Out of focus picture with EP projection method

[syedjz]

I am trying to take pictures of Jupiter using Eyepiece projection adapter method with my skywatcher 10" Dobsonian scope with canon 600d camera. eyepiece I have tried are 10mm and 25mm

I am getting following image for jupiter with various settings of focuser and the variable eyepiece adapter.

Variable adapter is as follows.

I have tried many sort of focusing, in out but no use. But with MOON everything works works gr8.

[ronin]

At a guess, really need more information, you still have autofocus on and Jupiter is too small for the camera to recognise as an object, it is a small brightish dot in a sea of black, the camera will not know what to do. So then the camera goes hunting for something to use as an object and starts to see the secondary and the spider so it attempts to bring that into focus. Presently looks like it cannot get to a decent focus for the secondary but that will not stop the camera attempting to do so.

At a guess the moon is big enough for the AF to identify as an object.

[Cornelius Varley]

If ep projection works when imaging the moon there shouldn't be a problem with Jupiter, the main problem is getting the telescope to focus with the eyepiece in the adapter tube . The camera should then see a focused image on the screen.  Adjusting the distance between the sensor and eyepiece affects the overall magnification of the image.

[Stargazer33]

Looks like the scope isn't focused!

[Alien 13]

When using an adaptor as shown you are moving the eyepiece at least an inch further away from the focusser (it does with my orion one) so I would be supprised if you had enough inward focusser travel to work It should however be fine to use with a barlow instead of the eyepiece.

Alan

[ahernep]

Hi Syediz,

Did you ever manage to get this working? I'm having similar issues when I tried my first effort of AP last night with Saturn. I admit I did not try the eyepiece with the adapter for the moon, just screwed the barlow lens into the nosepiece of the adapter was sufficient for that. I could use the same setup for Saturn but the image was obviously quite small so I tried with the 20mm eyepiece. Were you at the extreme of outward movement when you took that picture above? If so it's the same issue I'm having, it's coming into focus nicely as I move out then I hit the limit. It seems like I would need another 2" extension but that seems excessive when already using the Orion adapter. The camera is already quite far away as it is...

So from the end of the nosepiece to the CCD (around where the strap attaches) can be between 145mm - 180mm. Does it make sense that I might still need to add another 2 inches to achieve focus?

Also, just as an aside, if this is the formula for calculating magnification over primes focus:

Magnification over prime focus set up (Mopf)
Mopf= (Depccd-FLep)/FLep
Mopf= (100mm-20mm)/20mm = 4
The image is 4 times larger than that of a prime focus setup.

Where Depccd is the distance from the eyepiece lens to the CCD then is it the very top lens in the eyepiece we are talking about, so around here:

Does any of this make a lick of sense??

Thanks,
Peter.

 

[Alien 13]

With a frac you will need another inch or two of spacers with the orion adaptor, this is mine.

Alan

[ahernep]

Thanks Alan,

That's what I'm beginning to believe though it a reflector I have. So, is the extension above the piece between the photo adapter and the Orion adapter thus moving the eyepiece further out from the scope? For some reason I had it in my head that I wanted to get the eyepiece closer to the scope, in this case I might try taking the lens out of my barlow and using that as a small 1.5" or so extension. Might just do the trick...

Cheers,
Peter.

[Alien 13]

Thanks Alan,

That's what I'm beginning to believe though it a reflector I have. So, is the extension above the piece between the photo adapter and the Orion adapter thus moving the eyepiece further out from the scope? For some reason I had it in my head that I wanted to get the eyepiece closer to the scope, in this case I might try taking the lens out of my barlow and using that as a small 1.5" or so extension. Might just do the trick...

Cheers,

Peter.

If its a reflector you need to get the distance closer which would require major surgery or stick with a barlow lens in the adapter you can still get 2-3 times with a x2

Alan