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Seeking advice: real time vid cam for solar telescope

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#1 MarkDC

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Posted 04 August 2014 - 12:16 PM

Hello everyone,

 

We have a Coronado PST which we use for education and outreach.  I'd like find a video cam system which would allow us to send live, high-quality color video into our main lecture hall (which has RCA inputs).  

 

I've looked around but been unable to find good information on which camera(s) might be worth considering.  I'd sure appreciate any helpful advice or information.

 

 

Thanks,

 

 

Mark



#2 mclewis1

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Posted 04 August 2014 - 01:25 PM

Mark,

 

Virtually any of the video cameras discussed here in the EAA forum will do what you want.

 

You don't need longer exposures and extra sensitivity used in cameras designed for DSO work. 

 

I think your biggest decisions will be computer control and the size of the sensor. The popular 1/3" sensors are used in the latest small format cameras (LnTech, Mallincam Micro, AVS DSO-1, or one of the newer Samsungs). The Mallincam and AVS cameras have better computer control options and also come with some very helpful extras (1.25" nose piece, power supplies, control cables, etc.). 

 

You can also use the 1/2" sensor video cameras (Mallincam Jr Pro, Samsung SCB4000). They cost more and don't have the resolution of the 1/3" cameras that use the latest sensors. the benefit of the 1/2" sensor models is a larger field of view. You'll need to plan out what kind of observing you want to do (full surface, partial surface, prominences, etc.) to determine how much field of view you'll need.

 

All the cameras mentioned have a CVBS (composite video) output and can usually directly drive 50' of video cable. Longer runs are often possible but if a particular camera can't drive the extra distance say beyond 50' there are plenty of reasonably priced extension capabilities. In addition to extending the distance you also have the option of up converting to other video standards (component or HDMI for example).

 

I believe that PSTs also require a bit more back focus to use a camera so most folks will add a mild Barlow lens to help the camera come to focus.


Edited by mclewis1, 04 August 2014 - 01:37 PM.


#3 MarkDC

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Posted 05 August 2014 - 05:56 AM

Mark,

 

Great information, it's very interesting.  I will look at the cameras you mention.

 

Thanks,

 

Mark



#4 nytecam

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Posted 06 August 2014 - 03:53 AM

Hello everyone,

 

We have a Coronado PST which we use for education and outreach.  I'd like find a video cam system which would allow us to send live, high-quality color video into our main lecture hall (which has RCA inputs).   I've looked around but been unable to find good information on which camera(s) might be worth considering.  I'd sure appreciate any helpful advice or information. Thanks, Mark

Hi Mark - a webcam [with lens removed] would work just as well as video assuming your lecture hall can cope with multimedia presentations.    Here's some of my relevent Youtube vids via a $2 Walmart/Asda webcam [you needn't go that cheap but I do enjoy a poke at the big spenders!] thus https://www.youtube....=WPa763exBX8thu =PST streaming, https://www.youtube....h?v=uaHFQXmzmwM = terminator, https://www.youtube....h?v=K7Vc_B96Xy0 = PST CaK/Ha.

 

The main problem with video or webcam is getting the sensor close enough into the PST to reach focus.   I've successfully use a stack of red or plain [colourless] filters before the camera which act a plain glass 'wedge' that shifts focus outwards that vital few millimeters. Alternatively you could use a Barlow lens before the camera that will ensure focus can be reached BUT the solar image is enlarged and the whole disk may not fill the view. Good luck :grin:


Edited by nytecam, 06 August 2014 - 04:10 AM.


#5 Skylook123

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Posted 08 August 2014 - 06:42 PM

I've had no trouble with a Mallincam Junior PRO running from my back yard into my laptop with either 50' composite or 50' S-Video, and running from the laptop with 150' HDMI to a 42" monitor.  The length you have to transmit the signal might become the problem.



#6 James Cunningham

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Posted 09 August 2014 - 08:45 PM

The Mallincam SSI monochrome is also a good choice for Solar imaging.  



#7 ccs_hello

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Posted 09 August 2014 - 10:12 PM

Mark,

 

A left field view:

1. Most of the time, solar system and solar imaging is not in photon starvation situation thus no special imaging device is needed.

2. A lecture hall screen would be a big screen.  It deserves a high resolution feed for the high resolution projector such that students do not see blocky/pixelated images or moving images.

3. A high resolution digital imager feeding a PC thru USB2 tweak images as needed in the PC, then feed PC output to the lecture hall projector with its high resolution output.

    This is all digital except the initial image acquisition and final display projection.  No standard definition (SD) NTSC encoding and decoding involved to degrade the images.

4. You can display the incoming images in near real time, but they are still subject to the #1` enemy: seeing.  "Lucky imaging" rules.

You can run Ragistax to weed out/reject fuzzy images and only stack (many, many more) good images to gain high quality image result.  <-- Ask Solar System Imaging group for the current state of art technology to see how much delay it is. 

 

Recent popular imager is ZWO's ASI120MC (or MM) at 1280x960 resolution.  price is good.

A hint: buy from vendors that have been specialized in that astro sector.  Do not buy an imager which do not disclose exact which image sensor it is using.

 

Since you are talking about using PST (very narrow band H-alpha), a monochrome imager would give you the best quality.  You can tint the screen at a color of your delight (reddish)  in or near the final display stage.

 

Clear Skies!

 

ccs_hello


Edited by ccs_hello, 09 August 2014 - 10:19 PM.







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