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Equipment Discussions >> ATM, Optics and DIY Forum

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nicklane1
sage
*****

Reged: 03/04/08

Re: Post your home made scope new [Re: hardwarezone]
      #6261668 - 12/19/13 10:47 AM

Quote:

My lightweight short-tube 80 made with plastic bottles
Weight is 1.2 pounds.
Objective is bought online, eyepiece taken from junk binoculars.







That is pretty cool.
Lego blocks???


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hardwarezone
member


Reged: 04/26/13

Loc: Singapore
Re: Post your home made scope new [Re: nicklane1]
      #6261675 - 12/19/13 10:50 AM

Quote:


That is pretty cool.
Lego blocks???



Yes, there are 6 lego pieces that I use to nail the lens cell into the tube body.
I designed it to be detachable easily if I need to access the tube internal and baffles.


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nicklane1
sage
*****

Reged: 03/04/08

Re: Post your home made scope new [Re: hardwarezone]
      #6261694 - 12/19/13 10:57 AM

Quote:

Quote:


That is pretty cool.
Lego blocks???



Yes, there are 6 lego pieces that I use to nail the lens cell into the tube body.
I designed it to be detachable easily if I need to access the tube internal and baffles.




That is very resourceful.


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djc854
member


Reged: 11/22/11

Loc: Washington, DC
Re: Post your home made scope new [Re: StarStuff1]
      #6261851 - 12/19/13 12:46 PM Attachment (64 downloads)

My first scope - mirror, tube, and mount. It's 6" f/7.7. First light: April 2013. The mirror was originally ground by my grandfather in 1958. Scratches required its regrinding/polishing/figuring in Winter 2013. David

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tag1260
scholastic sledgehammer
*****

Reged: 10/07/12

Loc: Ohio, USA
Re: Post your home made scope new [Re: djc854]
      #6261879 - 12/19/13 01:01 PM

Would love to see a bigger picture of this. Sounds cool using your Grandfather's mirror. That in itself makes it a near perfect image, if you know what I mean.

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StarStuff1
Post Laureate
*****

Reged: 04/01/07

Loc: South of the Mason-Dixon Line
Re: Post your home made scope new [Re: tag1260]
      #6262612 - 12/19/13 08:37 PM

Agreed. Kool to keep a family scope functioning.

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djc854
member


Reged: 11/22/11

Loc: Washington, DC
Re: Post your home made scope new [Re: tag1260]
      #6263130 - 12/20/13 07:52 AM

Thanks. There are more pictures on the blog, which I set up for the sake of relatives who knew I was trying to get the old mirror up and running: Riccioli

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Pierre Lemay
member


Reged: 01/30/08

Loc: Quebec, Canada
Re: Post your home made scope new [Re: tim53]
      #6263806 - 12/20/13 02:03 PM Attachment (78 downloads)

Quote:

Paint (unless you're talking about black radiator paint) is an insulator. I'd be interested in a comparison test of painted versus unpainted vanes to see just which version would produce the hypothesized results.

-Tim.




Such a test was done years ago by André Couder, former director of the Paris Observatory (and inventor of the mask we use with the Foucault test). I believe the "theory" Brice is refering to stems from André Couder's 1949 article on Thermal Effects in Reflecting Telescopes.

I've been wanting to do this for some time, so I translated the summary of Couder's article that looks into spider vane thermal emissions (see attached). It is an interesting document which the english only speaking amateur astronomy community does not have access to. This summary was put together by French amateur astronomer Olivier Ruau. Very few experienced French telescope makers ever darken the vanes of their spiders because of information provided in Couder's article. Maybe there is a lesson there for those who can't read the language of Molière.

When we strive to make (or buy) a 98%+ Strehl ratio mirror, we owe it to ourselves to ensure the rest of the system (collimation; central obstuction; thermals; etc.) is up to the level of quality of that mirror. Hopefully the information contained in this article, generated more than 60 years ago, can be of help to improve the overall system performance of your telescope system.

Pierre Lemay


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Pinbout
Postmaster
*****

Reged: 02/22/10

Loc: nj
Re: Post your home made scope new [Re: Pierre Lemay]
      #6263932 - 12/20/13 03:07 PM

Quote:

so I translated the summary of Couder's article that looks into spider vane thermal emissions (see attached). It is an interesting document which the english only speaking amateur astronomy community does not have access to.




is there any versions on line?


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Pierre Lemay
member


Reged: 01/30/08

Loc: Quebec, Canada
Re: Post your home made scope new [Re: Pinbout]
      #6264139 - 12/20/13 05:01 PM

Quote:

[

is there any versions on line?




Of Couder's original article? Not that I could find. I will try to get in touch with the French ATM who did the french summary to see if he can scan and send a copy of the complete article.

Pierre Lemay


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Meep_Esq
member


Reged: 01/02/07

Loc: Dunedin, New Zealand
Re: Post your home made scope new [Re: Pierre Lemay]
      #6269118 - 12/23/13 05:49 PM

Well, it's a wee way from being finished, but I completed the milestone assembling the tube for my 8" f/13 newt. There's still lots of little jobs to complete, like the 2ndary, mounting everything, paint, etc, but it's starting to feel more real now!



I knew it was going to be tall - but seeing it in the real - Yep! It's tall!


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474747
super member
*****

Reged: 04/19/08

Loc: Florida, USA
Re: Post your home made scope new [Re: Meep_Esq]
      #6269344 - 12/23/13 08:07 PM

So Vaughn,
Did you say how you planned on mounting this thing?
Brian


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Sarkikos
Postmaster
*****

Reged: 12/18/07

Loc: Suburban Maryland, USA
Re: Post your home made scope new [Re: 474747]
      #6269411 - 12/23/13 08:35 PM

An aerial Newtonian.


Mike


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Meep_Esq
member


Reged: 01/02/07

Loc: Dunedin, New Zealand
Re: Post your home made scope new [Re: 474747]
      #6271166 - 12/24/13 05:56 PM

Most likely a wide-base dobson mounting. However I am intrigued by the possibility of making a holscomb-type mounting for it (See Mel Bartels website...) The long tube certainly lends itself to the idea, but logistically I'm not sure. But then half the fun of this slightly crazy project is to try out ideas. I've already refined the sandwich-construction mirror cell to refurbish my more conventional 8" Dob when I finish this monster. The combination of aluminium poles in wood pillow blocks and PVC tube is surprisingly rigid

At more moderate altitudes, the eyepiece is easily in the range of a medium stepladder.


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Meep_Esq
member


Reged: 01/02/07

Loc: Dunedin, New Zealand
Re: Post your home made scope new [Re: Sarkikos]
      #6271175 - 12/24/13 06:00 PM

Hi MIke. Although a ladder might be the conventional approach, I'm not ruling out using a zeppelin or space-elevator



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Mihai
member


Reged: 08/11/05

Loc: Romania
Re: Post your home made scope new [Re: Jim Curry]
      #6271961 - 12/25/13 10:40 AM

Quote:

4" f/12 Istar, powder coated, baffled, AP focuser.
Jim




Jim,are you satisfied with your refractor?...I intend to build one with the same lens,and I wold like to hear an opinion...thanks


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KevinS
super member


Reged: 12/27/11

Re: Post your home made scope new [Re: Mihai]
      #6287014 - 01/02/14 07:54 AM Attachment (37 downloads)

Surplus Shed 127mm x700mm F5.5 Achromat
mounted in marine diesel air intake tubing w homemade heater strips and modified reflector focuser

Edited by KevinS (01/02/14 07:55 AM)


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KevinS
super member


Reged: 12/27/11

Re: Post your home made scope new [Re: KevinS]
      #6287020 - 01/02/14 08:00 AM Attachment (38 downloads)

Same scope with recent mods
Birch plywood tube cage, carrying handle, three dovetail plates, heater wire connector mounts, vinyl wrap on OTA and natural finish dew shield

Edited by KevinS (01/02/14 11:46 AM)


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mikey cee
Postmaster
*****

Reged: 01/18/07

Loc: bellevue ne.
Re: Post your home made scope [Re: KevinS]
      #6287262 - 01/02/14 10:43 AM

Now that's a different color than I've ever seen before. Not bad. Mike

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KevinS
super member


Reged: 12/27/11

Re: Post your home made scope [Re: mikey cee]
      #6287297 - 01/02/14 10:57 AM Attachment (38 downloads)

Thanks Mike,
Originally, It was a Rustoleum Metallic Orange that I tried real hard to make work because it looked so nice. But I've given up. The stuff just stayed soft even after weeks of drying so I have ordered a CF looking vinyl wrap. Currently the dew shield is buffed natural aluminum with clear enamel. Also, a 7" tube for a sliding dew shield is on the way so it's going to change a little bit more. Here's first light, unguided Triangulum from my parent's NC front yard taken Dec 27. I didn't spend a lot of time processing this as the tracking was horrible. (The fault was my alignment, the AVX is a great mount)

Edited by KevinS (01/02/14 11:14 AM)


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