I recently acquired the new 100-400 II lens for my Canon 6D DSLR, and wanted to see how it worked as an alternative to my motor-driven 600mm refractor telescope. So I bought a dovetail bar, mounted the lens to it, and slid it into the mount in place of the telescope—you can see a pic of the configuration below. I transferred my green laser pointer to help with aiming via a hot shoe adapter, and voila!
Last night I took the first photos using the setup and captured the Orion Nebula, Horsehead Nebula, and Pleiades Cluster. I took a series of shots that need to be stacked & processed; and as you might expect, the images are somewhat wide-field. While waiting to stack the series, I processed a couple of single-frames in PS CS6. I’m pleased with the quality of these, and am anxious to see if the stacked ones look any better. FWIW, the Orion/Horsehead image was taken at 400mm, ISO 1600, f/5.6 with a 120 sec. exposure; Pleiades was taken at 400mm, ISO 3200, f/5.6 with a 120 sec. exposure.
This isn’t an endorsement of the telephoto over the telescope, but it’s nice to have another tool in the arsenal. Curiously, the lens cost about twice what the telescope did.
Very cool.
When the milky way core rises should be another fun opportunity.
The coma is well controlled, I only see a little on the big peripheral stars.
Tom_W wrote:
120 seconds - tracking mount, I presume?
I'm not much of an astrophotographer so I have to ask.
Yep thus the telescope mount. Tracking tends to be accurate for a 'short' period of time for this kind of stuff then you stack multiple shots for better resolution/lower noise.
Great test, wonder how it compares to the 400/5.6L
dwweiche wrote:
I'd also like to hear the story and setup behind your avatar, assuming that is also a shot of yours.
My avatar is the solar eclipse of May 20, 2012. The image was taken with my Olympus E-620 & 40-150mm lens off Hwy. 88 between Stockton, CA and Lake Tahoe about 6:30pm PDT. Specs are: 268mm (equiv.), f/14, ISO 100, 1/4000 sec.
cameron12x wrote:
You ought to try to image it. Maybe with a shorter focal length, but faster glass to get the full tail.
You'll probably need to stack images to get the best results. You should be able to do at least as well as the image below.
I did capture Lovejoy, but not with the new lens. I used the 6D on my telescope. But you're right, I should try with the new lens. Meanwhile, here's the image I got---again, it's a single frame. I've had a great deal of trouble processing the comet with my stacking software, DSS.
That's still a very nice image... thanks again for sharing.
I'm going to try to image the comet with my 6D and a couple of lenses, but the weather in central Ohio hasn't been good enough recently.
As for processing Lovejoy, I'd approach it this way. The coma of the comet is very bright, so you probably only need one good exposure for it (underexpose it, relative to the tail). I'd then capture multiple images, exposing for the very dim tail (Lovejoy's tail is very faint) and do some post processing.
I'd first crop all of the tail images, removing the section where the coma begins. Then I'd use DSS (or any other stacking software) to additively build up signal and improve the S/N ratio of the tail section. I'd then layer and paste the resulting stacked image into the image where you originally exposed for the coma.
Make sense? I think that could work well. Good luck!
