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Astrophotography - 101: How to get started.

dave.gt

Well-known member
I had mixed results while I was using Phase One getting the best results with the IQ1-100. I now use the GFX50s which has been a huge upgrade in Milky Way shots.

There is the rule of 500 when shooting night shots and wanting crisp stars. Divide 500 by the focal length in order to get a shutter speed long enough to capture the stars. This works well on any full frame sensor. What I've done is factor the 80% crop into the equation.

Full frame at 24mm I works out something like 20.83 seconds so I use 20-seconds on a Sony A7rIII beginning the ISO at 800 and working up and down till I like it.

The GFX is a tad more complicated - that same 24mm forks like this. Divide 500/24=20.83*80%=16.666 seconds. I would use 16-seconds and since I'm using the GFX I'd set the beginning ISO at 1000 and work upwards. It works for me.

Look for the darkest nights of the month which usually begin a couple days prior and after the new moon. Clear cool nights works well and expect to be outdoors between 2 and 4 am.

I've stabilized a camera on a telescope (XF/IQ) I've also used a small tracker using the Sony/GFX all of which allow for long shutter times while tracking. I reduced it all to just a tripod, no sleep and the 500 rule.
Don,

Thanks! That is great information! The rule of 500.... who knew?:toocool:

How would I factor the H5D-50c with an 80mm lens?
 

Shashin

Well-known member
Will,

Nice images, thanks so much!:)

The links you gave me have been keeping me busy this afternoon!:)

Looking up around here means looking into the light dome from the megalopolis 40 miles north of home. That being, of course the 120+ mile urban sprawl of Atlanta.:mad: But I can drive an hour south or three hours north of Atlanta to Brasstown Bald, but not too excited about the hundred of deer along the way. I need a cabin somewhere. Or a beach condo. Hmmmm...

This could be fun depending on where we wind up....
Dave, I would not worry about reaching dark skies too much. You can get quite a bit in less than idea situations. While this is not a city, the combination of a crescent moon and village lights did not wash out the Milky Way in this image (Fuji X Pro2, not MFD).



This was just after sunset when my wife and I stopped by the side of the road to eat our sandwiches. Sony RX-1 on a fixed tripod.



It might have helped being in Acadia National Park, but still, don't let perfection get in the way of good enough.

More importantly, have fun. Sometimes it is hard to tell if you are going to get something interesting.
 

dave.gt

Well-known member
Hmmm. I have an 810A, which has mostly been gathering dust, I hate to admit. This is good info Paul, thanks. I have not read much yet about the K1, and was not aware they had not addressed the white noise problem.

And thanks for your link. Extremely instructive.
Wow... I would love the D810a!!! It would be fantastic for my needs in the near future.:thumbup:
 

dave.gt

Well-known member
Thought I'd share this test I did last year. GFX50s, GF23mm f/4 8-seconds ISO 4000 shot April 21, 2018 at 0251 hrs
Oh, yeah!!!!!

The 50 sensor is absolutely capable of beautiful Astro work! Love that image, Don.:thumbup:

So what is the crop factor on the GFX50s?
 

Don Libby

Well-known member
Oh, yeah!!!!!The 50 sensor is absolutely capable of beautiful Astro work! Love that image, Don.:thumbup:So what is the crop factor on the GFX50s?
The crop is the same as what the P30 was/is which is around 80% or Crop factor for Fujifilm GFX system = 43.27/54.78 = 0.79 easier to just figure 80%...
 

dave.gt

Well-known member
Breath-taking, Ed!!!!:thumbs:

Time for a cup of coffee to allow the impressions of those images to sink in. Your Flickr pages are like my first motorcycle trip to Daytona Bike Week years ago with total sensory overload!:) ...so much to see, so many questions.;)

Thanks, Ed! I will be in touch soon. The links and advice already in this thread have dominated my time the past couple of days, so thanks to all!
 

dave.gt

Well-known member
Ed,

I am slowly working my way through your amazing website. Your images are generating more questions. I will be in touch as soon as I can get my head around them.:):):)

Thanks!:thumbup:
 

dave.gt

Well-known member
In the meantime, we finally had clear skies for a couple of days this past weekend. Just for grins, I was wondering what the H5D with the 80mm lens would do if I literally pointed the camera at the sky and played around with varying exposures.

After a few tries, my exposure time came down to less than 6 seconds. Some as low as 2 or 3 seconds and the stars were circular, so I presume the 500 Rule works!:thumbup:

Processing was interesting and the files are certainly malleable.

But,

The results were merely interesting and not worthy of sharing. Clearly, the 80mm lens is less than acceptable for what I envision, but then I knew that already. I remember riding the RK many times on tour over the years and wondering what was up an interesting road or where the many roads led. And sometimes I would take those roads only to be disappointed.

But my questions were answered and my knowledge of the area increased immensely.

This Astro "thing" is like that. Thanks to all for your comments and advice.:)
 

Shashin

Well-known member
Dave, that is the best way to learn. I would probably point my 80mm at the belt of Orion. The summer Milky Way is a richer target, but the winter one still has some gems.
 

dave.gt

Well-known member
Thanks, Will,

I need all the encouragement I can get at this point.:)
The gear is an issue I will work around, but like all things it will take time. It's a good thing the Milky Way Season is a few months away giving me time to practice.:thumbup:
 

Craig Stocks

Well-known member
I’ve never been able to feel satisfied with any of my night sky pictures. I think the fundamental problem is that stars a pinpoints of light with a wide range of brightness levels. We can’t represent pinpoints with 8 to 10 stops of varying levels of white so instead we represent stars as spots of varying sizes rather than brightness.

Add to that the problem of lens aberrations that distort the point of light so it’s not round and it’s very hard to create a wide field view of a star field that looks and feels like a true night sky. But it’s a fun challenge and I keep looking for the magic technique that will bring it all together.
 

dave.gt

Well-known member
I’ve never been able to feel satisfied with any of my night sky pictures. I think the fundamental problem is that stars a pinpoints of light with a wide range of brightness levels. We can’t represent pinpoints with 8 to 10 stops of varying levels of white so instead we represent stars as spots of varying sizes rather than brightness.

Add to that the problem of lens aberrations that distort the point of light so it’s not round and it’s very hard to create a wide field view of a star field that looks and feels like a true night sky. But it’s a fun challenge and I keep looking for the magic technique that will bring it all together.
Hi, Craig,

I understand that feeling. Somehow I feel the same way about a lot of my work, always have over the years, so maybe it is just a personality thing unique to me but it does keep me striving to do better on the next image. :) I personally enjoy your images very much.

There are so many images by other photographers that just blow me away and when I look closely at those, I see exactly what you described but the images are breath-taking. Landscapes really add to the composition and mood. And, of course, the images should be judged, imho, by looking at a print from the proper viewing distance. But pixel peeping can change our perception of a beautiful image.

As Will mentioned, our imperfect eyesight and the physical limitations of seeing small points of light millions of miles away is what it is. I still cannot get my head around that... reflected light on a relatively tiny object being seen from our location lightyears away... :shocked:

Whatever you are doing, just keep on doing it, I know I appreciate all the hard work!:thumbup:
 

sog1927

Member
Hi, Craig,


As Will mentioned, our imperfect eyesight and the physical limitations of seeing small points of light millions of miles away is what it is. I still cannot get my head around that...
In the case of individual stars, tens of trillions to hundreds of quadrillions of miles away (the nearest star [besides the sun] is over 20 trillion miles away and our own little galaxy is 600 quadrillion miles across, assuming I didn't misplace a decimal). The universe is a *very* big place and we are almost inconceivably tiny.
 

dave.gt

Well-known member
In the case of individual stars, tens of trillions to hundreds of quadrillions of miles away (the nearest star [besides the sun] is over 20 trillion miles away and our own little galaxy is 600 quadrillion miles across, assuming I didn't misplace a decimal). The universe is a *very* big place and we are almost inconceivably tiny.
^^^This is amazing!^^^

:thumbs:
 

dave.gt

Well-known member
You guys knew this was coming didn't you?:grin:

I am now inching closer to becoming sucked into the black hole of "Astrophotography"!

Here are two questions that confirm your devious encouragement regarding luring to the night skies::)

1. With the Milky Way Season still a few months away from us here in the north and central portions of the State of Georgia, what are the best options for shooting right now?
2. If I would like to photograph deeper into Space, what telescopes would you recommend for shooting something like the Horse Head Nebula in Orion?:)
 
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