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6/12/2021 |
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What would be a realistic exposure time on unguided nightscape photography? Do you use the NPF rule or any other rule? Alex. |
10,16
6/12/2021
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3
curtidas
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I make some test pictures and look closely at the stars. This works better for me than any equation.
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0,90
6/13/2021 |
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We've used up to 1200s unguided exposures but we also have a mount that is capable of doing it. Many are not. We use an ASA DDM60 which is a direct drive mount (no gears) and absolute encoders (it always knows where it is). |
0,90
6/13/2021
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1
gostei
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The short answer is it depends. It's going to depend on the capabilities of your mount, your focal length and aperture, and how good your polar alignment is that night. Since you said unguided, I assume you have a tracking mount. If you do not have any tracking at all, then yes, I would use the NPF rule. The NPF rule when set to accurate in my PhotoPills app has always been spot on for nice sharp stars. If you do have a tracking mount, then I will shoot what I know is good for exposure length (good histogram on subs) and check the stars for any trailing or egg shapes. If there is, then I go down on exposure length depending on how bad the stars look until they look good. I've had great results with 5 minute exposures with 120mm focal length (camera kit lens) with my Nikon D780 on a iOptron SkyGuider Pro when the polar alignment was good. Other nights, I have had to cut it down to 3 minutes because my alignment was not as good. Longer focal lengths (my scope with reducer is 382mm), I was anywhere from 2-5 minutes with an EQ6-R Pro. Since getting SharpCap Pro to increase my alignment accuracy, it's been on the higher side, but now I am always guiding unless I am using the SkyGuider Pro. |
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0,00
6/14/2021 |
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Hi Alex, Thank you for your comment. Unfortunately I only have a standard tripod thus guided photography is out of the picture, for now. But that would be my next question on a different thread... after the camera what would be the next logical step some better lens or a star tracker. |
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0,90
6/14/2021
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2
curtidas
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Hi Alex, Hello Alex, that is where the confusion for some users is coming from then. Guiding usually refers to using a secondary camera to send corrections to your tracking mount. Guiding assumes you already have a tracker of some sort. There is no way you are going to get more than a second to a few seconds exposures without any tracking. You'll need to take hundreds or more 1-3 second exposures to get details of any distant objects (it's a little different if you are talking Milky Way shots with <50mm lenses). This makes the stacking process take quite long, eats up harddrive space extremely quickly, and you still won't have the best color as an unmodified DSLR is not going to get much in such a short exposure length. It's still quite possible to get good images. I would suggest looking at Nico Carver's videos on just using a camera and a tripod. https://www.nebulaphotos.com/resources/m31/ So to answer your question with more certainty, you will definitely want to use the NPF rule on accurate for any deep space objects without a tracking mount. Also, a star tracker would be a good next step. With a star tracker you can go to a few minute exposures with good polar alignment and do quite well. I have the iOptron SkyGuider Pro. I've heard the star adventurer 2i has some new upgrades that people really like. Both are going to be around $450 USD. They make great mobile setups with a decent tripod. The only reason I would suggest against getting one is if you know you are going to get big into the hobby and mobility is not a major factor, then save your money for something like a SkyWatcher EQ6-R or better to have room for future growth when you get telescopes. If money is not a major concern, then get the tracker and get a nice mount later. |
0,00
6/14/2021
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1
gostei
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Hello! For a still tripod i managed to get round stars in 13s exposures with a 18mm lens of the milky way core (far from polaris, so fast-moving stars). After reading the thread it seems you don't have a star tracker. If you want to keep things cheap, I'd like to suggest an idea for shooting "wide-angle" (<150mm). After seeing how expensive proper mounts are (like the star adventurer), I just bought an inexpensive second hand cg-3 mount (the one that comes with a cheap celestron astromaster) that can be motorized (all together cost me about 90 euros). I got it today so idk how well it'll behave. I know I can achieve 5 minutes exposures with a 120mm lens with my unguided (but tracking) EXOS-1 mount (which is better than the cg-3), so I'll be happy if I manage to get 3min exposures on the cg-3 and the same lens (for smaller lenses, the time can go way up). If after this you discover that you like the hobby, I'd be happy to help in anything. See ya! |
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6/14/2021 |
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My personal experience (1 year so far) has been that I can get round stars most nights with 120s tracked (no guiding) exposures on both my Star Adventurer 2i and my EQ6-R. Sometimes I can do 3 minutes unguided but many times not. It's important to have good polar alignment. I use a Polemaster. If I didn't use PM or Sharpcap etc. I think these numbers would be short. I am also working at focal lengths under 550mm. |
4,82
6/14/2021 |
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60s @ 200mm (4"/px) 60-120s @ 135mm (10"/px, depending on polar alignment accuracy) 240s @ 40mm or wider All on a simple Star Adventurer and for DSOs. But similar exposures on a EQ3-2 RA-motorized or on a HEQ5 unguided. For landscapes/nightscapes, usually 30-90s at whataver FL 10 to 40mm. |
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0,00
6/14/2021 |
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Sorry for the confusion between unguided and untracked. Since a live in a 6 to 7 light pollution bortle scale, my plan is time to time to take a week end on the country side. I am planning to start with star trails and the Milky Way nigthspaces using an 18 - 55 mm f73.5-f/5.6 kit lens. This should give 6 to 7 seconds according to the NPL rule (with the 18mm f/3.5). Next step is to get a star tracker and go behond a minute exposure. I believe that a small start tracker would be the best solution for me because it fits anywhere! One step at a time  |
2,11
6/19/2021 |
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Hi Alexl, I have a couple of questions to ask. What experience do you have with capturing Nightscape images? What camera are you using? Are you wanting to capture these images using a single RAW file, or are you going to blend multiple images of both the foreground and sky and blend them to achieve your final image? If you would like to shoot just a single RAW file and process then I recommend the old 500 Rule and round the exposure time down. The 18mm lens you mentioned on a crop sensor camera results in 18-seconds so you can either choose 15 or 20 seconds in camera, I usually recommend the 15-seconds. This will result in a 2-3x increase of image data in your file, making it easier to get a result from the single file at the cost of a slight trailing of stars. If you are going to blend different files to achieve your final image then the NPF rule can work as you can combine multiple images of the sky and foreground to both increases your image data and reduces the noise. If you have a lot of experience with capturing the image and post-processing then the blended image should be easy to create. If you are relatively new to this style of photography then I would recommend attempting the Single RAW file and standard processing. |
