# Something Fun

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Bowser, Dec 4, 2017.

1. ### BowserLife is Fatal.Valued Senior Member

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I always thought it would be cool to make my own telescope. We went to comet party where there were telescopes of all kinds of shapes and sizes...

Xelasnave.1947 and river like this.

3. ### Xelasnave.1947Valued Senior Member

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The first using a shaving mirror which gave seven images all at once.
Total fail.
I later made a 10 inch Newtonian which turned out real special.
But its better just to buy one.
Alex

Last edited: Dec 4, 2017

5. ### SeattleValued Senior Member

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Grinding and polishing the lens (mirror) is the difficult and time consuming part, right?

7. ### Xelasnave.1947Valued Senior Member

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Yes but I used a mirror already built I only had to have it "silvered" (coated with aluminum) .
Building one is satisfying but they are so cheap these days.
I paid under $500 for a f5 newt 8 inch, add$300 for a coma corrector and $100 for a basic electric focuser,$35 for a camera connector ( T ring) $500 for guide scope and guide camera,$2000 for the mount, add a dslr camera and you have a reasonable basic set up for astro photography.
But its been cloudy since I made this current set up.
It is challenging because everything has to be perfect..next step up would be a dedicated narrow band camera and filter wheel (8 filters) $3000 and a 4 inch triplet refractor$3000.

Next step up $25 k mount,$10 k scope, $15 k camera and guiding. Alex Last edited by a moderator: Dec 5, 2017 8. ### Xelasnave.1947Valued Senior Member Messages: 4,142 Dup 9. ### Xelasnave.1947Valued Senior Member Messages: 4,142 Years ago I came up with a system like shown in the photo herewith. I never built it but haply to see someone did it. My reason was to reduce imaging time by gathering all narrow band images simultaneously. The photo shows what is called the Dragon Fly Array. It uses 400 mm fl canon camera lens and these lens used to cost$15k each the last time I saw one...however the lens is rather special and enables better photos than ever before.
I can't get cost down past \$6000 per scope , say using 80 mm x 400 mm fl triplet scopes...but I sure would like to build similar.
Alex

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10. ### Xelasnave.1947Valued Senior Member

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Dragonfly is an innovative, multi-lens array designed for ultra-low surface brightness astronomy at visible wavelengths. Commissioned in 2013 with only three lenses, the array is growing in size and proving capable of detecting extremely faint, complex structure around galaxies. The most recent upgrade—completed in 2016—saw Dragonfly grow to 48 lenses in two clusters.

[Scroll down to see a gallery showing the growth of Dragonfly.]

According to Cold Dark Matter (CDM) cosmology, structure in the Universe grows from the “bottom up”, with small galaxies merging to form larger ones. Evidence of such mergers can be seen in faint streams and filaments visible around the Milky Way Galaxy and the nearby M31 galaxy.

But the CDM model predicts that we should see more of this structure than is currently observed. However, images obtained using even the largest, most advanced telescopes today contain scattered light that may be hiding this faint structure.

Dragonfly is designed to reveal the faint structure by greatly reducing scattered light and internal reflections within its optics. It achieves this using commercially available Canon 400mm lenses with unprecedented nano-fabricated coatings with sub-wavelength structure on optical glasses.

Also, Dragonfly images a galaxy through multiple lenses simultaneously—akin to a dragonfly’s compound eye—enabling further removal of unwanted light. The result is an image in which extremely faint galaxy structure is visible.

The array began imaging targets in 2013 from its home at the New Mexico Skies hosting facility. Images have shown Dragonfly is at least ten times more efficient than its nearest rival and will be able to detect faint structures predicted by current merger models.

The original co-principal-investigators for Dragonfly are U of T’s Prof. Roberto Abraham and Yale University’s Prof. Pieter van Dokkum, and they have recently been joined by Harvard’s Charlie Conroy as the third co-principal-investigator. At the U of T, the Dragonfly team also includes graduate students Jielai Zhang and Deborah Lokhorst.

Funding for Dragonfly was provided by Abraham’s NSERC Discovery Grant, with initial funds provided by the Dunlap Institute and Yale University, and NSERC equipment grants awarded in 2014 and 2016.

11. ### Xelasnave.1947Valued Senior Member

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The latest set up

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13. ### BowserLife is Fatal.Valued Senior Member

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I think much of the thrill would come from doing it yourself and seeing its completion.

14. ### Xelasnave.1947Valued Senior Member

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Indeed. I was rather proud of myself when I competed my second scope.
So perhaps consider building one yourself.
You gave me the impression you are between hobbies so build one.

You will learn a great deal.
If you decide to make your mirror the longer the focal length the more forgiving it will be.
Alex

15. ### BowserLife is Fatal.Valued Senior Member

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It's a consideration, but first I would need clean the garage and organize the workbench. It's quite the mess.

16. ### Xelasnave.1947Valued Senior Member

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I expect you are right , well as so far as needing a workbench.
So you can get started by doing that.
It will give a balance to the problems you seem to have resisting spirituality.
Alex

17. ### BowserLife is Fatal.Valued Senior Member

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I'm in no hurry whatsoever. When and if it strikes me to give it a go, then I will.

18. ### Xelasnave.1947Valued Senior Member

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Everyone should read that book to get an appreciation why they should buy one.

Alex

19. ### DaveC426913Valued Senior Member

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I'd suggest you forego making your own lens. It's a lot of work, and the results may be quite a disappointment.
Buy the lens, make the rest.