Capturing Your Target
In the last postÂ I went through the process of modifing your web cam and setting up your laptop with the programs necessary to use a webcam for astrophotography. In this post I will go through the set up and use of one of these programs, Sharpcap.
Sharpcap is the program of choice for capturing webcam video of your targets. This program allows you to easily change the key settings of your webcam. This is a good thing as each viewing session will require different settings based on the viewing conditions and target you are trying to capture.
The first thing you need to do is identify the target you want to capture, the Moon and Jupiter would be to easy targets to work with as they are easily found in the sky. What I would recommend if try and find your target with a low mm eyepiece maybe a 6mm get it centered before swapping in the modified webcam.
Start up Sharpcap.
Depending on your scope specs you might want to attach a barlow as well. I found with my Skywatcher 150p i got better results when using a 2x barlow. Its up to you really, but give it a try with and without the barlow.
For this tutorial I will use Jupiter as my target, So after lining up Jupiter in my 6mm eyepiece and then swappingÂ it withÂ my modified webcam, we should see a view of it on screen in Sharpcap. If you do not, have a play with the focus on your telescope, I had this problem and it took me a while to realise my focus was way out. By playing with it the image came into view.
Spend some time here to try and get the focus as good as you can, this can be very difficult if it is a windy night or a lot of cloud as Jupiter will appear all wavey. One tip is to move to a star and focus on this then move back to Jupiter.
So now we should have a screen something like this.
As I mentioned earlier you should should spend some time getting as good as an image at this point, initally play with the focuser on your telescope, try to get aÂ viewÂ of the cloud bands, You will want to play with the settings on the right hand side of the screen as well, in particular the exposure.Â If you can see some of the moons of Jupiter in the image set the exposure so theyÂ just fall our out of the image.
Of course you can play this and sacrifice some detail on the planet to capture the moons its completely up to you.
Once you are happy with the focus and exposure there are a few other settings you should look at. The Colour / Space Compression should be set to RGB24. Depending on your viewing conditions the frames per second should be ideally set to 10. Set the resolution as high as you can.
|Â Â Â Â Â Â Â Â Â yyyyyyÂ||Settings I used for this CaptureFrame Divisor=1
Frame Rate (fps)=10.00
Colour Space / Compression=RGB24
Refocus if necessary.
You are now ready to start your capture, Press the Start Capture button in the top left of the screen.
You will then get asked how long a capture you want, I usually try to get about 4 mins but anything over a minute will do the job.
Press Start Capture.
Sharpcap will start recording.
Â Step 5
When Sharpcap is finished you will have a video file on your desktop. This is the file we will import into our stacking program in the next post.
Below is the capture I got and the one I will be working with.
In the next post we will import this into Registax for stacking.