Problems Extracting Real Data

[ICallHimGamblor]

Now that I am beyond my spiral artifact problem, I still can't ever extract useful data from my stacked images. Last night, I took three hours of lights of Stephan's Quintet (60x180sec). I took 20 darks, I have 25 flats and 15 biases, and still can only raise the cluster just barely above the image floor. I have the same problem on the two hour Hickson 93 that I restacked. I have a two-hour stacked image of the fireworks galaxy (NGC 6946) that I can't raise above a wisp of a hint of an image.

Either I am doing something wrong dev-ing and auto-dev-ing, or my use of the Wipe function is wiping my good data too, or something. I tried using the 'lassoo' mask as in the most recent tutorial, but no real luck.

Here is the stacked image on Astrobin: http://www.astrobin.com/58749/

No one ever publishes or discusses pre-processed stacks, so maybe there is something wrong with my imaging process, but I wouldn't know.

Do you have any suggestions?

I love your product and think your tutorials are fantastic. I just wish I could get the same results

[admin]

Now that I am beyond my spiral artifact problem, I still can't ever extract useful data from my stacked images. Last night, I took three hours of lights of Stephan's Quintet (60x180sec). I took 20 darks, I have 25 flats and 15 biases, and still can only raise the cluster just barely above the image floor. I have the same problem on the two hour Hickson 93 that I restacked. I have a two-hour stacked image of the fireworks galaxy (NGC 6946) that I can't raise above a wisp of a hint of an image.

Either I am doing something wrong dev-ing and auto-dev-ing, or my use of the Wipe function is wiping my good data too, or something. I tried using the 'lassoo' mask as in the most recent tutorial, but no real luck.

Here is the stacked image on Astrobin: http://www.astrobin.com/58749/

No one ever publishes or discusses pre-processed stacks, so maybe there is something wrong with my imaging process, but I wouldn't know.

Do you have any suggestions?

I love your product and think your tutorials are fantastic. I just wish I could get the same results

Hapy to have a look! Any way you can get me to the stacked TIFF/FITS data set (not just the jpeg on astrobin)?
It could be that a mere 180 seconds of exposure is not enough. Light pollution seems to be quickly overwhelming your data, so I'm not sure how far you can push exposure without some sort of LP filter, and even in the image on Astrobin I can see faint streaks (probably read noise) already.
Do you dither between frames? This will greatly help with diffusing some types of noise (read, bias) as well.
Unlike some other gradient/lp removal solutions, Wipe will never wipe beyond the noise floor (unless you really push it with some extreme values for aggressiveness + dark anomaly filter) as such it will never wipe small detail and outlines of any larger detail should always be visible, though very larger scale nebulosity may look 'drained' of their nebulosity (hence you protect such huge structures with a mask).

[ICallHimGamblor]

I will gladly provide you anything that will help. What exactly are you looking for? A zip file of all my raw lights? Or including all the calibration frames?

I have an LP filter, the standard Celestron one. If there is a better one, I will gladly buy it.

I do dither using BackyardEOS + PHP.

What else do you want to know? Oh yeah, I am capturing at ISO 400. I assume that's important to know as well.

[ICallHimGamblor]

I created a rar file of everything. It is 2.75G. How can I get this to you?

[admin]

I will gladly provide you anything that will help. What exactly are you looking for? A zip file of all my raw lights? Or including all the calibration frames?

I have an LP filter, the standard Celestron one. If there is a better one, I will gladly buy it.

I do dither using BackyardEOS + PHP.

What else do you want to know? Oh yeah, I am capturing at ISO 400. I assume that's important to know as well.

Just a zip of the stacked output from DSS would be all I need for now.
Do you know of a service like Dropbox or Google Drive?

[ICallHimGamblor]

Oh.. I understand (*embarrassed*).

I am uploading to google drive now.

[ICallHimGamblor]

Link is here: https://docs.google.com/file/d/0By0hG91 ... sp=sharing

I have never used google drive before, so let me know if this does not provide you with the access you need.

[admin]

Hmmmm... Had a look and that data is pretty poor for so much effort!

The field is anything but flat and the streaks are realy quite bad.
The data also seems stretched - it should be much darker with all but the brightest stars visible, especially if you used an LP filter.
What did you use to convert from RAW? Just DSS?

This is not really something that's a post-processing problem that ST can deal with. It seems like a stacking problem (incorrectly applied flats/darks/bias) or possibly an acquisition problem...

[ICallHimGamblor]

Not sure if this is good news or bad news, but at least there is hope that I can salvage this stuff.

Thanks for giving it a shot. I'm going to post this on CloudyNights and see what happens.

Thanks again, and I love your product.

[ICallHimGamblor]

I found out from CloudyNights that stretching was automatically applied to my image by DSS (which is terrible programming practice).

I have an unstretched version here: http://www.astrobin.com/58959/

Is there anything useful there?