what is video astronomy

[shirva]

hi folks,

i hope this post is looked at in an open way and is not out to cause offence to anyone and can be discussed in an adult manner.

yesterdays posts show that there is divided lines in regard what is video astronomy on a whole,various forums have set up video sections and have used the term eaa to cover video astronomy in a broad spectrum.

looking through the internet,,using the term what is video astronomy,, i found that there is no solid foundation to that question,one site stated that video astronomy started approx 15yrs ago,i know this to be untrue because i know a video astronomer in tazmania who has done it from the 60's, he used ex tv cameras ect and tv's with valves on it.

so we now have rough idea that video has been around a long time,but due to the high financial costs it has stayed out of the reach of most astronomers.

going back to the reference from the internet on video astronomy starting around 15 yrs ago the chap probably ment that was when it became financialy better for astronomers to use it,starting off with modified web cameras to look at the moon,then some electronic wizard made these do long exposure, we then see the progression on to cctv cameras very basic in the early days with no intregration but giving better views on planets and the moon due to better sensors,next up was the best thing from sliced bread for the video astronomer,,cameras with sense up or intregration, this function allowed exposure times to be increased and deep sky objects becoming easier to capture,a canadian company made vast improvements on these cctv cameras and are used world wide and have set the bench mark for years in terms of image quality using an analogue camera.

over the last year video astronomy has started to pick up.

is it due to the work that is done on forums,we dont know for certain but we know it is getting more popular.

my personal thought is the weather is making its mark,when i started on here in 2011 stargazing nights were more abundant and views of the stars ect were good,i now find its harder due to massed low clouds and a warmer climate with more rain and less colder nights.

some facts

more astronomers wishing to capture what they see are using video equipment,video used to be the poor relation to astrophotography but we can all say this is not the case given the money we constantly spend on persuing the best via video astronomy equipment.

we know we can increase the performance of a basic telescope using a video camera and make it find objects to a higher magnitude than a eyepiece and we can do it in colour and in faster times than astrophotography,this may also may be a factor in video capture getting popular.

so where are we now as a hobby

we have purists who like live views via a telescope to a screen. analogue and digital camera formats and may also broadcast these views via the internet or at outreach projects.

we have imagers who capture what they see on an electronic format,this can be further split down to include the above as well.

technology is changing is there a need to define ..what is video astronomy.

personaly i think there could and should be more clarity in the hobby,there are some who are confused with what is video astronomy and its role in astronomy as a section of the hobby.

please remember when posting a comment, that because there are no global defined rules to what is video astronomy, others may not share your views and have a different approach to this.

this post is to encourage an understanding of how ,, and why we do this and what we put in and get out of it..thanks for reading..davy

[nightvision]

Going deep quickly and cheaply, a brilliant way of spiking my imagination, a way of not starting a technology arms race, sharing a brief moment in time and space with anyone.......  oh.. and really helps with my deteriorating eyesight!  

[Macavity]

Almost POETIC there, Nightvision?

(Good summary of my own thoughts)

[JamesF]

For me I think video astronomy covers almost anything that involves real-time or near real-time observation using a camera rather than an eyepiece.  That might be raw real-time video, or it might be still images produced by real-time stacking and other processing.

I don't think it's particularly useful to say "X is the definition of 'video', therefore video astronomy must be consistent with X".  Language evolves and takes on new meaning, especially when it's applied in a new context.  How many people call their internet connection "broadband" without having a clue what "broadband" actually means, nor whether that is the way in which their internet connection is delivered?  I'm not really even sure that there's a need for a definition of "video astronomy" other than in the loosest terms.  If it were a competition then perhaps, but I hope here that we're not in a competition.  The point of SGL to me is for everyone taking part to get the most out of the hobby that they can.

I'm convinced the real-time stacking type of video astronomy is going to get more and more popular now the cameras are becoming more affordable, easier to use and computers (tablets even, perhaps) can handle real-time processing.  There are lots of people, particularly perhaps newcomers to astronomy, who want "Hubble-style" images, or something at least vaguely representative of that but don't want/can afford to get into full-blown astroimaging or don't have the patience for it or sitting at an eyepiece for hours regardless of how satisfying others amongst us might find that.

James

[The Admiral]

Having very recently been looking at threads such as "To stack or not to stack: 30 x 1s = 1 x 30s?" this thought was going through my mind today. In fact, that is why I specifically turned to this forum just now!

I have this impression, rightly or wrongly,  that "video" refers to "frames per second", whereas non-video astrophotography is about frames (or subs, call them what you will) whose durations are relatively long periods of time. However, I believe there seems to be a recognition that unless one is after the faintest of detail in the darkest of skies, short subs (i.e. seconds) are quite acceptable, and it does seem to me, as a complete non-expert just getting into the topic, that there is a convergence between between the two forms taking place, as software now enables us to more or less real time "develop" our images before our eyes. I suppose the question is, is there a real distinction between subs with durations a fraction of a second and those of several seconds? In a general sense, I suppose not as they are in a continuum of the same thing, except that looking at the charts produced by Martin in the thread cited above, I would guess that the sensitivity to faint objects will be lower for subs of a fraction of a second. In particular, the sensitivity appears to fall off more and more quickly as the sub length is reduced. Have I interpreted that correctly?

Ian

[Macavity]

In my understanding theoretical signal to noise ratio improves with increased length of "sub".

Hence "classical imagers" try to maximise the length of "sub" within a given *total* exposure.

Original video astronomy, via *integrating* cameras, stacking 256x... 512x... etc. very short 

(1/50 or 1/25s, if you include interlace) exposures may not have been an optimum strategy.

(But clearly it does work / help, hence the very real market for integrating video cameras)

Some of us go on to further stack the "integrated" frames (sometimes subtract darks) do a

bit of modest post-processing etc. If the data is there, and (my) time is available, why not?

Having a multiplicity of short frames does avoid much of a need for absolute "steadiness"

(accurately tracking) of the telescope and mount or the requirement of e.g. auto-guiding.

We get to use bigger telescopes and don't have to sit around for hours waiting for data. [jk]

To me, such are the distinguishing factors (from classical imaging) Not so much whether

we stack internally via hardware, externally via software or both - In real time or at leisure.

As we know, the boundaries are becomming ever more blurred (maybe not the best word)

[stash_old]

IMO The term "Video" means :-

1. Recording,manipulating(real time with internal camera or software stacking ) and displaying moving images/frames in a format that can be presented on a TV/Monitor and stored to replay in the same manner. 

The actual method is irrelevant so both analogue and digital signals are the same process as they are just a means to the end as defined above. 

There doesn't even need to be a telescope involved ,camera len's are fine too as they are  part of the input "Optics" in the workflow.

The storage of the results ("video") will of course be in anyone of the video formats.

All you need to do is then "video" an object which in our case is anything Astro.

Then it becomes cloudy and crosses the line:

What do you do with all this data(video) - anything you like we are all free to do whatever tickles our fancies.

How to display it - to stick to the definition above and to keep it "pure" then displaying the image should be video. However this is not always possible as some of the output would be very large and wouldn't make sense. So you can either do "Screen Prints" / time lapse's / movie editing to show what was happening (e.g. sense up improving the output).

You can of course process the "video" further (stacking/Photo enhancement )as video by nature are frames of single pictures put together  - stacking via whatever you software you like and post tweaking with e.g PShop to produce a single picture. 

Then I think well so long as the  process has met the definition above(1) who cares about the way in which people display  or post process  the data, so long as that its made clear what the process was - so any sneaky DSLR only pictures would be a no no  .

That's my idea of what I thought Video Astronomy was all about .

P.S. Toally agree with Nightvision  for those of us who's eye sight is not 100% true VA is a god send.

No offence mean't and none would/will be taken we are not all AI robot's - yet 

[Pete Presland]

A very interesting description in the OP of a field of astronomy that until recently I didn't was widely practiced. 

I am an "all rounder" myself, but mostly an imager. I have spent many hours staring at a pc screen watching the stream from my planetary webcam and there is no doubt the view is much more detailed this way than at the eyepiece, so I can see why attaching a video is so appealing.

The most appealing aspect of the video for me would be a colour image, instead of the grey/white fuzzy patch I am used to.

A quick question what's the budget of an "entry level" video camera? 

[johnno]

I'll keep this short and possibly sweet.

to me Video is using a camera instead of a eye piece, I'm not really bothered when someone says 'how deep can you go  or I captured xyz in so many seconds'  everyone's setup is different. You might have the same camera but your optic's and location may be poor

I just enjoy getting a object on my screen and playing a round with the software to get the best possible image from my humble setup and as short as a exposure as possible. 

[johnno]

A very interesting description in the OP of a field of astronomy that until recently I didn't was widely practiced. 

I am an "all rounder" myself, but mostly an imager. I have spent many hours staring at a pc screen watching the stream from my planetary webcam and there is no doubt the view is much more detailed this way than at the eyepiece, so I can see why attaching a video is so appealing.

The most appealing aspect of the video for me would be a colour image, instead of the grey/white fuzzy patch I am used to.

A quick question what's the budget of an "entry level" video camera?

Hi Pete, anywhere from about 50 pounds upwards,  you can get a used Samsung 2000p cctv camera and with a simple modification and a few bit's and bobs you can be up and running for less than a 80 quid.

There's just a wide variety of camera's to choose from up to a grand plus 

[Pete Presland]

Hi Pete, anywhere from about 50 pounds upwards,  you can get a used Samsung 2000p cctv camera and with a simple modification and a few bit's and bobs you can be up and running for less than a 80 quid.

There's just a wide variety of camera's to choose from up to a grand plus 

Thanks you for your reply, i would never have guessed it was so accessible at such an affordable price.

[johnno]

here's a couple of links by Steve Wainwright using a 2000p

http://www.qcuiag.org.uk/sam/

http://astrovideography.blog.com/

[Spacedout]

For me video astronomy is about replacing the eyepiece with a camera and monitor and then viewing either live or in as near live time as possible.  I then like to share my experience via a live video stream, recorded video or by taking a screen grab and posting it here and elsewhere.  

Some examples of what I perceive as live and near live video astronomy.

Karl

[HiloDon]

"What is Video Astronomy?"

To me this segment of astronomy incorporates electronic technology to enhance the viewing/observing experience. Whether it's called VA or EAA, the goal of enhancing the view of objects is the same. Another goal is to provide the view in real time or as short a time as possible. Extended exposure or processing time diminishes the real time viewing experience. A side benefit of this technology is producing good quality captures to demonstrate the technique or share the image with others.

I have recently had the opportunity to work on an outreach program at the Mauna Kea visitors center here on the Big Island of Hawaii. We have been using my Lodestar X2c in a C14 Edge with Hyperstar. At F1.9, the system is very fast and I can get good quality images on the screen in less than 30 seconds, many in 10 or 15 seconds. The most asked question from visitors is, "Is this live". That "live" feeling would be lost if it took two or three minutes. On the last Friday of each month, We also broadcast the images to Imiloa, the planetarium in Hilo. The viewers there enjoy seeing what's being viewed at the VIS center.

I think the "video" label came from the original technology available to enhance the view and replace the eyepiece. Recent developments in technology, especially with the development of live view software like Lodestar Live, have enabled single exposure cameras to function like video cameras. Both do an admirable job in enhancing the observing experience. And, let's not forget night vision technology, but I'll leave that for someone more experienced with it.

Don

[JamesF]

Recent developments in technology, especially with the development of live view software like Lodestar Live, have enabled single exposure cameras to function like video cameras. Both do an admirable job in enhancing the observing experience

This is one area where I feel people can get a bit hooked up on the language whilst missing the reality.  I think sometimes there's an inclination to believe that a "video" camera is somehow qualitatively different from a "single exposure" camera.

Analogue cameras may be a little different, but once you get into the digital world I don't really think there's that much of a difference.  A "video" camera might be one where you start the camera and it punts an image out at a given framerate.  If you don't pick each one up as it comes off the camera then you lose it.  A "single frame" camera you have to ask for an exposure when you want it and in the meantime it does nothing.  But do that repeatedly and you have output that's not really any different from a video camera.

In fact, if you look at, say, the Imaging Source CCD cameras, or the Celestron Skyris and Neximage cameras, they're actually more like video cameras.  Once configured they just push frames back to the computer and you take them or lose them. IIDC cameras (FireWire generally, though Point Grey make some USB ones) are the same.  By comparison the QHY5 series (both the old ones and new ones) are single exposure as, I think, are the ZWO cameras.  The driver has to repeatedly request frames from the camera.  Connect up an imaging application to either though and you'd not be able to tell which was which.

It's quite possible to do the same with pretty much any singe-exposure camera.  I've done exactly that with an Atik 16 and a QHY6.  These would probably not by any stretch of the imagination be considered video cameras, but it is quite possible to control them with oaCapture and use them like very slow frame-rate video cameras.  The output can even be saved as an avi file.  The masochist in me doesn't run so deep (well, ok, perhaps it does), but the same could probably be done with a DSLR.

So yes, I agree with Don.  The lines are becoming increasingly blurred (unlike the images

It should be interesting to see what's possible once ZWO release their cooled ASI224MC.  It's a still-frame camera that most people probably use like a video camera and due to it's excellent sensitivity may be very interesting for video astronomy once there's cooling to keep the noise from the CMOS sensor under control a bit.

James

[Dave In Vermont]

In my work as a bicycle-mechanic who builds custom cycles for people, the newest type of bikes are 'hybrids.' These were originally a blending of road-bikes, designed for speed and lightweight. And mountain-bikes, rugged frame & forks and being tough. Loosely speaking, a hybrid is a bike that can navigate varied terrain such as dirt and gravel-trails, while also able to go quite fast on paved roads. Not as tough as a mountain-bike, or as fast and light as a road-bike - but good for both within limits. For where I live, these are ideal.

I view video-astrophotography, or VAP, as being similar to a hybrid form. When asked what a hybrid bike should be, I say: "Whatever you want it to be." And the same goes for VAP. If you're satisfied running cams straight to a screen from the scope - go for it! Want to do frame-grabs and stack to pull out the best pixels? By all means - knock yourself out! Or how about both? I think you get the idea. There's room for all.

There's one member in these forums who uses the most inexpensive cams and easiest software, whom I won't name. But he knows what he likes and knows what he can afford, and makes it work like a champion! I admire that. A blending of science & artform to conjure an ineffable, unique gestalt of the universe.

'ta,

Dave

[Martin Meredith]

I was out last night with a couple of non-astronomer friends and during that time we viewed the large galaxy NGC7331 + the Fleas, the compact group of galaxies Stephan's Quintet, the globular M15 and the planetary nebula M27, the latter in mono, RGB and finally with HOS. The whole informal session lasted maybe 1 hour. We used 15s exposures throughout, but due to live stacking the amount of detail emerging while we were discussing the objects was tremendous, with total exposure time running to upwards of 5 minutes in most cases. We were comparing the shots with some of the long exposure photos in SkySafari and watching the brighter and then the fainter tails from Stephan's Q reveal themselves. Perhaps the biggest thrill was collecting the RGB for M27 and viewing it as mono, and then flicking the checkbox that turns it all into glorious colour.

Assuming the OP's question also permits the question "what is near real-time observing", that is what we were doing last night. There was no footage per se to broadcast. But there was always something to look at, with never a wait of more than 15s for the first image to appear i.e. a total wait of 1 minute in the entire session, but rather than "wait" I would say the "thrill of anticipation". The whole process was seamless, with the technology not getting in the way at all. The experience was entirely engrossing. 

So I'm uncomfortable talking about exposure times. With live stacking what matters is the initial wait,. If we really need to discuss what constitutes near real-time we should be talking in terms of sub length. But let's not sacrifice image quality -- and I don't mean quality in the AP sense, but in the astrophysically-relevant sense of seeing HII regions, knots, morphology, faint galaxies, gravitational interaction, etc. Using short exposures and live stacking there should be no problem in allowing the view of the object to improve for as long as we are discussing it. So runs of 5-10 minutes are absolutely fine with me. Yes, we can have good quality and near-real time viewing, and live stacking is the key. For me, it is live stacking that brings the dynamic aspect to observing. It seems like a crime to waste those extra photons that are accumulating by simply replacing one sub with the next... 

Martin 

[fondofchips]

No doubt there will be some would be Video astronomers reading this topic, and are still puzzled as to what Video Astronomy is and how to go about it.  That is where I was 6 weeks ago.

Start here - http://astrovideoforum.proboards.com/thread/1198/introduction-video-astronomy-tutorials   Thanks Ken (Dragon Man) for all your help.  Thanks to Karl (Spaced Out) for helping me after my camera purchase.

I was really scratching my head until I watched those videos, and for cost well after I've sold some of my eyepiece collection and surplus equipment it has not cost me a lot more than my observing gear.

The learning curve is a bit like starting over again, but I want to see more than I can through an eyepiece, and sit in the warm to see it as well.  So I'm hopefully going to be able to do that soon.

Clear Skies,

Fondofchips.

[stash_old]

Hmmm - IMHO reading thru the thread it would seem ,to me at least ,that the real problem is the question should there be a "VA" category at all or should it be re-merged with general Imaging (Not the Science category(cat) please !). Me I vote for a VA !

There are plenty of sub cats under imaging and there I think the problem lies - we need VA to have sub cats so that while the general technique/method (using whatever hardware/software) is adhered too it allows for branches. This would make finding info easier for beginners . Yes I know its probably cost / space bound but we are a growing area hence the "pain" i think we deserve it.

After all ,at present, Mods move threads to the appropriate place if they think the subject matter is better under Cat XYZ - thanks for all your work Mods !

However we should all take responsibility in self policing and ask ourselves does it really belong under VA or is it really better under Cat XYZ.

Just an idea! - have fun and clear skies !

[The Admiral]

This is one area where I feel people can get a bit hooked up on the language whilst missing the reality.  I think sometimes there's an inclination to believe that a "video" camera is somehow qualitatively different from a "single exposure" camera.

Analogue cameras may be a little different, but once you get into the digital world I don't really think there's that much of a difference.  A "video" camera might be one where you start the camera and it punts an image out at a given framerate.  If you don't pick each one up as it comes off the camera then you lose it.  A "single frame" camera you have to ask for an exposure when you want it and in the meantime it does nothing.  But do that repeatedly and you have output that's not really any different from a video camera.

In fact, if you look at, say, the Imaging Source CCD cameras, or the Celestron Skyris and Neximage cameras, they're actually more like video cameras.  Once configured they just push frames back to the computer and you take them or lose them. IIDC cameras (FireWire generally, though Point Grey make some USB ones) are the same.  By comparison the QHY5 series (both the old ones and new ones) are single exposure as, I think, are the ZWO cameras.  The driver has to repeatedly request frames from the camera.  Connect up an imaging application to either though and you'd not be able to tell which was which.

It's quite possible to do the same with pretty much any singe-exposure camera.  I've done exactly that with an Atik 16 and a QHY6.  These would probably not by any stretch of the imagination be considered video cameras, but it is quite possible to control them with oaCapture and use them like very slow frame-rate video cameras.  The output can even be saved as an avi file.  The masochist in me doesn't run so deep (well, ok, perhaps it does), but the same could probably be done with a DSLR.

So yes, I agree with Don.  The lines are becoming increasingly blurred (unlike the images

It should be interesting to see what's possible once ZWO release their cooled ASI224MC.  It's a still-frame camera that most people probably use like a video camera and due to it's excellent sensitivity may be very interesting for video astronomy once there's cooling to keep the noise from the CMOS sensor under control a bit.

James

So exactly what is the difference between a camera which is designed as a "video" camera and one which is designed for "single shot"? After all, taking the stated specs for the ZWO ASI174 for example, the max frame rates can be up to 740fps, depending on configuration, and that in anyone's book must surely be video. Or is a video camera, for historic reasons, one which outputs an analogue signal that requires digitizing, or a unit which outputs an avi file directly, rather than individual frames? Given that the heart of either system is a solid state sensor, presumably there can't be a world of difference between the two "types" of devices, more likely the difference must just lie in the way the respective signals are processed within the units themselves. I'm starting to ramble now so I'd best stop .

Ian

[Moonshane]

I cannot see a need to label anything as such. Surely we are all doing astronomy in the way we want to do it. I do see a split to some extent between imaging and observing but see VA as firmly in the former camp. I know many do both.

Does it really matter? I think not. Certainly not enough for anyone to get their knickers in a twist about. Life's too short to take such issues so seriously. I have not seen the other thread but feel that all views are valid given my comment above as we all do what is after all a hobby, for fun and enjoyment not for bickering over what is what or who is right.

Whilst the above may seem combative, it is in no way intended as such, just my honest view of this sort of thing.

[HiloDon]

Hi Ian,

I'll try to answer your questions, and others can either add to or correct what I write.

The classic "video camera" used for EAA has an internal processor and can be used as a stand alone with a composite monitor. The control of exposure and image is done with an on screen display. The output is either NTSC or PAL, just like standard definition TV. You can get video cams that have an HD output, but they don't have the sensitivity of the lower res cams. If you want to capture images or video from these cams, you need a video capture device to digitize the analogue signal and input it to a computer through a USB connection. For video a DVR will work as well.

The one shot cameras need computer control and usually have a USB connection. There are a variety of cameras with different sensors, sensitivity and frame rates, all controlled with software. Some software like Lodestar Live is designed to make the camera perform as a video cam as it cycles the frames continuously at a selected exposure time. It can also stack the images making it similar to the integration capability of the video cameras.

Hope this makes sense and helps.

Don

[JamesF]

So exactly what is the difference between a camera which is designed as a "video" camera and one which is designed for "single shot"? After all, taking the stated specs for the ZWO ASI174 for example, the max frame rates can be up to 740fps, depending on configuration, and that in anyone's book must surely be video. Or is a video camera, for historic reasons, one which outputs an analogue signal that requires digitizing, or a unit which outputs an avi file directly, rather than individual frames? Given that the heart of either system is a solid state sensor, presumably there can't be a world of difference between the two "types" of devices, more likely the difference must just lie in the way the respective signals are processed within the units themselves. I'm starting to ramble now so I'd best stop .

Ian

This is exactly why things are so blurred

In the cases I've already mentioned everything is digital all the way.

As far as I'm aware, the ASI174 is a "single shot" digital camera.  I can't be 100% certain because the API is closed so I've never seen the source code, but I've worked with the ASI cameras a fair bit and the nature of the API leads me to believe that it requests a frame from the camera, makes it available to the application, requests another, etc.  All the QHY, cameras that I've looked at work the same way, as do the Atik and SX ones.  Often the camera driver software (on the PC end) will continuously request frames from the camera and buffer them locally so to the application it looks like it has a constant stream of frames -- "video" in all but name.  For most of the cases we're talking about the frames are either monochrome or raw colour.  Where the application can get a standard RGB frame from the driver it's usually because the driver is doing the conversion internally.

Other cameras such as the Imaging Source astro cameras and the Celestron models I've already mentioned, as well as webcams such as the SPC900, Lifecam, Xbox Live cam etc. keep capturing frames once they're started and pushing them to the driver on the PC which can accept them and make them available to the user's application.  If for some reason the PC can't keep up the frames usually just get dropped.  Cameras that work this way that are intended for the astro market generally deliver mono or RGB frames, but it's not uncommon for webcams to encode the frames as luminance and chrominance data instead as that's perhaps more common for video transmission (or at least, may once have been).

The latter style is perhaps more akin to what people think of as video in the analogue world, but there's really very little difference between the two.  It's really just a case of where the frames coming off the sensor get made to look like a constant stream -- in the software (firmware) in the camera, or in the software (driver) on the PC.

In all of these cases the application software is what writes the AVI file, because actually that can involve quite a bit of processing.  An AVI file is really like a "smart container".  It can take the still frames, perhaps compress them, store them and also use compression across multiple frames if desired.  Many, many different forms of compression are supported, but some only work if the original frames are in a specific format.  For instance, very few compression methods can handle raw colour frames.

James

[DoctorD]

Fellow SGL'ers

Video Astronomy is, in my view, a way to enjoy our hobby using electronics to enhance the viewing experience with an emphasis on observing whilst at the scope (or in your shed/observatory).

Nothing else matters - I wonder if we had better weather here in the UK would we spend so much time and effort trying to define one small aspect of our hobby?

Clear skies

Paul

[michael.h.f.wilkinson]

Excellent summary, Paul. There is no need to bicker about the meaning of words. Just have fun with whatever kit you use. Video astronomy certainly started with fast, analog cameras, but has evolved to digital video, with all the vast improvements in flexibility, and the added ability to record and process on the fly. There is no need to start pointing fingers and saying that a certain way of using a video camera isn't "proper" video astronomy. Let people post where they feel it fits best. Just my tuppence