First DSOs pictures

[Simone_DB]

On 18/11/2023 at 16:50, wesdon1 said:

@Simone_DB Hi again Simone. My friend, I don't have time to go into detail, as there is a lot to answer here, but i'll do my best! One big issue that stands out to me is you say you used NR for Lights? If yes, DON'T. All the NR is done in post processing with Photoshop, Lightroom or whichever astro-processing software you choose to use! ( as a side note, I too found Siril a headache to use, so I gave up eventually! I use Photoshop now! ) Plus, the NR settings will potentially negatively affect your ability to manipulate/process the light frames in post processing ( it might actually be the reason you couldn't get Siril or photoshop to work with those Lights Files?? )

Your light frames should be taken with your DSLR settings in RAW, NO NR, white balance set to "auto" or "daylight", Metering Mode set to "evaluative", picture Style set to "standard" and your shutter set to "Bulb" ( I recall you are already experienced with daytime photography so I am sure you will know how to set all these settings ) 

1 - In astrophotography it's always a balancing act between getting as long an exposure as possible to maximise signal to noise ratio, while also avoiding light pollution effects and star trailing. In your individual circumstances that could mean anything from 5 seconds exposures to 10 minutes exposures! Then we want to get as many of those long exposures as possible to stack and process later on in post processing. 

2 - Yes Dark frames need to be shot with matching ISO, exposure length and crucially at the exact same temperature. It is actually rather difficult to match DSLR dark frames temperature to Lights temperature, so some people  myself included ) don't bother using them! With a dedicated cooled astro camera, you can easily match the temps with the settings in the software you use with them!

3 - I'm sorry but I can't adequately answer this question because I don't use my cameras histogram for lights, I simply do my Flat frames 5-9 seconds, depending on whether the daytime sky is cloudy, totally blue or something in the middle, like scattered clouds. I must point out though, this is just what personally seems to work for me, other people might well disagree with my methods! Sorry! 

4 - Bias frames are simply the fastest shutter speed possible, in preferably a darkish room at home, with lens cap on but also crucially cover your cameras viewfinder with black Sellotape/insulating tape! People forget that stray light can find it's way through here and onto your cameras sensor! 

I really wish I could have gone into more detail but as you will learn with experience in this hobby, there is a LOT to learn and there are so many variables depending on a multitude of factors, that to write it all down you'd end up with a short novel for an answer!! haha! ( that is the reason why in my first message to you, I recommended you start watching Astrophotography YouTube videos, you will learn so much faster actually seeing a person doing whatever it is they are talking about, which you won't get with just the written word! )

Best Of Luck Simone!

Wes

Hi Wes, thanks a lot for your time and your thoughts!

In order: I don't use NR, glad that you confirm that it's addressed in post processing. I'm using Siril and I also find it a bit tough, but also more detailed than others, according to my very limited experience with this kind of software, at least. But you're saying that you use photoshop; I didn't even know you can stack exposure with that, so I'll dig into it!

I take light frames in RAW, No NR and WB on "Auto". I'll check the metering mode (which I'm not sure if I know what is it).

Now I'm still using 20 or 30 sec of exp, but I'll try to use "Bulb" mode as soon as I can.

1 - I think I'm on the right track here. At the moment, considered my sky and skills, I'm working with 20-30 secs of exposure.

2 - Just one question here. I suppose the temperature we talk about is the sensor's. So if one put the cap on the telescope right after the lights (with no delay to allow the sensor to cool off too much, I mean), and keep on shooting, shouldn't he have the same conditions?

3 - Flat frames are the most mysterious to me, at the moment. So far I used two methods: the first one with a white shirt and a tablet. To have a centered histogram I had to do very short exps, 1/400th of sec or so). When my tablet decided to leave us forever, battery gone, I shot a yellow wall (i didn't know what else to do, I was in session 😅😞 it needed 3'' secs or so. I was shooting a faint target (M101),  so I don't know how to judge the work at the moment. Besides, I could do too few shots of Whirlpool galaxy, so I have to try again.

4 - 🆗I haven't taped the view finder, tough. I'll figure something out!

No worry pal, you (and the others) already gave me a lot of help! I'm watching tutorials, especially about the software. I'll improve my knowledge in time, I hope. 🙂

Lastly, ehm, a question that I'm a bit reluctant to ask, because I'm afraid it's somehow intrusive or cheeky: I'm very courios to compare my work, say for example with the image of M42 above, with someone else's starting from my shots. Is a common practice here on the forum to exchange source files to do such? If you or someone else is willing to have a try, let me know. I'm very courious about such a thing, because I don't have a means of comparison on the results.

Thanks again and have a great day!

 

 

 

[AstroMuni]

On 18/11/2023 at 11:03, Simone_DB said:

Hello, this is my first serious attempt to shoot M42. These are 80x20s ISO 200 shots. I used Biases, Darks and flats. Lightroom, Siril(ic) and some photoshop for stacking/editing. What do you think

Thats a great shot. Suggestion - if you post the calibrated image before any histogram transformation etc. here, experts (definitely not me 🙂 ) in this group will be able to process the image and show you the art of the possible.

Edited November 21, 2023 by AstroMuni

[Simone_DB]

2 hours ago, AstroMuni said:

Thats a great shot. Suggestion - if you post the calibrated image before any histogram transformation etc. here, experts (definitely not me 🙂 ) in this group will be able to process the image and show you the art of the possible.

Thank you! ☺️

I'll drop the file somewhere and post the link, I'm terribly curious! 🙂

[jjohnson3803]

Molto bello!  Unfortunately, I have no wisdom to share - I only dabble with my iPhone camera on my unguided 72ED now and then.

 

[jjohnson3803]

Just for an experiment, I opened your Pleiades shot with the default photo editor on my Windows laptop and set both contrast and saturation to 100.  It seemed to reduce the vignetting substantially and the increased saturation brought out star colors (there are a few red stars but maybe a couple are just hot pixels 😉).    FWIW. 

 

 

 

[Simone_DB]

1 hour ago, jjohnson3803 said:

Just for an experiment, I opened your Pleiades shot with the default photo editor on my Windows laptop and set both contrast and saturation to 100.  It seemed to reduce the vignetting substantially and the increased saturation brought out star colors (there are a few red stars but maybe a couple are just hot pixels 😉).    FWIW. 

 

 

 

Hi, grazie! 🤗 Well, the Pleiads was actually my first attempt to take some subs, but there are no flat files. One day I'll get back to them!

I managed (I hope), to copy M42 files in Dropbox, for @AstroMuni or whoever wants to give them a look! I included Lightroom metadata because maybe I edited them a bit, but if it's the case really  a bit, like a tad of "remove haze".

https://www.dropbox.com/scl/fo/coit00d6b6ztawedm1vjp/h?rlkey=1i3lx0rn2wntmy0o3p38txcp9&dl=0

Thanks in advance to anybody willing to play around with them! 🙂

Edit: I hope Dropbox's right. If you all use another site, please let me know!

Edited November 21, 2023 by Simone_DB

[AstroMuni]

I took the liberty of quickly running the M45 image thro Siril and here is what I got. Donuts and all 🙂 But looks promising. You will need to get more data to bring out the nebulosity and reduce noise in background @Simone_DB

 

Edited November 21, 2023 by AstroMuni

[AstroMuni]

43 minutes ago, Simone_DB said:

I managed (I hope), to copy M42 files in Dropbox, for @AstroMuni or whoever wants to give them a look! I included Lightroom metadata because maybe I edited them a bit, but if it's the case really  a bit, like a tad of "remove haze".

Where is the stacked version please? We just need the stacked version in Tif or FITS format, so you could even just upload it here

Edited November 21, 2023 by AstroMuni

[Simone_DB]

13 hours ago, AstroMuni said:

I took the liberty of quickly running the M45 image thro Siril and here is what I got. Donuts and all 🙂 But looks promising. You will need to get more data to bring out the nebulosity and reduce noise in background @Simone_DB

 

🤩Wow, I'm impressed, and a bit confused! I was expecting, of course, that any of you could make a better job easily but...didn't I upload a jpg pic? I always thought that very little could be done with such files!

[Simone_DB]

On 21/11/2023 at 18:16, AstroMuni said:

Where is the stacked version please? We just need the stacked version in Tif or FITS format, so you could even just upload it here

Ops, I think my reasoning was wrong: I thought you needed the original files, but I think I know why you don't. Here it is:

M42_DSLR_fin.tif

P.S. In the rush, I uploaded the .tif instead of the .fit

I'll do it again as soon as I get back home from work! 🫤

M42_DSLR.fit

Added the .fit file!

Edited November 23, 2023 by Simone_DB

[AstroMuni]

4 hours ago, Simone_DB said:

🤩Wow, I'm impressed, and a bit confused! I was expecting, of course, that any of you could make a better job easily but...didn't I upload a jpg pic? I always thought that very little could be done with such files!

I dont think its down to file format, but more to do with precision. Jpeg is typically 8bit so you are limited to having a pixel value range between 0-255.

[AstroMuni]

On 22/11/2023 at 06:14, Simone_DB said:

Added the .fit file!

@alacant your expertise is needed here 🙂

[Simone_DB]

1 hour ago, AstroMuni said:

@alacant your expertise is needed here 🙂

I agree! 😁

[alacant]

On 22/11/2023 at 07:14, Simone_DB said:

I uploaded the .tif instead of the .fit

Hi

The files don't seem to be equivalent or linear. 
Originals:

   

Anyway, there is an almost impossible gradient and a noise pattern which suggests lack of correctly exposed flat frames, circular pattern walking noise or electrical noise; the sort you get when recording to in-camera sd with a mains fed dummy battery. Perhaps send more details of the image acquisition at the telescope and what you did to process up to the point of posting the frames here? Otherwise, we can only guess the cause. Here for example is the red:

I don't feel confident pushing any further than this:

 

But hey, there is some nice detail emerging.

Cheers and HTH

**EDIT... Ah... Just seen. DSLR? So best without dark frames of any kind. Simply subtract the bias from each frame you take. Siril makes this easy.
That may well explain the noise artefacts.

Edited November 25, 2023 by alacant
dslr

[Simone_DB]

5 hours ago, alacant said:

Hi

The files don't seem to be equivalent or linear. 
Originals:

   

Anyway, there is an almost impossible gradient and a noise pattern which suggests lack of correctly exposed flat frames, circular pattern walking noise or electrical noise; the sort you get when recording to in-camera sd with a mains fed dummy battery. Perhaps send more details of the image acquisition at the telescope and what you did to process up to the point of posting the frames here? Otherwise, we can only guess the cause. Here for example is the red:

I don't feel confident pushing any further than this:

 

But hey, there is some nice detail emerging.

Cheers and HTH

**EDIT... Ah... Just seen. DSLR? So best without dark frames of any kind. Simply subtract the bias from each frame you take. Siril makes this easy.
That may well explain the noise artefacts.

 hI @alacant, Thanks for your time!

I'll attach one sample of lights and calibration files hoping that it can help to understand what I did right and wrong. I shot my flats trying to get a centered histogram, with a white shirt on the scope and a tablet shining a white light.

I always have these circular noisy coloured rings, which, if I recall it right, appear as I use the "extract background" function in Siril, and indeed I wondered what they were caused by. I'm glad you offered an explanation which I have to get, though. I used an old SD with old batteries. Are you saying that it could be the problem? In any case I just bought a new SD card and original Nikon battery.

I can't remember how I processed the image because I've not familiarized with Siril enough, so far, but I followed step by step this video. Unfortunatly it's in italian, but it shows which tools I used.

Can I ask you (and  @AstroMuni as well) how did you manage to obtain that result? As you said, there's alot of information I couldn't extract, and besides you got rid of those awful rings which I made them disappear as well at the expense of said details. The same happened with the Pleiads.

Thanks again the image is very neat! 😍

I'm attaching one of each files I worked with.

DSC_0081.nef DSC_0001.nef DSC_0470.nef DSC_0484.nef

[alacant]

22 hours ago, Simone_DB said:

what I did right and wrong

I'm guessing the darkest oif the frames is the bias, the next lightest the dark... (?).
Here is the calibration using only the bias and the flat. Gradient notwithstanding, relatively clean.

Now with -what I guess is- the dark. Much noisier.

I next try to find the offset from -what I guess is- the bias, so as to obviate the need for in-camera bias frames. It seems very low. 

Thoughts

I don't know where the noise in your -what I think are- stacked images (this post) originates. So...
Keep`it simple:

• Take a bias frame at 1/4000s in total darkness.
• Use Siril or WHY to find the offset as in the example above.
• Lose the dark and in-camera bias frames
• Calibrate the flat and light frames by subtracting the offset you found above.
• Clean the sensor
• Remoive any sd card from the camera.
• Download directly to your 'phone or a computer.

I've lifted this mostly from our dslr guru's recommendations: ,https://linuxcb.blogspot.com/2023/09/siril-dslr-processing.html

Cheers and HTH

Edited November 26, 2023 by alacant

[Simone_DB]

23 hours ago, alacant said:

I'm guessing the darkest oif the frames is the bias, the next lightest the dark... (?).
Here is the calibration using only the bias and the flat. Gradient notwithstanding, relatively clean.

Now with -what I guess is- the dark. Much noisier.

I next try to find the offset from -what I guess is- the bias, so as to obviate the need for in-camera bias frames. It seems very low. 

Thoughts

I don't know where the noise in your -what I think are- stacked images (this post) originates. So...
Keep`it simple:

• Take a bias frame at 1/4000s in total darkness.
• Use Siril or WHY to find the offset as in the example above.
• Lose the dark and in-camera bias frames
• Calibrate the flat and light frames by subtracting the offset you found above.
• Clean the sensor
• Remoive any sd card from the camera.
• Download directly to your 'phone or a computer.

I've lifted this mostly from our dslr guru's recommendations: ,https://linuxcb.blogspot.com/2023/09/siril-dslr-processing.html

Cheers and HTH

Hello @alacant, thanks for your thoughts. I'm sorry I didn't rename the files in order to easily distinguish them, anyway you guessed it right. I'm really having a hard time with the software, both because I'm trying to get to know all of them together, instead of focusing on one or two, and because they're all a bit tough, at the beginning at least. My second main issue is about identifying or distinguish the various sources of problems (the alignment, the camera, the moonlight, and so on...) and I suppose this is the reason of your suggestions here. So speaking about them:

- I'm taking the bias that way. With the cap and my hand covering the viewfinder of the camera. However, I don't know how to verify the actual achieved "darkness".

- I think I need to understand what you're talking about here (I don't know what the offset is, in this case) and I don't know what WHY is. I'll investigate those things.

- From your link, I get that darks and biases can lead to additional problems if not used (or produced) correctly. I'll investigate that.

- This concerns the point above, I believe. I'll check that out in Siril.

- Yes, my camera is some 12 years old and I never had it cleaned 🙄. Since we're here: there is something else I should check, should I bring it to a shop for maintenance?

- My camera has negligible built-in memory and I don't know how to shoot directly on an external device. I'll check that. I'd like to ask, tough, how come is it different, since you have a physical connection anyway. Wouldn't noise be produced anyway, just elsewhere?

Thanks for the link!

On a side note, just for sharing, Saturday I took some shots of Alnitak surroundings with quite disappointing results. I forgot I was willing to try the built-in automatic shooting tool, which it can maybe be used in "bulb" mode, but I'm afraid I have to figure how to follow objects more precisely. I still have no ideas how do you make several minutes exposures. If I got it right, there is some software that visually follow objects. I made maybe 85 pics 30'' each, and my horsehead was a black silohuette on a blacker background 😄. The Flame Nebula turned out better, tough. I wish I had used a D3100 modded camera I borrowed for that, there's a lot of red in that zone, and in fact, in Siril I have the red channel almost black, only stars are visible. Maybe I'll post a pic of my results.

It was a very cold night, about 1°C, and after shooting Orion, I would have taken one shot of that beautiful moon and Jupiter, but I realized my hands were so cold that I could barely use them, and I struggled to pack things.

I'm now thinking that I should take a break in bothering you all with questions*, and exercise on what I learned so far, study and read.

Thanks again, have a great week you all!

*If I manage to do that 😁

Edited November 27, 2023 by Simone_DB

[alacant]

39 minutes ago, Simone_DB said:

I don't know what the offset is, in this case) and I don't know what WHY is.

Hi. Sorry. English isn't my first language and I've learned how to write the technical form of it on this forum, so that's me just attempting to be pompous. And failing!
offset: a number derived from the bias which prevents negative cold pixel values. But please see below.
WHY: What Have You

39 minutes ago, Simone_DB said:

Wouldn't noise be produced anyway, just elsewhere?

It isn't, or at least there's less of it and other artefacts, but I've no idea why. Everything we post is from hands on experience. We gave up on trying to explain anything to do with astrophotography many moons ago!
HTH

Edited November 27, 2023 by alacant

[Simone_DB]

20 hours ago, alacant said:

WHY: What Have You

 

😆Oh my, I'm sorry! You're not pompous at all, my friend!

About the SD, of course we cannot explain everything, I guess this concerns electronic engineering! Thanks for the heads up and the clarification about the "offset".

OCIH (Of Course IT Helps 😄)

Alnitak.tif

Edited November 28, 2023 by Simone_DB