Betelgeuse - 50mm f/1.8 Camera lens

Tried a little experiment a few nights ago - I stuck a 50mm f/1.8 Canon FD lens onto the ST-8. This gives a FOV of 15.75 x 10.5 degrees. I then took a single 60sec exposure.

www.astroshot.com/Wide%20Angle/images/20...1-8%20Betelgeuse.jpg

Now, first off, I know there is a faint line through Betelgeuse - that's from removing the blooming. What's interesting to note however, is how deep the image is. I've checked the magnitude of some of the stars they go down to approx mag 11.5. Now, remember, 50mm is the focal length, therefore, the aperture of the lens is only 28mm.

Regards,

That's a good lens, right out to the corners. No coma visible.

There are many groups around the world using not much more than this kind of set-up to do nova patrols. I have seen camera platforms with five or six cameras arranged to cover the whole sky with one click. Keep the exposures short and you don't even need to track!

Phil.

Michael,

You have me jumping up and down with great interest. Did you use a Moog adapter to attach the lens to the ST-8? I was pushing the fellow to come out with such adapters and he sent me an email about a year ago telling me that he finally had something and he would update his website to indicate so.

If not from Moog, please let me know from where else, for I am also interested as well.

Anthony,

The adapter is made by SBIG. Note that it screws onto Canon FD lenses, not EOS. Adapters are also available for Pentax bayonet, Olympus, and Nikon. I tried one of my EOS lenses, but to no avail.

A couple of years ago, I was looking for a 50mm lens for my dslr. At the time, what I didn't realise was that there was the 50mm 1.8 MKI (FD lens for film cameras) and the 50mm 1.8 MKII (for dslr cameras). In my ignorance, I bought the former before realising that it didn't fit. When I did eventually get it to fit onto my dslr with an adapter I happened to have, it wouldn't come to focus for infinity, only for objects very near the lens. It was sitting up in the press unused ever since until I realised I could couple it onto the ST8. As it turns out, the lens is considered to be one of Canon's best and it only cost me about €30 on ebay. Nice change of luck!

Regards,

Michael,

Steven Moog (the fellow I originally referred to in my previous message) has adapters for both FD and EOS. There is a 2mm difference in the length of these lenses and, hence, for the need for the two adapters.

Of course, the EOS lenses are also wider.