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Author Topic: My Astrophotography Adventure  (Read 6231 times)

michael

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Re: My Astrophotography Adventure
« Reply #20 on: November 18, 2014, 01:29:00 pm »

Two fellows meet at a party.

The first says to the other..."Do you play golf?"

"No," says the second man. "Tried it once, didn't like it?"

"Do you play chess?"

"No. Tried it once, didn't like it?"

"Do you do photography?"

"No. Tried it once, didn't like it?"

At this point a child walks over and says something to the second man, who is clearly the little boys father.

The first man comments afterward..."Your only child I presume."
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NancyP

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Re: My Astrophotography Adventure
« Reply #21 on: November 18, 2014, 02:50:17 pm »

Who...whoo....whoooo.....who.cooks.for.youuuuuuuaaaaaaallll   (the memory aid for the cry of the barred owl, of which there are plenty in some of the areas where I do star-gazing/ astrophotography. Also, coyote yowls. Also, "hey, look at M# (their favorite Messier object, a galaxy or star cluster)" by neighboring observer with a telescope. I am partial to M45, and I even drive one. (Subaru, which is the Japanese name for the star cluster called the Pleiades in the West).
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nutcracker

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Re: My Astrophotography Adventure
« Reply #22 on: November 18, 2014, 04:04:48 pm »

Marvellous response from Michael.
The everpresent sense of fun and mischief make his (and Kevin's) presence at and on LuLa great fun as well as serious photography.

Sean
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PierreVandevenne

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Re: My Astrophotography Adventure
« Reply #23 on: November 20, 2014, 09:20:52 am »

I really liked the "yoga" comparison. Unless you start a very specific project (such as measuring variable stars, hunting for asteroids, measuring the light curves of exoplanets...) astrophotography is indeed somewhat pointless, and I love it that way. The pleasure is in the process as much as it is in the final result. Take it any other way and you'll be disappointed.

Anyone going into this for "results" will be sorely disappointed. There's a channel on youtube where talented pro photographers take cheap trash camera and try to take good pictures. I am a bit ashamed to say that in 99% of the cases, they take better shots with a $99 camera than I do with a $5000 one. But there is no such thing in astrophotography: better skies, more aperture and bigger CCDs always win.

The current most "rational" option if one wants "results" and one doesn't live in an ideal place is to rent time on pre-configured telescopes (for example http://www.itelescope.net/) - but where's the process? Or more correctly, that's a different type of process, more "excel" than "yoga".

Thank you for that very nice article Michael!

Ah, and one word about the stacking vs single shot issue: ideally, longer shots deliver more bang for the buck than the equivalent stacked exposure. However, in practice, it depends on many factors. The most important one for casual amateurs is the background brightness of the sky where one lives. The goal of each exposure is to maximize signal to noise ratio. If you live in a very dark sky area your sky brightness might be at magnitude 24 and you'll need to expose for a long time (depending on your aperture) to reach it. If you live in a suburban area with a sky brightness of mag 19, you'll hit the limit very quickly. Any exposure beyond that limit will drown weak signals in a sea of noise and drastically lower your dynamic range. Where I live, Belgium, one of the most light polluted zones of the world, I hit the limit after about 90 seconds. Above that, I start losing signal. And if I exposed for five unfiltered minutes, I would just get an uneven brownish/yellow image.
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NancyP

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Re: My Astrophotography Adventure
« Reply #24 on: November 20, 2014, 11:12:53 am »

Well, I learned something a few nights ago, our photo club had an amateur astronomer and local adjunct faculty member give an excellent talk about the sun, and on observation safety. A usable solar filter for visual use or photography can cost under $40.00 USD. Baader Planetarium distributes specialized OD 5.0 (16.7 stop) double-sided coated film in 20 x 29 cm sheets for about $35.00, with instructions on how to make the filter with some poster board, double sided tape, paper glue. OD 5 filter is safe for your eyes and sensor (don't get the OD 3.8 filter sheet if you want to use it for visual as well as photographic observation, it isn't enough filtration to be safe for eyes..
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Alan Smallbone

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Re: My Astrophotography Adventure
« Reply #25 on: November 20, 2014, 11:46:37 am »

Nancy you will be able to see sun spots but you will not see flares or any of that kind of detail. For that you will need a very expensive H-alpha filtered scope. But still fun anyways for a regular camera.
Thousand Oaks optical make screw threaded solar filters for cameras. The danger of film type filters is that if they get a pin-hole it needs to be patched. Here is the last partial solar eclipse taken with a Fuji X-T1 and 55-200mm with a Thousand Oaks solar filter
https://flic.kr/p/oT7WMe

Alan
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Alan Smallbone
Orange County, CA

michael

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Re: My Astrophotography Adventure
« Reply #26 on: November 20, 2014, 03:22:12 pm »

The solution for doing astrophotography in a light polluted area (such as a city) is to use a monochrome CCD camera and narrowband filters.

I'll be writing about this in the new year.

Michael
« Last Edit: November 20, 2014, 05:45:54 pm by michael »
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NancyP

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Re: My Astrophotography Adventure
« Reply #27 on: November 20, 2014, 05:12:42 pm »

Heck, if the Baader film gets damaged, you throw it away and splurge for another 35 buck Baader film.  ;D  No, it isn't going to be perfect. For 35 bucks, I will settle for "safe" and "shows the outline of the sun and any large spots" . The lecturer explained the difference between white light, Hydrogen line, and Calcium line observing/ photos. My baseline observation is "very large/long box or tube with foil pinhole at one end, window overlooking "screen" (white paper) at the other end", in other words, the good old camera obscura. Not even a real lens. Cost, free; anyone can make it, I made these when I was a kid. Not to mention the "look at the ground under a leafy tree for sun crescents" method.

Gosh, that's a large sunspot on your series, and it shows up beautifully.
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PierreVandevenne

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Re: My Astrophotography Adventure
« Reply #28 on: November 21, 2014, 04:55:02 pm »

Narrow band filters are a solution.

But starting with skies like this

You can still get results like this

without filters, simply by stacking and managing individual exposures so they have the optimun signal to noise ratio...

Just saying...

Canon 5D / FFC 550 2.7 / 50 stacked exposures of 2 mins at 200 ISO
« Last Edit: November 21, 2014, 04:58:48 pm by PierreVandevenne »
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