Astrophotography Dobsonian Style

April is always a good month for Star Gazers. In April you still have cold fronts come through with subsiding air behind them caused by High pressure. High pressure creates clear sky's for viewing without the cold you get in winter . This year I had planned to learn Astrophotography and that would take place during April. After reading some on the subject ,I realized I had nothing in the way of necessary equipment to get started. My two telescopes had no way of providing a platform as neither one of them had tracking capabilities.

I had a few ideas how I would get started. One was to buy a DSLR camera like a Cannon Rebel  and an adapter to take a picture through my telescope.













the second route I could buy a digital camera adapter and use my digital camera by snapping shots through the lens's and hoping for the best!.

You could even buy an adapter and use your phone.



BUT WAIT!!!!!!!!!!!!!!
There was another way. Since I was away from the hobby for awhile things had changed. The new way to do astrophotography is with the use of CCD( charge-coupled device) or CMOS(Complementary Metal-Oxide Semiconductor) cameras. The CMOS camera will be the future so I went with it.

Here are some CCD and CMOS video cameras:



These camera's use image capture software then image processing software..
You can watch the video real time,save then stack the images and create a photo of the best frame.

I ordered a telescope with an equatorial mount and motor drive made for tracking. The scope had 130mm aperture and would go well with the 5mp high speed burst CMOS video camera I had bought. The Telescope arrived and the mount was awful the motor drive would not work. I had to return the telescope which led to an exchange only to find out the telescope I exchanged for would be on back order for awhile. So as things came together ,I had all the equipment necessary to start......EXCEPT A TELESCOPE!!!!
I solved that issue today,I finally got the money back from my purchase and bought another Telescope which should be here soon...
Of course it was bigger than I wanted and it cost more. Never fails huh!!
Soon I will filming the sky through this:


Now back to the title of the Blog...
Dobsonian style telescopes are not designed for astrphotography and are not recommended but I had no choice or I would miss April and my window to learn before the Summer sky full of yuk and humidity strikes.
Which made me have to improvise because information is hard to find .  

So I cheated.....LOL
I came up with a technique to use a Dobsonian reflector to make videos and use it for astrophotography.
I did this by using the finder scope to project when the image would come into the field of view so I could set the camera up. The first pass I'd focus. the second pass I would set the gain,exposure brightness and frames per second.
The third pass through I would record then save for processing later..
It's a trick but it works.




So you can do astrophotography with a dobsonian you just have to be creative.
This is the rig the pictures above were shot with.

114mm Dobsonian Reflector and CMOS rig:


April was not wasted I am learning more everyday about capturing the image then processing it.
When my new Telescope arrives my learning curve for the new mount wont be hindered by learning software
evolved with astrophotography. Maybe it was a good thing?

Another great blog Gomey!

So, it looks like you have to have all of that hooked up to your laptop while viewing to capture the footage in the software?

exactly,you use your finder scope to find what you want t ,then you can focus the camera by computer. So you watch what the scope see's real time..

"When my new Telescope arrives my learning curve for the new mount wont be hindered by learning software
evolved with astrophotography. Maybe it was a good thing?"

Sounds like it. One less thing to worry about when it arrives. Nice job gomey.

oooh Gomey, have you seen this?

"The asteroid will approach Earth from the direction of the sun and will become visible in the night sky after April 19. It is predicted to brighten to about magnitude 11, when it could be visible in small optical telescopes for one or two nights before it fades as the distance from Earth rapidly increases."

Asteroid to Fly Safely Past Earth on April 19

My scopes can see down to Magnitude 12.7 and 14.8...but that all depends on time of day and how high in the sky it appears. The closer to the horizon an object is the more atmosphere you have to look through limiting the Magnitude you can see down to...


now Jupiter is at approx Mag -2, as you go up in numbers the dimmer an object gets...11 is the Magnitude of many DSOs (deep Space objects)


But I will know where to look and yes.....I will be looking

gomexwx wrote:My scopes can see down to Magnitude 12.7 and 14.8...but that all depends on time of day and how high in the sky it appears. The closer to the horizon an object is the more atmosphere you have to look through limiting the Magnitude you can see down to...


now Jupiter is at approx Mag -2, as you go up in numbers the dimmer an object gets...11 is the Magnitude of many DSOs (deep Space objects)


But I will know where to look and yes.....I will be looking

Hey Gomey. Just for mental reference, what would be a Mag-0? Saturn? Mars? North Star?

Speaking of mental, when I typed 'ref', in the above, spellcheck recommended 'retardation'.

JRnOldsmar wrote:

Speaking of mental, when I typed 'ref', in the above, spellcheck recommended 'retardation'.

I am SO leaving that alone!!

The star Vega is Mag 0...Saturn is at +1,the sun -26,full moon -13...in most cites you cant see beyond mag 4 with the naked eye...the big dipper stars are at 2

gomexwx wrote:The star Vega is Mag 0...Saturn is at +1,the sun -26,full moon -13...in most cites you cant see beyond mag 4 with the naked eye...the big dipper stars are at 2

Perfect reference points, Gomey. Thanks. And now I'm on my laptop, so no spelling suggestions this time around.

San....no luck on the asteroid...I tried

Damn....bummer Gomey!