Last night was clear so I set up the telescope on the deck and did a little star gazing. I also took this photo of Saturn. It's not as fully magnified as previous shots but that's because I was shooting with just the D70 hooked to the telescope without any of the telescope lenses.

Actually, in this case it was the D70 and a Nikon 1.4 Teleconverter. I'd got the idea of adding the teleconverter from a post by Colin, who has been shooting Saturn lately.

A teleconverter (TC) adds magnification and is placed between the lens and camera body. A 1.4 teleconverter turns a 200mm into a 280mm and a 1000mm telescope "lens" into 1400mm. Of course nothing is free, the extra magnification comes at the expense of losing an f-stop (i.e. less light gets through). So the f/2.8 200mm lens becomes an f/4 280mm lens and the f/8 1000mm telescope comes out as an f/11.7 1400mm.

Nikon, surely in a move to protect us from ourselves, makes their new TC so it only fits certain lenses. I couldn't get the Nikon t-mount telescope adaptor to snap into the TC and ended up snipping away extra metal on the t-mount (always jerry-rig the least expensive part) to adapt it. The restriction is kind of silly since the TC is a passive device: some glass and electrical thru contacts.

Before I tried out the teleconverter combo at night I decided to verify everything while it was still light out. Being a wimp I left the telescope inside and pointed it out the back, through the sliding glass window...yeah, even more glass in the path. Our house is pretty much surrounded by trees but all we need is a small opening and, as you will see, light will find a way.

After trying the telescope with and without the teleconverter I thought it would be interesting to compare the results to other zoom levels and lenses with the D70 and my old Canon A70 P&S. Below is the same scene with each lens. I'm not quite sure where the distant, white house is (shown in later photos) but I suspect that it is at least three or four miles away. The big white pine is about eighty feet away.

p.s. the first two were taken this morning, thus the difference in light...
p.p.s. if the pics are jammed together reload the page, I added a new style.

The last three photos are cropped out sections from full sized images. The originals were 3000x2000 pixels. I grabbed a 900x600 pixel area from each of the bottom three photos and resized to 400x267. This way we can see the details and compare magnification.

The two photos taken through the telescope were both taken with a 1/100 second exposure. The last photo is clearly dimmer from the addition of teleconverter (it's more obvious on the full image).

• info
  • 4 comments
  • permanent link
  • email this