Advice on live astro video

[Alien]

Hello, all. I am a new member here - just joined. Please could somebody offer advice on the following:

I would like to be able to control a GOTO mount remotely via PC, probably using Stellarium ASCOM connection. Then, have a live streamed image from the eyepiece using some sort of digital camera. I have done some reading and the Watec and Mintron devices look ideal. They claim to give live feed colour images, even of deep sky objects. If the images posted are to be believed they are full colour images of nebulae, galaxies etc etc.

My questions are:

- how does the quality of the live image compare to visually looking down a decent eyepiece?

- can feint objects such as galaxies and nebulae be imaged in full colour as claimed?

- what is the difference between Watec/Mintron and other cameras such as Imaging Source because both use a 1/2" CCD chip.

- in your opinion, is this the best way to achieve what I am setting out to do (above), or could there be a better way?

Thanks!

[Merlin66]

Live stream video infers short exposures - 1/60 sec or so.

With such an exposure you'd be limited to only the brightest of objects - moon, planets and the brighter stars.

[SteveL]

Merlin, I suggest you go take a look at what the Watec and Mintron cameras can actually do

Normal webcams only show the data they capture from the single frame, but the watec and mintron cameras stack them on the fly and output that image via a video outout that usually goes to a monitor screen.

I dont have one, nor have I used one, but they do get used a lot at outreach and public events.

[Merlin66]

Steve,

having never used one either, I assumed ( always a bad thing to do!) they were similar to webcam in video mode...

The only site I could find which talks about astronomy was:

www.mondatlas.de: Videokamera Watec WAT12NRC

Some impressive 10sec stacks; but is this classed as streaming video?

[SteveL]

The Watec/Mintron units stack on the fly, so you can kind of stream it to a monitor screen. The image builds up as you watch it.

[tinvek]

there's an article on video observing in the new edition of astronomy now, haven't read it properly but it's got some links for information so may be worth a look

[Alien]

Thank you all for your replies, that is very helpful. I have looked at the web link that Merlin gave and have found some more information about these astro video cameras on the Watec website and at modern astronomy. It seems that they are busily stacking images internally and sending an enhanced (I suppose slightly delayed) live image to the TV screen, as Steve says. They claim that it is like looking down an eyepiece with bionic vision because the built up image picks up additional detail and more of the visible light spectrum, i.e. you can see red and yellow on the live image.

There is a fan cooled Watec camera now for live deep sky imaging but is about £1000! The Mintrons are more like £250, either for a 1/3" CCD with fast scan rate, or a 1/2" CCD with lower scan rate. Not sure which to get...

I will have a look at the astronomy now article and see if it sheds any light.

Thanks again!

[tooth_dr]

After looking at both the 1/3" and the 1/2", I bought the monochrome 1/2" for my Dad. We've used it once so far, and it's truly excellent indeed. Far more is shown than what can be seen with the eye.

I pointed the Mintron at various objects and I photographed the TV screen with a DSLR camera. This is the sort of thing you could expect from to see live on the screen.

I'd probably avoid the colour one, as most of the objects won't really show the colours you get in long exposure photograpy. If you buy the monochrome version you can still use LRGB filters to create colour images. Although the colour is inherently less sensitive, this is overcome by being able to integrate 256 frames, as opposed to 128 frames with the 12v6 monochrome 1/2" version. But overall the difference in sensitivity is minimal, and the chip is bigger in the 1/2" version, and the price is similar.

I bought mine from Modern Astronomy, got a focal reducer, and DVD capture device (necessary to save images onto the computer)

Hope this is helpful

Adam

[mike.brightmore]

I use the monochrome Watec 120N and am very pleased with the video output to a TV monitor. It is quite a bit better than the view at the eyepiece. Some photos of the set-up and TV screen images on this ink http://stargazerslounge.com/imaging-sketches-unconventional/79493-remote-tv-images-unconventional.html

[Alien]

Adam and Mike

Thank you for the uploaded images and the links - I suppose seeing is believing! These are very impressive indeed. The human eye just would not be able to pick up that level of detail on faint fuzzies. Even on a very clear dark night M31 is mildly disappointing through my eyepiece..

Mike - your garden observatory setup is truly amazing, and really looks the business in red light with a starlit sky overhead!! The images on your link are very impressive, I think this is exactly what I am looking for. I do not have an observatory, just a flat circular concrete 'astro pad', but when I found myself laying grit mid-session to keep the ice at bay at -3deg C last year I started thinking 'there must be a better way'!

I have found a fan cooled version of the 120N+ for longer exposure but is v expensive.

Have either of you seen Steve Wainwright's blog? x-bit-astro-imaging: March 2009

He is using a new Mintron 73S85hp -ex -sw -r colour helix deep sky camera which I think just has a 1/3" CCD but 256 frame rate. The live colour images of nebulae are impressive. I think the Watec still beats it on resolution though.

[tooth_dr]

The Mintron works well, and is a good bit cheaper to buy than the Watec, but the Watec is better. It just depends what you want to spend really. Why not ring one of the astro companies selling the gear and get some good advice from them?

Good luck

Adam

[Peter Drew]

I've used a succession of Stellacam video cameras for a number of years now and have been very pleased with the "plug and play" no fuss performance. The Stellacam 11 operates on a maximum integration of 256 frames taking about 10 seconds to display the first image, after that the image refreshes before the initial one has time to decay giving the impression of a live view. I have to say that the recorded images with this camera in 10 seconds with a 12"SCT surpass the visual view with my 30" Dob. The important thing is to operate at as fast an F ratio as possible, ie F3.3 on a SCT. The most recent one I purchased was the Stellacam 111 which theoretically has infinite integration, however this is limited by the drive quality of the mount. I find that about 60 secs gives the most reliable results, that is still 6X more exposure. The Stellacam 11 is uncooled and can exhibit "noise" problems during the warmer time of year, the 111 has Peltier cooling which overcomes this to some extent. If you want to see M31's dust lanes, two central stars in M57 and the spiral arms of M33 in near real time then these cameras are ideal, they also have a nice freeze frame facility to allow you to examine or record the image for as long as you like.