Hi all, Given how well this one shot color camera did on M92, I thought I'd give it a go on M13 again. I previously shot it with a mono camera and LRGB filters. I have about 3 hours of 90s exposures on this version of M13. The camera, an ASI2600MC OSC. The scope is a TEC180FL with an astro-physics quad telecompressor/reducer which gave me a focal length of 907mm and a focal ration of F4.9 which is nice for imaging. I did the imaging unguided on an astro-physics 1100gto mount with absolute encoders.
M13 has been one of my favorite visual objects over the years. M13 is about 25,000 light years from us and has about 145 light years across.
At magnitude 5.8 it can be seen naked eye as a puff of light in dark sky locations.
Terri
@terri Nice image, Terri!! I shot M13 last night, too (as well as M3 again and M101), and I'm just struggling over processing it, so I'm not even going to post it since yours is so pretty. Great work!
Greg
@terri Nice image, Terri!! I shot M13 last night, too (as well as M3 again and M101), and I'm just struggling over processing it, so I'm not even going to post it since yours is so pretty. Great work!
Greg
Thank you Greg, I'm blushing... I find your images very good so I hope you're just joking!!
Terri
@terri Well, as soon as I finish I'll post it if you promise not to laugh. (Kidding -- you're always wonderful with your feedback!) I ran into a strange problem in PI where masks I created didn't have any effect, nor did the tab turn brown on the masked image. Very weird. I just saved the project, closed PI, and I'm going to try it again. We'll see...
Update...didn't work on one particular image. Masks seems to work on the others. Hmmm...have to investigate a bit more.
Greg
@terri Well, as soon as I finish I'll post it if you promise not to laugh. (Kidding -- you're always wonderful with your feedback!) I ran into a strange problem in PI where masks I created didn't have any effect, nor did the tab turn brown on the masked image. Very weird. I just saved the project, closed PI, and I'm going to try it again. We'll see...
Update...didn't work on one particular image. Masks seems to work on the others. Hmmm...have to investigate a bit more.
Greg
Well I could promise if that's what you want, but I think you know I wouldn't.
Terri
Well, here's my rendition of M13. (Figured out the PI problem in case anyone else has the same problem. Somehow, I toggled 'off' the Enable Mask on the image I was trying to mask. Just had to right click and Enable Mask again.)
I think I'm still over-exposing the core stars either in capture or processing, unless my scope can't capture them at finer detail. I was going to use less exposure time (120s) but I thought since I had a filter in place, I'd opt for just a bit longer. I'll try again using shorter exposures.
Askar 107PHQ
ASI2600MC Pro (OSC camera)
ZWO AM5 mount with guiding via ASIAir Plus using an ASI178mm mini and a 60mm F4 guide scope
Light Frames [Total Exposure 2:30] - Antlia Triband Ultra RGB filter -- 180s x 50 frames
All light frames calibrated with dark, flat, and bias frames
Pre- and post-processed in PixInsight
Additional post-processing in Photoshop for exposure adjustments and generation of jpeg
@greg-erianne Hi Greg, very nice and well done! Globulars take some time to get used to processing them. This is far better than my first M13. The copter is very clear!
Terri
@terri Thanks, Terri. That was so strange you mention about the copter! When I first saw it, I thought I introduced an artifact!
Thanks again for the globular cluster tips! I'm very grateful. (Although I have a lot to practice...)
Greg
@greg-erianne The other thing is that globulars are sensitive to exposure. So you want to keep the core stars from being saturated during capture. I used 90seconds for M13. I started out with 2 minutes, but with the moonlight that seemed to push some stars over the edge in the core so I backed off to 90s.
Terri
@terri Yeah, it was tough checking with the jpegs that come up on my phone. I checked and it looked like my exposures were not blowing out the core when I zoomed in on the pic, so I went with it. I'll have to keep it in mind next time I image a globular cluster.
Thanks, Terri!
Greg
