Approve the Cookies
This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies. Read More.
OK
Index  •   • New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Guest
New posts  •   • RTAT  •   • 'Best of'  •   • Gallery  •   • Gear  •   • Reviews
Register to forums    Log in

 
FORUMS Photo Sharing & Visual Enjoyment Astronomy & Celestial 
Thread started 27 Oct 2010 (Wednesday) 15:45
Search threadPrev/next
sponsored links
(this ad will go away when you log in as a registered member)

You don't need a telescope

 
MalVeauX
"Looks rough and well used"
Avatar
12,682 posts
Gallery: 1085 photos
Best ofs: 2
Likes: 7987
Joined Feb 2013
Location: Florida
Post edited 6 months ago by MalVeauX.
     
Nov 11, 2017 22:25 |  #2131

Pagman wrote in post #18494368 (external link)
its a laptop on top row of small keys there is a key next on the right from f11 called PRTSC SYSRQ but it does nothing, cant find it anywhere else.

P.

Hit the PRTSC key. That copies anything displayed into memory. Now paste it into a blank image in MS paint or whatever image editor you use.

https://www.youtube.co​m/watch?v=gc4GvcuL06g (external link)

Very best,


My Flickr (external link) :: My Astrobin (external link)

  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)
Pagman
I just hold the thing :-)
Avatar
7,875 posts
Gallery: 1488 photos
Likes: 4955
Joined Dec 2011
     
Nov 11, 2017 22:28 |  #2132

Done it -

P.


HOSTED PHOTO
please log in to view hosted photos in full size.


Olympus E-M1 and some Zuiko glass

  
  LOG IN TO REPLY
MalVeauX
"Looks rough and well used"
Avatar
12,682 posts
Gallery: 1085 photos
Best ofs: 2
Likes: 7987
Joined Feb 2013
Location: Florida
Post edited 6 months ago by MalVeauX. (3 edits in all)
     
Nov 11, 2017 22:33 |  #2133

Ok, see how on your histogram, the data spike is hugging the left side of your histogram? That's your first problem. You need to expose more. So for you, that means increasing ISO (you will need to go as high as your ISO can go basically). You want a histogram where that spike is 1/3rd of the entire histogram from the left (imagine that spike moved 33% to the right basically so that it occupies a spot in the histogram that is 1/3rd from the left). It shouldn't be a black image, you will see sky glow, you just have to deal with that with your limitations. Manipulate ISO until you get your histogram where it needs to be.

Then, start acquiring lots of exposures. As many as you can. Hundreds. Thousands even. You can use an intervalometer and get 3,600 x 1 second exposures over about an hour and a few minutes or so (giving your camera time to pause between exposures to reduce shake).

Then stack all that.

+++++++++++++++

Example of a histogram like I'm talking about (top right, it's hugging the 1/3rd area approximately, between 1/4th and 1/3rd), not hugging the left, and not in the middle.


HOSTED PHOTO
please log in to view hosted photos in full size.


Very best,

My Flickr (external link) :: My Astrobin (external link)

  
  LOG IN TO REPLY
Pagman
I just hold the thing :-)
Avatar
7,875 posts
Gallery: 1488 photos
Likes: 4955
Joined Dec 2011
     
Nov 11, 2017 22:40 |  #2134

MalVeauX wrote in post #18494375 (external link)
Ok, see how on your histogram, the data spike is hugging the left side of your histogram? That's your first problem. You need to expose more. So for you, that means increasing ISO. You want a histogram where that spike is 1/3rd of the entire histogram from the left (imagine that spike moved 33% to the right basically so that it occupies a spot in the histogram that is 1/3rd from the left). It shouldn't be a black image, you will see sky glow, you just have to deal with that with your limitations. Manipulate ISO until you get your histogram where it needs to be.

Then, start acquiring lots of exposures. As many as you can. Hundreds. Thousands even. You can use an intervalometer and get 3,600 exposures over about an hour and a few minutes or so (giving your camera time to pause between exposures to reduce shake).

Then stack all that.

+++++++++++++++

Example of a histogram like I'm talking about (top right, it's hugging the 1/3rd area approximately, between 1/4th and 1/3rd), not hugging the left, and not in the middle.

thumbnail
Hosted photo: posted by MalVeauX in
./showthread.php?p=184​94375&i=i92803931
forum: Astronomy & Celestial


Very best,


So I would be ok pushing the Iso 6400 or even higher Remember its a crop body not full frame, collecting lots of frames wont be a problem - every clear night I will just keep adding to what I have taken and keep the RAWS.

I really appreciate your help and info - thank you martin.

P.


Olympus E-M1 and some Zuiko glass

  
  LOG IN TO REPLY
Pagman
I just hold the thing :-)
Avatar
7,875 posts
Gallery: 1488 photos
Likes: 4955
Joined Dec 2011
     
Nov 11, 2017 22:42 |  #2135

Martin would possitive EC help say 1 - 2 full, stops?

P.


Olympus E-M1 and some Zuiko glass

  
  LOG IN TO REPLY
MalVeauX
"Looks rough and well used"
Avatar
12,682 posts
Gallery: 1085 photos
Best ofs: 2
Likes: 7987
Joined Feb 2013
Location: Florida
Post edited 6 months ago by MalVeauX. (2 edits in all)
     
Nov 11, 2017 22:44 |  #2136

Pagman wrote in post #18494380 (external link)
So I would be ok pushing the Iso 6400 or even higher Remember its a crop body not full frame, collecting lots of frames wont be a problem - every clear night I will just keep adding to what I have taken and keep the RAWS.

I really appreciate your help and info - thank you martin.

P.

You have no choice but to increase ISO. You cannot expose longer without a tracker. You cannot open up faster than F4. So your only choice is to increase ISO. Doesn't matter if it's a crop or not. It's all you can do at this point. So if you want data, you will need to increase ISO as high as it goes, and look at your histogram to get it close to 1/3rd filled from the left. Then get a ton of exposures. Literally, try to get an hour of data. The stacking process will help with the noise from high ISO. You will need lots of signal to noise ratio to be able to pull nebulosity out, but you may be able to see a decent bit of it even at the highest ISO your sensor can muster, with enough exposures stacked to increase the signal. 3600 exposures will give you 60 times the signal of a single exposure. That's what you need to be shooting for. Obviously beware, adding a lot of miles to your shutter on your camera doing this. Also, you really, really have to learn to process the data once you acquire it. It's not a magic bullet, it takes almost as much time to process to get the data as it does to acquire it. Again, see the tutorial I posted and specifically pay attention to the parts about curves & levels (requires measuring).

The alternative is to get a shorter, faster lens (such as an old M42 mounted, like a Vivtar 135mm F2.8 for cheap), or to get a tracker (Star Adventurer or iOptron SkyTracker, etc).

Very best,


My Flickr (external link) :: My Astrobin (external link)

  
  LOG IN TO REPLY
Pagman
I just hold the thing :-)
Avatar
7,875 posts
Gallery: 1488 photos
Likes: 4955
Joined Dec 2011
     
Nov 11, 2017 22:51 |  #2137

MalVeauX wrote in post #18494384 (external link)
You have no choice but to increase ISO. You cannot expose longer without a tracker. You cannot open up faster than F4. So your only choice is to increase ISO. Doesn't matter if it's a crop or not. It's all you can do at this point. So if you want data, you will need to increase ISO as high as it goes, and look at your histogram to get it close to 1/3rd filled from the left. Then get a ton of exposures. Literally, try to get an hour of data. The stacking process will help with the noise from high ISO. You will need lots of signal to noise ratio to be able to pull nebulosity out, but you may be able to see a decent bit of it even at the highest ISO your sensor can muster, with enough exposures stacked to increase the signal. 3600 exposures will give you 60 times the signal of a single exposure. That's what you need to be shooting for. Obviously beware, adding a lot of miles to your shutter on your camera doing this. Also, you really, really have to learn to process the data once you acquire it. It's not a magic bullet, it takes almost as much time to process to get the data as it does to acquire it. Again, see the tutorial I posted and specifically pay attention to the parts about curves & levels (requires measuring).

The alternative is to get a shorter, faster lens (such as an old M42 mounted, like a Vivtar 135mm F2.8 for cheap), or to get a tracker (Star Adventurer or iOptron SkyTracker, etc).

Very best,

Thank you martin next clear day I will have a real test and see how it goes.

Kind regards.

Pagman.:-)


Olympus E-M1 and some Zuiko glass

  
  LOG IN TO REPLY
Inspeqtor
I never knew that!
Avatar
6,385 posts
Gallery: 74 photos
Likes: 1034
Joined Mar 2008
Location: Elkhart, Indiana
     
Nov 11, 2017 23:23 |  #2138

Pagman wrote in post #18494363 (external link)
Screen shot - how? just cant remember how to do it.

P.


With Windows 10, I use "Snipping Tool" - I keep that on my desktop so I can find/use it quickly.


Charles
Canon EOS 60D Gripped * Canon EOS XSi * Flickr Account (external link)
Tokina AT-X Pro DX 11-20 f/2.8 * Sigma 17-70 f2.8-4 DC Macro OS * Sigma 150-500 f5-6.3 APO DG OS HSM
Canon 18-55 IS Kit Lens * Canon 70-300 IS USM * Canon 50mm f1.8 * Canon 580EX II

  
  LOG IN TO REPLY
MalVeauX
"Looks rough and well used"
Avatar
12,682 posts
Gallery: 1085 photos
Best ofs: 2
Likes: 7987
Joined Feb 2013
Location: Florida
     
Nov 12, 2017 07:28 |  #2139

Pagman wrote in post #18494382 (external link)
Martin would possitive EC help say 1 - 2 full, stops?

P.

No, shoot 100% manual, and simply push your ISO as high as it goes, and expose, and see where your histogram is.

Very best,


My Flickr (external link) :: My Astrobin (external link)

  
  LOG IN TO REPLY
Pagman
I just hold the thing :-)
Avatar
7,875 posts
Gallery: 1488 photos
Likes: 4955
Joined Dec 2011
     
Nov 12, 2017 18:31 |  #2140

I added anoter 100 or so frames at 1sec f4 Iso 6400 last night as there was a clear winters sky, I stacked them with my previous ones and ended up with about 140 stacked lights.
I worked on the final Tiff in both PS2 and LR5 here is my best so far.

P.


HOSTED PHOTO
please log in to view hosted photos in full size.


Olympus E-M1 and some Zuiko glass

  
  LOG IN TO REPLY
MalVeauX
"Looks rough and well used"
Avatar
12,682 posts
Gallery: 1085 photos
Best ofs: 2
Likes: 7987
Joined Feb 2013
Location: Florida
Post edited 6 months ago by MalVeauX.
     
Nov 12, 2017 18:33 |  #2141

140 stacked lights is giving you about 12 times the signal than a single image is, so you're starting to see some of the nebulosity. Keep going!

But remember, you'd be getting a lot more progress if your histogram was not hugging the left.

Very best,


My Flickr (external link) :: My Astrobin (external link)

  
  LOG IN TO REPLY
Pagman
I just hold the thing :-)
Avatar
7,875 posts
Gallery: 1488 photos
Likes: 4955
Joined Dec 2011
     
Nov 12, 2017 18:40 |  #2142

MalVeauX wrote in post #18494966 (external link)
140 stacked lights is giving you about 12 times the signal than a single image is, so you're starting to see some of the nebulosity. Keep going!

But remember, you'd be getting a lot more progress if your histogram was not hugging the left.

Very best,

I found it hard to move the histogram as I was at the extremes of my exposure 6400 Iso is as high as it goes on my D7100 and f4 the widest I didn't want to extend my sh time due to trailing as I understand 1-1.5sec is as far as I can go at 300mm(crop body) un tracked.

All I can do is keep stacking more and more as I take them - Sky conditions allowing.

P.


Olympus E-M1 and some Zuiko glass

  
  LOG IN TO REPLY
MalVeauX
"Looks rough and well used"
Avatar
12,682 posts
Gallery: 1085 photos
Best ofs: 2
Likes: 7987
Joined Feb 2013
Location: Florida
     
Nov 12, 2017 18:46 |  #2143

Pagman wrote in post #18494969 (external link)
I found it hard to move the histogram as I was at the extremes of my exposure 6400 Iso is as high as it goes on my D7100 and f4 the widest I didn't want to extend my sh time due to trailing as I understand 1-1.5sec is as far as I can go at 300mm(crop body) un tracked.

All I can do is keep stacking more and more as I take them - Sky conditions allowing.

P.

You may be interested in a DIY project then. You can build your own tracker with minimal cost. Your goal would be to get a few seconds of exposure which is very reasonable to achieve. If your current exposure is 1 second, F4 & ISO 6400, just getting to 2 seconds doubles your exposure. Getting to 4 seconds, or 8 seconds would be a huge gain of signal. You can build barn door trackers out of wood with a screw that are manual, nothing special required, just measurements, cuts, etc. It opens doors.

Very best,


My Flickr (external link) :: My Astrobin (external link)

  
  LOG IN TO REPLY
Pagman
I just hold the thing :-)
Avatar
7,875 posts
Gallery: 1488 photos
Likes: 4955
Joined Dec 2011
     
Nov 12, 2017 19:38 |  #2144

MalVeauX wrote in post #18494971 (external link)
You may be interested in a DIY project then. You can build your own tracker with minimal cost. Your goal would be to get a few seconds of exposure which is very reasonable to achieve. If your current exposure is 1 second, F4 & ISO 6400, just getting to 2 seconds doubles your exposure. Getting to 4 seconds, or 8 seconds would be a huge gain of signal. You can build barn door trackers out of wood with a screw that are manual, nothing special required, just measurements, cuts, etc. It opens doors.

Very best,


I will have to search DIY Trackers and see what I find.

On another note - I have Stellarium and set it to show constellations, but how can I physically find something like Andromeda, I had a look for it through my lens but even guesstiating off Stella I still could not find it.

P.


Olympus E-M1 and some Zuiko glass

  
  LOG IN TO REPLY
MalVeauX
"Looks rough and well used"
Avatar
12,682 posts
Gallery: 1085 photos
Best ofs: 2
Likes: 7987
Joined Feb 2013
Location: Florida
Post edited 6 months ago by MalVeauX.
     
Nov 12, 2017 19:45 |  #2145

Pagman wrote in post #18494997 (external link)
I will have to search DIY Trackers and see what I find.

On another note - I have Stellarium and set it to show constellations, but how can I physically find something like Andromeda, I had a look for it through my lens but even guesstiating off Stella I still could not find it.

P.

Finding a DSO requires navigation (degrees, etc). It's easier starting out to simply star hop. Find your DSO in stellarium. See what stars are near it that you can identify easily and quickly. Use them as guide points to get where you want to be. Depends how dark your skies are too. I can find Andromeda with my naked eye just looking up, but I'm under fairly dark skies. On my short scope (400mm), I use a laser pointer that is aligned with the scope to point it in the direction of an object I want to look at it quickly put it on it. Eventually you learn the sky and you can easily move from object to object based on common stars (like constellations).

Ex, here I'm pointing my laser at M42 before I move to my scope to look through as they're aligned. But I can literally see M42 with my naked eye, along with M31 (not in the same part of the sky, but easy to spot with naked eye), so it's easier.

IMAGE: https://farm1.staticflickr.com/408/32373782881_231c6d7f15_b.jpg
IMAGE LINK: https://flic.kr/p/RjL6​Ln  (external link) ST80_GreenLaser (external link) by Martin Wise (external link), on Flickr

Very best,

My Flickr (external link) :: My Astrobin (external link)

  
  LOG IN TO REPLY
sponsored links
(this ad will go away when you log in as a registered member)

604,833 views & 528 likes for this thread
You don't need a telescope
FORUMS Photo Sharing & Visual Enjoyment Astronomy & Celestial 
AAA
x 1600
y 1600

Jump to forum...   •  Rules   •  Index   •  New posts   •  RTAT   •  'Best of'   •  Gallery   •  Gear   •  Reviews   •  Member list   •  Polls   •  Image rules   •  Search   •  Password reset

Not a member yet?
Registered members may log in to forums and access all the features: full search, image upload, follow forums, own gear list and ratings, likes, more forums, private messaging, thread follow, notifications, own gallery, all settings, view hosted photos, own reviews, see more and do more... and all is free. Don't be a stranger - register now and start posting!


COOKIES DISCLAIMER: This website uses cookies to improve your user experience. By using this site, you agree to our use of cookies and to our privacy policy.
Privacy policy and cookie usage info.


POWERED BY AMASS forum software 2.1forum software
version 2.1 /
code and design
by Pekka Saarinen ©
for photography-on-the.net

Latest registered member is mashy
725 guests, 395 members online
Simultaneous users record so far is 6430, that happened on Dec 03, 2017

Photography-on-the.net Digital Photography Forums is the website for photographers and all who love great photos, camera and post processing techniques, gear talk, discussion and sharing. Professionals, hobbyists, newbies and those who don't even own a camera -- all are welcome regardless of skill, favourite brand, gear, gender or age. Registering and usage is free.