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Help Processing My Data


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I think this is the best quality data I've captured to date and this is a result of a number of hours in photoshop!

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I'm quite please with it but i would like to know if there's any more I could get from the data?

There was one problem, DSS didn't stack the darks correctly and so I had to crop the frame quite a bit. I had stacked the data before and the darks did seem to work but I didn't save the file. Now when I tried stacking again, the darks don't seem to have done their job (although the flats did work).

I've uploaded the stacked TIF if anyone would be kind enough to have a shot processing it :)

https://www.dropbox....6s_MB_MD_MF.TIF

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I've tried in Gimp (Debian laptop) but as my processing skills are next to null points... I wasn't able to do much. Can't figure out that curves / levels thing yet :(.

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post-24807-0-39070600-1368323667_thumb.j

I processed this in Pixinsight, quickly. This might all be jargon so ask if you want clarification, I did some dynamic background extraction (not a very good job but I still did). I applied the SCNR noise reduction algorithm. I then neutralized the background and did some foreground colour balancing. I stretched the image. I applied some noise reduction. I reduced the blackpoint and did a small bit more stretching. I then did a masked unsharp mask and a masked colour saturation boost. And voila, here is the image.

It definitely needs a fair bit more exposure, it is quite noisy. The data you have though is quite good. I like the detail in M51 especially, its just the background that is pretty messy. More exposure will also allow you to bring out the faint gas in the background that you obviously captured, but is hidden in the noise.

Jacob

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Thanks Jacob. Yes, really need more data, just need the clouds to go away (and the moon to stay down!).

I noticed there is a band of colour around the edge of the frame which looks like sensor noise which I thought the calibration frames would have taken care of.

Here's some detail of the calibration frames & lights (including a screenshot of the masters in Pixinsight with screen transfer function applied) and the stacking process.

Lights

22 off 300sec ISO1600 Temp 16-19C

Single Sub STF

post-6495-0-10860000-1368347205_thumb.pn

Bias

20 off 1/4000 ISO1600

Master Bias STF

post-6495-0-27355700-1368347211_thumb.pn

Darks

12 off 300s ISO1600 Temp 16-18C

Master Dark STF

post-6495-0-20227300-1368347215_thumb.pn

Dark Flats

20 off 1/4 ISO1600 Temp 21-22C

Master Dark Flat STF

post-6495-0-92105900-1368347208_thumb.pn

Flats

20 off 1/4 ISO1600 Temp 22-23C

Master Flat STF

post-6495-0-46283200-1368347303_thumb.pn

All these were stacked in DSS using "Average" on the darks and bias, "Median" on the flats and "Sigma Kappa" on the lights. (I also tried stacking in Pixinsight using the Batch Preprocessing Script, but results were the same).

Stacked & Calibrated STF

post-6495-0-53952200-1368347199_thumb.pn

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Russell,

Here's what I came up with, bear in mind that I have downloaded PixInsight last night and just watched a couple of tutorial videos from Harry's astroshed website.

I did crop the image in PI.

This is the first time I use a proper software and do this kind of work, and I'm pretty pleased with the result.

There are some experienced people on this forum that can do a much better job than what I've done....

2fbdc1fd-4c3d-4781-bfec-10bd90627a39_resized.jpg

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Thanks Gonzo, that looks really great for a first time with new software. You've really kept the background noise at bay.

Here's where I got to in the end, managed to boost the colour a bit while trying to keep the noise down.

post-6495-0-77229200-1368355371_thumb.pn

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Hi Russell,

We seem to be leading parallel threads on virtually the same image! Looks we are reaching a similar endpoint.

By the way, which of your cameras did you use for this? I can see more pink in yours, but you have a modded DSLR by the look of it, mine is unmodded.

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Hi Russell,

We seem to be leading parallel threads on virtually the same image! Looks we are reaching a similar endpoint.

By the way, which of your cameras did you use for this? I can see more pink in yours, but you have a modded DSLR by the look of it, mine is unmodded.

Hey Neil, yeah looks like we're reaching the same end! I'm not sure if the pink is down to the mod, but yes I am using a modded 1100D for these images.

I'm still working on your image but struggling to get any more out of it than what's already been done. I'll post it up when I'm finished.

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Russell,

Thanks mate, don't waste too much time on it, I think I've pushed goodwill to the limit with acouple of people....

Not a problem for me as I'm still learning. It's good to be able to compare against others as the processing step is a bit of an art, so I never no if I've gotten the best from the data or not.

As others say though, more data is always better. Have a look at this DSLR image of M51, it's got over 17 hours of data!

http://www.astronomersdoitinthedark.com/index.php?c=121&p=396

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It might be obvious, but I think the key is really about collecting data in the first place.

No matter which camera you use, you need lots of data.

Agree entirely on this. My 80mins is way too short (see my related thread on M51 today), but at the moment I'm still experimenting with techniques and don't want to spend many hours on one object (want to improve my kit first). Hence just trying to see what can be squeezed out of anything with clever processing!

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Well I thought the low number of darks was causing the problem witht the red border in the STF version of the stacked image. So I took 40 in total and tried stacking again. Got exactly the same result :(

Would really like to know what the problem is as it's going to result in cropping a fair bit of the frame.

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Didn't get too different a result to the others, so I had a quick 10 minute play in photoshop, mainly concentrating on trying removing the gradients in the edges of the background which I ended up cropping a small amount off. Next was attempting to boost the colour of the galaxy and stars. It's a little over saturated now but you can see the intention.

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