M101 again, with some more data added

[Jannis]

I was happy with my first attempt at M101 but felt it needed more data. It took a while for the next clear night to come, but eventually it did.

First nights data is 62x 120s exposures at ISO800 with the half lit moon up on the sky.
The 2nd nights data is 42x 300s exposures at ISO800 with no moon on the sky.
All data captured with my unmodded 550D, trough the explorer 200.

I wasn't sure weather to use all data from both nights, or drop the first nights data due to the moon. In the end decided to use all the data, adding up to 5 hours 34 minutes total exposure.

I decided not to cut and noise-reduce the background so strongly this time.
I'm quite happy with it, and a lot more faint details are visible compared to my previous attempt. What do you guys think?

 

[pyrasanth]

I think that's a great image. This is a target I'm currently working on. Have a look at this thread

I will need another 28 hours of data to finish the full colour version. Have a look at the last image close in. There are lots of smaller galaxies beginning to show after 9.5 hours of L data.

You have a little bit of noise in the galaxy but that's probably down to the smaller image scale compressing the data. I really like the colour balance in your image & hope my attempt come out as well.

Clear skies to you & all.

[Jannis]

Thanks.

It's a bit noisy still yes, i was hoping for less as well. maybe i can lower it a bit more by adding more data later.
I guess i also have to accept that it is after all a 6 year old entry-level DSLR and i can't expect wonders. But it won't stop me from trying at least...

I will at least for sure try to add some Ha, but not yet sure if I'll use the unmodded 550D or the QHY5L-II-M for that.

[kendg]

Very nicely done. More data is always better 

[RSM]

Nice work Jannis. I'm working on the same target myself at the moment, posted my first effort a couple of days ago. One question I have, you have two different exposure times over the two nights. Did you stack them all together or stack the different exposure times and then combine. I was limited to 4 min exposures due to the night moonlight vs my LP filter.

[Jannis]

Thanks.

For stacking, i simply put all the exposures in DSS and stacked like normal. I used Kappa-sigma Clipping.
If i understand correctly DSS will automatically stack all the identical exposures (and matching calibration files) first, then combine them. You have a group function in DSS as well, for stacking data from different days, but i didn't use this as i didn't take any new calibration frames.

Should this be an incorrect way of stacking the frames, or someone knows a better way to stack them in DSS, please let me know.

[laudropb]

Very nice image.

[RSM]

49 minutes ago, Jannis said:

Thanks.

For stacking, i simply put all the exposures in DSS and stacked like normal. I used Kappa-sigma Clipping.
If i understand correctly DSS will automatically stack all the identical exposures (and matching calibration files) first, then combine them. You have a group function in DSS as well, for stacking data from different days, but i didn't use this as i didn't take any new calibration frames.

Should this be an incorrect way of stacking the frames, or someone knows a better way to stack them in DSS, please let me know.

Doesn't look like you're doing it wrong to me, judging by your nice image. I stack in PI so might have to do a bit more manual work on them rather than let DSS do all the work, but interesting that it separates and then combines. I'll try it both ways and see what happens. That's sometime the best way to learn, trial and error and get it wrong a couple of times :-). 

[ultranova]

That's come out really nice, 

Sometimes less is better if the subs taken are not up to scratch,

but on this occasion it doesn't look like it done no harm.

well done

Paul