My first DS Image (Advice)

[Iem1]

Hey guys,

I captured my first images of a deep sky object last night after failing several times previously to locate targets.

I would love some feed back on the image from experienced Astrophotographers so I can continue to learn and progress. I did not manage to capture much data, I spent about 45 minutes taking 80 second exposures at ISO 1600 ..I chose 80 seconds to be on the safe side, assuming my manual polar alignment and being unguided would start to have an impact.  The 1600 ISO seemed a little too steep, I much preferred the results with 3 minute exposures at 800. Unfortunately less than halfway through my 3 minute 800 ISO imaging the sun started to rise and ruined the session -.- 

Important lessons were learned and it was a lot of fun, even with only managing ~18 minutes of useable data!

Here is the Andromeda Galaxy, x6 3 minute exposures at ISO 800 with x2 Dark frames at same settings (Camera battery died during), taken with an Astro modified Canon 600D, Sky guider pro and WO Zenithstar 73 + field flattener . Minimal processing done in GIMP.

I have a flattener but notice the stars around the edge seem a bit off...But I think this is most likely due to my polar alignment. 

Any feedback welcome, cheers guys

 

Andromeda (Final Image - Large).tif  

 

[steppenwolf]

I think that ISO 800 is a good compromise and you have some nice, worthwhile data there. The star shapes don’t look like poor polar alignment to me as each corner shows a similar pattern so I would recommend that you experiment with the spacing of the camera from the field flattener to try and improve the star shapes. That said, this is a nice image especially considering the short integration time.

[tomato]

That’s a fine M31 first DSO image. I can only echo Steve’s comments, the star shapes look like a camera spacing issue, as the elongation is similar in all 4 corners and the centre stars are good.

I understand from your previous posts you are based in the UK so this image wasn’t captured in Astro darkness, the quality of your DSO broadband images will improve once the dark nights return.👍

[Felias]

I'm a beginner myself, but I'd say that the main issues are lack of focus and the flattener not being in the right position. As steppenwolf says, it's the corners that show elongated stars, so it's not an issue of polar alignment. In case you want a comparison with one taken under similar conditions, I'll post a fast one of Andromeda from after my session last night. I took it just to check how the galaxy fits within the FOV of the WO Z61 and my cropped (not modified) Canon sensor. It's just 30 second, 800-ISO shots for a total of a 10-minute exposure. All taken after dawn (around 3 AM), although the sun was still below the horizon. Polar alignment was probably wrong, since the Star Adventurer loses it if you sneeze, but it wasn't worth correcting for this trial. Anyway, noisy as it can be (no flats, bias, etc) and not worth investing much time in post-processing (DSS and PS), but it shows the possibilities of a basic, portable setup when Andromeda becomes a better target.

 

[Iem1]

Thanks for the comments and tips guys.

I had another go last night with mixed results, managed around 40 minutes of data with 3 minute subs at ISO 800, I think I made a little progress on back spacing issues, but I made the mistake of setting up on fairly long grass on the side of a mountain and I think the rig slowly sunk during the shoot, which added star trail occasionally and drop the target in the frame. That or polar alignment was slightly off (I personally blame the grass... :D)

Had a bit more of a go at processing the stacked image in GIMP and using StarNet to isolate Andromeda to try improve things...Results are so so, but it is only my second astro image so I should not be expecting too much to be fair. I do not think too much can be done with this quality of data, but it is a start.

Before Processing:

 

After Processing:

 

[Budgie1]

That's looking much better with the back spacing, an even size to the stars across the image now. The focus may be a little out, so use the Bahtinov Mask in the lens cover of your Z73 to focus on a bright star and then swing to your target.

Andromeda has a very bright core and this can get blown out with longer exposures. Maybe try 60 or 90 second exposures at ISO 800 and take as many as you can, this increases the amount of data but also reduces the noise in the stacked image.

Top Tip: There's a temptation when you first start to go object-hopping during a session. Don't, stick with your target for as long as you can and get as much data as you can, it'll pay off when it comes to processing the final image.

With the calibration frames, I used to spend hours taking darks at the end of a session with my DSLR, then I read that these could be replaced with Bias frames, alongside Flats and Flat-Darks (dark-flats). When I tried it with my standard EOS 2000D & astro-modded EOS 1300D I can't say I noticed any difference when not using dark frames, so I never bothered with them again. It may be worth experimenting to see when you get more time imaging but it's a pointer that would have meant I collected more subs instead of finishing early to do darks.

[Iem1]

39 minutes ago, Budgie1 said:

That's looking much better with the back spacing, an even size to the stars across the image now. The focus may be a little out, so use the Bahtinov Mask in the lens cover of your Z73 to focus on a bright star and then swing to your target.

Andromeda has a very bright core and this can get blown out with longer exposures. Maybe try 60 or 90 second exposures at ISO 800 and take as many as you can, this increases the amount of data but also reduces the noise in the stacked image.

Top Tip: There's a temptation when you first start to go object-hopping during a session. Don't, stick with your target for as long as you can and get as much data as you can, it'll pay off when it comes to processing the final image.

With the calibration frames, I used to spend hours taking darks at the end of a session with my DSLR, then I read that these could be replaced with Bias frames, alongside Flats and Flat-Darks (dark-flats). When I tried it with my standard EOS 2000D & astro-modded EOS 1300D I can't say I noticed any difference when not using dark frames, so I never bothered with them again. It may be worth experimenting to see when you get more time imaging but it's a pointer that would have meant I collected more subs instead of finishing early to do darks.

Thanks for the tips Budgie!

I am going to try them tomorrow night, all fingers crossed the clear skies continue...this insufferable daytime heat is worth it if the nights stay clear in my opinion

I will keep ISO 800 but drop exposure time to 75 seconds and get as much data as possible.

I do use the built in mask to focus, but I think I need to use brighter stars to increase ease/accuracy.

I am going to try take Flats (light flats?) and Bias calibration frames to aid tomorrows session, determined to produce a good quality M31 image and it is helping me check progress by trying to improve quality on the same target, easy to see progress/mistakes.

Thanks again guys, the feedback is invaluable in pointing me (and the rig!) In the right direction

[Budgie1]

4 minutes ago, Iem1 said:

I do use the built in mask to focus, but I think I need to use brighter stars to increase ease/accuracy.

If you don't use it already, don't forget about the Live View on the screen with the zoom function on the 600D. Zooming to x10 makes it much easier to focus.

If you find the atmospherics are making the star jump around too much then take a 2 or 3 second image of the focus star with the mask on and this will give a better indication of where central spike is.  

[Iem1]

Just checking I understand the back spacing with my flattener, have I got the right start/end point to be implementing the distance?

I will test it out in the field later, planning around 1.5 - 2 hours worth of 75 Second exposures at ISO 800, and I will take flats and bias frames tomorrow before processing. Hopefully get a solid image of M31  

Any advice is appreciated.

 

[Felias]

31 minutes ago, Iem1 said:

Just checking I understand the back spacing with my flattener, have I got the right start/end point to be implementing the distance?

I will test it out in the field later, planning around 1.5 - 2 hours worth of 75 Second exposures at ISO 800, and I will take flats and bias frames tomorrow before processing. Hopefully get a solid image of M31  

Any advice is appreciated.

 

 

I would just follow the instructions in the FLO webpage. I did this with my Z61 and WO flattener and it was fine, without having to measure the distance to the camera:

https://www.firstlightoptics.com/reducersflatteners/william-optics-adjustable-flattener-for-zs73.html

It says you should lock it at 11.4 mm, so I would try that.

 

PS: Andromeda is not in the best position these days, it's too low and only rises when the sun is coming out. Why don't you try the North America nebula instead? You may get an hour of decent data after the moon sets and before dawn.

 

 

 

Edited July 19, 2021 by Felias

[Iem1]

18 hours ago, Felias said:

 

I would just follow the instructions in the FLO webpage. I did this with my Z61 and WO flattener and it was fine, without having to measure the distance to the camera:

https://www.firstlightoptics.com/reducersflatteners/william-optics-adjustable-flattener-for-zs73.html

It says you should lock it at 11.4 mm, so I would try that.

 

PS: Andromeda is not in the best position these days, it's too low and only rises when the sun is coming out. Why don't you try the North America nebula instead? You may get an hour of decent data after the moon sets and before dawn.

 

 

 

Thanks for the suggestions Felias! They are much appreciated.

I had one last shot at M31 last night, managed 1 hr 58 of data of 60 second exposures at ISO 800. I took 20+ Darks and 20 Bias, but I did not realise I needed to keep focus in order to take flats. And I disassembled the rig last night, planning to take flats today and I do not think I can repeat the same focus -.- Kicking myself for that! I will post the stack, a minimal stretch and a more complex process so you guys can see my work process start to finish. I do not think the data is particularly good, and my processing skills are just awful too

Stack (no editing)

Stacked & Small stretch

After "Processing"

(Getting error codes on this upload, will try attach seperate below)

 

[Iem1]

Final process:

[Felias]

1 hour ago, Iem1 said:

Thanks for the suggestions Felias! They are much appreciated.

 

 

Hope it was useful! Nice pictures; I'll be away for almost a month without the telescope (not even a camera), but I'll try to image Andromeda myself later in the summer. 🤞

[Iem1]

25 minutes ago, Felias said:

Hope it was useful! Nice pictures; I'll be away for almost a month without the telescope (not even a camera), but I'll try to image Andromeda myself later in the summer. 🤞

Looking forward to seeing it!

Il be heading out tonight to try my hand at the North America nebula/Pelican nebula as you suggested, figure we have 1-2 more clear nights ahead and I want to make the most of it. Will research recommended camera settings etc and post results here

[Clarkey]

Just picked up on this post. From the first to last M31 there is a huge improvement. Star shapes, focus and overall image has got much better. Well done! Just think what you can do when there are some real dark skies. Keep up the good work.👍

[rickwayne]

Second image shows a bit of star elongation along the DEC axis -- if you're not guiding,  that's a sign that your polar alignment is a smidgen out. You can do a drift test near the meridian and celestial equator, then nearer on the horizon near the CE, to double-check before you start sequencing. I'm a fan of the DARV method myself for that (https://www.cloudynights.com/articles/cat/articles/darv-drift-alignment-by-robert-vice-r2760).

Right on for your first couple of DSOs!

[Felias]

I hope you don't mind, but I have tampered a bit with your stacked file. I did a fast 5-min job on levels/curves in PS, and then some sharpening/denoising. I could improve the core with a bit more of work, and I didn't even bother touching the stars, but I just wanted to show that you can still get more from your current data. I would invest plenty of time in learning how to process your pictures; some basic techniques can dramatically improve your results. 😉

 

[powerlord]

give startools trial a try. watch a few youtube tutorials on how to use it - otherwise you won't have a clue. but 10 mins of tutorials later you'll be surprised what it can pull out your basic unstretched stack.

[AstroMuni]

On 17/07/2021 at 16:44, Iem1 said:

Here is the Andromeda Galaxy, x6 3 minute exposures at ISO 800 with x2 Dark frames at same settings (Camera battery died during), taken with an Astro modified Canon 600D, Sky guider pro and WO Zenithstar 73 + field flattener . Minimal processing done in GIMP.

Thats a lovely image for a first attempt at DSOs. I would suggest you have a go at capturing M81, 82 and even the Whirlpool galaxy perhaps before attempting nebulae. As a beginner myself, I find that nebulae need a lot more post processing to get the best out of them and that is a dark art by itself

[Iem1]

Thanks for all the comments and tips guys! Much appreciated 

I managed to gather 1 hr 20 minutes of data on the North America and Pelican nebula, 2 minute exposures at ISO 800. I took x20 Dark, Flats and Bias frames.

my WO Z73 doesn't quite have the FOV to capture both in their entirety, so I wanted to capture the 'Gap'  between them. I know it will not be winning any awards, but I am super pleased with the result!

I will have a few go's at processing, see if I can improve on the below image  (Is it me missing something in editing, or is my focus a touch off? My stars seem chunky :D)

Any hints/tips/suggestions welcome, Thank you

 

[Felias]

59 minutes ago, Iem1 said:

Thanks for all the comments and tips guys! Much appreciated 

I managed to gather 1 hr 20 minutes of data on the North America and Pelican nebula, 2 minute exposures at ISO 800. I took x20 Dark, Flats and Bias frames.

my WO Z73 doesn't quite have the FOV to capture both in their entirety, so I wanted to capture the 'Gap'  between them. I know it will not be winning any awards, but I am super pleased with the result!

I will have a few go's at processing, see if I can improve on the below image  (Is it me missing something in editing, or is my focus a touch off? My stars seem chunky :D)

Any hints/tips/suggestions welcome, Thank you

 

Glad to see you had a go at the NAN! 👍 Nicely framed with the Pelican too. I see that the stars are round even in the corners, so the flattener works. They still look a bit out of focus, or maybe there was dew on the lens? I'm sure you can still stretch this, for more than an hour of data with a modded camera I would expect more nebulosity. Compare it with my Z61 image with an unmodded Canon, less than 30 min and all the wrong settings (I'll come back to this object later in the summer!), and you'll see what I mean: https://stargazerslounge.com/topic/378083-eventually-first-image-of-the-north-american-nebulae/?tab=comments#comment-4095268

If you can share your stacked, unprocessed image, I may give it a go tonight...

 

[Felias]

5 hours ago, AstroMuni said:

Thats a lovely image for a first attempt at DSOs. I would suggest you have a go at capturing M81, 82 and even the Whirlpool galaxy perhaps before attempting nebulae. As a beginner myself, I find that nebulae need a lot more post processing to get the best out of them and that is a dark art by itself

Wouldn't a modded camera be more suited to nebulae than to galaxies? And now it's a good time to try the summer nebulae...

[Iem1]

Here is the stacked image straight from DSS;

(I notice my images seem to come out of DSS looking already stretched? The video tutorials I see, they basically have black images until they open up the processor and do the initial stretch. Not sure why my images look so different coming out of DSS)

I think dew is an issue, I do not have a dew heater (On the way) ..Was hoping i would get away with it in the summer months, but the grass and even my equipment bags collect dew and become a little damp in the early hours...Guess I should assume "If there is dew on the grass there is dew on the glass"

Stacked from DSS;

Stacked (1).TIF

 

[AstroMuni]

1 hour ago, Felias said:

Wouldn't a modded camera be more suited to nebulae than to galaxies? And now it's a good time to try the summer nebulae...

You are correct about a modded camera being more sensitive to IR, Ha etc, so if you were shooting with an unmodded camera before then you should see a bigger difference in nebula vs galaxies when you switch to a modded camera. Again if the galaxy has a high IR emission then you would see that difference there too.

Its just that in my experience nebulae (as their name suggests), are nebulous 🙂 and need a lot more Post processing to extract details. If you have right software AND the skills - GO FOR IT But galaxies and globular clusters are easier targets IMO and this is based entirely on my experience as I climb the steep curve of AP. My journey can be seen in the link in my signature.

Edited July 21, 2021 by AstroMuni

[Felias]

36 minutes ago, Iem1 said:

Here is the stacked image straight from DSS;

(I notice my images seem to come out of DSS looking already stretched? The video tutorials I see, they basically have black images until they open up the processor and do the initial stretch. Not sure why my images look so different coming out of DSS)

I think dew is an issue, I do not have a dew heater (On the way) ..Was hoping i would get away with it in the summer months, but the grass and even my equipment bags collect dew and become a little damp in the early hours...Guess I should assume "If there is dew on the grass there is dew on the glass"

Stacked from DSS;

Stacked (1).TIF 103.11 MB · 1 download

 

Mmm, are you sure that DSS is not stretching the images before you save them? Your stacked Andromeda seems fine, though. Dew IS an issue, this weekend I came back home soaked. It doesn't help that the grass in my observing place is as tall as my waist, I'd say! Anyway, I have done a bit of streching while eating a sandwich (late lunch for me today), and this is what it looks like after levels/curves and enhancing the contrast. A bit of star reduction too, all in PS. Not a thorough job, but it gives you an idea that the data are not the end to your pictures; processing is just as important. Hope it helps. 🙂