• everyone in a party can see the same object at the same time
• the party members can freely discuss the object on the screen
• I can be sure everyone can see the image because I can point to it
• less dead time vs. standing in line to view through an eyepiece
  
• fainter detail can be captured/seen because of  extended integration times
• objects can be seen around bright moon conditions 
• color is more obvious vs. eyepiece views
  

While capturing images with a video camera won't compare with a good CCD or DSLR, it can give an eyepiece and small scope a run for the money.

(scroll down to the bottom of the page for actual pictures taken at Brommelsiek park with a SDC-435 and 160mm focal length zoom lens)

1. Samsung SDC-435 video camera  pixels 678(H) x 494(V) or other low light security camera that can record in very low light conditions.
   
2. Power supply--AC adapter to provide 12v 500ma for Broemmelsiek and/or fused DC cord to provide 12v 500ma for field work
3. 1.25" to C-mount lens adapter to use OTAs with focuser
   
4. Frame grabber to get video to the computer
5. OTA/Lenses (mine listed below.  Any will work if they are fast enough)
   • Celestron C-8 (must use focal reducer for DSOs)
     
   • Apogee 90mm f/6.1 refractor (should use focal reducer for DSOs)
     
   • Vicon 16-160mm f/1.8 zoom lens ($40 on EBay see bottom of the page for more information on possibilities with this lens)
   • Philips 12-240mm f/1.6 zoom lens  with 2x extender (see bottom of the page for more information on possibilites with this lens)
   • ETX-70
     
6. BNC to RCA adapter and RCA cable (RadioShack)
7. Computer for video display and capture or monitor for display
8. Alt/Az or EQ mount
   
   Additions (add as needed depending on your hardware and location)
    
9. Focal Reducer:  f/6.3, 0.5x, or Meade f/3.3
10. Light pollution filter
11. IR/UV filter (if you remove the stock filter)
    
12. 2" nose piece to SCT for Meade f/3.3 FR
13. T-mount to C-mount adapter for Meade f/3.3 FR
14. Flip mirror
15. various home made adapters to hold filters & focal reducers 
    
    
    
    
     

The bottom line is that it will probably run you about $200 to get into video via this route.

Nose pieces are also available for 2" to C-mount.

Video works best with more light.  Some people say the SDC-435 works best at focal ratios less than f/4 and I agree.  If your optics are slower than f/6 you will need to add a focal reducer to get good results with DSOs.  Longer focal lengths and larger focal ratios should give acceptable results with the moon and larger planets.

The SDC-435 has a 6mm chip (1/3").  Longer focal length optics will probably have difficulty seeing large DSOs.  A program like CCD Calculator should really help to give you an idea of what can be seen with your optics and a video camera.  See:  http://www.newastro.com/book_new/camera_app.php

Even a moderate telephoto DSLR or 35mm camera lens works well.  A 200mm focal length lens will capture a 76x57 arcminute field with the SDC-435's small chip.  In contrast, using a Celestron-8 with a Meade f/3.3 focal reducer captures a field of view of 25x19 arcminutes.  If you wish to use camera lenses rather than a telescope search for either C-mount, CS-mount, or CCTV lenses and you will probably be able to avoid adapters although you will need to play with the lens flange to sensor spacing. 

Adapting a zoom lens to the camera is an adventure.  Spacing between the lens flange and camera sensor is very critical if focus is to be held throughout the entire zoom range.  The spacing is adjusted by a combination of adding C-mount spacers and/or screwing the camera in/out from the lens.   Adjust the spacing to focus on a distant object at the shortest focal length with the lens racked in/set on infinity.  Slowly zoom to longer focal lengths and check the focus.  If the focus does not hold, return to the widest focal length and readjust.  This is DIFFICULT but rewarding because afterwards you have a digital zoom finder.  It makes finding and centering the object on the chip much easier.  This is an important concern when a line of people is forming during a public viewing session!

Notes and Details:

I'll first say that if you've never seen live video of DSOs you should probably take a visit to the Nightskynetwork at http://www.nightskiesnetwork.com/  On a dark night you may see up to twenty people broadcasting video of DSOs at the same time.  You'll either love it or hate it.  If you love it, you'll probably get into video.  If you have a way to connect to the Internet at your observing site you'll probably broadcast at some point.

Surfing around the Internet in the fall of 2010, I found some references to Samsung's SDC-435 low light security camera (Google it to see actual deep sky pictures).  I noticed some interesting images and comments about how well it performs... up to 8.4 second integration at 0.0001 lux.  I can't afford a Mallicam (the Cadillac of astronomy video), but I did notice some of the people on the Nightskynetwork did use the 435.  Doing a quick check of prices I found that it was in the affordable range and  I took the plunge and ordered the 12v NTCS version from buy.com about $135 with free shipping.  It arrived in 3 days.  There is a guy who sells from Korea for slightly less, but it will obviously take longer to arrive.

Inside the box were four things (notice no power source or lens provided):

1. the video camera (tiny little thing) with a c-mount lens adapter,
2. CS-mount lens adapter (really just a spacer),
3. rubber body cap,
4. instruction manual (see: http://www.eposcctv.com/manuals/EPOS%20CCTV%20SDC-435.pdf).
   

The camera produces a video out signal via a BNC connector.  The video can be displayed on a monitor or computer if a frame grabber is available.  Software can either display the video on a computer screen, record individual frames or record video. 

Like most cameras there is an IR filter that covers the sensor and like most filters it cuts of the light produced by the Hydrogen alpha line.  Do take the time to remove your filter. I did.  Unlike DSLRs, the filter is quickly and easily removed.  If you do remove the filter, do use a new IR/UV filter like Baader's that passes the light from the Hydrogen alpha line.  Join the Yahoo SDC-435 group to see filter removal directions.

The camera is adjusted by pressing the five buttons (up/down/right/left/set) on the back (see picture).  It does cause the image to "jump" on the computer screen.   You can find soldering modification on the Internet that move the buttons to an external box.  I'm not brave enough to do that mod.

While there is some debate as to how much cooling helps with the 435, I opted to drill a few holes in the top and add a cooling fan to pull air through the camera body.  I've also added a male/female plug to supply power rather than just screw the 12v wall wart to the power terminals.

front of camera

SDC-435 Sensor and IR filter

From the various online reports, CNs, and the SDC 435 Yahoo group, I knew I'd need to put some parts together to make the whole thing work.  The first part of the puzzle would be a AC power supply since there is no supply with the video camera. I got a 12v 500ma wall wart plug type from EBay for $10 and shipping.  

It should be possible to power the camera via a 12v battery because it doesn't draw much power.

Dazzle 100 DVD

The next problem to solve would be connecting the video camera to my telescope.  I found a 1.25" to C-mount adapter at eBay for $20.  It screws into the C-mount on the video camera.  It is plastic so I hope there are no disasters in the future there.  It does have threads on the 1.25" side to mate filters or a focal reducer, so that's a plus.  It just happens to the correct length for the required spacing with my 0.5x focal reducer...double plus!

I later found Agena Astro has the nosepiece in metal.  It helps remove heat that eventually leads to amp glow.

While a 2" nosepiece is available, it and the filters would cost much more than one for 1.25".  Since vignetting won't be a problem with the tiny 6mm chip, I opted for the 1.25" route.

Lately I've been using a flip mirror between the OTA and the Apogee.  One end of the flip mirror has a 2" focuser tube and the other has a T-mount thread.  As a result I connect the SDC-435 to the flip mirror with a T-mount to C-mount adapter.  There is enough room inside the adapter and back of the flip mirror to hold both a .5x focal reducer and Baader SemiAPO filter.  I use an old 40mm eyepiece in the flip mirror as a wide field finder in case slews are not spot on.  The combination helps although in focus was a problem for a while until I made a holder that fit inside the flip mirror.

1.25" to C-mount nose piece

You might think that you need a equatorial mount since you are dealing with a camera and photography.  This isn't really necessary since the maximum integration time is 8.5 seconds.  Alt/Az works just fine.  If you do try imaging with the 435 you'll eliminate field rotation by using DeepSkyStacker since it can correct for rotation.

It is possible to connect various DSLR lenses to the SDC-435 with an adapter.  Adorama has a variety of these adapters like a Canon FD or EOS to C-mount adapter for my old Canon FD lenses or newer EOS ones.  For what's it's worth, my old Vivitar 400mm f/6.3 lens covers about 1 degree field when coupled to the SDC-435.

It is possible to rig an adapter that fits inside to hold a 1.25" IR and light pollution filter. 

I'll also point out that there is an adapter that will let you mount board camera lenses (M12 mount??)  like you see on webcams.  It is just a metal disc with c-mount threads on the outside and a hole with the lens threads on the inside.  You won't find any board lenses in longer focal lengths, but if you are interested in wider field work it certainly is a option.  As with a webcam you focus these lenses by screwing in/out until best focus is achieved. 

If you have an interest in AllSky cameras you can get a board camera 2.1mm or wider (1.8mm) fisheye lens and mount it on the 435 (search eBay for 2.1mm lens). You should get almost the entire sky in the frame.  It should produce really interesting results during meteor showers or of the entire sky.  An acrylic dome may prevent dew.

I'm pretty sure there is an adapter out there that will connect the SDC-435 to most  OTAs, current brands and many of the popular older lenses.  I do have a number of medium format Kowa lenses that I don't think that I can find an adapter for but prowling around ebay for C-mount adapter should give plenty of options.  Once you find an adapter you can get older 35mm lenses that should work.

One of the more challenging features of using the camera is adjusting the settings in the following  eight areas.  Use the following as a starting point for your work.  See the SDC-435's documentation for further details.

• Set to manual when attached to optical tube

• Set to 1
• Set to Manual and select the shutter speed here 256x is 4.2 seconds.  You may need to adjust the shutter speed for each object you view for best results.  You will change this setting often!
  
• Set AGC to low or high (automatic gain control)
• Off (use the shutter above to set the shutter speed--1/120,000 to 8.4 seconds. 
  (Sutter speeds like x512 are approximately 512/60 or 8.5 seconds)
  

• ATW if stock IR filter is in place, Manual if you remove the IR filter and adjust for best results

• Samsung Super Dynamic Range OFF
  

• Off

• Noise reduction ON

• Color

• Under Monitor set LCD or User
• Adjust horizontal and/or vertical flip as needed
  

• Apogee 550 FL with .5x FR for FOV 46x61 arcminutes for 275mm @f/3
• 100 bmps stacked with Deep Sky Stacker
• Integration 512x (8.4 seconds)

Grabbing individual frames is a very easy way to record an image for later review or proof of object.

You will notice lens aberrations if you use a focal reducer and the spacing isn't correct.

When using long integration times it takes a while for the screen to update.  When slewing from one object to another bright areas in the first image take a while to disappear from the screen, sometimes obscuring the second object for a while.  It may take a minute or so for the second object to be fully revealed.  You erase the old image faster  by going into the menu and reducing the exposure time to about x16 and then stepping back up to the longer integration time, but it takes almost as long as letting it sit and the "dissove" to new image is kind of fun to watch.

Some times changing the shutter speed too quickly "locks" the camera.  Change the shutter speed to a much faster setting and slowly change the speed to slower usually corrects the problem.

Hot pixels will appear as the camera gets warmer or older.  Stacking software may think that they are stars and produce strange results.

Amp glow will slowly build as the night progresses.  You probably won't notice it on the computer screen, but if you record video, you'll probably have to deal with it.  Taking darks should help.

Unless your mount is much more solid than mine, pressing the controls on the camera will cause the image to shake for some time.

I've mentioned that the 6mm chip is pretty small.  Unless your GOTOs are spot on, you may have a bit of difficulty locating the DSO in the camera's field.  Swapping the camera for a parafocalized longer focal length eyepiece or using a flip mirror can really help locate and center the object. 

While on the subject of small chip, if your mount suffers from drift from poor alignment or periodic error, you'll notice the object wandering in the field.

Looking at the computer screen all night does kill night vision pretty well even when you cover it with rubylith.  Curb your excitement when you see a particularly difficult object like the Horse Head Nebula, the visual observers will want to see, but then complain about you destroying their night vision.