Looking at the night sky through a telescope is an amazing experience, and one that I've wanted to be able to record somehow. I've been wanting to try my hand at astrophotography for a while now, so I decided to see if I could make a camera adapter for my telescope (an old Meade 4500 Newtonian). I wanted something easy to make, and which used stuff I had laying around if possible.
I had the idea to use a cardboard tube to make an adapter from. The end result, after a bit of experimentation, is a surprisingly secure mount, made at zero cost to myself. I'm not expecting the mount to be long lasting, as it's quite common to get condensation while observing at night, which may cause problems with the cardboard. Still, even if I only get a handful of uses, I can soon knock up another mount in about 20 to 30 minutes.
It's important to note that this mount isn't really suitable or photographing anything but the moon, and other bright objects (planets like Venus and Jupiter may be bright enough). Photographing faint objects requires a computerised mount, a DSLR, and long exposure times. One last thing, this is my first Instructable, and while I thought I took enough photos during the process, I discovered a few things that I missed. Hopefully what photos I do have should be enough.
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Step 1: Materials and Tools
In order to build this mount you'll need the following materials:
- A cardboard tube that will fit over the telescope eyepiece mount (something like a kitchen wrap roll).
- Something to fit between the cardboard tube and the camera's lens, I used a scrap piece of PVC pipe
- Electrical tape
You'll also need a few tools:
- Sharp Knife
It's worth noting at this stage that my telescope takes 1.25" eyepieces. For telescopes that take 2" eyepieces a kitchen wrap tube won't be big enough. Perhaps a mailing tube could work, though.
Step 2: Making the Camera Mount
To mount the camera in the cardboard tube I needed something that would fit tightly around the camera's lens, and fit tightly in the tube. Rummaging around in the shed I found a short section of PVC pipe which fitted perfectly around the camera's lens. The section of lens the pipe fitted to was about 5mm long, so I cut the tube to that length.
The PVC pipe was slightly too small to fit tightly in the cardboard tube, so I wrapped it in electrical tape until it fit tightly. In order to prevent the cardboard tube from ripping, I then wrapped 3 or 4 turns of electrical tape around the top of the cardboard tube. Now that the camera mount is sorted out it's time to cut the tube to length, and finalise how the tube will be attached to the eyepiece mount.
Step 3: Mounting the Adaptor to the Telescope
In order to be able to take photos through the eyepiece the camera needs to be held so that its lens sits where your eye would while looking through the telescope. I found the easiest way to do this was to simply cut a vertical slit in the cardboard tube for the eyepiece thumb screw to fit into, and slide the tube over the eyepiece mount. One hassle I ran into was that the cardboard tube interfered with the rack for the focusing mechanism, so I cut a slot for this.
In order to get the correct distance for the camera to the eyepiece, I pointed the telescope at a tree, mounted the camera, and slid the tube up and down until the picture on the camera screen was right. Once I determined that I cut the tube to length, and made a pencil mark on the tube to line up with the eyepiece thumbscrew. At this stage I realised that my cardboard tube was a millimetre or so too big, so I used some of the off cuts of the cardboard tube to adjust the fit.
I used more electrical tape to secure the extra cardboard to the eyepiece mount. This shouldn't interfere with normal operation of the telescope, so it can be left on permanently. The cardboard mount can now simply be slid on and off as needed. I was fortunate to discover that if necessary I could still look through the eyepiece with the adaptor attached.
Step 4: Testing the Mount
Having got everything fitted nicely, I decided to test the mount. Due to an extended period of overcast weather, I haven't been able to test the mount at night. I did however take a test shot of the next door neighbour's conifer. The first photo is my compact camera at full zoom. The second is the shot through the telescope, showing an impressive amount of detail, including insects flying around the tree.
Because the slightest movement of the telescope results in massive movement on the camera, it is necessary to either use a remote shutter release (if you're lucky enough to have a camera with one), or to use the self timer on the shortest setting, to ensure that the telescope is not shaking when the photo is taken.
It's also worth noting that my telescope is a Newtonian design, so the eyepiece is more often than not pointing upwards. On a refractor or Schmidt-Cassegraine type telescope this mount probably will not work, as the camera would tend to fall out of the adaptor. Perhaps it would be possible to use rubber bands to secure the camera.
We had a clear night sooner than expected, so I took the opportunity to grab some photos. Unfortunately I didn't have a suitable eyepiece to get a photo of Venus or Jupiter, but I did manage a very nice shot of the half moon before retreating inside to escape the cold.