First Attempt @ Imaging Jupiter

[gsfergy]

Equipment: Celestron Nexstar 8SE, Nikon D5200 DSLR

Problem: Using my standard eye-piece and align mode, I have Jupiter tracked and in focus. I switch to my T-ring/DSLR and nothing! The closest I've come here is a "O" shaped light ring which I believe would be Jupiter.

My Troubleshooting: If I put my eye-piece back in, and fiddle with the focus knob I can duplicate what my DSLR was imaging.

Thoughts?

[romx]

it is probably a case of adjusting focus on your scope, each lens or piece of equipment needs diferent focus so it is probably out of focus when you switch

[romx]

the position may have also moved a little due to angles on what the lens/camera can see but im almost positive the main issue is scope focus

[gsfergy]

it's a focus issue, played with the focus dial on the scope and started to have success -- camera settings also seem to be the culprit...

it's gonna be quite the learning curve

[knobby]

As you say, its focus... The donut shape is what you get when you're near focus but not quite there. Slowly tweak to make the donut smaller til you achieve focus. Stick at it, its amazing when you get it right

[gsfergy]

Thanks for the replies. I am frustrated that it's not as easy as I had thought. But nothing is easy with this amateur astronomer stuff

I guess there are no other "focusing" tools or tricks I can try? Basically, once I attach the camera I'm stuck using the scope's focus knob?

[romx]

Thanks for the replies. I am frustrated that it's not as easy as I had thought. But nothing is easy with this amateur astronomer stuff

I guess there are no other "focusing" tools or tricks I can try? Basically, once I attach the camera I'm stuck using the scope's focus knob?

Yep thats about the size of it, it should focus in quite easily once you change over though

[PeterCPC]

You can solve this by using a Bahtinov mask. You focus on a bright star first then swing round to your imaging target BUT leave the focuser alone.

Peter

[Stargazer33]

It's because the cameras image plane is further back than the eyepieces focus position. You would get the same effect if you put an extension piece (not a barlow, just a hollow tube) between your scope and your eyepiece. You are increasing the focal length so you have to re-focus. You could always measure the difference in focal length between your eyepiece and camera and add an extension tube together with a parfocal ring set to that distance. You should be able to focus with your eyepiece and then swap to the camera and you would be pretty close to focus straight off.

[gsfergy]

It's because the cameras image plane is further back than the eyepieces focus position. You would get the same effect if you put an extension piece (not a barlow, just a hollow tube) between your scope and your eyepiece. You are increasing the focal length so you have to re-focus. You could always measure the difference in focal length between your eyepiece and camera and add an extension tube together with a parfocal ring set to that distance. You should be able to focus with your eyepiece and then swap to the camera and you would be pretty close to focus straight off.

Thanks southern! I just googled what you were saying and I found a nice little "how-to" video on YouTube

[gsfergy]

You can solve this by using a Bahtinov mask. You focus on a bright star first then swing round to your imaging target BUT leave the focuser alone.

Peter

Thx Peter. I'm going to try this tonight!!! *skies permitting of course*

[stufft]

Thanks southern! I just googled what you were saying and I found a nice little "how-to" video on YouTube

share the video

[Pete Presland]

Thanks southern! I just googled what you were saying and I found a nice little "how-to" video on YouTube

that is pretty much what i have done, find an eyepiece/barlow combo that is close to your imaging equipment focus point and use that.

[soundwave]

share the video

I don't know if this is the specific video gsfergy was talking about, but it also explains the focus issue and suggests to use a barlow.

This should jump directly to the part about the focus:

http://youtu.be/cYTmsfpL0M4?t=2m35s

[soundwave]

And a video by Celestron for a SCT (they use a t-adapter there, but don't mention any focal problems that might happen)

http://youtu.be/EJZxI6fD0wE?t=5m42s

[ardbeg74]

On the Bahtinov, it works on jupiters moons too. Though im using the ASI when i do it, I see no reason it would't work with a DSLR, couple of sec exposure, max iso ought to do it. 

Once you find where the focus is, a pencil line on the focuser tube will get you close next time. 

Cheers

Mark