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Considering dabbling with video astronomy

Bobby1970

By Bobby1970
in EEVA - Reports

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Peter Drew

Peter Drew

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I can recommend video astronomy as a no or little fuss medium for producing satisfying images. The camera you identify would give good lunar and planetary images with your Skymax 127 and DSO's with the Startravel 102. No more "thinking" needed.   :smiley: 

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Bobby1970

Bobby1970

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I have done 20 seconds with my slr. But am intrigued by the video astronomy and the low light capabilities of the cameras. Am I right in thinking that they would be much more sensitive than my slr.?

Sent from my D6503 using Tapatalk

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johnno

johnno

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The PD camera is a good low budget starter cam with 10 second integration and your 102 500m f4.9 scope will do nicely. Don't forget your doing electronically assisted astronomy.  ie replacing the eyepiece with a camera  viewing in near real time as possible and the image quality will be nowhere near as good as a dslr camera.

I've used the skywatcher alt/z mount. The camera will refresh the image to whatever exposure or senceup setting you've selected  ie if you've set it to 10 sec you'll have a new image every 10 sec's and you will eventually get field rotation. You will have look at it as time lapse when using a alt/z mount depending on how long you want to view the image.

Have a look in the Tread " what is video astronomy ' In this section, I made a post with a link with someone using a Samsung 2000p camera which is similar to a PD camera and it will give you a idea what can be achieved. hope this helps you

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DoctorD

DoctorD

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Hi

I started out with a Skymax 102 MAK on  an AZ mount with the SDC435/SCB2000 camera - have a look in my gallery at some of the images I managed to grab.

http://stargazerslounge.com/index.php?app=core&module=search&do=user_activity&search_app=gallery&mid=11951&userMode=all&sid=266059f4e5c836ad92a3f96f3ac6e51e

If you want to look at DSO's I'd recommend a reducer for both your scopes but in particular for the MAK - the F3.3 can be used to good effect with a little distortion if you can get hold of one and a MAK-SC adapter ring.

HTH

Paul

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Bobby1970

Bobby1970

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There are some good shots there as far as i am concerned.

I am trying to get my head around the whole thing still though.

Am i right in saying that the higher the integration the "longer exposure" the image displayed is ?

Is it then possible to take multiples of the single integrated image and stack them?

Or is my thinking all wrong?

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johnno

johnno

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Some of the software that we use has provisions to enable to stack on the fly or capture a series of exposures and save them and use other external programs like registax, and others.

Here's Ken recording a live session using a Samsung 4000 which is the next camera up  from a 2000p, this is what you'll see on your monitor screen, you'll notice streaks in the video which is the scope slewing to different objects and then the image will settle when it has completed it's first intergration.

http://ballaratman.wix.com/videoastronomy

http://ballaratman.wix.com/videoastronomy#!videos/cf4n

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DoctorD

DoctorD

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Hi

The video cameras with SENS-UP work by integrating (or keeping the electronic shutter open) for a number of fields, each field being 1/50 of a second for a PAL camera or 1/60 of a second for an NTSC camera.

So the SDC435/SCB2000 with a SENS-UP of 512 has an effective exposure of 512x1/50= 10.24 seconds.

So effectively the higher the integration, the longer the exposure.

Some cameras also have a noise reduction algorithm which can effectively extend the integration time further.

You could capture these and stack them later using a PC.

Given the amount of work done on the SDC435/SCB200 9same camera sold under two model numbers), I'd recommend finding one of these on e-bay  as a starting point.

HTH

Paul

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Bobby1970

Bobby1970

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Some of the software that we use has provisions to enable to stack on the fly or capture a series of exposures and save them and use other external programs like registax, and others.

Here's Ken recording a live session using a Samsung 4000 which is the next camera up  from a 2000p, this is what you'll see on your monitor screen, you'll notice streaks in the video which is the scope slewing to different objects and then the image will settle when it has completed it's first intergration.

http://ballaratman.wix.com/videoastronomy

http://ballaratman.wix.com/videoastronomy#!videos/cf4n

Thats an excellent website.

From what i have read on there it sounds like i should get some decent results with my alt/az mount.

It seems to me that alt/az is more useable for video astronomy than it would be for astrophotography and i like the sound of that as i am not as keen on getting an EQ mount.

I have a 0.5 focal reducer too. Do i attach this to the front of the camera ??

Thanks again

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Martin Meredith

Martin Meredith

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Hi Bobby

I own a mount (AZEQ6) that is capable of being used in EQ or alt-az and have never once used it in EQ mode, so yes, alt-as is definitely fine for this style of observing!

Also, you don't have to sacrifice image quality so long as you gather enough photons. The approach I follow is to live stack lots of short exposures (I typically use subs in the range 5-30s depending on sky conditions -- the better the sky, the longer the sub). That way, I get an image quickly, the image builds up gradually over the time I observe the object -- often for 5 to 10 mins or more in the case of very faint stuff -- and by the end of the observing process the image quality can be quite good. Win-win!

The secret is to find live stacking software that copes with field rotation. While short exposures will ensure you get no significant field rotation within each individual sub, when you stack a lot of them (say several minutes worth) the stacking process will have to handle the rotation you get between subs. I'm fortunate enough to use the excellent LodestarLive, but it only works with certain SX cameras. There are other live stacking solutions (DSSLive, AstroLive, AstroToaster) out there for other cameras capable of dumping FITS for each sub into a named directory.  I don't know if they are an option for the camera you're looking at as I haven't used them, but you can find some good results with them described on the EAA forum on Cloudy Nights.

Good luck!

Martin

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Bobby1970

Bobby1970

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The PD camera i was looking at comes with a capture device either for windows or a Mac (which i have). I was thinking of grabbing the images with this thne using some external software to stack those, possibly in windows if needs be.

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JamesF

JamesF

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Others are probably better placed to advise on this, but if you're connecting the camera to a PC I wonder if perhaps using a USB-connected camera might be a better option?

To me it seems a little odd perhaps to take a digital image, turn it into composite video which is connected into some sort of frame-buffer card to turn it back into a digital image again.

I appreciate that there are reasons why people might want a composite video output (to display on a television, or because of long cable runs perhaps), but given reasonable software on the PC end I'm not sure what benefits a camera with video output has.

James

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fondofchips

fondofchips

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Others are probably better placed to advise on this, but if you're connecting the camera to a PC I wonder if perhaps using a USB-connected camera might be a better option?

To me it seems a little odd perhaps to take a digital image, turn it into composite video which is connected into some sort of frame-buffer card to turn it back into a digital image again.

I appreciate that there are reasons why people might want a composite video output (to display on a television, or because of long cable runs perhaps), but given reasonable software on the PC end I'm not sure what benefits a camera with video output has.

James

A (Digital) USB camera is best when starting the hobby as then a video grabber isn't needed to save pictures.  An analogue camera like the Mallincam needs a video grabber to convert from analogue to digital to save and broadcast the pictures.  The Mallincam has 2 analogue video outputs, one shows exactly what the camera sees and the other goes to the video grabber.  That way you know the camera is working OK at all times, and as a backup a colours bars option is available to test the PC to camera connection.

I'm a bit puzzled at the analogue output but it can be shown on a normal TV screen which is good for group viewing.  It also means that the picture can be seen on a normal TV and the PC monitor is still free to show Stellarium/CDC/EQMOD/Sharpcap etc, being used to get the camera on target and control the exposure.

It's all part of the challenge of video astronomy, and like all other forms of stargazing there are loads of different ways of doing it.

So my way isn't necessarily the right way.

Clear Skies,

Fondofchips.

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johnno

johnno

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I'm giving the analog side of it because that's the link he'd shown in the OP, and it's a cheap starter camera, but if he wants to dive into the deep end he can go for a usb camera like the Lx2 @ 500+ pounds or a Mallincam sky raider priced roughly the same

Its not  case of usb vs analog, its how much he wants to spend on his first  camera.

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Bobby1970

Bobby1970

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this subject caught my interest firstly beacause of the low cost, and secondly the fact i could maybe still get some acceptable deep sky images with my zlt az goto. I am not keen on going down the EQ route and spending longer setting up and hours and hours gathering data.

So its a combination of the two.

If a USB camera is an option i would be interested, but it sounds as though to get something with the same sensitivity it would cost much more than the video cam i linked to.

I used to have a modded SPC900 that i did some planetary images with, but never had much success with dso's due to the small sensor size making it difficult to get objects centred in the frame.

I assume the sensor size on the video cam i linked to is much bigger, an i guess the USB imagers will be the same?

But considering the limitations of the alt/az mount will there be any difference between usb and analogue in what i can actually capture and for how long?

Some really interesting posts so keep them coming :-)

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JamesF

JamesF

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I'm giving the analog side of it because that's the link he'd shown in the OP, and it's a cheap starter camera, but if he wants to dive into the deep end he can go for a usb camera like the Lx2 @ 500+ pounds or a Mallincam sky raider priced roughly the same

Its not  case of usb vs analog, its how much he wants to spend on his first  camera.

The Lodestar certainly isn't a cheap option, but there are others.  I don't know what they're like in terms of functionality however.

The new Altair GPCAM for instance comes with some sort of real-time viewing application.

James

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Bobby1970

Bobby1970

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The Lodestar certainly isn't a cheap option, but there are others.  I don't know what they're like in terms of functionality however.

The new Altair GPCAM for instance comes with some sort of real-time viewing application.

James

Hmmmm

That Altair GP cam looks interesting.

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JamesF

JamesF

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It does, and it would potentially double as a planetary cam and perhaps a guider too.  I have no idea what the software is like, but there are at least a couple of SGL users who have one.  There are probably other cameras too.

James

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