D3000 PLUS T-ring & Adapter

Bazp

Hi
Im new to Boards so apologies firstly if this isn't the right place for me to post this.

I have a Celestron Telescope AstroMaster130EQ-MD with a T-Ring , a T-Adapter and a Nikon DSLR D3000.

I have attached all the hardware up fine, When I focus on the moon now with a standard lenses its perfect , until I switch to my Nikon D3000 through the telescope all im getting is fuzz, no focus. Ive googled it and put the camera to Auto but still all I see through the camera is a blur.

Can you help or advise thanks

Kersh

If you cant achieve focus at all, when racked in and out my bet would be that, as with most standard reflectors, with all of the attachments, and the depth of the camera body, you dont have enough "in-focus" to achieve focus.

Thats why some manufacturers have shortened their tubes and tagged their scopes "for astrophotography" or they have added a "direct DSLR attachment" to the focuser, to eliminate the need for the T-Adaptor (basically the T-Ring screws to the focus tube)

You could move the primary up the tube as far as it will go on its adjusters, and that might help, as it will push the focal point back out of the tube, but success here will depend on how close you are to correct focus.
Re-collimation will be necessary though.

Bazp

Thanks for the reply. Unfortunately I'm quite new to this so may need you to dumb it down a tad. Attached is what I have.

Kersh

Ok, firstly, does your T-adaptor have thumbscrews? That object inside my orange circle in the pic looks like a barlow. If it is, then that could be the problem. If it isnt a barlow . .

.....I have attached a rough pic edit (which wont rotate the right way up for me!) trying to explain it a bit more.

The area in the orange circle is essentially "dead space" that is pushing your camera too far outside the telescope itself.

A standard eyepiece, like what you use, probably focuses somewhere near the blue line.

The sensor on your camera is out where the red line is.

Your focuser wont go "in" anymore, in order to get the red line to where the blue line is (the focal point).

Your only solution is to either somehow get rid of the deadspace inside the orange circle, or ....

...down where the green arrows are, there is 3 adjusters for aligning the primary mirror. You can screw all of these in as far as they can go, which pushes the primary mirror up towards the focuser (do them 1 at a time, half turn at a time) - However, you will have to re-align the primary mirror with the secondary mirror if you do this.

I suspect your camera is too far out for this method to be successful (it will only give you about 10-15mm).

Bazp

Inside your orange circle is just part of the T-adapter, not a Barlow that I am aware of. I pulled it out slightly just for the picture. When using it at first this was pushed the whole way in. Basically I screwed my 55-200mm lense from camera, attached black t-ring and then screwed in the t-adapter which then slides straight into the scope where the lense goes. Supposedly this was all explained when this was bought for me and was supposedly plug and play.

Kersh

T-Rings & T-adaptors are a bit hit and miss depending what scope they are used on.

For instance, I have a 10" Schmidt-Newtonian, that wont focus a Canon DSLR, I just cant get in close enough. All my other scopes will focus it.

Checkout this thread -http://stargazerslounge.com/topic/126763-dslr-help/

Bazp

Thanks Kersh, you have been more than helpful. I will try a few things and fingers crossed it works.

Stargate

Kersh wrote: »

Ok, firstly, does your T-adaptor have thumbscrews? That object inside my orange circle in the pic looks like a barlow. If it is, then that could be the problem. If it isnt a barlow . .

.....I have attached a rough pic edit (which wont rotate the right way up for me!) trying to explain it a bit more.

The area in the orange circle is essentially "dead space" that is pushing your camera too far outside the telescope itself.

A standard eyepiece, like what you use, probably focuses somewhere near the blue line.

The sensor on your camera is out where the red line is.

Your focuser wont go "in" anymore, in order to get the red line to where the blue line is (the focal point).

Your only solution is to either somehow get rid of the deadspace inside the orange circle, or ....

...down where the green arrows are, there is 3 adjusters for aligning the primary mirror. You can screw all of these in as far as they can go, which pushes the primary mirror up towards the focuser (do them 1 at a time, half turn at a time) - However, you will have to re-align the primary mirror with the secondary mirror if you do this.

I suspect your camera is too far out for this method to be successful (it will only give you about 10-15mm).

Excellent explanation Kersh !

ZeRoY

I had this exact scope and couldnt get prime focus either with a Canon 1100D - with the already short focal length moving the mirror isnt really an option. Its really only designed to do afocal photo (using eyepiece) or visual observing.

peter1892

ZeRoY wrote: »

I had this exact scope and couldnt get prime focus either with a Canon 1100D - with the already short focal length moving the mirror isnt really an option. Its really only designed to do afocal photo (using eyepiece) or visual observing.

Interesting...I have the same scope myself but haven't had much luck using it for imaging. The moon is OK, anything else is very difficult to do.

Also the weight of my camera is a problem as when I do get it to focus it doesn't hold steady for long (I've tied various tripod acrobatics but to no avail!).