Lucky Imaging

[xelasnave]

Even before I came across the concept of lucky imaging I felt lots of short subs is better than fewer long subs...

So check this video to hear how it is done...I have been doing 30 second subs but apparently under one second is the go

But I loved hearing the presentor say "high iso and short subs" or close to that

It is a little drawn out but worth watching all the way thru and I am sure everyone will be able to relate to "things going wrong" ....

https://youtu.be/5s9xbZ5G-wk

[RyanJones]

It’s an interesting topic. Myself and Stephàne have been discussing this topic recently. One of the challenges that presents itself though is how many images you have to stack in your integration. I for one don’t have a computer that can handle several thousand 30mb files. Also atmospheric disturbances are helping to hide flaws in my optics lol. The shaper the image, the more I’m going to see lol.

Ryan

[Startrek (Martin)]

Alex

I’m regard to lucky imaging , I’ve watched Cuiv the lazy geek for a while and he uses lucky imaging techniques too from his apartment balcony in the centre of Tokyo Bortle 9

Some of his Galaxy images are absolutely incredible however they required hundreds and hundreds ( up to 1000 ) of 20 to 30 sec subs

For those who use the new generation cameras QHY268 or ZWO2600 series , these produce 50MB files and therefore you require a computer with huge storage and processing power if your going to pursue this technique long term

Cuiv has many computers and remote storage so he is well set up for this type of imaging

He’s proven that good images can be achieved under adverse conditions using this technique

He’s also posted some of his images on CN

Check his YouTube channel out , there’s a episode on it a year or 2 ago about lucky imaging

Martin

[xelasnave]

Originally Posted by Startrek

Alex

I’m regard to lucky imaging , I’ve watched Cuiv the lazy geek for a while and he uses lucky imaging techniques too from his apartment balcony in the centre of Tokyo Bortle 9

Some of his Galaxy images are absolutely incredible however they required hundreds and hundreds ( up to 1000 ) of 20 to 30 sec subs

For those who use the new generation cameras QHY268 or ZWO2600 series , these produce 50MB files and therefore you require a computer with huge storage and processing power if your going to pursue this technique long term

Cuiv has many computers and remote storage so he is well set up for this type of imaging

He’s proven that good images can be achieved under adverse conditions using this technique

He’s also posted some of his images on CN

Check his YouTube channel out , there’s a episode on it a year or 2 ago about lucky imaging

Martin

Hi Martin..I follow Cuiv (subscribed) and really like his content..in fact he convinced me to tryout the Asiair plus and started me down the road to learning the important stuff in imaging.

My little lap top manages rather well (better than my fesk top actually) but my daughter has given me her old gaming computer and she is going to rebuild it for me to make it pretty flash and dedicated to stacking primarily...everything will be replaced except the case and power supply..I could buy one built but she has just built a rather decent one and I would like to give her more experience in building...I will have the components list very soon so I plan to open a thread in the computer section seeking input as to if we/she has made the best selection of bits...

Currently what I do is to run an external drive off the lap top so huge files is not a problem...I use 3x drizzle which without the external drive gives me messages like...you need 350gig space and you only have 120 gig available...but with the external drive there is no problem..as I type I am stacking 231 subs from the ZWO 2600 OSC and did 350 from the Mono earlier...I am going to try and stack both later today to push the limits I have not idea how that will go

After watching that video I am going to see just how high I can push the gain and how short the subs on the 115 mm and later on the RASA which is down having new heater ring fitted and attention to cabling.

Alex

[Dave882 (David)]

It’s indeed a very interesting prospect. I’m still skeptical about how “deep” you can go with very short exposures even if stacking 1000s together. This however is only based on my eaa experience and the big difference in depth obtained by for example 10min of 60sec exposures vs 10min of 10sec exposures.

I know there are some calculations to determine the minimum exposures required to overdone sky noise or something like that. I’m guessing that might have something to do with it.

Having said this, for brighter targets it’ll be excellent. I was doing a little project on the homunucleus nebula (nice and bright) and took a variety of exposures with my c14 @3900mm of different lengths from 2min down to 0.5sec. The difference in detail I got in the lobes was huge. I ended up learning I needed exposures under 500ms, and will revisit when Carinas back up. Anything over 2sec was a write-off in comparison. But this is now verging on planetary imaging so none of this should be any surprise.

It’s so hard to do an apples for apples comparison with stuff like this, because even with planetary lucky imaging the seeing and sky transparency changes so much from night to night.

[Stephane]

Hi Alex, what an interesting topic. One point I learnt in the video is that to double resolution (according to some Exeter University paper), exposures need to be less than a second and only the best 10% are used. That’s a lot of effort for marginal gain. However the idea that we amateur astrophotographers can theoretically even slightly break past the limiting factor caused by our atmosphere is very exciting indeed.

Astrobiscuit has a discord server where several imagers combine their data for DSO lucky imaging. I look forward to seeing what they can achieve. Perhaps we will start to see more of this type of astrophotography in the future. I would like to give this a go one day, but still have much to learn in the mean time.

[xelasnave]

Look at the whole video and at least the end where he displays an image that he and another member of Bat contributed.
Alex

[Dave882 (David)]

Originally Posted by xelasnave

Look at the whole video and at least the end where he displays an image that he and another member of Bat contributed.
Alex

At 22:40 he says they got some lucky imaging data from 2 people, but also included 385hrs of other longer exposure data gathered by other contributors. The final image includes all the data as far as I can tell. I would love to see the result from JUST the lucky imaging data but I suspect it would not be nearly as deep as the final product. You simply can not pick up that really faint data with sub-second exposures with a normal size telescope. Detail within a bright galaxy core or PN… well that may be a different story.

[xelasnave]

I always go for at least 385 hours

How do you get 385 hours?

How do they check subs is what I would like to know..it near sends me bats with only with a couple of hundred...
I am trying to stack 510 at the moment ..a couple of hours to go and it has been going for six hours ..trying to stack OSC and Mono but I am not hopeful as I have had two failures already...but I do have a stack of OSC and a stack of HA to combine in Startools when this current stack is complete...so I will see if they can be combined later tonight...it would be great if the total stack works and use it as a luminance...but so far the two stacks look pretty decent leaving aside the aspect of colour...

I have not looked at the sky but the lappy is tied up stacking ...

Alex

[gb44 (Glenn)]

Hi Alex

I would use ImagePlus' grade tool for sorting out the best frames to stack. Maybe accept the best 10%

On short exposure/high gain topic I have followed Łukasz Sujka on Astrobin and he has posted pics of PN taken with these techniques. Really good stuff.
Heres a link to a pic of his https://www.astrobin.com/418782/
I do remember he said he would check even 800 frames individually to get a decent stack.

Here's what he reckons/writes
<<Welll, It's quite difficult to find some tutorial.
But in general there is few important rules which I think are the most important:

- camera with low readout noise (1eV-2eV or less) - ASI 178, 183, 290 - cooled versions
- bigger aperture 8'' minimum. 10'' is ok, 12'' or more really nice
- a lot of subs - 300 is absolute minimum. Good standard is 1000. But of course more is better
- high gain to achieve lowest redout noise as possible (80-85% is what I usually use)
- short subs - usually below 10s. But less is better
- stacking in Siril or Autostakkert3
- processing like normal photos with more agressive stretch>>

GlennB

[glend (Glen)]

Originally Posted by xelasnave

I always go for at least 385 hours

How do you get 385 hours?

How do they check subs is what I would like to know..it near sends me bats with only with a couple of hundred...
...

Alex

Hmm, 385 hours of my life? And that's just combined imaging time. I too use terabyte drives to over come laptop storage restrictions, but cannot see building the equivalent of a Bitcoin processing machine to do Hyper EAA.
Too expensive, time wise for me. Good luck.

[xelasnave]

Originally Posted by gb44

Hi Alex

I would use ImagePlus' grade tool for sorting out the best frames to stack. Maybe accept the best 10%

On short exposure/high gain topic I have followed Łukasz Sujka on Astrobin and he has posted pics of PN taken with these techniques. Really good stuff.
Heres a link to a pic of his https://www.astrobin.com/418782/
I do remember he said he would check even 800 frames individually to get a decent stack.

Here's what he reckons/writes
<<Welll, It's quite difficult to find some tutorial.
But in general there is few important rules which I think are the most important:

- camera with low readout noise (1eV-2eV or less) - ASI 178, 183, 290 - cooled versions
- bigger aperture 8'' minimum. 10'' is ok, 12'' or more really nice
- a lot of subs - 300 is absolute minimum. Good standard is 1000. But of course more is better
- high gain to achieve lowest redout noise as possible (80-85% is what I usually use)
- short subs - usually below 10s. But less is better
- stacking in Siril or Autostakkert3
- processing like normal photos with more agressive stretch>>

GlennB

Thanks for drawing all that to my attention ..much appreciated.

Alex

[xelasnave]

Originally Posted by glend

Hmm, 385 hours of my life? And that's just combined imaging time. I too use terabyte drives to over come laptop storage restrictions, but cannot see building the equivalent of a Bitcoin processing machine to do Hyper EAA.
Too expensive, time wise for me. Good luck.

Well I have the benefit of time on my hands and many many decades ahead to get all this done.

Alex

[xelasnave]

Well the good news..the huge stack of both OSC and Mono went thru but for whatever reason the file sizes are different for individual stacks so I cant combine in Startools..I will just process the stacked OSC and Mono image and see how that turns out as getting that done was the main goal really.
I hope to open a new thread later and post the result.
Alex

[glend (Glen)]

Originally Posted by xelasnave

Well the good news..the huge stack of both OSC and Mono went thru but for whatever reason the file sizes are different for individual stacks so I cant combine in Startools..I will just process the stacked OSC and Mono image and see how that turns out as getting that done was the main goal really.
I hope to open a new thread later and post the result.
Alex

Can you not just layer them in Photoshop?

[Rerouter (Ryan)]

The process was decided to be stacks of stacks early on, For the first test object of eagle nebula about 1 year back I got about 17,000 non lucky subs from people to answer if we needed every sub, or only well done stacks

Once you have that stack it gets combined with others with some very detailed pixinsight tricks to keep it in linear space as much as possible, the write up for the image on astrobin goes into the process used for that image.

How it started was I took a question too seriously and kick started the BAT almost 1 year ago, working out what the limits where and what programs could be used, but now its evolved into its own thing with smarter people than me the paper for resolution improvement vs time has some extra factors relating to apeture, but for the 6-14 inch for amateur's its close enough to not worry about,

He did actually show the stacked lucky image in the video when he was talking at the end on discord, that and some other lucky contributions were given a higher weight than the deeper data from what I can understand to preserve there details,

[xelasnave]

Originally Posted by glend

Can you not just layer them in Photoshop?

with different sizes it is not easy even in Photo Shop...at least for me.
alex

[Dave882 (David)]

Originally Posted by xelasnave

with different sizes it is not easy even in Photo Shop...at least for me.
alex

It may or may not be the best option available, but APP (astro pixel processor) handles data from different sources, sizes, cameras, scopes etc quite easily. It’ll stack it all together without any problems. The only challenge is blending the seams if there is an overlap between data with vastly different LP or noise profile. Then you can play with the fits file in startools or ps etc.

[xelasnave]

Originally Posted by Rerouter

The process was decided to be stacks of stacks early on, For the first test object of eagle nebula about 1 year back I got about 17,000 non lucky subs from people to answer if we needed every sub, or only well done stacks

Once you have that stack it gets combined with others with some very detailed pixinsight tricks to keep it in linear space as much as possible, the write up for the image on astrobin goes into the process used for that image.

How it started was I took a question too seriously and kick started the BAT almost 1 year ago, working out what the limits where and what programs could be used, but now its evolved into its own thing with smarter people than me the paper for resolution improvement vs time has some extra factors relating to apeture, but for the 6-14 inch for amateur's its close enough to not worry about,

He did actually show the stacked lucky image in the video when he was talking at the end on discord, that and some other lucky contributions were given a higher weight than the deeper data from what I can understand to preserve there details,

You are the most famous person that I have ever spoken to...good on you and thanks for contributing here.

When I get the RASA 11 working to my satisfaction I hope to perhaps go for 5 to 10 second subs as so far all my experiments point to that working for me..which may not fit the science but out of the available approaches I think that may work for me...certainly with the funny seeing of late...I am lucky in so far as I dont know what I should be doing so I am not limited to low gain for example

thanks again

alex

[Dave882 (David)]

Originally Posted by Rerouter

The process was decided to be stacks of stacks early on, For the first test object of eagle nebula about 1 year back I got about 17,000 non lucky subs from people to answer if we needed every sub, or only well done stacks

Once you have that stack it gets combined with others with some very detailed pixinsight tricks to keep it in linear space as much as possible, the write up for the image on astrobin goes into the process used for that image.

How it started was I took a question too seriously and kick started the BAT almost 1 year ago, working out what the limits where and what programs could be used, but now its evolved into its own thing with smarter people than me the paper for resolution improvement vs time has some extra factors relating to apeture, but for the 6-14 inch for amateur's its close enough to not worry about,

He did actually show the stacked lucky image in the video when he was talking at the end on discord, that and some other lucky contributions were given a higher weight than the deeper data from what I can understand to preserve there details,

Thanks for that explanation. Yes blending the lucky stack in with the deeper data will certainly add something positive (with the right post processing skills!!). I’d be very interested to know how Light Pollution is factored into the resolution equation. After seeing some results from others I’d be keen to try and hit some PNs (or even galaxies) lucky imaging with my c14 but feel I may be restricted by B6/7 LP at my location limiting me to only the brightest targets.