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domus
2011-May-04, 12:13 PM
My first try at dangling the SLR from my very small scope, and first post here.

Before moving on to the bigger stuff, I thought I'd play around with my ancient little scope and see if I can get the SLR to photograph a decent picture through it.

It's a very small refractor; D=50mm, F=600mm. I got a T-2 adapter and a .965" camera adapter that takes eyepieces.

All fits well, but I can't get any sort of sharp image (not even near), with or without eyepieces.

Since I'm an utter newbie at this, I'm sure I'm overlooking something quite basic, so if anyone can point me in any kind of direction, I'd be very grateful.

Added later on, since I can't find the option to delete messages: removed the eyepiece holder and focus returned. Apparently distance too long to reach focus with holder in place.


Cheers,
Dom

RickJ
2011-May-04, 06:45 PM
Many small scopes made for visual use can't reach focus with cameras. Usually reflectors can't focus in far enough and refractors can't focus out far enough. The former is cured by moving the mirror forward, the latter by adding extension tubes.

Before you do anything you need to find where focus is. Remove the camera and point the scope at the moon. Now using a piece of paper as a view screen find where the paper needs to be in relation to the eyepiece and focuser's position for a clear image.

When using eyepiece projection, sounds like this is what you are doing, the distance from the eyepiece to the film controls the power. It can quickly get too high, far beyond what a small scope can handle. First find focus without the eyepiece (prime focus). Often the eyepieces that come with 0.965 size focuser scopes are of a design that can't project an image to film but require a lens (or your eye's lens) to create a focus. Even if it is a type (Ramsden usually) that can these project a very curved image unsuited to flat film (your retina is curved, film isn't). Better to use a barlow to project to film. It usually has less distortions and curvature. Again, like in any projector, the further you project the larger the image scale so by adding distance you can increase the power.

Anyway, once you can see a focused image on the white paper screen you will know where the camera's sensor must be and adjust accordingly.

Also search out a local astronomy club. There you can get the hands on help beginners greatly need.

Rick

domus
2011-May-06, 09:50 PM
RickJ,

Many many thanks for your patience and very complete reply! I'll follow your directions.

Cheers,
Dom