M20 Trifid Nebula

Discussion in 'My Astrophotos' started by ROBERT T SCHAEFER JR, Jul 30, 2020.


    ROBERT T SCHAEFER JR Cyanogen Customer

    May 13, 2018
    152mm A+M Refractor(OfficinaStellare-1200mmF/L) thru a TeleVue 2.5XPowerMate using a BreakThrough X4-UV 49mm filter with step-rings to 48mm , on an Astro-Physics 1200GTO Mount at 1xSiderealGuideRate and 10secGuiding exposures with a Simple Auto-dar using ' 4500.0 ' for the 'Pedestal' in Camera2 'Options' using a ZWOASI120MC-S thru MaximDL Pro V6.16 and with a CanonEOSII RebelT7i modified UV-IR @ Hutech thru MaximDL Pro V6.16 I did a 47secISO6400 image first which was also the first one to be stacked as the 'Reference' image which might have more area background 'light' than a lower ISO does as a 'Reference' frame ... and then Autosave Sequences as two 47sec exposures with a 67secISO100 'flush' frame between 'light' frames of ISO200 , 400 , 800 , 1600 , 3200 , and 6400 ... and two 67sec exposure Autosave Sequences the same way and three 87sec exposures using ISO400 , 800 and 1600 and then the M20 went into a tree .... not all the images could be used and ISO200 usually had 'banding' but there were twenty usable 'light' frames and I Sum stacked them , I did various commands to the image to show the most I could . It would be better to try to get the Trifid Nebula starting in May for more sky time . {{ Doing RAWMonochrome Autosave-Sequence imaging as the first image a 67secISO100-Flush image hopefully to clean-out the sensor and a 35sec Delay-Between and then a 67secISO200 'light' frame and then a 35sec Delay-Between and then a 67secISO100 Flush image and this was repeated but each usable 'light' frame was a higher ISO so a 67secISO400 'light' frame was next until a 67secISO6400 'light' frame , this is an Autosave Sequence for ' 1 ' frame for each ISO and keeping the same 67secISO100-Flush the same to remove 'banding' if it existed and then a clean 'light' frame hopefully will happen .... this takes awhile but might work and then ISO200 , ISO400 , ISO800 , ISO1600 , ISO3200 , ISO6400 , and ISO12800 can be used and SUM stacked ..... this 67sec method will help make a dim galaxy core and also an Autosave Sequence of a 67secISO100-Flush to start and then a 35sec Delay-Between and then a 127secISO200 'light' frame and then a 35sec Delay-Between and then a 67secISO100-Flush and then a 35sec Delay-Between and then 127secISO400 'light' frame ... etc. , etc. , etc. . I made another Autosave-Sequence for 187secISO200 etc. and also a 247secISO200 and a 376secISO etc. Autosave-Sequence all starting with a 67secISO100-Flush 'light' frame to monitor 'banding' if it exists and it does and sometimes it doesn't . I don't 'stack' the good 67secISO100-Flush 'light' frames with the others but it might work . Supposedly 'banding' in images can happen when doing long exposures one after the other because 'electrons' can get forced down into the bottom of the 'sensor' floor and not download when an exposure in over and then during the next long exposure they can float up into the substrate and cause a pattern which might be the 'banding' ... so I'm trying Autosave-Sequences using this proceedure which seems to keep the good 'light' frames cleaner .. but sometimes one gets 'banding' in it and it can't be used . This M20 Trifid Nebula is the one I first tried this idea on and I used the 67sec Autosave-Sequence and the 127sec Autosave-Sequence and a 187sec Autosave-Sequence but clouds came out and I didn't get the ISO3200 and ISO6400 images ; also , there is a Sequence for 376secISO3200 and 376secISO6400 starting with a 67secISO100-Flush 'light' frame and one in between the ISO3200 and ISO6400 'light' frames .... these longer exposures are needed to get the outer galaxy area to be visible and the more of them the better to build it up .... and the shorted 'light' frame exposures are used to show the galaxy cores preventing 'over-saturation' from the long exposures . This is the result .x This image wasn't into 'focus' but I was monitoring the RAWMonochrome Autosave images after download at a 12.50% View to watch for the 'banding' if any and there usually isn't in the good 'light' frames ... but sometimes in the Flush 'light' frames and if there is 'banding' in a good 'light' frame then another 'light' frame at the 'banded' ISO needs to be re-done . Some other night I will try the M20 earlier and try to get two complete Autosave-Sequences per exposure time valued Autosave-Sequence which would be twelve and if the sky permits I'l use the 247secAutosave-Sequence all with the ISO200 thru ISO6400 setting .x This image was Sum stacked and then I used the "DigitalDevelopment - Gaussian Blur : 1 " and the 'screen-stretch' that turns to a 65535 Max-Val status is showing but I used "PixelMath" and "AdjustSaturation" and "ColorSmoothing" and some other smoothing so there aren't drastic alterations to the look after the "DigitalDevelopment" but twice the amount of images might help alot .x

    [[[ the 'Bleeding' images are a single 'light' frame for 47secISO1600 and there shouldn't be any bleeding stars . But at different times that night the Camera1 Canon RebelT7i would say dis-connect or some other message and the image doesn't download . I eventually removed the DSLR's battery and put it back in and eventually it remained ON but ISO200 usually had 'banding' . Maybe after Windows does an Update it takes awhile for the laptop to work OK ..... I saw the message about the shutter not closing on download . ]]]
    artem likes this.

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