M51, over 5 hrs worth of data. Anyone wants to have a go?

[pixueto]

Dear all,

M51 has become a bit of an obsession now to me. I'm trying all my kit with this one to see what it can be done (usinga a 200P on an EQ5 mount). This one is made of 5', 6', 7', 10' and 15' subs, bias, darks and flat frames also taken. I initaially had loads of trouble with my astronomik LP filter but at least now there is some colour in the picture -although the colour balance is probably wrong.

I was wondering if someone would like to have a go with the DSS file and see what it comes up as it is hard for me to see if the picture is worth at all due to my very limited processing skills.

Here is the link to the Tiff file that came out of DSS:

https://dl.dropbox.com/u/81776321/M51%20LP%20Filter%205hr%2022mn%20embeded%20adjustments.TIF

Thanks for watching and for your help!

[Gina]

Nice image Would benefit from longer subs and plenty of them but there is plenty of detail in there waiting to be teased out

[Jessun]

pixueto, I'm new to this too, so can't bring anything too interesting to the table, but it's cloudy here so I gave it a quick go.

Nice capture there!

[pixueto]

pixueto, I'm new to this too, so can't bring anything too interesting to the table, but it's cloudy here so I gave it a quick go.

Nice capture there!

Thanks Jessun. Did you use the jpg or the Tiff file for the histogram stretching?

[Jessun]

The tiff. It just so happened that we cropped out pretty much the same section:).

Here's the same one with the stars tweaked.

[pixueto]

An update on that one, this time I kept the 80% best subs and the tiff file looks much better. If you want to have a go here is the link to the Tiff file :

https://dl.dropbox.com/u/81776321/M51%20LP%20Filter%204%20hr%2057%20mn%20applied%20changes.TIF

[pixueto]

I tried a new reprocess following a tutorial setting first the bright and dark points and then using curves. I am really trying hard to get the debris from the galaxies' collision but I don't seem be able to achieve it without saturating the core of the galaxies. I find it hard to believe that there isn't enough data there after 5 hours imaging with 5', 6', 7', 10' and 15' subs!?!!?

[Jessun]

Curves - levels - curves - levels etc, less agressive iterations each time. That seems to be a 'standard' start on things.

The good guys can keep the core intact, while I find that I sometimes need to process it separately to tune it down a bit if it runs away on me.

5 hours is not a huge amount of time on M51. Nothing wrong with doubling it :-)

[pixueto]

5 hours is not a huge amount of time on M51. Nothing wrong with doubling it :-)

Really? M51 will end up being my obsesion! i'm thowing everything I've got at it!

[dark star]

Great image of M51! I am just starting out and have so far managed around 8 minutes in total on M51, you can sort of guess it is there! So I am very impressed by your image.

I get washed out images with my Canon 20d DSLR after only around 1 and a half minutes. I assume this is due to bad light pollution and I need a LP filter.

What were the issues you had with the Astronomik filter and how did you solve them? As I am thinking of getting an Astronomik CLS EOS clip filter.

Regards

David

[pixueto]

Great image of M51! I am just starting out and have so far managed around 8 minutes in total on M51, you can sort of guess it is there! So I am very impressed by your image.

I get washed out images with my Canon 20d DSLR after only around 1 and a half minutes. I assume this is due to bad light pollution and I need a LP filter.

What were the issues you had with the Astronomik filter and how did you solve them? As I am thinking of getting an Astronomik CLS EOS clip filter.

Regards

David

Hi David,

Initially I used DSS with the usual settings and with the subs taken with the Astronomik clip filter, the final picture came up in black and white! Then I found this thread:

http://stargazerslounge.com/showthread.php?t=88368

and following the advice worked wonders for me. With the LP filter, make sure that nothing about WB is ticked in DSS and the programme seems to correct the colour balance while stacking.

Where about in London are you? I've got a fair amount of LP here in Sidcup but now with the clip filter it seems to be alright.

What kit are you using? Can you take guided subs?

[dark star]

I am using a Canon 20D, equinox 80ed refractor and HEQ5 mount. I am using astrophotography tools (APT) to control the camera. I also have a 250mm reflector, but the camera will only focus with this with a barlow.

I am in Woodford on the London/ Essex border. I am a long way away from guiding yet! I have only just figured out polar aligning properly with a polar scope and using the HEQ5 mount, aligning the go to etc. (I have only had it for a few weeks).

I have a problem with dark spots on my images, which I am pretty sure is dust on the sensor, so the next step is to learn how to clean this.

I am going to see how long exposures I can get unguided, although I do have a DMK41 camera which I could probably use as a guide camera. I have enough to learn about processing etc. for the time being! My first images are pretty bad, but I am learning! Galaxies are probably not the best objects to start with!

I am waiting for a serial cable to be delivered so I can set up an imaging plan in APT using bulb exposure. At the moment I am just using a remote cable and timing using a watch! (or 30 seconds exposure or less).

How long should I be able to get unguided with good polar alignment?

Regards

David

[pixueto]

I am using a Canon 20D, equinox 80ed refractor and HEQ5 mount. I am using astrophotography tools (APT) to control the camera. I also have a 250mm reflector, but the camera will only focus with this with a barlow.

I am in Woodford on the London/ Essex border. I am a long way away from guiding yet! I have only just figured out polar aligning properly with a polar scope and using the HEQ5 mount, aligning the go to etc. (I have only had it for a few weeks).

I have a problem with dark spots on my images, which I am pretty sure is dust on the sensor, so the next step is to learn how to clean this.

I am going to see how long exposures I can get unguided, although I do have a DMK41 camera which I could probably use as a guide camera. I have enough to learn about processing etc. for the time being! My first images are pretty bad, but I am learning! Galaxies are probably not the best objects to start with!

I am waiting for a serial cable to be delivered so I can set up an imaging plan in APT using bulb exposure. At the moment I am just using a remote cable and timing using a watch! (or 30 seconds exposure or less).

How long should I be able to get unguided with good polar alignment?

Regards

David

I'm myself quite new to all this, as I started imaging in January. Lots to learn!

About the exposures, some people here manage to do between 1 and 3 minutes unguided. In my case, I always went for 1 minute subs when unguided but you have a very nice rig; guiding shouldn't be too difficult with your kit.

The dark spots are very common and very easily removed. Get hold of a small photography specialised blower and apply 2 or 3 times avoiding touching the sensor (don't overdo it). Also taking flat frames will solve the problem.

Instead of the laptop you could also buy a very cheap remote timer and set your exposures from there (I actually prefer this even though I'm using a notebook for guiding too).

[pixueto]

Another rework, this time with Pixinsight. Well, when I try to shaarpen the image a bit, a lot of noise comes up. Can I fix this with more lights, more darks or both?

thanks

[squeaky]

Hmmm... can't get anywhere near the standard of you guys...

[Gina]

What processing software are you using Richard?

[squeaky]

Paint Shop Pro X3

Roughly speaking, after cropping I did...

• One Step Photo Fix - which auto corrects for noise, contrast etc
  
• Fade Correction - which lifted the misty bits but turned it very blue
  
• Temperature Correction (upwards to get warmer and lose the blue)
  
• High Pass Sharpen
  
• Digital Camera Noise Removal
  

I'm sure I could do better but it would take lots of playing around with all the individual settings that are hit by the built in auto stuff. Something I'll want to do, as time goes by. Given how few opportunities I've had for imaging (two) since I got my kit - it's nice to have other people's raw shots to practice with on rainy days.

[Zakalwe]

There's loads in there:

I used Photoshop.

2 x passes of Gradient Xterminator

Lots of levels and Curves.

3 x false Luminance layers, each blended with a decreasing opacity

A couple of High pass filters.

Flattened the image.

Another pass of High Pass

A tweak of Match Colour.

Any good?

[squeaky]

Beats the socks off my effort. I need to find the equivalents of PShop's gradients, levels and curves in my PSP X3 and then learn how to use them.

More hours/days/weeks of homework and study

[davew]

Not being a DSLR image taker I thought I'd have a play and it made a nice change.

As you can see I can't get rid of the noise without killing the thing off

Good fun, thanks,

Dave.

[pixueto]

Thank you guys! I am very much interested on getting the debris coming from the galaxies collition but, as you already said, the noise takes over. I'm thinking about getting another couple of night's data. What would you recommend: short 1-2 mins without a light pollution filter or longer 10 - 15 min subs with the astronomiK LP filter? Which subs would also be better to bring out the colour?

[Zakalwe]

You need longer subs.....there should be a lot more data in there 5 hours worth. Really short exposures get swamped with read out noise. Plus using a dslr on these warm nights will result in more noise.

[Quatermass]

I downloaded that tif to take a look at it for you it was very noisy but had good detail. I think there are 3 things that make a big difference a very dark sky for a start then if its a warm night shorter subs and lots of them I took about 85 80 second subs at 1600 iso for my shot and it came out ok with those. plus 60 darks flats and bias shots.

I know that being able to do longer subs is great but it does increase the noise levels with an uncooled slr camera. I think your biggest issue is not having a very dark sky and light pollution. But i guess your doing all you can to get rid of that LP.

[pixueto]

I downloaded that tif to take a look at it for you it was very noisy but had good detail. I think there are 3 things that make a big difference a very dark sky for a start then if its a warm night shorter subs and lots of them I took about 85 80 second subs at 1600 iso for my shot and it came out ok with those. plus 60 darks flats and bias shots.

I know that being able to do longer subs is great but it does increase the noise levels with an uncooled slr camera. I think your biggest issue is not having a very dark sky and light pollution. But i guess your doing all you can to get rid of that LP.

So would you agree that the main problem with that tiff is noise rather than detail and colour?

I really don't have a chance of imaging this target later on in the year when the nights are cooler. Although alkaid (my guide star) is circumpolar, it's moving now to the east where all the light coming from the City will make it impossible to even try.

I'll go for 80'' subs then without LP filter at ISO800 and see how it goes when I add everything to the 5hr stack. Do you think that adding lots of dark frames at 17 degrees Celsius (that's the temperature in the garden at the time I got the 15min subs) will help to improve the noise problems noticeably or is it a matter of taking more and more subs?

Thanks

[Quatermass]

Well pix all I can suggest is what I have learned from doing my M51 it is clear from the image that you have a lot of detail in the galaxy but the noise then becomes and issue. You can reduce noise by using lots of subs darks and flats I have found that if I use about 80 short subs 80 seconds or longer and add to that 60 darks flats and bias shots then the noise is not an issue for me. Guiding at 5 minutes in this warmer weather is going to increase that noise problem.

My advise is try it and see what you get. Take 80 short subs at 1600 or 800 and leave the camera on your scope and take the darks the same night with a remote timer or backyard eos. In the morning take the flats and bias shots about 60 of them. When there stacked line up the rgb channels and boost the saturation to 18 percent to bring the colour back in. Then process it.

Thats is what I did but I do have a good dark sky and it was about 5 weeks ago. Noise is your problem the detail and color are all there.