M51 ...... and calibration subs disaster

[TareqPhoto]

Hi all,

So after long time of no imaging i decided to return back to do imaging as requested from people, and here is the brief/short story about it.

I asked only in Arabic groups on FB about what they would like to see me do in the next or coming time so i can focus better on doing imaging at best, and i gave them 4 choices [Nebulae, galaxies, clusters and the Moon], and to my surprise, they chose galaxies no doubt followed by nebulae, so i listened to them and wanted to start with galaxies if i return back to imaging, so i gave them another choice about which of two only galaxies they would like to see, M51 or M101, and they chose M51, and so the imaging started .....

I kept my 8" F/5 Newtonian sleeping for long time although i modified it slightly to do the job, but it is really very difficult to use the Newtonian that large if i didn't get used to it, but i know that i bought it for galaxies and small clusters anyway, so i gave it a try on that night of 23rd April 2020.

I put the Newt, then i wasted so so long time only to balance it, i really don't know how people can do it, so anyone has using 200mm [8"] F/5 on EQ6 mount help to do it, then i decided that if i spend the whole night only on balancing then i will never make it, and the time is running out as well as the target was high but the sunrise time isn't much far, nearly 3 hours, so i left balance at best i can do anyway, then i had another time wasted for collimation in the yard with no light, even when i turned on my lights around it was not that clear on the scope, so i tried hard to collimate it quick as i can and just live with it, and third i came to the issue of doing star alignment, that also wasted my time, so it is nearly 1 hour wasted only to make my setup ready, and then i started to do imaging regardless of the issues, and i used my guiding system i bought for the first time with the newt, it did the job but the issues are there from everywhere, the sky was clear.

I took only Lum filter lights, and the subs after that, and later within 2 days i processed my subs to see the results, and it was 2 mixed news:

1. The calibration subs RUINED my light and overall final result

2. I CAN image galaxy from my SKY, what do you think?

Here is the result processed by someone after i uploaded the FITS file asking for processing, i stacked by myself in PI

Here are the links for the files:

https://drive.google.com/file/d/1s3gowBGjDIK1cYHG3tcHU_rgKpkNVMxa/view?fbclid=IwAR1C3Xqyn9ZxDPhJ96Ck0dROfH8RT5Gn_TJ8F_oUI39m0z-X9sVFYzPnMY4

https://drive.google.com/file/d/1NslNxQDTfYvCvcFkHaphpzUziNqOiAen/view?fbclid=IwAR2OjJZ8Dd-32MnKeothMzTUw1WEpyJCXdWO4EZ7QkS75752frwK3GwWRIE

And here are the single frame examples from Dark and Flat that ruined it:

https://drive.google.com/file/d/1SUuvUc_3lztKIIhyn92ClDxREd-7SAnB/view?usp=sharing

And the guy asked me the single light exposure for inspecting so i did that too:

https://drive.google.com/file/d/1Lcnwre6gHv_WzeidW6jwECOIkZZS2s-o/view?usp=sharing

I took new dark files only almost under same settings of light in my room, i will test that sooner or later, but i am surprised to see this happen, bias doesn't have that problem, and i covered the scope very well, and i used T-shirt method for the flat and it was working for me before, so i am not sure if my PI processing was bad or i have to try again or i just have to forget it and image again whatever, i want to image another galaxy as well, but first i need to know those issues with subs, will they repeat again or it was a one time mistake or there is something i have to think about.

 

At the end, i am really happy to get back to imaging, and someone advised me to forget about Lum and just got for RGB and create Synthetic lum from there, it is a great idea actually, but the problem is that i am not good in creating synthetic L and also i am not sure how good my RGB will be anyway.

Telescope: Meade LX70 8" F/5 R8

Camera: QHY163M

Mount: Skywatcher AZ-EQ6

Filter: Cyclops Optics LUX-Series L

Exposure details: 65 x 120sec [i deleted 6 bad frames to end up with 59 only], Gain 75 Offset 15 @-10C

Darks: 25

Bias: 200

Flat: 50

[TareqPhoto]

I forgot to mention two things:

1. Guiding setup: QHY mini guide scope + QHY5L-II-M
2. Those 6 frames i deleted were bad because it was like someone moved the scope/mount or the guiding is off and i was exposing for 30 minutes unguided with movement in all directions not one, so i don't know what happened there for those 6 frames, and there somewhere in the middle of another good frames, this is what i call it a true "CURSE" when you are doing everything but still fail.