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How to photograph the Milky Way


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Oh yeah, and as far as lenses that show very low amounts of aberration when used wide open, I and many of the other landscape astro photographers really love the Rokinon / Samyang line of primes:

Rokinon 12mm/2.0

Rokinon 14mm/2.8

Rokinon 24mm/1.4

Rokinon 35mm/1.4

Rokinon 85mm/1.4

And there are others too like the Sigma 35mm/1.4, Sigma 18-35mm/1.8. 

All of these lenses have very low levels of coma or astigmatism and usually only suffer from minor chromatic aberration. 

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I took delivery yesterday of an old Tokina 400mm FX  f/5.6. On my D5100 it behaves as a 600mm. A brief break in the clouds allowed a single shot of Vega. I was pleased to see no coma or CA, although wide open. I was able to split Lyr 6&7 as well. Yes on a tripod, although that may change in the next couple months.

@Lonelyspeck,  you are using an EQ mount then, right? If you reduced ISO and took 25 images with darks  and stacked, maybe M42 wouldn't look so small.

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hobsey, I personally do not have experience with the Tokina 11-16mm/2.8 but most reports I have seen indicate that the Mark II version of the lens performs very very well. Lens Tip has a good review of its astigmatism/coma performance: http://www.lenstip.com/379.7-Lens_review-Tokina_AT-X_116_PRO_DX_II_AF_11-16_mm_f_2.8_Coma__astigmatism_and_bokeh.html

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@Lonelyspeck,  you are using an EQ mount then, right? If you reduced ISO and took 25 images with darks  and stacked, maybe M42 wouldn't look so small.

kalasinman, 

I took that challenge on and tried it with all the data I took that night (only 8 exposures but some at lower sensitivity and alternate exposures. (total of 23 minutes of data) I also alternated my processing method and boosted the red channel a bit to bring out Barnard's Loop. There's definitely a lot more going on now.

Here are the results:

orion-1.jpg

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lonelyspeak - can i ask a big favour?

Could you post up just one of your unedited exposures that you used for the above image?

I'm just after some visual guidance on what a single sub would look like before stacked with multiple subs and then stretched etc - just so I can compare what I'm getting in RAW from my own camera.

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Thank you for all the information, and the images. What you're describing makes sense and it's good to know the lenses you've found to be good wide open.

I think a lot depends on what you hope to get out at the end of the day, and therefore what optical issues you're prepared to accept in the final image. As much as I'd like to use my 50 f/1.4, wide open, the end results are dire (from an astronomy perspective), and I don't really want to throw away that much of the edge of the image to get rid of all the aberattions. At f/3.5 the star shapes are good, but the amount of red CA in the middle is quite high (it can be processed out to some extent, but ...) The 50 f/1.8 is not as good as the f/1.4 at f/3.5.. Having said that my Sigma 150mm f/2.8 Macro lens wide open is really rather good (but then macro lenses are designed to have a really flat field, and my astro testing supports that).

Most people just starting out however, are likely to only have the 18-55 kit lens, and that's ok wide open @ f/3.5 (bit of blue CA on the Canon IS lens).

Personally I'm not so sure on the high ISO, but then, a lot will depend on the camera noise handling... from my reading, and I may well be remembering this wrong, the best overall response on Canon cameras is between ISO400 and ISO800 taking into account all the noise factors. Given that the ISO is actually an indication of the digital signal amplification applied to the sensor readout (and not the actual sensor sensitivity), using a much higher ISO doesn't actually gain you more signal, although, I will admit I find it easier to process images at ISO800 than ISO200. 

My main astro camera is a 450d, and is ISO limited to 1600, and whilst I have used that level for shorter tracked exposures (under 1 minute), the high number of subs I used helped balance out the noise (168 was the maximum I've used). 

As in all photography, go for the settings that produce the results you want to achieve at the end. 

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lonelyspeak - can i ask a big favour?

Could you post up just one of your unedited exposures that you used for the above image?

I'm just after some visual guidance on what a single sub would look like before stacked with multiple subs and then stretched etc - just so I can compare what I'm getting in RAW from my own camera.

nicks90, 

All of the original RAW files are available for download here: https://drive.google.com/folderview?id=0B4mVJ2lbrwb1a2dWdkhyQ3k0R2s&usp=drive_web

I just did another process on the stack for this: 

ian-norman-orion-processed-1400.jpg

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lonelyspeak - can i ask a big favour?

Could you post up just one of your unedited exposures that you used for the above image?

I'm just after some visual guidance on what a single sub would look like before stacked with multiple subs and then stretched etc - just so I can compare what I'm getting in RAW from my own camera.

How about 12 of these

pelitest1.jpg

Make one of this.

pelitest2.jpg

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