New Tutorial: M27. Revealing external faint halo

[Silvercup]

Hola:

La versión en castellano (Spanish version):

http://www.aacadiz.com/zona_trabajo/tutorials/m27/en/esm27procexample.html

Un saludo. Silvercup.

[Nocturnal]

Excellent work! I was away on vacation for a week and missed the original post somehow.

[dhalliday]

Silvercup
OK...so having the Ha M27,and now some OIII M57...I am KEEN to try this...
BUT...when I try to multiply the images in step 2...I realize I do not know how to use Pixel Math..

How do we multiply...?
How do we "edit"..or "parse" for that matter...??...when I tpye "+" it seems to add,and "_" subtracts...otherwise I seem lost...
Do we somehoe "tell" PM what keystrokes mean what math function..?

How did PM know what *~ means...?

Sorry,but I am lost...
Also lost about what you did with "curves" to the image after the "ATrous" thingy...
Could I have not just stretched the residual image in histo...?

I need REAL simpelton advice,if possible

PS
Could you put up whatever you get from M57 just to keep me motivated here...?
Hoping for more help...

Dave

[Silvercup]

Hi Dave:

You must read about operations on any programing language. Anyway we only use simplest operations usually.

+ is sum,  - is substrac, * is multiply, / is division

If you want x raised to y you must use x^y, and so on.

If you click Pixelmath Edit button it opens Pixelmath Expression Editor, in the right pannel you will see Functions, Operators and Punctuators. Under Operators you will see all Pixelmath operators.



One of them is ~ that means invert.

In Step2 you must multiply Original Image (clonned) by the inverted of the Small Scales Image ie the image generated in Step 1. Pixelmath knows what to do  .

After Atrous I do a CurvesTrans like this aprox.



See your m97 Image06 on Filckr 

Best. Silvercup

[dhalliday]

Silvercup
As Bogart said..."this could be the beginning of a beautiful friendship"...
Also appreciate that you are also on the "poor mans website" (Flickr)

I think it just goes to show how lost we can be (in downtown Paris..) until someone just points out the Eiffel tower,and says "walk in this direction..."
Maybe this goes back to R Nulmans issue...(!!)

OK..enough bad metaphors...I will try this math...

thanks a bunch

Dave

[Jordi Gallego]

Excellent work Silvercup, thanks for sharing it

[Silvercup]

Hi:

Thanks for the comments. I'll try to do a Common Tasks with Pixelmath tutorial for new users.

Best. Silvercup.

[sleshin]

A PM tutorial would definitely be appreciated. Look forward to it.

Steve

[Carlos Milovic]

Hey Silvercup, that's a great idea. You may focus on image-image operations, such as the one needed to create or merge masks. Also a manual "calibration" example would be nice.

[dhalliday]

Here is the latest result,and some details.
Silvercup has been slipping me tips on Flickr...
Thanks !!
http://www.flickr.com/photos/daveh56/4600250038/

Dave

[Nocturnal]

How much is your drift per image Dave? Seems your stars aren't very round. I'd try to fix that first. It'll sharpen up your images quite a bit.

[dhalliday]

Sander
Its around 2 pixel/frame...ie over 20 minutes. (as per DSS info)
Focus using NB filters is problematic for me..I am going to try using the Astrodon parfocal clear (NB) filter...

I am also using "Morphology" to shrink my stars...but a ratty coma remains..
Settings in ACDNR remain an issue also...my stars seem to go a bit fuzzy...should try some star masked decon on them...
Any other excuse I have left out...?

I am working the whole set of issues...slowly.

Dave

[Nocturnal]

Dave, 2 pixels per image is much too much. My recommendation is to focus on getting that resolved rather than trying software 'tricks' to fix your images in post processing. I don't know if you bought your CGE Pro hoping to improve star shape but most likely it will not until you remove the differential flexure. You need to find and fix the source of differential flexure in your setup. Once you get below 0.5 pixels per sub your images will get dramatically better.

Unfortunately it's hard to debug differential flexure from a distance. I grab imaging and guide cam and try to move them relative to each other. If that doesn't show where the movement occurs I examine each joint between the two cameras. If those are all rigid the optics are the last option. I would think your Vixen has no internal flexure but it could happen. Check the focusers and all adapters, rings etc. first.

[Nocturnal]

I forgot to add that I'm glad you at least *know* your DF per frame. Many people are clueless about it and instead blame poor guiding or optics. That's why I wrote that wiki page You can't fix a problem till you identify its source.

[Niall Saunders]

Hi Dave,

In my case, DF is working against me now, limiting my maximum exposure to about 1/2 worm period (on my LX90, that is around 4 to 5 minutes).

Whilst I await you 'throwing out that 'rubbish' CGE Pro', I am giving serious consideration to the TS OAG-9
(see http://www.teleskop-express.de/shop/product_info.php/language/en/info/p641_Off-Axis-Guider---nur-9mm-Baulaenge---T2-Anschluss---fuer-CCD.html)
as a cost-effective solution to at least eliminate the DF component in my imaging setup, allowing me to then concentrate on whatever residual problems I may then have.

Obviously, with the weak dollar-euro rate at the moment, I will gladly send over an OAG-9 in axchange for the CGE Pro, and would even consider covering the postage, you being a good mate and all . . . . .

Seriously though, it might be a 'food for thought' idea for you.

Cheers,