I'm a little disappointed in the amount of noise still left in this image after 6 hours of integration, but I think part of it is that I shot this over two nights with a nearly full moon on each night, and only a neodymium/UV-IR cut filter. Hopefully, that's why it's still so noisy. (But you know me...the second image is de-noised -- I couldn't resist since I think it's aesthetically more pleasing.)
I am anxious to calibrate/integrate this in PixInsight since I think it's preprocessing is better than APP. But I have to figure out how to run the WBPP for multiple sessions first! Might be a while before I figure it out.
AT60ED w/ field flattener (360mm fL)
ASI2600MC Pro (OSC camera)
SkyGuider Pro with guiding via ASIAir Plus using an ASI120mm mini and a 30mm F4 guide scope
Baader Neodymium + UV/IR Cut filter
240s x 91 [Total Exposure 6:04]; with dark, flat, and dark-flat frames
Stacked in Astro Pixel Processor (APP) and post-processed in Photoshop
Hi Greg, nice capture! I've never imaged the Iris... it's on my list.
One thing, can you share what the background levels are? You have some filters on there, which may be cutting the background sky really well, which means little to no signal. What is the image average for signal (usually close to background level)? I do note when I do narrow band sometimes, I get almost no signal for the background. You are shooting color (which needs more signal than a mono camera with single color filter IMO), and then putting a couple more filters on top of that. It may just be low signal.
Terri
Hi Greg, nice capture! I've never imaged the Iris... it's on my list.
One thing, can you share what the background levels are? You have some filters on there, which may be cutting the background sky really well, which means little to no signal. What is the image average for signal (usually close to background level)? I do note when I do narrow band sometimes, I get almost no signal for the background. You are shooting color (which needs more signal than a mono camera with single color filter IMO), and then putting a couple more filters on top of that. It may just be low signal.
Terri
Good thoughts, Terri. I used just one external filter (Baader Moon & SkyGlow) besides the Bayer on the sensor. Is there a way to quantitate the background level (SNR)? Might be able to do that in PixInsight, but I just downloaded the trial version a couple of days ago and still trying to figure it out.
Thanks again!
Greg
Hi Greg, use the Statistics process under the Image heading, or just Statistics if you list all processes. The mean and Median numbers are interesting. Make sure the scale is set to 16bit. This will tell us in a range of 0-65535, how much signal you have.
Terri
Hi Greg, use the Statistics process under the Image heading, or just Statistics if you list all processes. The mean and Median numbers are interesting. Make sure the scale is set to 16bit. This will tell us in a range of 0-65535, how much signal you have.
Terri
Great! I’ll give it a try when I get home. Thanks again, Terri.
Greg
Hi Greg, use the Statistics process under the Image heading, or just Statistics if you list all processes. The mean and Median numbers are interesting. Make sure the scale is set to 16bit. This will tell us in a range of 0-65535, how much signal you have.
Terri
Hi Terri,
I don't think I know what I'm looking at/for here. I wasn't able to pre-process this image in PixInsight (have to figure out how to do multiple sessions yet), so I just loaded a TIF of the output from APP after I extracted the stars, stretched the nebula, then added the stars back again. Not sure if that's the right image to do this on, but the statistics info from that processed image are below. If I should run the stats on a pre-stretched image or an image different than the one on which I ran them, please let me know!
Thanks!
Greg
IrisNebula_Session_1_2_session_1_session_2_crop_StarsPlusNebula2
R G B
count (%) 99.87751 99.98264 99.96801
count (px) 26053575 26081000 26077183
mean 6871.2 7049.2 6953.3
median 6440.0 6796.0 6742.0
avgDev 3121.0 2428.6 2310.6
MAD 2701.3 2022.3 1933.3
minimum 2.0 2.0 2.0
maximum 65347.0 65533.0 65475.0
@greg-erianne Hi Greg!
This is one of my favorite targets!
You have WONDERFUL dust clouds that show up! I couldn’t get them, but then again, it was when I began imaging, and you have just over 6 hours. I’m really impressed with this..
Maybe I should try re-processing my data.
Maura
@greg-erianne Hi Greg!
This is one of my favorite targets!
You have WONDERFUL dust clouds that show up! I couldn’t get them, but then again, it was when I began imaging, and you have just over 6 hours. I’m really impressed with this..Maybe I should try re-processing my data.
Maura
Thanks so much, Maura! Yes, I've been wanting to image this for quite a while and since we had a couple of clear nights, I thought I'd go for it despite the nearly full/full moon (>= 95% both nights). Terri had a good thought about the S/N and using a color camera. Sure, try reprocessing your data since you have a lot more experience! You never know...
Greg
