Advice greatly appreciated - Forums

Topic starter

Sep 16, 2021

Hey Everyone,

Im pretty much a beginner in terms of what i see on Astrobin. I once dabbled in astrophotography about 10 years ago and never got the hang of it. Im more passionate about it now and have posted my first acquired images from night of 14th into 15th.

I joined Astrobin with the purpose of learning more from everyone and would ask that anyone with time can have a look and give as much advice as possible. I am even happy to share RAW data on google drive of anything i capture from my bortle 2 skies.

One note. I am aware of an anomoly on all 3 of my pictures which appears to be a mark on my camera sensor which ill deal with today.

Looking forward to hearing from anyone with helpful advice.

P.S im not in anyway snowflake, so say it as it is

Rgds

Ricky Graham

Steven

Sep 16, 2021 · Edited: Sep 16, 2021

Hello Ricky!

welcome to AstroBin I guess. The images look great for sure.
And yes, I can see the anomaly in the images. Have you tried using "Flats" in the calibration to deal with those? that should get rid of them just fine.

Either way, AstroBin has a special section: "Request for Constructive critique"
Here it is!

Here people can post an image to ask for critique. This post might be better suited there

Ps. Very jealous of your Bortle 2 skies!

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Ricky Graham

Topic starter

Sep 16, 2021

Thanks Steven,

waiting on stuff to clean sensor. I did use flats but not many. My battery died in camera and as yet I don’t think there’s a dummy battery for the Nikon z50.

I only managed 5 darks, 5 flats and 5 bias. Maybe I’m doing something wrong with the flats. I used an iPad white screen at 50% back light through a cotton sheet at 1s exposure. I was disappointed the first didn’t help.

either not doing them correctly or not enough of them. I usually aim for about 15

rgds

Ricky

Christian Großmann

Sep 16, 2021 · Edited: Sep 16, 2021

Hello Ricky,

I think your images are a great starting point and they are not bad for sure. What I see is, that your last two posted images show vignetting on the corners, that should be corrected by the use of flats. I guess, there went something wrong during image processing? Using only 5 Flats may not be the best option, but nevertheless the result should be pretty usable. Your image of M31 does not have these dark corners.

Beside that, I am sure you are on the right path. What I also realize in your images is the stronger noise. But that's the way things are with such an (uncooled) sensor for everyday use. The noise will be much better if you take more subs. Your images are 1h each and this is not much. I learned to concentrate on less targets (usually 1) per night or invest even more time.

Your basic data is quite good. With a bit more image processing, your pics can get really close to others. Especially in astro photography, image processing is really a necessity. But please don't compare yourself to other people. Process the data the way you want it to look like. It can be very frustrating to imatate someone else and you don't want to go down this rabbit hole. Comparing the images in terms of processing techniques or to improve your own skills is another thing.

Clear skies

Christian

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Die Launische Diva

Sep 16, 2021

Hi Ricky,

I think you are on a good track. As others said, learn to take and use flats because, eventually, dust wins (but don't say that to your SO :happy-1

. If you are using the same camera for daytime photography and you are bored retouching the skies with the "heal" tool, it is fine to clean the sensor. (Personally I would send the camera to a professional when the situation becomes unbearable). But for astrophotography this isn't necessary. With flats you kill two birds with one stone: you correct for vignetting (the reduction of image brightness towards the edges) and for dust shadows.

Bortle 2?

Cheers, and clear skies!

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Dave B

Sep 16, 2021

Excellent images , what software are you stacking and processing in ? , I never could get my head around photoshop, gimp , then I found Startools a far easier learning curve and even the default parameters will give you a good image but don’t let it’s simplicity fool you very powerful software and very reasonably priced, good support on the Startools forum and Ivo Jager st developer extremely helpful and the trial isn’t time locked take as long as you like you can’t save result until bought but you can screen grab .
https://www.startools.org/ a few things to do before stacking all to do with parameters in the most common stacking programs https://www.startools.org/links--tutorials.

regards Dave

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Ricky Graham

Topic starter

Sep 16, 2021

Dave B:
Excellent images , what software are you stacking and processing in ? , I never could get my head around photoshop, gimp , then I found Startools a far easier learning curve and even the default parameters will give you a good image but don’t let it’s simplicity fool you very powerful software and very reasonably priced, good support on the Startools forum and Ivo Jager st developer extremely helpful and the trial isn’t time locked take as long as you like you can’t save result until bought but you can screen grab .
https://www.startools.org/ a few things to do before stacking all to do with parameters in the most common stacking programs https://www.startools.org/links--tutorials.

regards Dave

Hi Dave my software is DSS and photoshop for processing

Nicholas Gialiris

Sep 16, 2021

Nice images and great start. Lots to learn in this hobby. Definitely more flats will help with the “dust bunny” in the same spot and vignetting. I had the same thing with my DSLR and I bought a good quality sensor cleaner kit that eliminated it. Have since moved to a dedicated cooled cmos camera.

The more light subs you can take the better as it will greatly improve the signal to noise ratio and since you are imaging from a bortle 2 (very envious) will make a huge difference.

Another plug for StarTools as Dave mentioned; incredible software for the very low price that appeals to the very beginner and seasoned expert with powerful features. Forum led by creator Ivo Jaeger is second to none.

Clear skies!

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seanhagerty

Sep 16, 2021 · Edited: Sep 16, 2021

Looking at the last two pictures you posted, it appears you need to spend more time on calibration frames. I have found this being the cause of most of my image problems (incorrect or inadequate calibration frames). Dedicate a time to collecting those frames and spend some time getting them right. They are needed, especially with a DSLR.

Your images are pretty good. Nice framing, colors are not over processed and artificial. Your integration time is fairly short, try gathering more data on each of these targets. You will be surprised what that does.

I took a picture of the SADR region recently. I spent a LOT more time on my image. I am wondering why yours turned out better!!

I have not seen where you mention a tracking mount, do you use one? Also, look at Star net ++ for some help with the stars.

Sean

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Ricky Graham

Topic starter

Sep 16, 2021

Nicholas Gialiris:
Nice images and great start. Lots to learn in this hobby. Definitely more flats will help with the “dust bunny” in the same spot and vignetting. I had the same thing with my DSLR and I bought a good quality sensor cleaner kit that eliminated it. Have since moved to a dedicated cooled cmos camera.

The more light subs you can take the better as it will greatly improve the signal to noise ratio and since you are imaging from a bortle 2 (very envious) will make a huge difference.

Another plug for StarTools as Dave mentioned; incredible software for the very low price that appeals to the very beginner and seasoned expert with powerful features. Forum led by creator Ivo Jaeger is second to none.

Clear skies!

A dedicated camera will be my next purchase. In the mean time the cleaning kit came for the DLSR and ive cleaned the sensor. Its now spotless and the whole image train been done so hopefully ill have solved that problem. As for the flats, everyone has a different idea on how they should be taken. Is it worth taking them in auto mode on a dlsr?

Ricky Graham

Topic starter

Sep 16, 2021

Looking at the last two pictures you posted, it appears you need to spend more time on calibration frames. I have found this being the cause of most of my image problems (incorrect or inadequate calibration frames). Dedicate a time to collecting those frames and spend some time getting them right. They are needed, especially with a DSLR.

Your images are pretty good. Nice framing, colors are not over processed and artificial. Your integration time is fairly short, try gathering more data on each of these targets. You will be surprised what that does.

I took a picture of the SADR region recently. I spent a LOT more time on my image. I am wondering why yours turned out better!!

I have not seen where you mention a tracking mount, do you use one? Also, look at Star net ++ for some help with the stars.

Sean

Hi Sean,

Thanks for the tips. Im hopping around the sky like a dafty just now getting a feel for different DSO. Ive only one battery for the DLSR which limits me for taking flats. The reason i didnt collect more was because the camera had already died and it was 4am. I went on to try and get a few calibration frames. Id love to get a dummy battery so i can power the camera from mains to eliminate the restrictions.

The equipment i use is

NEQ-6 Pro Mount
William Optics Guidestar 61 - 340mm f/5.9
ZWO ASI120mm min
William Optics Fluorostar 91 Apo Triplet - 540mm f/5.9
Nikon Z50 DLSR
William Optics P-Flat6AIII Flattener

Sequence generator pro, DSS, Platesolve 2, Photoshop

Die Launische Diva

Sep 16, 2021

Also, look at Star net ++ for some help with the stars.

There is a lot of buzz nowadays for that tool, but I consider it to be still at an experimental stage, and believe it is unnecessary or even harmful for a beginner. Why star reduction is so essential at this stage? Is this more important, say, than properly focused and tracked images? Or the properly flat-corrected images? A simpler processing workflow with only the bare essential steps is easier to troubleshoot and faster to produce good images. And the great thing about Ricky's images is that it seems to be the result of a basic and simple workflow.

Let's stop hiding technical flaws (which can be eliminated once and for all by learning the basics) by using complex and most of the time unnecessary processing steps.

P. S. I am taking the advantage of Ricky's encouragement to say it as it is!

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Ricky Graham

Topic starter

Sep 16, 2021

Does anyone have any advice on taking flats? Or a decent tutorial?

Well Written

Nicholas Gialiris

Sep 16, 2021

Here are some notes I compiled when I was learning all this and using my Canon T5i (unmodified); hope it helps.

HOW TO TAKE FLAT FRAMES FOR ASTROPHOTOGRAPHYFlat frames are 1 of 3 important support files when calibrating images to produce the best image from raw data Basics of Flat frames·         Shoot at same ISO or Gain as Light frames·         Keep camera connected to scope or lens·         Maintain same focus as Light frames·         Shoot minimum 15-20 Flat frames·         Temperature not important
Flat frames are loaded into DeepSkyStacker to calibrate the final image. DSS creates a Master Flat from the set of flat frames and corrects the uneven field of the final image. Without adding flats, the stacked image may show noticeable vignetting and many dust spots over the image.
·         Use a White T-Shirt over the telescope objective as a filter when pointed at a bright source of light such as the dawn sky. The intensity and consistency of the light source has a big impact on the quality of flat frames.Camera Settings·         For DSLR, “AV“, or Aperture Priority mode is ideal for shooting flats as the camera will decide correct shutter speed to properly expose the image. ·         With the right level of brightness and evenly lit filter (like a T-shirt), AV mode will take an excellent flat frame. Depending on camera/scope configuration, will see some slight vignetting and dust particles in the flat frame. ·         When in doubt, have a look at the histogram. The flat frame histogram shows the image is well exposed, and dust particles from the camera sensor are evident.
Exposure Time of a Flat Frame·         There is no set exposure time for a flat frame; with DSLR and white t-shirt method, when shooting flats at ISO 800, the peak of the data hits the right side of the histogram at a lightning fast 1/4000 shutter speed.·         If the data clips the right side of the histogram, indicates light source is too bright. Dim light source by adding another layer of t-shirt or point somewhere less intense.·         20 flat frames per session create a useful master flat file for DeepSkyStacker to calibrate the image
Taking Flats at night·         Use a reliable source of artificial lighting that evenly covers the entire telescope objective. A white t-shirt will still be used, to further dim the brightness of the light source; double-up on t-shirt layers if needed.·         Pointing the telescope straight up will help balance the lightbox and keep it flat against the objective.·         Important the light source lays completely flat against the telescope objective.
Examples of artificial light sources to shoot flat frames·         Laptop screen (all white, dimmed)·         Tablet screen (all white, dimmed)·         Dedicated astrophotography flat box·         Artists tracer box (dimmable)

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Die Launische Diva

Sep 16, 2021 · Edited: Sep 16, 2021

Ricky Graham:
Is it worth taking them in auto mode on a dlsr?

https://www.myastroscience.com/proper-flats-with-dslr

The message there is that if you are using a DSLR and its light meter, you probably need to overexpose your flats and not rely on the auto exposure readings. And stay away from very short exposure times to avoid shutter shadow or potential flicker from your artificial light source. Longer exposure time can be achieved by dimming the light source (I use a thick white sheet of sketch paper).

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Dave B

Sep 16, 2021

Ricky Graham:
Does anyone have any advice on taking flats? Or a decent tutorial?

on your Nikon go for a histogram of about half way , canon was about 1/3rd the histogram , use a tablet and dim it as low as it will go on my Nikon D5300 I found 1/3rd didn’t work properly for me , once you move to a cooled set point Astro camera you’ll find calibration frames work better, dither between frames (very important) that way you won’t need darks just bias and flat frames that way you’ll eradicate walking noise .

Ricky Graham

Topic starter

Sep 16, 2021

Dave B:
Ricky Graham:
Does anyone have any advice on taking flats? Or a decent tutorial?

on your Nikon go for a histogram of about half way , canon was about 1/3rd the histogram , use a tablet and dim it as low as it will go on my Nikon D5300 I found 1/3rd didn’t work properly for me , once you move to a cooled set point Astro camera you’ll find calibration frames work better, dither between frames (very important) that way you won’t need darks just bias and flat frames that way you’ll eradicate walking noise .

I think I’ll just shift to a dedicated cam. Quite like the idea of my Dlsr on the guide skope with a sky tracker for some good portable stuff from time to time!

I’ll try the flats to improve images. I’ll do a little more sky hopping to get a feel for different targets, more for my processing than anything else and then concentrate on integration time when the cold nights come in

Ricky Graham

Topic starter

Sep 16, 2021

Ricky Graham:
Dave B:
Ricky Graham:
Does anyone have any advice on taking flats? Or a decent tutorial?

on your Nikon go for a histogram of about half way , canon was about 1/3rd the histogram , use a tablet and dim it as low as it will go on my Nikon D5300 I found 1/3rd didn’t work properly for me , once you move to a cooled set point Astro camera you’ll find calibration frames work better, dither between frames (very important) that way you won’t need darks just bias and flat frames that way you’ll eradicate walking noise .

I think I’ll just shift to a dedicated cam. Quite like the idea of my Dlsr on the guide skope with a sky tracker for some good portable stuff from time to time!

I’ll try the flats to improve images. I’ll do a little more sky hopping to get a feel for different targets, more for my processing than anything else and then concentrate on integration time when the cold nights come in

Am I right saying that flats are not temperature dependant and as long as the image train is untouched I can do them anytime

Dave B

Sep 16, 2021

Ricky Graham:
Ricky Graham:
Dave B:
Ricky Graham:
Does anyone have any advice on taking flats? Or a decent tutorial?

on your Nikon go for a histogram of about half way , canon was about 1/3rd the histogram , use a tablet and dim it as low as it will go on my Nikon D5300 I found 1/3rd didn’t work properly for me , once you move to a cooled set point Astro camera you’ll find calibration frames work better, dither between frames (very important) that way you won’t need darks just bias and flat frames that way you’ll eradicate walking noise .

I think I’ll just shift to a dedicated cam. Quite like the idea of my Dlsr on the guide skope with a sky tracker for some good portable stuff from time to time!

I’ll try the flats to improve images. I’ll do a little more sky hopping to get a feel for different targets, more for my processing than anything else and then concentrate on integration time when the cold nights come in

Am I right saying that flats are not temperature dependant and as long as the image train is untouched I can do them anytime

That is correct 👍

Nicholas Gialiris

Sep 16, 2021

Correct, Flats are not temp dependant; critical item is you do them with the scope/camera/focus in the exact same way you took your lights; don't change that or will have adverse effects. Unlike Master Darks and Bias which can be re-used, Flats need to be taken after every image session.

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Ricky Graham

Topic starter

Sep 17, 2021

Ive taken a couple of different flats in aperature priority on my nikon z50.

Flat 1 is at the camera settings with the histogram at just under half way.

Flat 2 is with an over exposure of 0.3 and just over the half way mark.

Anyone care to comment? and advise? I cant really see anything but i did clean the camera sensor today. Ive left the in .NEF so you can view the histogram

https://drive.google.com/drive/folders/1lYZg1qpBu6aiCfx5EbMLE96fNSXTY00P?usp=sharing

Die Launische Diva

Sep 17, 2021

I think there is room for more exposure time, maybe it can increased up to 1 second. But for this you should find a way to examine the linear histogram and not that from the back of the camera, or those obtained from usual photo manipulation software.

Also there are no apparent dust shadows, only one very faint dark streak, hopefully due to some unevenness of the light source (maybe from the t-shirt or the sheet of paper) and not some residue form the cleaning procedure. It is very faint though, nothing to bother with.

You can always experiment and take a series of flats with increasing exposure time and calibrate the same image and then inspect the result for flatness.

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Ricky Graham

Topic starter

Sep 17, 2021

Die Launische Diva:
I think there is room for more exposure time, maybe it can increased up to 1 second. But for this you should find a way to examine the linear histogram and not that from the back of the camera, or those obtained from usual photo manipulation software.

Also there are no apparent dust shadows, only one very faint dark streak, hopefully due to some unevenness of the light source (maybe from the t-shirt or the sheet of paper) and not some residue form the cleaning procedure. It is very faint though, nothing to bother with.

You can always experiment and take a series of flats with increasing exposure time and calibrate the same image and then inspect the result for flatness.

That Coukd be from the crease in the hankerhief I used? My guess is that. Like I say the sensor has been cleaned so maybe all good

Ricky Graham

Topic starter

Sep 18, 2021

Running my calibration frames first tonight waiting on the moon doing one

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