First DSOs pictures

[Simone_DB]

Hi, yesterday, after some weeks of bad weather, there was a pretty clear night, so I decided to make my first attempts to shoot some objects. The pictures were taken with a Nikon D5100 at direct focus and a coma corrector. The objects are the Andromeda Galaxy, the Pleiads and a couple of objects, another galaxy and a double cluster* I didn't identify (I used the "tour" feature of the Synscan). I made some editing in lightroom: essentially cropping and "removing haze".

I think I used the remote of the camera wrong when I shoot Andromeda, because it's a 96 secs exposure, but it wasn't my intention to have it so long, and in fact it is blurry, I suppose for alignement issues.

Whatever hint, suggestion, advice or opinion is extremely welcome, and also I have a couple of questions:

-As you can see (I hope) there are some circular black artifacts in the pictures. I'd like to know what is the reason for those. Besides I think the sensor is dirty, can I clean it or does it require professional maintenance?

-In some pictures, near the center, there seems to be a brighter area, what can cause that kind of halo?

- Are there some basic lightroom settings/regulations for DSOs?

Thank in advance! 

* double cluster in Perseus, I believe. 

Edited November 9, 2023 by Simone_DB

[wesdon1]

13 minutes ago, Simone_DB said:

Hi, yesterday, after some weeks of bad weather, there was a pretty clear night, so I decided to make my first attempts to shoot some objects. The pictures were taken with a Nikon D5100 at direct focus and a coma corrector. The objects are the Andromeda Galaxy, the Pleiads and a couple of objects, another galaxy and a double cluster I didn't identify (I used the "tour" feature of the Synscan). I made some editing in lightroom: essentially cropping and "removing haze".

I think I used the remote of the camera wrong when I shoot Andromeda, because it's a 96 secs exposure, but it wasn't my intention to have it so long, and in fact it is blurry, I suppose for alignement issues. . What can cause that?

Whatever hint, suggestion, advice or opinion is extremely welcome, and also I have a couple of questions:

-As you can see (I hope) there are some circular black artifacts in the pictures. I'd like to know what is the reason for those. Besides I think the sensor is dirty, can I clean it or does it require professional maintenance?

-In some pictures, near the center, there seems to be a brighter area, what can cause that kind of halo?

- Are there some basic lightroom settings/regulations for DSOs?

Thank in advance!

@Simone_DB Hi and welcome Simone!

Beautiful pics Simone! Much better than i managed my first time taking pics of space!

In answer to first question - I am 99.99% sure that your camera sensor is absolutely fine and does not need cleaning. What appears to be happening in your pics is a phenomena known as "Vignetting". i would suggest you google "Vignetting" to learn more about the causes and the solutions

second question - There seems to be a combination of 2 things happening here...Vignetting and light reflections causing parts of your pics to have brighter patches. Light reflections can often be caused by light pollution from street lights, household lights, even stary moon light can cause this. I would strongly suggest you start watching YouTube videos about Astrophotography, because you will learn so much in a much shorter time than if you were only reading up about the hobby. here are some great suggestions for YouTube Astrophotography channels...

*Astrobackyard

*The narrowband Channel

*Astrobiscuit

*Small optics

and there are many many more great Astrophotography channels besides the above YouTube channels I have suggested. 

best of lick Simone! and remember, this website is also a brilliant resource for advice and inspiration!

Clear Skies, wes.

Edited November 9, 2023 by wesdon1
missed a bit

[Simone_DB]

25 minutes ago, wesdon1 said:

@Simone_DB Hi and welcome Simone!

Beautiful pics Simone! Much better than i managed my first time taking pics of space!

In answer to first question - I am 99.99% sure that your camera sensor is absolutely fine and does not need cleaning. What appears to be happening in your pics is a phenomena known as "Vignetting". i would suggest you google "Vignetting" to learn more about the causes and the solutions

second question - There seems to be a combination of 2 things happening here...Vignetting and light reflections causing parts of your pics to have brighter patches. Light reflections can often be caused by light pollution from street lights, household lights, even stary moon light can cause this. I would strongly suggest you start watching YouTube videos about Astrophotography, because you will learn so much in a much shorter time than if you were only reading up about the hobby. here are some great suggestions for YouTube Astrophotography channels...

*Astrobackyard

*The narrowband Channel

*Astrobiscuit

*Small optics

and there are many many more great Astrophotography channels besides the above YouTube channels I have suggested. 

best of lick Simone! and remember, this website is also a brilliant resource for advice and inspiration!

Clear Skies, wes.

Hi Wes, thanks for your kind words! I signed up some weeks ago and I must say that this site is a treasure and the fellow members are kind and extremely collaborative! 😀

Since I like photography, I'm aware of vignetting issue, and I'm quite sure in lightroom there is a feature to fix it. I'll give a look at it! Besides I live in a polluted area (even from light), so what you're saying is quite likely to be the case.

I'll check the channels you suggested me for sure, since I'm doing the first steps and every information source is important.

Take care man, thanks again!

[wesdon1]

38 minutes ago, Simone_DB said:

Hi Wes, thanks for your kind words! I signed up some weeks ago and I must say that this site is a treasure and the fellow members are kind and extremely collaborative! 😀

Since I like photography, I'm aware of vignetting issue, and I'm quite sure in lightroom there is a feature to fix it. I'll give a look at it! Besides I live in a polluted area (even from light), so what you're saying is quite likely to be the case.

I'll check the channels you suggested me for sure, since I'm doing the first steps and every information source is important.

Take care man, thanks again!

@Simone_DB Oh well thats a huge advantage you have, already having experience with cameras/photography! Hopefully you'll find solutions in Lightroom for image aberrations my friend! 

best of luck with your new journey in photography. Astrophotography is a steep learning curve but it really is so rewarding when you reach little milestones! 

Clear Skies! 

Wes.

 

[Swillis]

Hi @Simone_DB,

Looks like a good start. 

The blur/trails looks like it is probably due to the camera/scope/tripod being knocked or a gust of wind. 

Are these single images? You will want to take many many images and stack them in software (eg SIRIL, DSS, or many others, everyone has their own preference). Something else you will want to do in that software is to use calibration frames. Flat frames (short exposures with an evenly illuminated field) will correct for the vignetting and also help to remove the dark patches you observed. These are dust motes on the optics. They are usually not worth cleaning off and are easily dealt with using flats, but the flats need to be taken each session as the dust can move. 

In addition to the channels suggested above I would add 'nebula photos'. Which has some useful tutorials. But there are so many others there. But this forum is incredibly helpful. Don't be worried to ask a silly question, you won't be the only one who has the same question.

Another great source of information is the book 'making every photon count', which is a great introduction to astrophotography. Well worth a read, or two. 

Welcome to the rabbit hole. 

Good luck

Simon

[Simone_DB]

1 hour ago, Swillis said:

Hi @Simone_DB,

Looks like a good start. 

The blur/trails looks like it is probably due to the camera/scope/tripod being knocked or a gust of wind. 

Are these single images? You will want to take many many images and stack them in software (eg SIRIL, DSS, or many others, everyone has their own preference). Something else you will want to do in that software is to use calibration frames. Flat frames (short exposures with an evenly illuminated field) will correct for the vignetting and also help to remove the dark patches you observed. These are dust motes on the optics. They are usually not worth cleaning off and are easily dealt with using flats, but the flats need to be taken each session as the dust can move. 

In addition to the channels suggested above I would add 'nebula photos'. Which has some useful tutorials. But there are so many others there. But this forum is incredibly helpful. Don't be worried to ask a silly question, you won't be the only one who has the same question.

Another great source of information is the book 'making every photon count', which is a great introduction to astrophotography. Well worth a read, or two. 

Welcome to the rabbit hole. 

Good luck

Simon

Hi Simon, thank you for your reply! I also thought the trails are the result of some movement. I would exclude wind, it was a calm evening, but I'm so unexperienced that sometimes I find myself lacking awareness when something wrong happens. That will improve I guess 🙂

Yes, those are still images, but I'm really eager (and a bit scared 😬) to begin to use stacking software. Do you have any suggestion on a title, for a beginner?

I think I'm not familiar yet with the concept of "flat frame". You mean that (vignetting and dirt spots wise), I should stack many short exposures shots (a few seconds?), or that I should take just a few of them, and those would be what you call "calibration frames"? Sorry for the confusion!

I think I have to buy the book, you're not the only one here who suggested it to me. The thing is, It appears as there's not an italian version, that twould be a bit less tough. But I think I'll take it, surely it will help me to cope with many doubts!

Thanks again, have a great day!

Simone

Edited November 10, 2023 by Simone_DB

[AstroMuni]

1 hour ago, Simone_DB said:

I think I'm not familiar yet with the concept of "flat frame". You mean that (vignetting and dirt spots wise), I should stack many short exposures shots (a few seconds?), or that I should take just a few of them, and those would be what you call "calibration frames"? Sorry for the confusion!

Hi Simone, you are correct - the flat frame will help get rid of the imperfections. Here is the histogram view of your image (done in Siril) and you can see them. Usually flat frames are taken by covering the lens with a white cloth and pointing to a not very bright sky (we need to achieve an even lighting). If you google you will find many websites explaining the intricacies of these. Good luck.

 

[Simone_DB]

Oh, ok! It's giving the software a reference to subtract undesired elements kind of technique, I guess? I'll dig into that, thanks a lot!

Edited November 10, 2023 by Simone_DB

[AstroMuni]

9 minutes ago, Simone_DB said:

Oh, ok! It's giving the software a reference to subtract undesired elements kind of technique, I guess? I'll dig into that, thanks a lot!

Thats right. And you will come across the terms darks & bias as well so get reading 🙂

I have the same mount as you and you should be able to get pretty good exposures upto 60s (30s as a minimum) without any star drift. But the key to this is getting your scope properly polar aligned. (ie. the mount rotation axis pointing to true north). The polarscope on your mount should help you achieve that quite easily.

[Simone_DB]

20 minutes ago, AstroMuni said:

Thats right. And you will come across the terms darks & bias as well so get reading

🙂👌 I'm going to!

20 minutes ago, AstroMuni said:

I have the same mount as you and you should be able to get pretty good exposures upto 60s (30s as a minimum) without any star drift. But the key to this is getting your scope properly polar aligned. (ie. the mount rotation axis pointing to true north). The polarscope on your mount should help you achieve that quite easily.

I must say this mount is really neat! I am impressed by its precission. I was expecting worse, because of my inexperience. But I must have improved somewhat with alignment, because I had some issues on previous days, but recently everything worked fine. I use an app called "Polar clock".

Thanks!

 

[AstroMuni]

10 minutes ago, Simone_DB said:

I must say this mount is really neat! I am impressed by its precission. I was expecting worse, because of my inexperience.

Next step up is to buy a cable to connect mount to a computer & then its a doddle 🙂 The software helps you do the slews, alignment etc. Depending on whether you prefer using a Mac or Windows I would recommend:

- Kstars/Ekos for Mac/Linux

- NINA for Windows

Edited November 10, 2023 by AstroMuni

[Simone_DB]

3 hours ago, Swillis said:

In addition to the channels suggested above I would add 'nebula photos'. Which has some useful tutorials.

I'm checking it out now. I must say the guy is nice and very thorough! 😉Thanks!

[Simone_DB]

1 hour ago, AstroMuni said:

Next step up is to buy a cable to connect mount to a computer & then its a doddle 🙂 The software helps you do the slews, alignment etc. Depending on whether you prefer using a Mac or Windows I would recommend:

- Kstars/Ekos for Mac/Linux

- NINA for Windows

Great, noted! 😀

[Simone_DB]

On 10/11/2023 at 11:02, AstroMuni said:

Thats right. And you will come across the terms darks & bias as well so get reading

Hello, after a weekend of reading, doing some activity and accomplishing nothing, this morning I woke up with the dilemma about wether hassle you all once again. Jokes aside, since I suppose you all remember how difficult this thing is at first, you understand how I need a "push" to get past the first hurdles. While I was working, 1.62x10^5 questions came to my mind. I selected a few (all the following questions concern DSOs):

- Light, Bias, Dark and flat frames (so far, I've read this article):

     1) Light frames, as I get it, are the RAW shots. Am I suppose to get visually individual good shots, or can I use longer exposures to save clicks even if results are withishier? Should I keep my ISO low, since I have to stack a lot of shots? Should I use NR reduction on long exp (this in particular is important because it doubles exp times).

     2) Can dark frames be shot just with the (capped) camera? They must match the ISO and exp settings of the lights, so I can make a set a library for different settings that I can use (almost) indefinitely, but the important thing is that they must be shot at the same temperature of the shooting site. Is all that right?

     3) To take Flat frames I can put a white shirt on the telescope with a light source above it, and take shots that match light frames exp, but they have the histogram quite centered. Sky shots often have the histogram crammed on the left side, so how I achive that? I read that the camera orientation matters, hence do I take them every session or I find a way to align the camera always the same?

 4) I've got no particular doubts on Biases. Same temperature and ISO as lights, fast shots. Can they be taken with the capped camera?

- Software: I lived a nightmare. I tried to use Siril, but without light, daks, etc. it's useless. I've tried to download and use some scripts that should allow its use without said files (just to practice), but no luck. So let's just leave it for now. I then tried to use Lightroom together with photoshop, but when I try to export them in the latter, LR says that it failed because "photosop wouldn't open" (same using panorama, photoshop levels or whatever). Is it a common issue? Dispite the message, in a couple of occasion it succeded in creating new frames in LR, but I probably don't know how to use it or they're just too bad. They are some 25 frames of Alnitak surroundings taken at 800 ISO (maybe too much), 13'' exp with NR on long exp on. I hoped, not too much actually,  to see a glimpse of nebulas, but no luck.

I understand those are quite a bunch of questions, and I'm aware enciclopedias were written about what I'm asking, but while I study, if someone wants to comment, share advices, point me to a direction, seen what I have done so far, I'd be immensely grateful. Consider that, for frustration, I ate a lot of spaghetti, played a lot my mandolin and gesticulated a lot more than usual, which denotes a stressful condition for an italian.

Thank you!

 

 

Edited November 13, 2023 by Simone_DB

[Swillis]

Hi @Simone_DB,

I think the number of questions only goes up I'm afraid!  I have something like 6.02214076×10²³ (there is an Italian reference in there for you!)

But seriously, I think the encyclopedia you talk about is this forum. So many people are prepared to help. I'm new to this too, but hopefully I can pass on a few of the things I have learnt along the way. 

 

1) yes, these are the images of the object you are interested in. I checked this page https://astrophotography.app/nikon.php and it recommends an ISO of 200. So that's probably a good place to start. Those with experience of your camera may be able to offer advice also. 

2) darks are difficult with a DSLR. As you mention the temperature should be matches to the lights. This is almost impossible to achieve without a cooled astro cam. I use a canon and for that it is recommended NOT to use darks as the canons do something in the background to account for dark signal. I don't know about Nikon's but you could try with and without darks and see what the results are like. Or maybe just forget about this but for not and keep it simpler. (one less thing to get the mandolin out for)

3) take flats every session, as dust can move about. I use an LED drawing pad turned down as for it can go and with a few pieces of paper on top. The method you describe is essentially doing the same thing but using a t-shirt instead of the paper, and a different light source. Some people use a cloudy sky, it doesn't matter as long as it is evenly illuminated on you camera sensor. You might need to play with the exposure length a little to get the histogram where you want it. 

4) yes, put the cap on, and set the exposure to as short as it can go. Bias frames can be reused. 

 

As for software, that's another learning curve. SIRIL is great but it can take a bit of figuring out. Try deep sky stacker to start with. But don't be tempted to play with the curves in it. Just take the autosave file out the end into Photoshop etc...

Good luck and keep going. You will get there soon and once you start getting some images it will be worth it. (plus there will be a heap more questions!)

Simon 

[Simone_DB]

4 hours ago, Swillis said:

Hi @Simone_DB,

I think the number of questions only goes up I'm afraid!  I have something like 6.02214076×10²³ (there is an Italian reference in there for you!)

 

Oh, Amedeo The Great, king of moles! ☺️

4 hours ago, Swillis said:

1) yes, these are the images of the object you are interested in. I checked this page https://astrophotography.app/nikon.php and it recommends an ISO of 200. So that's probably a good place to start. Those with experience of your camera may be able to offer advice also.

Great, thanks a lot. I got a Nikon D5100, so that should be it! And should I keep NR on long exporus on? Sorry for the insistence, that's a feature that doubles exp times, and I'd be glad to avoid it, if the calibration in Siril has the same purpose!

4 hours ago, Swillis said:

2) darks are difficult with a DSLR. As you mention the temperature should be matches to the lights. This is almost impossible to achieve without a cooled astro cam. I use a canon and for that it is recommended NOT to use darks as the canons do something in the background to account for dark signal. I don't know about Nikon's but you could try with and without darks and see what the results are like. Or maybe just forget about this but for not and keep it simpler. (one less thing to get the mandolin out for)

Ok, thank you! As a matter of fact I was contemplating a cooled cam as next purchase, but since I see they don't exactly give them away, I could ignore it for now. All I want to do now, is getting acquainted with the tools.

4 hours ago, Swillis said:

3) take flats every session, as dust can move about. I use an LED drawing pad turned down as for it can go and with a few pieces of paper on top. The method you describe is essentially doing the same thing but using a t-shirt instead of the paper, and a different light source. Some people use a cloudy sky, it doesn't matter as long as it is evenly illuminated on you camera sensor. You might need to play with the exposure length a little to get the histogram where you want it.

Ok 👌! And do I want to put the histogram centered, as the article that I linked says, or should I put it like the light frames?

4 hours ago, Swillis said:

4) yes, put the cap on, and set the exposure to as short as it can go. Bias frames can be reused.

👌

I'll try "Deep sky stacker" and see how it goes.

Simon, I thank you for your time! I hope to be able to show something new soon.

Edited November 13, 2023 by Simone_DB

[LandyJon]

3 hours ago, Swillis said:

2) darks are difficult with a DSLR. As you mention the temperature should be matches to the lights. This is almost impossible to achieve without a cooled astro cam. I use a canon and for that it is recommended NOT to use darks as the canons do something in the background to account for dark signal. I don't know about Nikon's but you could try with and without darks and see what the results are like. Or maybe just forget about this but for not and keep it simpler. (one less thing to get the mandolin out for)

Some great advice for you there so far, just to add some thoughts while reading through ...

The darks you could do fresh for each session, thus achieving the (close enough to) same temperature conditions as you light frames.  The advice so far seems to be 30-60s exposures, you'll want a good half to one hour min total exposure time to see some good detail so adding 5 mins worth of lens cap on for 5-10 dark frames could be worth it.

You can then stack (I was going to suggest DSS but its been mentioned, it can stack just lights with a warning box suggesting adding calibration frames but will stack none the less) ... but do a stack with the darks, flats, bias and stack again just flats and bias, see if the darks make enough difference to be worth including in your sessions or not. They likely will but not knowing your sensor or expectations etc. you can make the decision if the added work load is worth the result.

1 hour ago, Simone_DB said:

And do I want to put the histogram centered, as the article that I linked says, or should I put it like the light frames?

Flats you want the histogram centred, its giving the sensor a complete coverage of mid level illumination, not max brightness (full well) not zero illumination but right in the middle, where it can best differentiate the differences in brightness.  Stacking will then gradient eliminates that from your light frames to even out the sky background, getting rid of that central glow as well as any dark dust spots.

 

1 hour ago, Simone_DB said:

As a matter of fact I was contemplating a cooled cam as next purchase

Yes, hold off on big investments like that till you understand whats going on within sensors (the book suggested will help, theres also a good YouTube of a lecture I'll try find) and how both sensor and pixel sizes affect your field of view and sampling rate and you can get the right astro camera for your scope and target interests.

Robin Glover Lecture on imaging with CMOS ...

I learnt a lot about sensors from this.

Edited November 13, 2023 by LandyJon

[Simone_DB]

33 minutes ago, LandyJon said:

The darks you could do fresh for each session, thus achieving the (close enough to) same temperature conditions as you light frames.  The advice so far seems to be 30-60s exposures, you'll want a good half to one hour min total exposure time to see some good detail so adding 5 mins worth of lens cap on for 5-10 dark frames could be worth it.

You can then stack (I was going to suggest DSS but its been mentioned, it can stack just lights with a warning box suggesting adding calibration frames but will stack none the less) ... but do a stack with the darks, flats, bias and stack again just flats and bias, see if the darks make enough difference to be worth including in your sessions or not. They likely will but not knowing your sensor or expectations etc. you can make the decision if the added work load is worth the result.

Flats you want the histogram centred, its giving the sensor a complete coverage of mid level illumination, not max brightness (full well) not zero illumination but right in the middle, where it can best differentiate the differences in brightness.  Stacking will then gradient eliminates that from your light frames to even out the sky background, getting rid of that central glow as well as any dark dust spots.

 

Hi @LandyJon, thanks for your suggestions! An actual example of timings is handy for the next session out! And yes, I think I'll go with DSS, I just saw a video about it, and it seems easier for a newbie.

Also, thanks a lot for the clarification about the flats, now I got better why I should take those shots! 😉

I'll check the video as soon as I can. I thank you for your time!

 

[Swillis]

3 hours ago, Simone_DB said:

should I keep NR on long exposure on?

I would turn it off. As you point out it will double exposure time, and you are losing control of the process. It may do something to the images which is not ideal, and you would not be able to retrieve the 'original' non-NR image (if that makes sense?)

Try @LandyJon's suggestion of stacking with and without darks and see how much difference it makes. 

 

[LandyJon]

12 minutes ago, Swillis said:

I would turn it off. As you point out it will double exposure time, and you are losing control of the process. It may do something to the images which is not ideal, and you would not be able to retrieve the 'original' non-NR image (if that makes sense?)

Try @LandyJon's suggestion of stacking with and without darks and see how much difference it makes. 

 

Indeed, not knowing anything about it, but I'm guessing its a Noise Reduction thing, to do it 'properly' you want your lights as RAW as you can get them, then deal with the noise in stacking (with calibration frames) and post processing in photoshop (or other).

This way you can trial and error removing the noise, but always go back to the beginning.  If the camera has adjusted the image before saving you'll never be able to undo that step if its not helped or worse has removed data from your image.

[AstroMuni]

10 hours ago, Simone_DB said:

I tried to use Siril, but without light, daks, etc. it's useless.

Download Sirilic https://siril.org/docs/sirilic/ it should make your life easier 🙂 No need to worry about scripts.

 

[Simone_DB]

14 hours ago, Swillis said:

I would turn it off. As you point out it will double exposure time, and you are losing control of the process. It may do something to the images which is not ideal, and you would not be able to retrieve the 'original' non-NR image (if that makes sense?)

Try @LandyJon's suggestion of stacking with and without darks and see how much difference it makes. 

 

Hi Simon, thank you! Yes, it makes sense! I don't know either how NR is handled by the camera, that's, if it's a metadata that can turned on and off. Anyway I'll try not to use it.

I'm not sure to have the experience to see the differences with or without darks, but I'll try for sure! 🙂

14 hours ago, LandyJon said:

...to do it 'properly' you want your lights as RAW as you can get them, then deal with the noise in stacking (with calibration frames) and post processing in photoshop (or other).

Yes, that's my idea, too. I think it's ideal to work with unprocessed RAW, I think it could also help to better control and understand the processing with softwares. Plus, I have a gut feeling that denoising works better with external programs that with the embedded software of the camera.

 

10 hours ago, AstroMuni said:

Download Sirilic https://siril.org/docs/sirilic/ it should make your life easier 🙂 No need to worry about scripts.

 

Thanks Atromuni! I stumbled upon Sirilic just yesterday on a Youtube video. I was looking for Siril and I didn't notice it was talking about the other one☺️I quit watching it, because I thought it was a plug-in or something, but due to what you told me, I have to try it! 🙂

[Simone_DB]

Hello, following the suggestions of many members, I managed to process my first image with Siril/Sirilic. I took 39x20s shots of the Pleiads at ISO 200. I used Darks and Biases (15-16 of each type), but not Flats because I still have to figure out how. The image is very dirty and I think that I'll have the sensor cleaned, because I've never done that in 12 years 😶.

Any technical comment is welcome. Thanks!

 

M45_DSLR_exp.tif

Edited November 15, 2023 by Simone_DB

[Simone_DB]

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?

Edited November 18, 2023 by Simone_DB

[wesdon1]

On 13/11/2023 at 10:01, Simone_DB said:

Hello, after a weekend of reading, doing some activity and accomplishing nothing, this morning I woke up with the dilemma about wether hassle you all once again. Jokes aside, since I suppose you all remember how difficult this thing is at first, you understand how I need a "push" to get past the first hurdles. While I was working, 1.62x10^5 questions came to my mind. I selected a few (all the following questions concern DSOs):

- Light, Bias, Dark and flat frames (so far, I've read this article):

     1) Light frames, as I get it, are the RAW shots. Am I suppose to get visually individual good shots, or can I use longer exposures to save clicks even if results are withishier? Should I keep my ISO low, since I have to stack a lot of shots? Should I use NR reduction on long exp (this in particular is important because it doubles exp times).

     2) Can dark frames be shot just with the (capped) camera? They must match the ISO and exp settings of the lights, so I can make a set a library for different settings that I can use (almost) indefinitely, but the important thing is that they must be shot at the same temperature of the shooting site. Is all that right?

     3) To take Flat frames I can put a white shirt on the telescope with a light source above it, and take shots that match light frames exp, but they have the histogram quite centered. Sky shots often have the histogram crammed on the left side, so how I achive that? I read that the camera orientation matters, hence do I take them every session or I find a way to align the camera always the same?

 4) I've got no particular doubts on Biases. Same temperature and ISO as lights, fast shots. Can they be taken with the capped camera?

- Software: I lived a nightmare. I tried to use Siril, but without light, daks, etc. it's useless. I've tried to download and use some scripts that should allow its use without said files (just to practice), but no luck. So let's just leave it for now. I then tried to use Lightroom together with photoshop, but when I try to export them in the latter, LR says that it failed because "photosop wouldn't open" (same using panorama, photoshop levels or whatever). Is it a common issue? Dispite the message, in a couple of occasion it succeded in creating new frames in LR, but I probably don't know how to use it or they're just too bad. They are some 25 frames of Alnitak surroundings taken at 800 ISO (maybe too much), 13'' exp with NR on long exp on. I hoped, not too much actually,  to see a glimpse of nebulas, but no luck.

I understand those are quite a bunch of questions, and I'm aware enciclopedias were written about what I'm asking, but while I study, if someone wants to comment, share advices, point me to a direction, seen what I have done so far, I'd be immensely grateful. Consider that, for frustration, I ate a lot of spaghetti, played a lot my mandolin and gesticulated a lot more than usual, which denotes a stressful condition for an italian.

Thank you!

 

 

@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

Edited November 18, 2023 by wesdon1
missed a bit