Improving photography

[nanoman]

Dear All

I managed to see the rings of Saturn through the eyepieces of my nexstar last night. Though i could get this in sharp focus (despite it being very small) through the eyepiece, on switching to the SLR the image was both far from centre and very very blurred. this could, of course, be adjusted through the telecope focus but i found this to be an almost impossible task (lying on the floor, tweaking the focus while squinting at a tiny white dot in the SLR viewfinder). Is there a better way to capture photographs? I am attaching the best shot i was able to acheive - a million miles away from some that i have seen posted. I could also (obviously) do with more magnification but think this could only be achieved with either a new telecope or by attaching a lens between camera body and the telecope (not sure if this is possible). Once again, any suggestions hugely welcome.

JJD

[nanoman]

sorry - i`ll try to attach this properly now

(click to enlarge)

[winfij]

Hi JJD,

What scope are you using, also what is the (D)SLR?

How are you attaching the SLR to the scope - are you using a push-fit nosepiece or a t-adapter, or something else?

The more detailed info you can supply, the better the advice we can offer.

Cheers,

John

[nanoman]

Dear john

Many thanks.

Its a nexstar 4SE with a Canon 30D SLR attached to the rear port of the telecope through a t mount adaptor.

JJD

[winfij]

Hmm, that makes things a little tricky then.

Normally to increase the image scale you would place a barlow lens between the camera and the scope, but you can't easily do that with a t-mount.

You could possibly fit a 1.25" nose piece to the t-mount and then insert that into a barlow - the vignetting which will result shouldn't matter for planetary imaging since the target will only fill the center of the chip anyway.

However, for planetary imaging dslr's aren't really the best choice anyway - you'd be better off using a webcam, since focusing is easier with the live display on the computer monitor and the hundreds/thousands of frames you can quickly capture can more easily be processed to use just those in the best moments of seeing.

Registax and K3ccd are popular tools for this purpose.

Hope that helps.

John

[EA2007]

Hello again Nanoman,

I had exactly the same probem the other night aswell. Don't worry, its not you, its the scope. As I mentioned in the other post, its very prone to vibration and focusing via an SLR viewfinder is near impossible.

As 'Winfij' said, attaching a 2x or even 3x barlow lens would be tricky given your use of the t-mount. I would only purchase a barlow if I were doing planetary work, due to the small field of view that the maksutov provides then most DSO's wouldn't appreciate it. I tried to image M44 the other night aswell and well I only got a very small portion of it (I know its a big wide field object anyway) and virtually no background stars due to my scope giving up tracking after 50 seconds.

I am however moving onto another scope (and better mount) sometime in the near future.

If its clear tonight (please please) then I shall have another go at getting some images but Saturn just appears small and out of focus when using an SLR. Even if it is focused the wobble from my SLR shutter destroys the image anyway. 1.5sec.max exposure (for Saturn) is near enough the same as the 1sec 'shakedown' time, ah well!

[Cloudwatcher]

I have not owned the make of scope you have I'm afraid but I have had some success with the 127 Mak using both a Barlow lens and adaptors that carry eye pieces. Mind you with a DLSR attached to the scope I have to twiddle the focus knob an enormous number of times to achieve correct focus after having previously used an eye piece and diagonal for visual observing. Anyhow, I'm attaching some piccys of the kit used which may help in your quest.

As far as having to adopt strange postures to look through the viewfinder,have you tried using your camera with the diagonal in place? It saves a lot of backache and grubby knees! The nose pieces of the adaptors shown unscrew and will fit the T-ring of your camera and into the 1 1/4" diagonal for prime focus imaging and or a Barlow lens can be used in the same way. The alternative is to purchase an angle finder like the one shown to slip onto the Camera.

Hope this is of some help and will be interested to hear how you get on.

Cheers

CW

(click as usual)

[nanoman]

Many thanks for all those replies - much appreciated. I have opted to spend a little more money and add a Nexstar CCD to the configuration which should give me live imaging and capture. The suggestion seems to be that only a good SLR will capture deep sky objects/systems so i may well go for one of those "diagonal" adaptors also.

JJD