M94; Finally a pleasing result after a nearly 2 month struggle with the data

[timastrovirus]

After a massive 2 month struggle to process this dataset (due to multiple factors, including poor guiding in a lot of subs, sub-performing flatfields resulting in added gradients that DBE just could not deal with propperly in addition with LP gradients, forgetting to check if collimation was still in order, resulting in this being an 80% crop of full FOV), I finally managed to make something pleasing to the eye out of it.

Data was captured between February 27th and March 6th, and consists of 696 subs of 3 min (TEC@ 0°C, gain 565, offset 25) calibrated with 50 darks, 11 flats, 50 bias, and 50 darkflats). Pre-processed in DSS 4.2.6, processed in PI. Total integration 34.8 hours, from my backyard observatory under Bortle 5-6 skies.

8 inch Newton@F/5, Baader MPCC mk II, Altair Astro 269C Pro TEC, NEQ6 EQMOD, QHY5 9x50 finderguider, CCDciel, PHD2, DSS 4.2.6, PixInsight.

[TerryMcK]

Some nice detail in there.

[timastrovirus]

Thans Terry, it is quite amazing how well sigma-clipping stacking can deal with even moderate guiding issues, while still preserving fine detail. I had to include a lot of frames with clearly visable guiding errors in the stars, to get to the amount of exposure I was aiming for.

 

[ApophisAstros]

Like it ,  i see you applied Bias and Dark Flats on this , i have heard that Dark Flats can do the job on their own as Bias is taken at very short exposure time as Dark Flats are , just mentioning hope havenn`t spoke out of turn? It may be my monitor but i have a slight green Hue ?

But a great capture.

Roger

[timastrovirus]

Thanks Roger,

 

I used both bias (for the dark frames) and darkflats (for the flat frames) as my flats were exposed for 10 sec, and was not sure if the bias would be OK for those, just to be safe, and easy to aquire. With regard to the green hue, you may be right, although I haven't got any other responses suggesting this, however I am a massive color blind (both in green and red spectrum), and therefore very poor at noticing color casts on my images. I did use ACDNR (which should do the same as PS Asta La Vista Green plugin) on the color data, but if more people point out a green cast on this image, I might as well do another pass with ALVG in PS to get rid of it.

Edited April 30, 2022 by timastrovirus

[Dmack1]

Thats a nice result. Ifound it a very tricky target to process in order to get the outer ring. You did well.

 

[Carastro]

A good result after your struggle. 
 

Carole

[rwillits]

Nice results. Never give up  🙂  .

[woodblock]

Looks fantastic to me. That faint halo around the galaxy is very interesting.

 

I'm new to imaging but can I ask how you are able to get those faint features such as that halo without completely burning out the centre of the galaxy?

[timastrovirus]

15 hours ago, woodblock said:

 can I ask how you are able to get those faint features such as that halo without completely burning out the centre of the galaxy?

 

I did it by stretching the data in multiple small steps, see the attached screens as an example. I start off by doing deconvolution on the linear data, this will ensure that faint detail can be recovered later on. After that, 2 itterations of Histogram Transformation, followed by a masked stretch, this will blow out the core a little bit. Using HDR Multiscale Transform and Local Histogram Enhancement, detail within the core is recovered and further enhanced. All of these are PixInsight Processes and most of them are also applied using masking to preserve certain parts of the image, but I have used Photoshop in the past to do similar, step-wise stretching of the data.

[woodblock]

Thanks for that. I obviously have a lot to learn.