evan
01-24-2016, 05:48 PM
I recommend a standard Newtonian reflector. They are basic scopes, easy to build and the mirrors are reasonably cheap. The best thing is that they are easy to make with a tracking mount, much easier than a Dob. I am highly biased because I much prefer astrophotography rather than looking through the eyepiece with the human eye. These days astrophotography is so much easier to do with digital cameras. Then by using a computer to do image stacking even a small scope can produce images equal to much larger scopes using old fashioned film. Stacking actually increases resolution. Few mirrors are good enough to approach the actual Rayleigh Limit imposed by the wavelength of light so by stacking images each image contains information that the others don't have and the effective resolution is increased.

The nicest thing about astrophotography is staying inside where you don't freeze your butt and still take pictures. Even a six inch scope can do pretty nice work and is small enough to be very portable.

This is my six inch scope I still have:
Cross your eyes 3D

http://ixian.ca/pics12/3d6scope2.jpg


This is online Newtonian design software: http://stellafane.org/tm/newt-web/newt-web.html

macona
01-24-2016, 05:58 PM
Join the Rose City Astronomers, they have a DIY group that meets over in St Johns to make mirrors and build telescopes.

http://www.rosecityastronomers.net

old mart
01-24-2016, 06:58 PM
Great idea, be careful to ensure that you don't try to build something too big for the machinery you have. One advantage of a trussed dob is no huge tube to make.

Paul Alciatore
01-24-2016, 07:44 PM
Telescopes are not that difficult to build. Some of the photos show really nice looking, works of the machinist art. But that is not necessary.

The first decision is refractor (lens) or reflector (mirror) so you need a primary lens or mirror. Although a mirror can be made in any garage, lens making is more involved. But these can be easily and inexpensively purchased.

You need a tube. But you don't have to take that literally. A square tube made of wood is just fine. Aluminum pipe will work.

You need a mirror or lens mount. Mirror mounts can be purchased to fit standard pipe. Or making one is not that difficult.

Then there is the eyepiece. They sell focusing eyepiece mounts. Or you can make one. A reflector style scope will also need a diagonal mirror because the eyepiece is mounted on the side of the tube.

That's the scope itself and all of the above can be done in any garage, even without a lathe or metal mill.

The mount can get trickier. The traditional mount is an equatorial mount that allows tracking the movement of a star with one motion around one axis. It is somewhat harder to make as two bearings and an additional pivot joint are required. And it needs to be well balanced if it is to be easy to use. The Dobsonian mount is easier to make but it requires motion about two axis to track the motion of a star. Not so important for just observing, but not so good for photography. With a Dobsonian mount, astrophotography not only requires two axis motion to track the star, but the film or camera must also be rotated to keep the image properly oriented on the film or sensor. A computer is almost required for that three axis motion. The Dobsonian is a good choice for a first scope if photography is not anticipated. And the Dobsonian is almost self balancing. Only the scope itself needs to be balanced and that can be accomplished by choosing the mounting point for the bearings.

So, nothing above is beyond the easy capability of any garage. Even fancy woodworking machines are not automatically needed. It can be done with hand tools.

I say go for it. And have fun star gazing.

kitno455
01-24-2016, 09:41 PM
I've made several, and was working on another one just now.

The easiest for a beginner is probably a reflector, some variation on the Stellafane plans: https://stellafane.org/tm/dob/ You would adjust the design for whatever your local skillset is. Mirrors can be purchased cheaply, everything else can be made.

However, if you think he would like to use it for terrestrial purposes, a small refractor is also nice. Similarly, you can buy the objective lenses, and make everything else.

You might find some inspiration from this thread: http://www.cloudynights.com/topic/404751-post-your-home-made-scope/

allan

Mr Fixit
01-24-2016, 10:18 PM
Wow Gang,
The links are terrific! I have lots of research to do but the first is how serious my grandson is about this. I'm not going to discourage him, but it really looks like a project, and I would want it to be fun not a drag. I may try the link Macona sent and maybe a visit to a celestial event might be enough for now.

TX for the info.
Chris :)

tyrone shewlaces
01-24-2016, 10:31 PM
Another option is to go ahead and buy a cheap scope you can both look through now and then, as well as being right there to point at weak parts of the cheap design you wish to not have in your home-built scope.
Also, the old saying is true with telescopes - the optics is everything. Well OK not all of everything because the mount counts for a lot, but you can also have the two to compare the optics too once your superior one is working. You were counting on putting good quality optics in it too I hope.
You can still see some fun things with a cheapie scope. It's just not as good (sometimes pretty awful) but it's still better than the naked eye.

edit to add: Just took a quick look at the local craigslist and there are a BUNCH listed. Many cheapies, some interesting and easy to pack & carry, and run between $25 and $150, then there are some nicer ones around $500 and a couple up around $1K. I saw a couple that looked like Schmidt-style (short and portable) which work kind of like Dobsonians in that it's just point & look, but you could fit two on a TV tray. Those would be joyously easy to just grab and go a lookin'. With one of these, you could do some valuable practice with actual observing while you're making progress on the project. Good for inspiration, both the observing and the frustration with the cheap scope, hehe.

kitno455
01-24-2016, 10:36 PM
Another option is to buy a used scope on craigslist. I've gotten a couple fixer-upers that way that worked out nicely. The price is often very good, because people buy them, and only use them a few times, then realize they take up space. You need to do some research there about what is worth having. Another suggestion is binoculars. They might be more useful to him. A nice set of 7x35s are often reasonable.

allan

boslab
01-25-2016, 01:46 AM
I've been looking for some 25x70 binoculars myself, with a stand, easier to store than a scope, the sky is perpetually cloudy these days, not the clear winter nights I remember as a kid, all it seems to do is rain.
If I had the sky conditions I saw in the US I'd be building an observatory in the garden, dome and all!
Looks like a fascinating project to try!
Mark

Evan
01-25-2016, 04:39 AM
If you buy a scope pay no attention at all to the advertised "magnification" of the scope. Department store scopes hit that hard but what matters more than anything is the ability to collect light, the size of the mirror or lens. Magnification only matters for planetary viewing. I take many of my best photos without a scope at all, just the camera mounted on a tracking drive. Perhaps a good place to start is to try some astrophotography with a digital camera that can do at least a 30 second exposure on a double arm drive. A double arm drive is a method of tracking the sky motion and that is what really matters for taking good photos. It is dead simple to make and the rewards for the effort are big.

Have a look here: http://davetrott.com/inventions/double-arm-barn-door-drive/

The double arm drive is a perfect introduction to astrophotography and you can make it with sticks of wood or you can get very carried away such as the one I made.

http://ixian.ca/pics12/mount.jpg

http://ixian.ca/pics12/award.jpg

I think I may have to have a word with Dave about attribution on a photo or two he has online.

tyrone shewlaces
01-26-2016, 12:08 AM
If you buy a scope pay no attention at all to the advertised "magnification" of the scope.

I forgot about that, and Evan is absolutely correct. Cheap scopes have "wobbly" optics, wobbly mounts and toy eyepieces (oculars). They will be easily surpassed by a decent home-made effort, and the main optics are usually low-quality enough that puttig a high-quality eyepiece on it won't even yield much for results. That sounds pretty bad, but they will still be magnitudes better than naked eye, depending on what you are looking at, i.e. viewing the milky way in one piece is still pretty awesome naked eye if the sky is very dark. Really all you need to do if buying a cheapie is look at it and get the one with the largest diameter that is ALSO easy enough to just pull out and start looking through, which means while a 6" reflector is kind of impressive to have on display, and it will gather more light than a smaller one, it is much more cumbersome to get out and set it up for use, especially if you need to haul it to a darker viewing site. There are some handy little 4" Schmidt-Newtonian scopes out there that are nice and easy to handle. I have one I got a couple decades ago for $30 and I still get it out once in a while to use as a spotting scope, so even though the optics are cheap, it can still be useful. It's still better than naked eye (especially my eyes) and it packs to the size of a fat clarinet case.

Anyway, ignore any of the propaganda printed on the box of a cheap scope. If you decide to get one, just use three criteria - 1. size and ease of use 2. price 3. is anything important missing or broken?

CCWKen
01-26-2016, 11:05 AM
Are you building the scope for you or a nine year-old?

Why does he need mirrors, nano-arch tracking, digital photography capability or any of that? What started as a simple machine project to share with his grandson has turned into a 10-year NASA project. :)

Added:
Sorry. Perhaps I'm showing my envy. I haven't seen my grandsons except in pictures and only see my 8-YO great-grandson 3-4 times a year. I don't think I'd trust him with a pair of pliers though. :) I tried to show him how to drill holes with a drill press but he was too intrigued with the spinning chuck and tried to grab it. :(

Dragons_fire
01-26-2016, 02:34 PM
I agree with CCWKen, if its for the nine year old, make it a simpler project. If you do a google search for homemade telescopes there is a bunch of fancy stuff that comes up, but also a lot of other ones that are rough cut from toilet paper tubes. Some sources of cheap lenses that will work ok are old projection tvs, camera lenses, magnifying glasses, etc...

If you're looking for something that is also a machining project, i would recommend looking at some of the cardboard tube designs online and redesigning them with some brass or aluminum tubing. then he could learn the basics of how the scope works (lens spacing and such), machining and still have something to use after to learn a little astronomy.

Mcgyver
01-26-2016, 03:56 PM
Are you building the scope for you or a nine year-old?


agreed.....built anything with a nine year old lately? works great if the build is an hour or less and they're doing the doing.

I'd get him sticking the plastic crap out of the blue bin together with a hot glue gun, and find a telescope cheap on craiglist

Evan
01-26-2016, 05:45 PM
" What started as a simple machine project to share with his grandson has turned into a 10-year NASA project. "

I suggest you go to the link I posted and look at what it takes to make a double arm drive. It can be built with a saw, a drill and a screwdriver for a few dollars. It needs an AC synchronous motor and a bolt in a nut for the drive. All you need is a camera tripod to put it on and any camera that can do at the very least 15 seconds and much better 30 seconds will do the job. The best cameras are the old ones with low pixel counts. The pixels are much larger and have much higher quantum efficiency than the ridiculous 20 megapixel cameras. By far the best if you can find one is the Nikon 4300 and only that specific model. It has a true large pixel CCD sensor with up to one minute exposure and noise subtraction using dark field exposure. I still use that camera as it is the best I have in certain ways. Pixel consistency is perfect and the lens resolution is perfectly matched to pixel size. There isn't another camera like it.

DennisB
01-26-2016, 05:57 PM
Try going to http://www.willbell.com/ and look for a couple basic books. "How to make a telescope" by Jean Texereau and "The Dobsonian Telescope" by David Kriege and Richard Berry.
The last title is considered by many to be the current best reference if you are looking to build.

A 6" basic altitude azimuth (Dob) would be good for any beginner especially since you are helping a 9 year old.
Forget the tracking to start and just build a nice telescope.
Dennis

kendall
01-26-2016, 09:28 PM
I agree with CCWKen, if its for the nine year old, make it a simpler project. If you do a google search for homemade telescopes there is a bunch of fancy stuff that comes up, but also a lot of other ones that are rough cut from toilet paper tubes. Some sources of cheap lenses that will work ok are old projection tvs, camera lenses, magnifying glasses, etc...

If you're looking for something that is also a machining project, i would recommend looking at some of the cardboard tube designs online and redesigning them with some brass or aluminum tubing. then he could learn the basics of how the scope works (lens spacing and such), machining and still have something to use after to learn a little astronomy.

In a way that's good thinking, but if you want to spark a lifelong interest in something you don't want to give them 'throw-away' junk.

Mr Fixit
01-26-2016, 11:43 PM
Hello Gang,

Had the dude over for part of the weekend and the idea is still alive BUT,, were going to check out the local club (Tx Macona ) for a viewing night first to see if he has a lasting interest. I have looked at the book titles mentioned and our library has one I've ordered. We're on a journey here and time with the kid is #1.
I'm sorry to hear CCWKen about your limited access, hang in there and try and keep in touch with them. Thanks for all the comments everyone! Will update this as things progress if they do.

TX
Mr fixit for the family
Chris :)

CCWKen
01-27-2016, 09:57 AM
In a way that's good thinking, but if you want to spark a lifelong interest in something you don't want to give them 'throw-away' junk.
As long as the tasks take less than five minutes to complete and instructions less than eight seconds, it may be possible to spark an interest. Don't count on an attention span any longer than that. A goldfish has a longer attention span. We already live in a "throw-away" society. You won't be changing that. To maintain a free-choice interest, it would be good to let the child keep a part of the project/task and have him return with the part on the next visit. Add to each accomplishment.

Rosco-P
01-27-2016, 01:08 PM
Are you building the scope for you or a nine year-old?

Why does he need mirrors, nano-arch tracking, digital photography capability or any of that? What started as a simple machine project to share with his grandson has turned into a 10-year NASA project.

+1 to the above. Maybe a simple project to see if he can maintain his interest long enough to finish it. Build a periscope, two mirrors and some PVC pipe or build it out of Luan plywood. Something he can take and play with without supervision.

Evan
01-27-2016, 07:02 PM
The best thing about doing photography, which is very easy, is that you have something to show people. It is something they can't see or do like you did and that impresses others. You have something to show for your work and it is something that you can show anywhere and everywhere, a picture.

Even just starting in astrophotography using a cheap camera with just the right specs, placed on a tripod at night with nothing to build at all is a very good way to start. Then you can show something like this:

I took this with the Nikon on a regular tripod. It was a 30 second exposure and during the exposure I waved a flash light on the various trees. That's all.

http://ixian.ca/pics12/orionsnow.jpg

Most important of all, it is something you can do together with the child.

macona
01-28-2016, 03:13 AM
Personally for a first scope I would pick up something like a little Meade Maksutov , the ETX-90. With the ability to "goto" starts, planets, etc, it makes it a whole lot more interesting for the beginner astronomer and are probably more likely to keep at it.

http://www.skiesunlimited.com/meade-etx-90-maksutov-cassegrain-portable-observatory.html?gclid=CjwKEAiA8qG1BRDz0tmK0pufw3Q SJACfn6olePzgbsH5exfpBAea7ktII0fX71bXVvv9C1UkkkLj_ hoCMxPw_wcB