DSLR through my Skywatcher 200 (Dobsonian)

[Phil73805]

Hi All, after years of pressing my smartphone camera to the eyepiece and taking pictures of the moon I tried attaching my DSLR (An old entry level Canon) to my Skywatcher 200 (1200mm focal length) on a dobsonian mount. I could not achieve focus whichever way I went. However, it seemed that what was needed was to be able to move in more than was available. What am I doing wrong? How can I get the camera to focus?

[ronin]

Doing nothing wrong. The scope is set up for visual and you are attaching a DSLR, the camera sensor is sat in the body of the DSLR so the DSLR body needs to move inwards more to get the sensor at the focal plane.

Solution is you attack the scope and move the mirror upward by about 20mm. This pushes the focal plane out by the same and so now (hopefully) the focal plane and the SLR sensor coincide.

Catch is that then an eyepiece is in the wrong place so you need a short extension tube for visual use.

Oh yes, after moving the mirror you will need to recollimate the whole thing.

[Pankaj]

I have a 10" solid tube skywatcher dobson. With it I am able to achieve focus. Try attaching the camera directly in the 2" focuser...without using the 1.25" adaptor. 

Alternatively, if you have to use the camera with the 1.25" adaptor, then attach a barlow directly in the T Ring and insert in the focuser.

Either ways, you will get super pics of the moon. This one I took through mine.

Regards

Pankaj

[Phil73805]

17 minutes ago, ronin said:

Doing nothing wrong. The scope is set up for visual and you are attaching a DSLR, the camera sensor is sat in the body of the DSLR so the DSLR body needs to move inwards more to get the sensor at the focal plane.

Solution is you attack the scope and move the mirror upward by about 20mm. This pushes the focal plane out by the same and so now (hopefully) the focal plane and the SLR sensor coincide.

Catch is that then an eyepiece is in the wrong place so you need a short extension tube for visual use.

Oh yes, after moving the mirror you will need to recollimate the whole thing.

Ronin, I'm going to have nightmares just thinking about that!

Pankaj, I'll give that a try and report back, thanks

 

[Cornelius Varley]

38 minutes ago, Phil73805 said:

Hi All, after years of pressing my smartphone camera to the eyepiece and taking pictures of the moon I tried attaching my DSLR (An old entry level Canon) to my Skywatcher 200 (1200mm focal length) on a dobsonian mount. I could not achieve focus whichever way I went. However, it seemed that what was needed was to be able to move in more than was available. What am I doing wrong? How can I get the camera to focus?

Achieving focus will depend on how you have attached the camera to the focuser. The current SW200 has a 2"/1.25" focuser which has a direct SLR connection. This is shown in the video

 

[tooth_dr]

As stated above you should be able to get it to work.  Ifyou can post a picture of your focuser and attachments it will be easier to see what’s happening. I I’ve tried this successfully with a SW 200 but it has a focal length of 1000mm at F5 not like yours at 1200mm so it ‘might’ be different. 

Here is what will be needed to get you close enough to the mirror to focus. The T adapter screws onto the adapter that comes with the scope. This slips into the 2” focuser opening. You should have about 10mm to spare.  These are photos I took of my own camera and adapter  

 

[knobby]

+1 for a Barlow.