DMK and Registax question!

Gasman · #1 10-02-2007, 10:48 AM

Hi Guys
A friend of mine suggested taking red, green and blue shots with my DMK and then using the Trichromy setting in Astroart to combine the images and I read recently that Registax can actually do this for you but I`m not sure how anyone suggest please how this can be done or are there any other/quicker/better ways of doing this. Also while my ordered filter wheel is on its way to me is there any way I can line up exactly the three different images on screen as I have to keep removing the camera to change filter for the shots giving a rotational misalignment for the colour processing.
Cheers and clear skies

Steve

[1ponders] (Paul) · #2 10-02-2007, 10:58 AM

Hi Steve.

I use either ImagesPlus or AstraImage to do my aligning and combining. Its very easy using these. Unfortunately not free though. I found that ImagesPlus does a better job of aligning, and adjusting the colour, but I prefer AstraImage's deconvolution and maximum entropy routines for "sharpening". You could also use Registar for aligning your images, but again it's not free.

You can use Photoshop to align them by layering each final colour channel image and use difference blend to line them up. Just remember to turn the blends back to normal when adding the next layer. Once you have done that you crop the lot to make each layer the same size. You can then combine them using a new document and inserting each layer from the first document into the respective colour channel. I haven't done it so I'm not sure of the exact process.

Don't know how to do it in Registax.

iceman (Mike) · #3 10-02-2007, 11:12 AM

Hi Steve.

I wouldn't bother with RGB imaging until you get a filter wheel - the rotation will be difficult to properly correct when recombining. It's possible, but painful.

StargazerX1 · #4 10-02-2007, 11:59 PM

Steve,

Almost any IP program (MaximDL, Iris, AIP, etc) will combine mono RGB images into colour. Astroart should do this as well as any other, but I have not used that program.

But since you wanted to know - in Registax you can open processed still images with appended _R, _G and _B; e.g. Jupiter_R.fit, Jupiter_G.fit and Jupiter_B.fit. Check the process in colour box, set a quality setting low enough so it won't throw out one of the colours(!), align, limit to 3 obviously, stack and go from there. Registax will also do LRGB - but I have not tried that.

I would recommend using Registax to only get your preliminary mono results, and stick with Astroart or Iris or something else to get your final result.

Mikes right, don't waste your time until you get a filter wheel. Although Registax 3 claimed to do rotation compensation, it never worked well, and v4 does'nt do it anyway.

Glenn Jolly
Gilbert, Az USA

Gasman · #5 12-02-2007, 04:42 AM

Thanks again for the advice guys.
I just tried what Glen suggested using red1_R.bmp,blue1_B.bmp and green1_G.bmp and just got another mono image? do they have to be saved as .fit files to combine for a colour image?
Cheers
Steve

StargazerX1 · #6 12-02-2007, 08:07 AM

Steve,

I think its even worse than that. When I RGB combined 3 24 bit mono bitmaps of Mars I took 2 yrs ago, I got a completely black image, even though it stacked correctly. The 32 bit FITS format that Registax4 now supports did not work either. Only the mango 16 bit Registax FITS format worked for me.

I use Bird's fixfits program on Registax FITS files before using more compliant (with the FITS standard) software. Because of all of this I cannot recommend using Registax for this task. Use a more full featured IP program like Astroart or Iris (or many others) for this task.

Glenn Jolly
Gilbert, Az USA

Gasman · #7 12-02-2007, 11:11 AM

Thanks for that Glenn. I just tried converting a saved red.bmp image with Registax into a .fit file and got three seperate .fit files red_R_R,red_R_B and red_R_G ???? It gets more complicated by the hour ;-( pretty sure I`m making it harder that it needs to be. Think I`ll have a go with Iris, looks a good application.
Regards Steve

StargazerX1 · #8 12-02-2007, 11:07 PM

Steve,

Registax looks at your saved red.bmp as a color file, even though its just a spread of grays, so when it was saved again as a fits file it wrote out in 3 colors - which are all pretty much the same!

Bitmaps should seldom be used in image processing except as a final result.

Glenn Jolly
Gilbert, Az USA