I have a Baader U Venus filter which covers 320nm to 380nm and did 12h of UV channel in 10min subs on eta Saturday and Sunday night. Same framing as my IR channel so I could do a bicolor with UV mapped to blue and IR mapped to red. UV imaging is hard yakka so I'll never complain about Sii anymore. The moon was up and the contrast was a little better when it went lower but it still doesn't seem to be affected by skyglow too much, same as IR which is great for me in my "Las Vegas" backyard.
Here's the blend result UV UVIR (50%) UV and the separate channels IR, UV, then blend. There's a bit of info about the filter and UV imaging here.
Marc,
I’m impressed if you can achieve that.....
With spectroscopy (ATIK314L) I was struggling to get a good signal below 3700A.
I did 10min subs @-20c, 12.6h in total. I dithered each frame. Drizzle combined in pixinsight then binned back 2x2 to native res. It is still a little noisy even after that much integration. Scope is the FSQ106N. I don't know if it having a fluorite element helps with sensitivity. I want to try with the CN-212 next as there is no glass in the imaging train.
Thanks Greg. Yeah I have all those filters so it's fun to try different parts of the spectrum. I also have a H beta that's close to Oiii. Might see if I can use this as a green channel maybe.
Fascinating Marc!
My most recent image of Eta Carina was taken without a UV/IR filter, only whatever the bayer matrix blocks so I do wonder how much signal from these frequencies bleeds into the data. Given the amount of exposure time that you've had to put in so far I don't think it would be much compared to the straight RGB component.
Fascinating Marc!
My most recent image of Eta Carina was taken without a UV/IR filter, only whatever the bayer matrix blocks so I do wonder how much signal from these frequencies bleeds into the data. Given the amount of exposure time that you've had to put in so far I don't think it would be much compared to the straight RGB component.
There seems to be a fair bit of bloating on some of the stars. I did an hour or so on M42 in UV and there are some halos and internal reflections on the brightest blue star in the field to the right of the main nebula. I've also noticed some stars almost invisible in IR flaring like a light house in UV and vice versa. I guess we don't notice that doing RGB because the Lum filters are already UV/IR cut. As you pointed out all you see in those pics is outside of the usual RGB space we image in, including narrow band emission lines.
An enlightening post Marc & the blend in image 3 is quite special.
Well done for pushing the envelope .
Cheers,
Tony
Quote:
Originally Posted by DavidU
Excellent Marc, what a cool idea.
Thanks for the feedback guys.
I have bucket loads of IR shot with the old Q from the last astrofest so now with the winter milkyway slowly coming back I'll be spending a lot more time doing UV from home this winter to complement the data I already have and experiment with some psychedelic blends.
One wonders what is the source of the UV nebulosity. You kindly sent me the transmission data for the UV filter, and it's clear that negligible OIII or H-beta are going to be getting through. There are other hydrogen lines, and perhaps calcium.
One wonders what is the source of the UV nebulosity. You kindly sent me the transmission data for the UV filter, and it's clear that negligible OIII or H-beta are going to be getting through. There are other hydrogen lines, and perhaps calcium.
Thanks Mike. I added it to the pics thumbnails.
Quote:
Originally Posted by Merlin66
Hot O B stars emit most of their energy in the UV - Black Body curve for hot stars > 20000K
Yes that's was I was reading too. I highlighted on the spectrum the area each filter covers and the corresponding QE for the QHY9.
