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Is it possible to setup your GoTo Scope to your TV

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#1 NorthWolf

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Posted 14 January 2013 - 06:15 PM

Just an idea..is it possible to setup a Celestron 9.25 SCT Telescope to a TV, I'm talking about connecting a wire from the telescope or some type of equipment connected to your telescope to a TV? Would be useful for cold nights and to view the sky from the comfort of a couch sometimes. Just a thought.. :question:

#2 A. Viegas

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Posted 14 January 2013 - 06:18 PM

Of Course!! This is why so many use the Mallincam! It has simply composite and s-video outputs. So an older TV that has those inputs would happily become a large screen DSO viewer, albeit the resolution would not look too good on a very large TV... but 20-24" it would be fine.

Al

#3 NorthWolf

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Posted 14 January 2013 - 06:24 PM

Wow...that's just sick lol... I think I'm going to be up all month researching this...haha love this hobby, it's endless!

Is it pretty much any telescope that you can do this with? I'm pretty much going to end up with a C9.25 and probably a solarscope (Lunt 60 or Coronado 60) within the next few months.

Is there a specific type of mount needed? Wire(s)?

Would a TV with HDMI be best? DVI?

Thank you!

#4 mclewis1

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Posted 14 January 2013 - 08:02 PM

Pretty much any scope with some form of tracking works for video. You want to be able to have between 2-30s exposures capability. A goto alt az mount will usually track well enough, as will a low end gem with just an RA motor. Ideally you'd like have faster optics (f5 or faster) which helps shorten the exposure/integration times and helps to bring out color in many objects. If you have a reasonable scope that isn't by itself "fast" you can add a small focal reducer to most cameras which would help things out. "Fast" also means shorter focal lengths which makes things easier on your tracking.

Once you have a scope and mount (a C9.25 on a CG-5 would be a great setup) you can look at cameras. Here you tend to get what you pay for ...

>$100 Samsung (or similar) security camera
$300-400 Security camera with 1/2" sensor (larger than the popular 1/3" models)
$500+ This is where the purpose built video cameras start
$1200+ This is where the high end Mallincam's start

With a security type of video camera you'll also need ...
- a Cmount to 1.25" adapter (so the camera can be mounted anywhere you can insert an 1.25" eyepiece).
- a 12v 500ma power supply

The camera's purpose built for astronomy tend to come with all the bits and pieces required.

The output of any of these cameras is a composite NTSC video stream. You'll often see this type of connection on many older TVs (look for a female RCA jack that will have a yellow center). The back of the cameras usually have a BNC style connection point. You can easily find inexpensive pre made BNC to RCA video cables in the 25-50' range.

On more modern TVs you may only see something like component video connectors (in addition to things like DVI or HDMI connectors). Component video are those 3 RCA connectors with green, red and blue centers and often marked Y, Pb/Cb, Pr/Cr. In some cases you may be able to plug the composite connection from the camera into the green Y connector and in some cases this won't work. Beyond that with more modern TVs you'll need adapters to convert the composite video from a Security/Astronomy camera to something the TV can handle.

Something else a lot of folks with these video cameras do is to connect then to a PC. You'll need a simple USB video frame grabber which are available starting in the $15 range and a the PC (laptops work well out at the scope).

Lots of info on different cameras and such in this forum. For remote control of a mount have a look in both the Mounts and Astronomy Software and Computer forums.

#5 mich_al

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Posted 14 January 2013 - 10:28 PM

Well, I did it with a CGEM, C9.25, MFR-3, .6 Focal Reducer, Mallincam, 50" Plasma, PC and a bunch of stuff in between. It all worked pretty good but I spent more time putting it together than I ever spent using it. I just like being outside at the eyepiece.

On another front, a standard Mallincam is best for looking at nebulas and DSO's. You really want another kind of camera for Solar, Planets or the Moon.


#6 NorthWolf

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Posted 14 January 2013 - 11:02 PM

Thanks mclewis1! That was very informative! I will refer to this post for a while.

How come there is no HDMI type of setup yet?

#7 S.Boerner

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Posted 15 January 2013 - 10:13 AM

mclewis1 has pretty much covered all the bases. One addition is that many of the camera options above are going to get you a very small 1/3" sensor. You'll get a view similar to a 6mm eyepiece. Your SCT combined with such cameras will give you a FOV such that you won't be able to fit many of the larger DSOs on the screen. You'll only be able to see parts of these DSOs. A solution will be a cheap focal reducer.

A quick look at CCD Calculator (google it) shows that a Samsung SDC-435 or similar low light security camera coupled with a 9.25" f/10 SCT AND a .5x focal reducer gives a FOV of 5.3x11 arcminutes. That's still pretty small for most bright DSOs.

#8 mattflastro

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Posted 15 January 2013 - 11:57 AM

mclewis1 has pretty much covered all the bases. One addition is that many of the camera options above are going to get you a very small 1/3" sensor. You'll get a view similar to a 6mm eyepiece. Your SCT combined with such cameras will give you a FOV such that you won't be able to fit many of the larger DSOs on the screen. You'll only be able to see parts of these DSOs. A solution will be a cheap focal reducer.

A quick look at CCD Calculator (google it) shows that a Samsung SDC-435 or similar low light security camera coupled with a 9.25" f/10 SCT AND a .5x focal reducer gives a FOV of 5.3x11 arcminutes. That's still pretty small for most bright DSOs.

Not exactly.
First of all, all video cameras including Mallincams will have small fields of view at prime focus , not only the 1/3" sensors .
1/3" sensors have a 6mm diagonal, 1/2" sensors have 8mm diagonal, that's a minor increase in the field of view given an otherwise identical scope setup .

But of course , if you use a 1/3" sensor you don't set up your scope the same way as for an 1/2" ccd.

Any f/10 SCT has a FOV of at least 1 degree .

Using proper reducers for your CCD size you should be able to get most of this 1 degree FOV on your CCD .
Google " focal reducers for dummies " and you'll find a couple of good articles/postings on the subject.
A x.33 focal reducer with maximum extension tubes achieves a larger reduction than implied by its name , down to x.22-.24 on f/10 SCT's .
This alone yields a FOV of over a half degree .
Also, a x.33 reducer can be placed on the scope followed by a x.5 reducer on the camera for further FOV increase .
And last but not least, reducers that illuminate a 1/3" CCD are cheaper than reducers for larger CCD's , so it's easy to experiment .

#9 mpgxsvcd

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Posted 15 January 2013 - 02:19 PM

Thanks mclewis1! That was very informative! I will refer to this post for a while.

How come there is no HDMI type of setup yet?


I use a Panasonic GH3 and the Orion StarSeek Wi-Fi Telescope Control Module to completely control and view my Celestron CG-5 mount and telescope wirelessly.

Wireless GH3 camera
http://www.dpreview....anasonic_dmcgh3

Wireless mount control for $140.
http://www.amazon.co...ils_o00_s00_i00

The GH3 will transmit a wireless live view of what is on the camera's LCD screen or it can transmit the captured images to an iphone or Android device.

You can then hook up the phone via HDMI to any TV you like.

If you want to do a wired connection you can also do 1080p @ 60 FPS directly out of the GH3 to any HDMI TV. It will give you a live view from the camera with or without the overlay icons.

I am using this setup to wirelessly transmit to a near by car this weekend. My kids and their friends want to look through the telescope but they don't want to brave the cold. My setup allows them to do both.

This is an example of what they see on the phone.

Attached Files



#10 NorthWolf

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Posted 15 January 2013 - 03:06 PM

Very nice.

#11 barbarosa

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Posted 15 January 2013 - 10:52 PM

My version with an SCT on an alt-az goto mount

Celestron f/6.3 corrector-reducer

diagonal

.5x reducer

c-mount adapter

Samsung SCB-2000 or LN-300

75 Ohm coax to USB frame grabber at mount

10m USB extender cable to Laptop

SharpCap freeware to view/adjust image (Stellarium to control scope)

HDMI connection to plasma display on wall

Me on a Stressless recliner :D

#12 1965healy

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Posted 23 January 2013 - 07:56 AM

I've been thinking about adding video to my setup, thanks for a great intro guys!

#13 Undermidnight

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Posted 23 January 2013 - 10:00 AM

Oh wow.. this is awesome! The Orion Nebula picture is just fantastic. One of the things I want to do someday for public outreach is get a video system setup.

(Although I am still an eyepiece guy at heart :grin:)



Jason

#14 Dennis_S253

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Posted 23 January 2013 - 10:38 AM

Hello all, I have read on the Samsung SCB-2000 that they recommend removing the IR filter on the camera and using a IR/UV filter that screws into the barrel.
Mark quoted...
"You want to be able to have between 2-30s exposures capability"
Can you explain this a little more? Does this mean it's not a live feed? I get confused here. THX..

#15 mclewis1

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Posted 23 January 2013 - 11:56 AM

Dennis,

Here we get into the definition of "live" and "near live".

A video camera is constantly putting out a video signal (usually in the standard NTSC or PAL formats). In NTSC format the signal is updated at almost 30 times a second. Compare this with a regular imaging camera connected to a PC where you get one image after the exposure and download and any image processing (some cameras now come with software that automates much of this and provides consecutive exposures as well).

Within the video camera the sensor can be read at very different rates. It can certainly be read at very fast rates (for viewing bright objects like planets, moon, etc.) but can also be set to expose for a longer period of time (for faint deep space stuff). The longer the exposure the more light is gathered (just like in any other camera) but the difference is that the video output is continuous. Once a longer exposure is complete another exposure is started, and this goes on continuously until you change the camera settings.

So if someone wanted a 7 second exposure (or also called "integration" in some cameras) they would see the continuous video signal (~30 frames/second) with updates also occurring every 7 seconds.

At a few second exposures the display appears very "live" (this is good for finding stuff, focusing etc.), as you increase the exposure times you start to notice the delay (allowing you bring out fainter objects), as you get into 10s of seconds there is an obvious wait between updates (but this allows you to go "deep" to see faint details).

In all of this you aren't waiting on a PC to finish downloading and processing an image. You can change the brightness, contrast, color balance etc. at any time with immediate results.

So you'll often see the term "near live" to describe this not too delayed type of viewing.

#16 Dennis_S253

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Posted 23 January 2013 - 12:46 PM

Thx Mark, this stuff is so cool.

#17 CharlesW

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Posted 25 January 2013 - 10:59 AM

If you run the camera through your laptop/desk, a $99 Apple TV box will allow you to see anything that is on your computer on your TV screen using wifi. I have a 24" iMac desktop that enlarges nicely on my 60".

#18 NorthWolf

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Posted 23 February 2013 - 02:54 PM

Thanks mclewis1! That was very informative! I will refer to this post for a while.

How come there is no HDMI type of setup yet?


I use a Panasonic GH3 and the Orion StarSeek Wi-Fi Telescope Control Module to completely control and view my Celestron CG-5 mount and telescope wirelessly.

Wireless GH3 camera
http://www.dpreview....anasonic_dmcgh3

Wireless mount control for $140.
http://www.amazon.co...ils_o00_s00_i00

The GH3 will transmit a wireless live view of what is on the camera's LCD screen or it can transmit the captured images to an iphone or Android device.

You can then hook up the phone via HDMI to any TV you like.

If you want to do a wired connection you can also do 1080p @ 60 FPS directly out of the GH3 to any HDMI TV. It will give you a live view from the camera with or without the overlay icons.

I am using this setup to wirelessly transmit to a near by car this weekend. My kids and their friends want to look through the telescope but they don't want to brave the cold. My setup allows them to do both.

This is an example of what they see on the phone.


Do I need to have a Panasonic GH3 to get this setup? What other lesser priced cameras have this ability?

Also, is the video from these type of cameras as good as a HD camcorder?

#19 mpgxsvcd

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Posted 23 February 2013 - 05:03 PM


Do I need to have a Panasonic GH3 to get this setup? What other lesser priced cameras have this ability?

Also, is the video from these type of cameras as good as a HD camcorder?


Currently the GH3 is the only one that can do the AP in a live view like this and has wifi built in. Other cameras will come out later this year that will have it.

The 1080p @ 60 FPS video in the GH3 is the single best 1080p HD video camera you can buy. No camcorders can match its 50 mb/sec 1080p @ 60 FPS mode and its ultra low light video capabilities.

There are some 4K cameras that offer more resolution. However, those cameras usually cost more like $7000-$10,000.

#20 NorthWolf

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Posted 24 February 2013 - 02:24 PM

Hey mpgxsvcd, thx for the info, is it possible to attach the GH3 with an adapter to the eyepiece or diagonal of the 9.25" SCT Celestron scope?

#21 guyinthesky

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Posted 24 February 2013 - 03:55 PM

i use a "video sender" i got for $25 off ebay. its 2 small units, one broadcasts the video signals, and the other receives it in the house and plugs into the tv. no wires, and works well. another option.

#22 Relativist

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Posted 25 February 2013 - 02:11 AM


This is an example of what they see on the phone.


Please let us know what the settings were for this particular frame grab/picture.

#23 mpgxsvcd

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Posted 25 February 2013 - 07:40 AM



This is an example of what they see on the phone.


Please let us know what the settings were for this particular frame grab/picture.


I think this one was +3-3 stops of in camera HDR with ISO 12,800. It is a series of an 8 second, 2 second, and 1 minute jpg exposures all combined in camera.

#24 Qwickdraw

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Posted 03 March 2013 - 11:24 AM

Of Course!! This is why so many use the Mallincam! It has simply composite and s-video outputs. So an older TV that has those inputs would happily become a large screen DSO viewer, albeit the resolution would not look too good on a very large TV... but 20-24" it would be fine.

Al


For newer televisions you can also purchase a component to HDMI converter for under 100 bucks.

#25 mclewis1

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Posted 03 March 2013 - 02:42 PM

Actually what's needed is a composite or S-Video to HDMI scaler. Component video won't help with most video cameras but your point is well made, these scalers are indeed available starting at well under $100 and things don't look great when really blown up.

I've played around with composite and S-Video inputs from a Mallincam to an HD TV (in my case there were native connections on the TV ... no external up conversion scaler). Even on a small 19" display I can see a difference between composite and S-Video ... the S-Video feed looks a little bit better (bit smoother and less obvious scan lines) and I expect this to be even more apparent on larger displays.






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