Horsehead and Flame Nebulae image
Tim C
Attached is my first attempt at the Horsehead and Flame Nebulae in Orion. I used a Televue NP101 4 inch refractor on a Paramount MX mount and a QSI 690 CCD camera. The image was taken on 19 December 2014 from my back garden observatory. The image consists of luminance 25 x 120s exposures unbinned, red, green and blue 8 x 120s exposures binned x2, and finally Halpha 10 x 120s exposures binned x2.
This was quite a challenge to process as I have been trying to work out how to successfully align and combine the binned images in Maxim DL and also to blend the Halpha channel into the combined LRGB image in Photoshop. I feel I've learned quite a lot by trying this. I hope you enjoy the image.
Tim Coskun
brian mills
Tim,
That’s a belter of an image – well done!
Brian
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Tim Coskun
Many thanks Brian. I’m glad I finally managed to get a half decent image from the sub-exposures which I knew looked OK!
Tim
John Mills
A great image for your first attempt at the Horsehead and Flame nebs. Were your subs autoguided? With a PMX it should be possible to get good tracking over several minutes unguided. When using a remote 10" RCT on a PMX, I go for 600s subs, but that is using an OAG with QSI 683wsg camera. Try aiming for longer exposures? Especially in Ha to get a good signal to noise ratio.
One thing I noticed - If I zoom into your image and view it full size, there appears to a misalignment between the LRGB layers? More noticeable at the top of the image than at the bottom. I use Maxim here and pre-align the images in the stacking process using the 'star matching' option. When the subs are combined into LRGB image sets, I then align those to each other (using the Align command in Maxim). That should ensure when you convert the FITS files to TIFs and bring them into Photoshop, they should all match up perfectly. You can always crop out the edges if there is some overlapping after making your LRGB image.
Clear skies :-)
John M
Tim Coskun
Hi John
Thanks for your comments. The sub-exposures were unguided so I think in future I will go for longer subs to improve the signal to noise ratio. The next task I want to do is to get familiar using an OAG (Starlight Xpress Lodestar) with the mount and the camera which I have not done yet. I have a 2nd hand Celestron C11 which I want to use to image galaxies in a few months’ time so I will need to get competent autoguiding with that setup.
The slight misalignment in the image is I think due to the Halpha channel which I applied over the LRGB image as a new layer in Photoshop. There might be an image scaling issue there. I combined the Halpha channel that way because I haven’t been able to figure out how to blend the Halpha channel with the red channel in Maxim yet. I think there is a way of doing it but I don’t find the Maxim manual very clear on this point. If you’ve done this before then could you let me know how it’s done?
Cheers
Tim
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John Mills
Fine on on your comments. Is your QSI 690 camera the WSG version with the internal filter wheel and the guide camera prism? You'll have no problem using a SX Lodestar. They are very sensitive and can work happily with faint guide stars. The 'Guide' window of Maxim is easy to use and with your PMX you will get excellent results. You will certainly need to guide using a C11, but using OAG you shouldn't have any problems.
As for image processing, I only use MaximDL for calibrating, stacking and aligning the image sets. Maxim is great for camera control, guiding, stacking, etc, but I have never had any success of producing a decent LRGB image using it. When the image sets have been aligned, I import them into Photoshop and do all the colour combining using that. That also includes mixing Ha data with the red channel. You may find this link useful? - http://starizona.com/acb/ccd/software/ps_hargb.aspx
Another useful program is FITS LIBERATOR - a free download from ESO - http://www.spacetelescope.org/projects/fits_liberator/ -
This allows FITS files to be pre-scaled so saving a lot of work using levels and curves in Photoshop. It will convert the FIT files to TIF's so they can be further processed, colour combined, sharpened, etc in PS.
I'll send you a 'crib sheet' I made a few years ago with the help of Nik Syzmanek. It goes through the steps to produce an LRGB image using MaximDL and Photoshop.
Hope the weather is better where you are (in Oxted?) than it is here :-)
Cheers,
John
On 02/02/2015 23:09, Tim Coskun wrote:
Hi John
Thanks for your comments. The sub-exposures were unguided so I think in future I will go for longer subs to improve the signal to noise ratio. The next task I want to do is to get familiar using an OAG (Starlight Xpress Lodestar) with the mount and the camera which I have not done yet. I have a 2nd hand Celestron C11 which I want to use to image galaxies in a few months’ time so I will need to get competent autoguiding with that setup.
The slight misalignment in the image is I think due to the Halpha channel which I applied over the LRGB image as a new layer in Photoshop. There might be an image scaling issue there. I combined the Halpha channel that way because I haven’t been able to figure out how to blend the Halpha channel with the red channel in Maxim yet. I think there is a way of doing it but I don’t find the Maxim manual very clear on this point. If you’ve done this before then could you let me know how it’s done?
Cheers
Tim
From: alta...@googlegroups.com [mailto:alta...@googlegroups.com] On Behalf Of John Mills
Sent: 02 February 2015 22:38
To: alta...@googlegroups.com
Subject: Re: {Altair_B - 5318} -: Horsehead and Flame Nebulae image
Hi Tim,
A great image for your first attempt at the Horsehead and Flame nebs. Were your subs autoguided? With a PMX it should be possible to get good tracking over several minutes unguided. When using a remote 10" RCT on a PMX, I go for 600s subs, but that is using an OAG with QSI 683wsg camera. Try aiming for longer exposures? Especially in Ha to get a good signal to noise ratio.
One thing I noticed - If I zoom into your image and view it full size, there appears to a misalignment between the LRGB layers? More noticeable at the top of the image than at the bottom. I use Maxim here and pre-align the images in the stacking process using the 'star matching' option. When the subs are combined into LRGB image sets, I then align those to each other (using the Align command in Maxim). That should ensure when you convert the FITS files to TIFs and bring them into Photoshop, they should all match up perfectly. You can always crop out the edges if there is some overlapping after making your LRGB image.
Clear skies :-)
John M
On 01/02/2015 21:30, Tim C wrote:Attached is my first attempt at the Horsehead and Flame Nebulae in Orion. I used a Televue NP101 4 inch refractor on a Paramount MX mount and a QSI 690 CCD camera. The image was taken on 19 December 2014 from my back garden observatory. The image consists of luminance 25 x 120s exposures unbinned, red, green and blue 8 x 120s exposures binned x2, and finally Halpha 10 x 120s exposures binned x2.
This was quite a challenge to process as I have been trying to work out how to successfully align and combine the binned images in Maxim DL and also to blend the Halpha channel into the combined LRGB image in Photoshop. I feel I've learned quite a lot by trying this. I hope you enjoy the image.
Tim Coskun
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