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Forum: Photographic Technique
03-27-2018, 06:05 PM
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One thing you can do but it will change your magnification and the brightness of the image, is use a Barlow lens. The Barlow fits the 1 1/4" eyepiece holder, and will throw the point of focus out far enough for you to be able to focus at infinity with the camera. The Barlow lengthens the effective focal length of the telescope which may be a good thing if you're trying to take a photo of planets or small angular objects, but will go against you if you want wider coverage. A Barlow is an achromatic negative lens in a holder, similar to a focal length extender ("teleconverter") used with a camera but in a telescopic Barlow, the negative lens is located in a 1 1/4" tube which places it such that the focus point can be extended enough to reach a camera sensor attached to it with a T mount & 1 1/4" adapter.
Another alternative is to take your mirror mount out and shim the mirror, moving it closer to the eyepiece end of the scope. The downside of that is that you probably won't be able to focus on infinity objects with eyepieces after it's done (though you can get an eyepiece extension tube which will allow eyepieces to be used). Also, you will need to be familiar with aligning your scope (adjusting the mirror) since that will have to be done after adding any shims.
Some scopes use a very long rack and pinion focuser which allows both cameras and eyepieces to be used but it's a little uncommon with hobby scopes like yours. I would try the Barlow - you might need a little experimenting to get it to work, but it should allow a camera to be used. Be careful though since the camera will really be "hanging out there" and might get knocked off - also you'll probably need to hang some weights on the back end of the scope to counter-balance the camera since it will make the scope top heavy.
Oh, and there's one other method - eyepiece projection which uses a special adapter to hold an eyepiece and allow it to project an image into your camera. Again, it really cuts down on the image brightness and is best for photographing small objects like planets. There is an adapter formerly offered by Orion which does this for you.
Orion 8725 1.25in 2x Ultrascopic 3-Element Barlow | eBay
https://www.ebay.com/i/323156175565?chn=ps&dispItem=1 |
