What's the line between EAA and 'normal' astro imaging?

[fwm891]

With the patchy weather lately I've been playing with different bits of kit from a 12 inch f4 newt where I've tried taking what I would consider to be EAA recording Jupiter or Saturn with as fast frame rate as possible while its image drifts across the fov. Also putting the same scope on an EQ platform and doing the same but for extended runs of thousands of frames at a time. Even shooting DSO's off the EQ platform with the 12 inch Dob using 5 - 10 second subs. Then this week I put a telephoto lens (400 mm) on a short vixen style bar and fitted it on my CEM60 and shot 30 sec and 60 sec unguided subs on different objects as they apeared through different cloud formations.

On processing the unguided telephoto shots I kept asking myself are these EAA or normal astro images? As usual I don't know....

Enlightenment welcome.

Happy New Year too.

 

Couple of the targets both 20x 30 second subs. 1250 iso @ f5.6, full frame Nikon 800E and a Sigma 120-400 lens.

[M40]

Great pictures 👌 

As to the eeva question, I think you have given the game away in your post with the word "processing". My thoughts are that eeva doesn't involve post processing and any software used is carried out the time so it's more or less as live as it could be. If you stood outside by the side of your telescope and played on your laptop there and then, and managed to get that image of M31 within a few minutes, I would say yes it's eeva. Whichever way though, I do like that picture 👍

[RobertI]

I feel the lines between EAA and imaging are becoming more blurred as the evolving capabilities of the camera and software allow people to achieve new things. But I would say that ‘technically’ EAA is using a sensor and screen to create a near-live view. The goal is observing and investigation rather than aesthetics and perfection. But the EAA software is becoming so good that it’s perfectly normal to spend time fiddling with the image the next day(s). And EAA software allows multi-spectral imaging, which isn’t exactly real time, but is significantly quicker than traditional long exposure imaging. You could argue that EAA is ‘imaging made easy’!

Very nice images by the way  🙂

 

Edited December 31, 2022 by RobertI

[tomato]

 Great results!
I haven’t ventured into EAA, but I take it to mean almost real time imaging, e.g watching a stack of subframes building up as you watch the screen. In it’s purest form I would say it’s using those amazing image intensifier eyepieces but I’m still hoping for a price breakthrough on these devices which I doubt will ever happen.

[fwm891]

Many thanks for the comments. I'll have a play with 'live' stacking next time I'm out. 🙂

[Xilman]

2 hours ago, tomato said:

 Great results!
I haven’t ventured into EAA, but I take it to mean almost real time imaging, e.g watching a stack of subframes building up as you watch the screen. In it’s purest form I would say it’s using those amazing image intensifier eyepieces but I’m still hoping for a price breakthrough on these devices which I doubt will ever happen.

My take: who cares?  Imaging is imaging and what label you put on it is irrelevant as long as you find value in producing something which pleasing and/or useful.

When observing VS, undoubtedly "useful" in some sense and hardly ever "pretty" in a different sense, I generally take 30-120 second subs and stack in real time until the signal to noise ratio is either high enough for a useful measurement to be made subsequently, or to indicate that the object is to faint to be measured. Am I doing EAA?

[RobertI]

Although I tried to define EAA above, I think the subject of what constitutes EAA, and more controversially which forum one should post in, has been the subject of some extremely heated debates in the past, both on SGL and CN. The whole debate is probably best avoided, especially as we just don’t have enough posters for EAA, NV and VS for it to be a problem on SGL. I think if people feel an EEA contribution is of more value to imaging folk, then they may politely suggested that the poster also posts in the imaging forum, but I can’t recall any issues of this sort recently. Keep doing what you’re doing @fwm891, it’s good stuff. 

Edited January 1, 2023 by RobertI

[Xio1996]

@fwm891 Amazing images. My scope is a CPC-800 running at F6.1, so I miss out on those wide field views. I agree with the last comment from @RobertI . Placing a camera where my eyepiece was and allowing my scope to be controlled remotely (7m away outside!) was the best decision I ever made. All of sudden I saw colour and detail I never saw at the eyepiece. I just enjoy the view in the warmth of my home 😀 When I describe what I do I call it EAA. It has really enhanced my love of observing the night sky. Happy New Year!

 

Pete

[StevieDvd]

Having gone through the route of using a Samsung CCTV camera and integrated video sessions to try and see an on screen colour image my take on EAA is that the images are not for processing but for assisted viewing.  Imaging is the term I'd associate with capture and post capture processing.  Given the frustration, and my poor results back then, the likes of Sharpcap & the Rpi mini-computers with todays cameras makes my concept of EAA much simpler. As do these new fangled smart telescopes like the Dwarf.

Easily Accomplished Astronomy

Call it what you like. Someone else's definition is their issue, which should not detract from your enjoyment.

 

 

 

[Xilman]

I should, perhaps, define some terms.

 

An image consists of the totality of a finite set data which is spatially-organized at discrete locations on a 2-dimensional surface.

This definition includes traditional photography, digital and analogue. It also includes ultrasound and MRI images, of little or no interested in the field of astronomy. It excludes the visual cortex' interpretation of an optical image cast upon a retina though, of course, the latter is an image. The information may take many forms and may itself be multi-dimensional. For instance, it may be a simple count of particle (typically photons but perhaps neutrinos, electrons, or nuclei) numbers or a measurement of intensity. It may be a linear or circular polarization measurement; it may be the wavelength) or frequency or particle types and/or energy; it may be combinations of these. A common combination would be intensity as a function of wavelength as seen in LRGB and SHO images.

Imaging is the process of collecting and preparing for subsequent processing the data contained in an image. Note that subsequent processing includes as a special case doing nothing with the collected data.

I take as given the above definition of EAA:  I haven’t ventured into EAA, but I take it to mean almost real time imaging, e.g watching a stack of subframes building up as you watch the screen.

 

With that out of the way, I can try to clarify my earlier post which has clearly confused at least one reader.

Among my astronomical interests, I observe variable stars (henceforth abbreviated to VS) through an imaging camera attached to a telescope. Some of these VS are some times too faint to be registered or to be measured with adequate accuracy from a single image.  Consequently, I take a number of sub-images and stack them where they can be viewed on a computer screen. Some times the VS of interest becomes measurable from the stack; some times it remains invisible or unmeasurable after what I decide has been a only just tolerably long integrated exposure time.

As far as I can tell, my activity at the telescope and computer screen falls well within the definition of EAA as given earlier.

 

Regardless, I don't actually care what label is attached to my activity or to that of others. The "pleasing and/or useful" quality of the procedure is what is important, not the technological process by which it is performed. So why do people get so het-up about it?

Paul

[PeterC65]

For me EAA / EEVA means close to live, so watching live stacks build up or observing the Moon / Planets via live video on the night. Anything requiring offline post processing, usually done the following day, is AP.

I've been experimenting with EEVA for the last six months and find it a very useful tool to add to my visual observing arsenal. It's by far the most useful tool I've added, more useful than any particular eyepiece / filter / the Binoviewer. But these are all tools that I break out on the night for specific purposes.

I do think the difference between EEVA and AP matters as the two techniques require different methods and different kit. It's hard to get advice about EEVA on SGL as most advice is given from an AP perspective. Mostly I've been learning by trial and error, my own research, and by interpreting what the AP people do within an EEVA context. I would certainly have benefited from some EEVA specific advice.

 

[Xio1996]

You have a point @PeterC65 that SGL has a smaller band of EAA'ers and hence less information, a point noted by @RobertI, in an earlier post .

An alternative forum has much more activity and hence greater, dedicated information on EAA setups and techniques. That community also has a set of rules that define what can be posted. The OP's question about his images being EAA or AP would have been answered simply in that forum, as they were processed and hence that would break the (CN EAA) community rules. 

However, my view and I think the view of other people in this thread, so far, is as @Xilman stated 

1 hour ago, Xilman said:

The "pleasing and/or useful" quality of the procedure is what is important

and as @StevieDvd posted

2 hours ago, StevieDvd said:

Call it what you like. Someone else's definition is their issue, which should not detract from your enjoyment.

I really enjoyed viewing your images  @fwm891 and your post has encouraged me to strap a DSLR to the top of my mount and give some wider imaging a shot 😀

[Martin Meredith]

The alternative forum has more traffic and posts, and is a great place for equipment advice. Oddly though, I've always found that -- even accounting for fewer posts -- SGL has more information on, and discussion about, the DSOs being 'observed' using EEVA techniques. Its good to have complementary fora!

[fwm891]

4 hours ago, Xilman said:

  I haven’t ventured into EAA, but I take it to mean almost real time imaging, e.g watching a stack of subframes building up as you watch the screen.

 

Surely once you view a 'live stacked' image you have in effect 'processed' it ?

Edited January 1, 2023 by fwm891

[Xilman]

38 minutes ago, fwm891 said:

Surely once you view a 'live stacked' image you have in effect 'processed' it ?

Perhaps so.  I merely quoted some other person's definition.

As noted, I don't care what it's called but I would like to find out why people espouse such strong opinions on the matter.

[PeterC65]

18 hours ago, fwm891 said:

Surely once you view a 'live stacked' image you have in effect 'processed' it ?

The distinction between EEVA and AP is about immediacy not about processing. Processing that is close to immediate is fine for EEVA. Slower processing is for AP.

For DSOs I only use EEVA. That means 4s exposures live stacked for a few minutes as I watch the image build up. I never go beyond 15s exposures and only live stack for more than a few minutes when I'm observing something very faint (the Horsehead Nebula for example) and then only while I'm deciding what target to observe next. I capture snapshots of the live stack as it develops and just before I stop. These I use as a record of the observation session and to make side by side comparisons (which filter is best, which scope is best, with / without a Barlow, more / less frames in the stack). Side by side (after the event) is the only way, I find, to properly compare setups. By doing this I'm gradually figuring out what works best for different object types.

For the Moon and Planets I use EEVA and AP. When I'm using EEVA that means live video, as live stacking doesn't seem to be possible (there are no stars to align the frames). EEVA images are no better than via an eyepiece I find, and not as good as with the Binoviewer, especially for the Moon. So I also capture the live video frames for subsequent post processing (the following day) which I consider to be AP.

I am planning to capture some 4s frames from DSOs to compare (after the event) live stacked snapshots with post processed versions. I have tried this in the past and the live stacked images were much better, but I've learned more about post processing so will try again.

Many will wonder why the distinction between EEVA and AP matters, and it is because they are different things, like the difference between visual with an eyepiece and with a Binoviewer. My EEVA setup uses a lightweight AZ mount, only one (uncooled) camera, and I do not collect darks or flats. None of this would be right for AP. For that I should be using a really stable EQ mount, a guide camera with its associated software, and I should be taking darks and flats at the same temperature as my temperature controlled camera.

 

[Xilman]

3 hours ago, PeterC65 said:

The distinction between EEVA and AP is about immediacy not about processing. Processing that is close to immediate is fine for EEVA. Slower processing is for AP.

For DSOs I only use EEVA. That means 4s exposures live stacked for a few minutes as I watch the image build up. I never go beyond 15s exposures and only live stack for more than a few minutes when I'm observing something very faint (the Horsehead Nebula for example) and then only while I'm deciding what target to observe next. I capture snapshots of the live stack as it develops and just before I stop. These I use as a record of the observation session and to make side by side comparisons (which filter is best, which scope is best, with / without a Barlow, more / less frames in the stack). Side by side (after the event) is the only way, I find, to properly compare setups. By doing this I'm gradually figuring out what works best for different object types.

For the Moon and Planets I use EEVA and AP. When I'm using EEVA that means live video, as live stacking doesn't seem to be possible (there are no stars to align the frames). EEVA images are no better than via an eyepiece I find, and not as good as with the Binoviewer, especially for the Moon. So I also capture the live video frames for subsequent post processing (the following day) which I consider to be AP.

I am planning to capture some 4s frames from DSOs to compare (after the event) live stacked snapshots with post processed versions. I have tried this in the past and the live stacked images were much better, but I've learned more about post processing so will try again.

Many will wonder why the distinction between EEVA and AP matters, and it is because they are different things, like the difference between visual with an eyepiece and with a Binoviewer. My EEVA setup uses a lightweight AZ mount, only one (uncooled) camera, and I do not collect darks or flats. None of this would be right for AP. For that I should be using a really stable EQ mount, a guide camera with its associated software, and I should be taking darks and flats at the same temperature as my temperature controlled camera.

 

This is an interesting analysis. Thank you.  I take away four things immediately.

First, that a guided telescope on a solid EQ mount is suitable for EEVA but may be more suitable for AP than one which is not. This bears in with my experience as I have attached a video camera to my scope and can provide wobbly views of Jupiter and epsilon Lyrae on request. I viewed those videos in real time as they came in. The latter target was to see whether subsequent work (i.e. not EEVA) could yield resolution substantially better than that set by the rather poor seeing. I have not yet performed that work.

Second, your use of live stacking of short sub  to determine when to give up on one target and change to another is exactly what I do with variable star observing, though my typical sub is 30 seconds long. (After all, I am interested in things which may be as faint as 20th magnitude.) Again, it appears that I am engaging in EEVA with this activity.

Third, your subsequent processing of identically the same data sets means that you perform both EEVA and AP, but sequentially. My non-video capture software (MaximDL) performs automatic dark and flat application between reading the data from the CCD and displaying it on the screen --- emphatically not post-processing and undoubtedly pre-processing akin to converting a linear stream of electrical charges from the raw detector into a 2-dimensional array of intensities and/or colours on a computer monitor. Presumably, my careful examination of the raw subs to discard useless ones (poor guiding, badly placed cosmic rays or satellite trails, etc), plate solving, stacking, photometry and data reduction, all count as AP.  I can live with that characterization without complaint.

Fourth, and by far the least important, I think you may be both correct and short-sighted when you say that live stacking is impossible without stars to guide alignment. My view is that situation is an indication of the pitiful levels of performance of computers in common use. Off-line stacking is clearly possible, as we often see the results. It should be possible once the hardware and software can perform feature-mapping and deconvolution on millisecond time scales. I make this prediction with a degree of confidence because that is exactly what professional telescopes are doing when they switch on the active optics gear.

 

Paul

P.S.  Sadly, a binoviewer would be completely useless to me. My eyes point in different directions and have different astigmatism. It is the same reason why I can not use contact lenses but have to wear spectacles, and why I keep one objective lens cap in place when using binoculars.