Probably my best M20 so far to date but due to incorrect flats and bad gradient (maybe caused from the moon?) i had to crop this right down to size. have to wait until next year for another attempt at it.
Any advise to take good flats and applying to an image will be appreciated.
Ezy with the Moon present no flat will save you. The Moons polluting gradients are horrific compared to the data you need for a decent image. You will also lose all very faint nebula signal. Only narrowband is realistically possible with the Moon present and even then that technique works better without any Moon.
I agree with Bert, there is not much that can be done to circumvent the effects of the moon, especially a full one. My solution is to not image on those nights or when the moon 80%+. I typically do other tasks such as pointing accuracy runs, take calibration frames or plan the next object acquisition. After all, there is no point wasting precious time collecting calibration frames when the skies are dark with no moon.
Regardless, its still a nice image. What it could have been if acquired with no moon is anyone's guess, but feel certain it would be spectacular. The problem with image processing out gradients is how much nebulosity of the extended object will be lost. You need to be careful with automatic background flattening tools. Subtraction masks in photoshop give you incredible flexibility but are complex and time consuming to get right. This is always a compromise. If you can escape to dark skies on new moon nights, you'll always have cleaner data than those stuck in the suburbs. You'll know when you've acquired good data, as it will be a pleasure to work with requiring a simplified processing work flow.
I agree with Bert, there is not much that can be done to circumvent the effects of the moon, especially a full one. My solution is to not image on those nights or when the moon 80%+. I typically do other tasks such as pointing accuracy runs, take calibration frames or plan the next object acquisition. After all, there is no point wasting precious time collecting calibration frames when the skies are dark with no moon.
Regardless, its still a nice image. What it could have been if acquired with no moon is anyone's guess, but feel certain it would be spectacular. The problem with image processing out gradients is how much nebulosity of the extended object will be lost. You need to be careful with automatic background flattening tools. Subtraction masks in photoshop give you incredible flexibility but are complex and time consuming to get right. This is always a compromise. If you can escape to dark skies on new moon nights, you'll always have cleaner data than those stuck in the suburbs. You'll know when you've acquired good data, as it will be a pleasure to work with requiring a simplified processing work flow.
Thanks jase. I wish ive got the flexibility to image when there is no moon. Has been either "you image with moon or image with rain & clouds" i normally try to image the opposite direction of the moon.
Hi Eric, great shot ! Given the moon state when you took it really great. I have a question for you - do you use any deconvolution in your processing? Also do you have any idea what the seeing was like when you took the shot (or the FWHM) ? The reason I ask is I am always impressed with the sharpness of your images...I do not seem to be able to get my focus as good - perhaps I have a collimation problem or it may be my processing? I am shooting at F6.3 and sometime 9 so my focus should be less critical...
i normally try to image the opposite direction of the moon.
