Disappointed with DSO views? I have the answer!

[Bazzaar]

Oh.. found this BTW... Bargin Samsung SDC435 camera - £89

Samsung SDC-435PH - 1/3" 600TVL High Resolution, Day & Night Camera 230V AC

Be aware, that is the main powered version. I think the low voltage 12v dc ones are preferable (your choice obviously)

makes life easier if everything at the scope is powered from your powertank/battery.

Barry

[Bazzaar]

Plus can these video cameras stack on the fly? That's what makes the Mintron interesting. The live feed itself isn't that mind blowing. But once it started overlaying the images M51 really came alive.

Yes

[Bazzaar]

This is my thinking also John. I would feel like I'm two timing my EP's if I didn't use them

I think the problem is the solution. Yes it would be great to sit under LP skies but still get to view the cosmos but I feel it would soon become a slippery scope into imaging or watching a TV screen and leaving behind the true qualities of astronomical observing.

Watching a TV screen for me would detach me from the experience and not truly appreciate what it is I am looking at. BUT!!! I can't help thinking this would be a great idea for those nights when you finally get a break in the cloud only to find a high altitude haze is making visual observing impossible. Would I become an arm chair observer? Would it be like watching a program on TV? I don't know? Would the challenge of getting better images become more the interest than the actual observing itself maybe?

Those thoughts of becoming detached from the experience is a valid one. I dont expect to replace all my observing with the video cam, I'm not going to forgo the thrill of seeing M42 or Jupiter live and direct AND in better resolution. Lets not forget this idea is to enable viewing that cannot be achieved normally. I can report though when I got M51 on screen for the first time the sense of accomplishment and achievement was up there with other top experiences from this hobby.

Barry

[Bazzaar]

Would be nice to have a list of the right sort of CCD/TV video cameras are suitable pls.

See post #16 of this thread

[cathalferris]

Another application for this when used for public outreach, would be to have a camera set up on e.g. a 6" f5 equatorially mounted reflector, displaying b/w on a small red-filtered screen for the group to see. Then right next to the screen to have a larger scope with eyepieces so that one could show a group what to look for, then to give people the real view one-by-one, so that the people looking through the eyepiece have an idea of what to expect when looking through the real eyepiece.

[Mutley]

At max integration you are looking at an exposure time of just over 10 seconds.

Paul

Thanks Paul - I guess then performance is going to be compromised on non-tracking mounts.

[Bazzaar]

My thoughts exactly Russ. But I can't help being a bit sceptical about performance on an alt-az mount. Bazzaar would you mind doing an experiment for all us Dob users? Try it with the tracking turned off and see if there is any image deterioration - maybe try this with different image integration times ? What is your 'scope's objective focal length as well?

great thread BTW.

Excellent suggestion, I'll see what I can do.

You raise a good point about about focal length, I use a SW 200p with 1000mm f/l. The camera sensor is 1/3" type, small. You dont get much of the sky in the picture, and it gets worse with bigger scopes, assuming f/l goes up accordingly.

I said in my opening post that I thought firstly of all those people that get into the hobby with a small goto scope and find they cant see many DSO's, these cameras will help them enormously.

But the bigger scope owners? hmm, might actually be more issues to over come. Focal reducers might be the order of the day, or you could buy the cameras that have the 1/2" chips, except they cost 4 times as much!

Dob users, you generally have lots more light to play with than other scope users so maybe can get away with shorter integration times to shorten the trails. The Samsung range has image stabilisation that may align a few frame successfully before the drift defeats it.

Barry

[MLyons]

Size of scope is way less important than focal ratio.

I use a 14" Meade SCT and also an 80mm Refractor.

The refractor is a native f6 and I have a focal reducer that makes it about f 3.5 that I use on it.

Here's an 8 second image of the Carina area taken through an 80mm achro (hence the purple fringes on the brighter stars)

[MLyons]

If you want to see an example of live video with high magnification "picture in picture" using a webcam as the PiP source go here:

YouTube - ‪snoylm's Channel‬‏

[Macavity]

Not rocket science, but I've certainly CLAMPED a scope for MAK127 white light or PST solar imaging. Registax seemed to cope OK with the Sun drifting across frame. Idem the Moon / Planets. A modest Alt-Az Syncan driven mount allowed stacking of multiple second. integrated DSO frames. I had made some (positive) experience with Deep Sky Stacker, where I sense it was detecting field rotation and removing it...

Then I bought an HEQ5 and the "troubles" began... [mostly joking]

[russ]

Yes

Awesome, all sounding very interesting.

[Macavity]

Awesome, all sounding very interesting.

A cryptic exchange almost worthy of:

Father Ted - An Ecumenical Matter

(Just messing about)

[R2-ditt0]

I am so glad I came across this thread.......have been tempted by "the dark side" for a while but cost has been prohibative lately.....then I got a bit lucky with a recent car purchase(I am a mechanic and will make a fair few quid when I fix and sell her on)....and I was thinking of getting a decent dslr.....question to all you people of experience,is this a good cheaper alternative?.....all I want is to be able to be in the running for picture of the week one day!

[Rob]

Those are really good results.. I think the age of Video has arrived. I'm not sure about the others, but I've really waited for the technology to catch up. Those examples prove to me its really getting there now.

Now i would be real excited to obtain results like that on a screen mounted in the shed!. I have mains power in there, and a box full of Video Conference equipment I've just ripped out at work!

Cool.. I'm liking this more and more.

[Bazzaar]

I think it wrong to compare video cameras and DSLRs, its apples and pears. DSLRs are much higher resolution, higher bit depth(16 bit versus 8) quality imaging machines. But they demand huge investments in time and hardware and post processing to get their superb results.

The advantage of the video camera is bish-bosh instant DSO on a system you may not have even been able to see it on. But it is low resolution low quality output, relatively speaking.

Barry

[spaceboy]

Just what would you need to get set up Barry?? Is it just the cam, laptop with software (is that free?) a power tank and PC interface?? Dose the user need IT skills?

[Macavity]

I think one aspect it took me a while to get my head around was the rate of frame production versus the software sampling rate. Video Cams maintain an image on the screen etc., but this is updated at a variable rate. This can be anything from 10s of (unique) frames per second to one (unique) frame every 10 seconds. The process of writing this stuff to disk (AVIs etc.) is asynchronous.

Fortunately, software like GSTAR3 (qv) have a number of presets, so you can match the rate of data production of UNIQUE images to data writing. Simply, you don't want to be writing a whole host of identical images to disk? <G> But a basic understanding of this concept, rather than REAL IT skills, is mostly all you need...

[Bazzaar]

Indeed Macavity how they work in detail is complex.

There will be at least two frame buffers, an output frame and an input frame.

The output frame is used by the video circuitry and displays a "still" of the last captured input frame, and outputs it repeatedly at 25 fps, PAL video.

The input buffer is where the magic happens, the sensor chip will have been "open shutter" for the set exposure time. Confusingly this is referred to as "sens up" by the manufactures and is expressed as multiples of a single video frame of 1/50th sec, but it doesnt stack say, 512 frames , it is an exposure of 512x1/50ths as a period of time, in this case 10 seconds(ish). That long exposure is read to the input buffer and the sensor cleared and set off on another exposure. The digital image processor then then gets to work on the input frame buffer and applies the noise reduction, dynamic range, image stabilisation feature that may have been enabled. Finally updating the output buffer with the new frame to display.

It may even be cleverer than that! It seems to be able improve the image over multiple exposures, it may averaging over time.

Gawd!

I've attached my images from last night to show what all the techno mumbo-jumbo results in.

I must comment on conditions last night, grim, the Ring nebula shot was through cloud, M11 was with rapidly on coming daybreak

Barry

[Bazzaar]

Just what would you need to get set up Barry?? Is it just the cam, laptop with software (is that free?) a power tank and PC interface?? Dose the user need IT skills?

Hi space boy,

you will need:- camera, 12V dc, C mount adapter, video/AV lead.

If you just want to view you need a TV with video/AV in, or, a laptop/PC with a video capture interface.

If you want to go on and record the images you need capture software, like AMcap or(what I use) Sharpcap, these are free,there are others.

Once you have images on your PC/laptop you can then go on to post processing software like DSS, Registax, these are free.

The further you go, the more IT skills you need.

The processing of images is an art in its self, I dont profess any skill there, I do hardware!

[cgarry]

I have a Watec 120N that I bought second hand and have only ever used it once for 20 minutes. One thing I noticed was that with the hardware integration at maximum and the gain turned right up there were lots of hot pixels and they actually looked a bit like a star field. This was using a little CRT monitor rather than capturing the image on a laptop.

If I captured the video on a laptop, is there a way to remove these hot pixels using a stored dark frame while watching the video in real time?

Cheers,

Chris

[Bazzaar]

Thanks Paul - I guess then performance is going to be compromised on non-tracking mounts.

I did try some shots without tracking, not good:(

anything over 1/2 second showed trails. I only tried the brighter objects, and it did still give an image, debatable whether an improvement over the old eyeballs.

I should think that tracking Dobs would be ok.

[Bazzaar]

If I captured the video on a laptop, is there a way to remove these hot pixels using a stored dark frame while watching the video in real time?

Cheers,

Chris

Yes there certainly is, but I cant advise much on this as I'm still learning it myself. I'm looking into DSS, deep space stacker software to do this. May I suggest the Imaging part of the forum for more info?

Barry

[Bulkins]

Hi space boy,

If you just want to view you need a TV with video/AV in, or, a laptop/PC with a video capture interface.

This bit confuses me a little . When using a laptop, as I understand it, a Samsung will have a BNC connector which will have to interface to an external video capture device and that device will have to interface to the laptop USB interface. I have only been able to find one such capture device - a rather cheap EZCAP device which appears, euphemistically speaking, to be extremely unreliable with Windows 7 and for which I'm not even sure if the correct cable can be obtained (i.e. with a BNC connector at one end). Modern Astronomy appear to sell a USB2 video capture device similar to the EZCap for use with the Mintron cameras but the details emphasise Windows 2000/XP - I suspect because of known Windows 7 problems.

Is there anyone who has actually gone down this route who could advise on specific components that are known to work?

PS Excellent thread.

[garethmob]

just came across this on CN it might help

Telescope Reviews: Tyro Samsung 435 Users Look Here...

[Bazzaar]

This bit confuses me a little . When using a laptop, as I understand it, a Samsung will have a BNC connector which will have to interface to an external video capture device and that device will have to interface to the laptop USB interface. I have only been able to find one such capture device - a rather cheap EZCAP device which appears, euphemistically speaking, to be extremely unreliable with Windows 7 and for which I'm not even sure if the correct cable can be obtained (i.e. with a BNC connector at one end). Modern Astronomy appear to sell a USB2 video capture device similar to the EZCap for use with the Mintron cameras but the details emphasise Windows 2000/XP - I suspect because of known Windows 7 problems.

Is there anyone who has actually gone down this route who could advise on specific components that are known to work?

PS Excellent thread.

I have an EZCAP device, it works fine. I use a desktop PC with Win7 64bit and a laptop with Win7 32 bit.

You have probably found a clone/fake version, sometimes badged Easycap or EzCAP, China and Hong Kong outlets are flooding the market with them, note the different spelling. Specifying Win2000/XP onlyis one of the clues to a rip-off.

The one I have was from EzCAP 116 USB 2.0 video capture. Supersedes EzCAP DC60+. World wide delivery.

Me using one should not be construed as a recommendation, its still cheap and others are available;

Hauppauge WinTV USB-Live2 USB 2.0

Compro VideoMate C200 PLUS USB

for instance, the choice is yours.

The connector problem, yeah annoying, commercial video products generally use BNC, consumer video products use RCA phono.

Generally.

You will need to get an adaptor.