TheSkySearchers

Creating a Lunar Mosaic using a CMOS Camera

This tutorial will show you how to capture and create a lunar mosaic using a CMOS camera. A CMOS camera comes from a few different manufacturers such as ZWO, QHY, and Altair Astro, such to name a few of the more popular brands.

Depending on the sensor size of your camera and the focal length of your telescope, you may or may not be able to fit the entirety of the lunar disk within a single frame. If you cannot, building a mosaic following these steps will allow you to easily construct a full-disk image. And even if you can fit the full-disk into a single frame, by adding a barlow lens or a focal extender in front of the camera can allow you to capture more detail on the lunar surface. The resulting composite image (mosaic) will offer better resolution and treat the eye with nice sharp detail of the Moon.

In order to accomplish these steps, you will need the following tools:

A telescope
A mount
A CMOS camera
Appropriate USB cable
A laptop computer
Capture and processing software

Your telescope can be of any design, though scopes with a larger focal ratio (slow scopes such as SCTs and MCTs) will capture smaller portions of the Moon in each panel, often necessitating more captures to build the mosaic. Scopes with smaller focal ratios (fast scopes), such as shorter refactors and reflectors, will typically encompass larger swaths of the Moon, and that means fewer panels for your mosaic. In addition, faster scopes will gather more light quickly, needing shorter exposure time compared to a slower scope.

For your telescope mount, a motorized mount is the best option as this will allow the Moon to remain in position during the capture process. This is doable with a manual mount, but be prepared to hold the scope on target as carefully as possible. This can be a bit frustrating at first, but practice makes perfect when using a manual mount.

A laptop computer is handy as it can be easily taken outside and placed next to the mount and provides the means to operate the CMOS camera, capture the data, and properly store it for processing after capture. The majority of the software available is Windows compatible, though there are options for using other operating systems as well.

For the purposes of this tutorial, I will be using freely available software: SharpCap 3.2, Autostakkert!2, Registax 6, GIMP, and Microsoft Image Composite Editor. At the end of the tutorial I will also be employing StarTools 1.5, but it does require the purchase of a license (at a reasonable cost) to be able to save your work. StarTools is optional to this tutorial and by no means required.

First things first. You need a reasonable clear sky with the Moon available. Since the Moon is quite bright, it can readily cut through thin clouds and sludgy skies and does not require full dark to capture. It is helpful, though, when building a mosaic, to work as quickly as possible if it is not fully dark yet. Otherwise, some of your frames may have a lighter background compared to others as the Sun is still sinking lower below the horizon.

Set up your mount and scope as appropriate, install your CMOS camera (and barlow or focal extender if used), connect the camera to the computer, and open up your capture software. In this instance, we will be using SharpCap 3.2 to capture our data.

I am assuming at this point that you are familiar enough with your equipment that you can get the Moon located and reasonably centered in the frame and have some experience doing this.

For this tutorial, I will be using my Stellarvue SV102T telescope (a 4” apochromatic refractor) with my Celestron Advanced VX mount (a motorized, electronic equatorial mount), my ZWO ASI174MC color CMOS camera, and a 2× barlow lens. The ASI174MC coupled with the 714mm focal length of my scope allows the full lunar disk to fit comfortably within the frame, but by adding the 2× barlow to the mix, I can get in closer to the lunar surface and capture more detail. I usually start off without the barlow so that I can more easily center the Moon with a wider field of view. After I get the Moon centered, I’ll then add the barlow, refocus, and adjust my framing accordingly.

It can be helpful to pan around a bit on the Moon while watching the view on the laptop. This will help you determine how many individual mosaic panels you will need and also adjust your exposure so that the brighter areas of the lunar surface are not blown out (over-exposed). For my cam, scope, and barlow, I find that 3 panels will cover the entirety of a thinner crescent Moon, while 6 panels will nicely cover a quarter to full Moon. The Moon we are capturing on this night is just past quarter phase, so I’ll need to capture 6 panels.

You’ll notice that the image of the Moon on your laptop screen is showing the effects of atmospheric turbulence. The Moon will appear as if it is at the bottom of a pool of water. The more turbulent the atmosphere is, the more the Moon will appear to waver and undulate. This can make it difficult to capture a nice clean shot. To get around this, we’ll not be making single exposures. We’ll be capturing data as a video (AVI or SER formats). This will allow us to quickly capture hundreds of frames. Using our processing software later will allow us to easily sort these frames by the quality and stack the best of the lot for a sharper image. I like to capture my videos using RAW16 and SER format. I typically have my Gain set at 50. Exposure may vary depending on the brightness of the sky or the phase of the Moon. And don’t forget to ensure your color balance is optimal. In SharpCap, I like to tweak my color balance by letting the software auto-select. Once it settles on that, I turn off the auto color balance so that things don’t change between captures.

Next, I’ll select a starting point for my first video capture. In this case, I’ve got the scope sitting on the northeast (upper right) portion of the lunar disk. I’ll be working my way down the disk from this point. Once at the bottom, I’ll move west (left) and work my way back up. Since there are many craters on the lunar surface to use as reference points, it is fairly easy to keep your bearings and ensure that each capture overlaps the previous ones. This is beneficial so that your resulting mosaic does not have any unfortunate gaps in the image. Allow yourself plenty of overlap so that you can crop out stacking artifacts later during processing.

Make sure you are focused as best as you can achieve. Watch the prominent craters and try to make them as sharp as possible. It will not be as sharp as the view through an eyepiece but do try to make it as sharp as you can on the screen.

Here is what my laptop screen looks like at this point:
My exposure time is set for 18 milliseconds, my gain is at 50, and I am capturing a SER video file as RAW16. It is important that you not change these settings until you have finished capturing all of the panels for your mosaic.

After clicking the “Start Capture” button on the upper left of the screen, I’ll set my number of frames to 1000. Thus, my resulting SER video file will contain 1000 frame of lunar data. Depending on your exposure, computer memory, and processing speeds, a 1000 frame SER file will take between 30 seconds to a few minutes. Using the AVI file format or RAW8 can go more quickly, but you’ll end up with shallower data and less detail.

Once SharpCap indicates your capture is complete, it is time to adjust the field of view to encompass our next portion of the lunar surface. Using the craters along the bottom of my present field of view, I’ll move the scope until these craters are higher up. Watch the right side of your screen as well to try to keep the Moon in a similar position with regards to side-to-side framing. It doesn’t have to be exact by any means. Reasonably close will suffice. This will help you out later on during the mosaic building process.

After moving the Moon up some, my screen now looks like this:
Click “Start Capture” again and hit the OK button to pull in your next 1000 frame video file. Once that is done, adjust again and repeat:
Now that I am at the bottom of the lunar disk, I’ll adjust the field of view by sliding the Moon to the right:
Capture that field of view, and then work your way back up:
And then for the last panel:
Once that is done, you have now successfully captured your required panels for your mosaic. For my utilized settings, these six panels have resulted in 24.6 GB of data collected in less than 10 minutes!

At this point, you can stop and bring the laptop back inside, continue to capture more data, or whatever you wish to do. Enjoy!

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When you are ready to process your video files, you’ll need two pieces of software from the list provided above. For this step in the process, we’ll be using Autostakkert!2 and Registax 6. Autostakkert!2 will open each of our video files that we captured, analyze and sort each frame by quality and then stack the best of these into a single image. We’ll then be moving these stacked images over to Registax 6 for some wavelet sharpening.

I find it helpful to have both of these programs open at the same time. On my PC, as soon as Autostakkert! is done stacking, the image will automatically open up in Registax. That is a handy little feature that can speed up the process some.

In Autostakkert!, locate your video files. SharpCap will typically create a folder on your desktop (or where ever you told it to) called SharpCap Captures. Inside this folder, you’ll find a subfolder typically named with the date of your imaging session. Inside of the subfolder you’ll find your video files, typically named with the time of capture.

Open the first video file in Autostakkert!. Your screen should now look similar to this:
On the left panel, you’ll see the large “Open” button. Directly under that, you will see an array of options. You’ll want to choose “Surface” under Image Stabilization. Under Quality Estimator, I find that Gradient and Local (AP) work well. Feel free to experiment though. It doesn’t cost you anything but time.

Over on the right-hand panel that contains the image of the Moon, make sure the green X within the green box is sitting somewhere on the lunar disk. If you need to move this, place the mouse pointer to the desired location, press the CTRL button on your keyboard, and click the mouse at the desired spot.

Next, click the “Analyse” button on the left.

Autostakkert! will evaluate each frame and then sort all of them by quality, best to worse. I find that I get the best-stacked image by using only those frames with a quality rating of 75% or better. This is typically done by using the best 10% of the frames, in my case. To select the best 10% of the frames, find the “Stacking Options” area on the left panel. I always select TIF as my output format and under “Frame percentage to stack” I put 10 (for 10%) in the left-most box.

After analyzing has completed, we now need to set our Alignment Points (AP). On the right panel to the left of the image, you’ll see the Alignment Points box. About halfway down, you should see AP size. For lunar captures, larger alignment points result in better stacking results in my experience, especially with thin crescent Moons. I set my AP size to 144. Once that is done, click the “Place AP grid” button. You should then see a series of green boxes and red dots appear over the lunar image.
Next, move back over to the left panel and click the “Stack” button. Autostakkert! will now begin aligning the best 10% of the frames and stacking them into a final stacked TIF image. Once that is done, your screen should look like this:
It is time now to move over to Registax. If you had both Autostakkert! and Registax open, you should find your stacked image waiting on you when you switch over to that program. If not, you can open it in Registax by going to the appropriate subfolder and selecting the image. Autostakkert! will create an additional subfolder within the folder containing your video files to place your stacked images in.

Once your image is open in Registax, you should see something like this:
On the left-hand side of the screen, you will see a series of sliders. These are the adjustments for wavelet sharpening. You can spend some time adjusting these to your liking and the image on the screen will change accordingly. Just make sure you use the exact same settings for each of your individual images.

I have played around with these wavelet sliders quite a lot and I’ve found that for my personal taste that I like to move only the first two sliders. How far you need to adjust these can also depend on the scope used to capture the images with. If I am using my SV102T APO (as is the case here), I move the first slider out to 8.0 and the second to 4.0. If I am using one of my achromatic refractors (not as sharp of an image), I have to move the first slider to 25.0 and the second to 10.0 to achieve reasonable sharpness.

Once you have your sliders adjusted to your liking, click the “Do All” button on the upper left. This will apply your wavelet settings across the whole image. If you don’t like the results, adjust the sliders and do it again. Be sure to make note of your settings so you can use the same ones on your subsequent frames. You can also “Save Scheme” so that you can easily recall the same settings in the future.

After that, click the “Save Image” button to the right of the “Do All” button to save your sharpened image. I always save these to my desktop or a special folder so that I don’t get them intermixed with my stacked images out of Autostakkert!. Less confusion for me that way.

Repeat the Autostakkert! and Registax process for each remaining capture.

Here is the first panel image after stacking in Autostakkert!:
And here is the same image after applying wavelet sharpening in Registax:
You will notice that on the sharpened images, the edges contain either a white line or small gaps in the image data. These are stacking artifacts and we need to trim that off. This is where allowing plenty of overlap during capture with SharpCap comes into play.

You can trim off these stacking artifacts with any image editor and its cropping feature. In my case, I’ll be using GIMP (GNU Image Manipulation Program). GIMP is similar in function to Photoshop and is freeware. It is a powerful tool to have. In GIMP, I’ll open all six of my images at the same time. After selecting the cropping tool, I’ll trim the edges off of each image and export the cropped image as a new TIF file. This effectively saves my cropped image over the top of the uncropped version since it is no longer needed. Here is are my now sharpened and cropped panels for my mosaic:
Notice how clean the edges are now? This is key to getting a nice seamless mosaic with the next steps.

To composite these 6 images into a single image of the lunar disk, we’ll next go to Microsoft’s Image Composite Editor (ICE). ICE makes mosaic building a very easy process.

Once you have ICE open, you should see something like this:
Click the “New Panorama” button at the top left and select all 6 of your sharpened and cropped images you’ll need to assemble the mosaic (or however many you have).

You should now see something like this:
Now, click the “NEXT” button on the far upper right. ICE will now analyze your images, get them properly aligned, and present you with the results underneath a grid overlay.
You can adjust the roll setting to orient the Moon to your liking. Since I was careful with my camera orientation prior to capture, I will make no adjustments here. Click “NEXT” again.
This screen will allow you to crop the edges of the mosaic to make it nice and square. Once you get that done to your liking, click “NEXT” again.

You will now see your final image. On the right, you will see options for saving your mosaic. I always use TIFF format and keep my image scale at 100%. Click the “Export to disk” button and save the file where ever you like with the appropriate file name.

Congratulations! You’ve just built a lunar mosaic!
At this point, you are essentially done. You’ve got a very nice lunar mosaic on your hands. Great job!

*The following steps are completely optional using further image processing steps. Here I am using StarTools, but you may, of course, use any graphics editor that you like to enhance the image to suit your tastes. It is your image so make it how you like it!

I like to go one step further to bring out a little more color in my image to really highlight some lunar features. To accomplish this, I use the color module in StarTools. I open my mosaic file in GIMP and re-export it as a TIF file and save it with no compression by choosing the “None” option right above “LZW”. This allows StarTools to properly utilize the data contained within the file.
Once in StarTools, I’ll open my mosaic as a Non-linear sRGB source, and choose the “Attempt to reverse stretch, activate tracking” option. Next, I’ll use the “Develop” feature, run the digital development slider up to 50%, and keep the results. After that, I’ll use the color module, accept the defaults, and I’m done. Now I have this:
I find that this particular StarTools process works very well with composited images (mosaics) but tends to go a bit too far with single-frame images. I’ve not yet worked out a workflow for that.

Anyway, that is my process in a nutshell. I hope you have found this useful and insightful!

Best of luck with your own lunar imaging. I look forward to seeing your results!

**NOTE: These processes can be easily adapted by users of DSLR cameras. The use of Autostakkert!, Registax, and MS ICE will be largely the same, for the most part.

Nice complete step by step account! Now if I could only overcome my attachment to glass plates....

With my current setup I doubt if I'll ever have a need for this. However, as a big fan of well-written documentation; nicely done!!

Hope everything is good with you all

yeah boi!, i'll have a read

bladekeeper wrote: ↑Sun Oct 13, 2019 12:49 am
Now, click the “NEXT” button on the far upper right. ICE will now analyze your images, get them properly aligned, and present you with the results underneath a grid overlay.

2019-10-07 (15).jpg

wow!, I thought you made it look easy, maybe because it is !!! it almost sounds too good to be true ahah

does microsoft ice do panoramas of night scape as easily ?

i'm guessing if one would do a high magnification mosaic of the moon say at f30 they would be better of with a dither program and a sturdy mount ?

i've also done some reading about pixinsight and luna mosaics which really isn't support but with some tweaks, it seems people create a reference frame ie with something like ICE as you have done and then run it though gradient merge mosaic in pi ,i guess this would be useful if anyone has any differential gradients to fix.

so i got the scope out,seeing is a little better,did another collimation and decided to have some fun with your tutorial ,two images left and right at about f30-f40 (12m fl)

so it works well at very close up and it was so easy to do!, i have some artifacts from stacking from a bad frame but other then that it turned out seamless and pretty good. using my eq6 and 12'' , it has a bit of drift that i have to manual slew while imaging to get back on track ,so big panels will be hard to do.

Beautifully done, Bryan.

Thanks for taking the time to share.

Clear, Dark Skies

Nicely done Bryan! Well presented, that was a lot of work on your part!

Hardest part for me is getting the individual 'panes' so they overlap some but not too much. Some guess work involved in that

Thanks for outlining this process Bryan, it's very helpful.

I am trying to use wavelet sharpening in Registax 6 and get this below.

The original looks better.

I am exporting the NEF file from Lightroom as a TIFF

we should make this thread a sticky or at least copy the original post ,maybe we can have a tutorial section , i tried my luck at 6 panels with my small planetary camera, the pay out isn't that big as i should of used my asi1600 as it would of made the same fov...

The mount was drifting all over the place, i found out the f ratio (f36) 10800mm fl.

instead of starting a new thread i think i'll keep posting here and give some feedback.

mactech wrote: ↑Sun Oct 13, 2019 3:02 pm Thanks for outlining this process Bryan, it's very helpful.

I am trying to use wavelet sharpening in Registax 6 and get this below.

The original looks better.

I am exporting the NEF file from Lightroom as a TIFF

Screen Shot 2019-10-13 at 11.01.51 AM.png

Screen Shot 2019-10-13 at 10.59.05 AM.png

I've had similar results, though typically when I've used 8-bit data, especially monochrome. 16-bit tends not to do this for me. Do you know the format of your data?

bladekeeper wrote: ↑Mon Oct 14, 2019 12:40 am

mactech wrote: ↑Sun Oct 13, 2019 3:02 pm Thanks for outlining this process Bryan, it's very helpful.

I am trying to use wavelet sharpening in Registax 6 and get this below.

The original looks better.

I am exporting the NEF file from Lightroom as a TIFF

Screen Shot 2019-10-13 at 11.01.51 AM.png

Screen Shot 2019-10-13 at 10.59.05 AM.png

I've had similar results, though typically when I've used 8-bit data, especially monochrome. 16-bit tends not to do this for me. Do you know the format of your data?

Thanks Bryan, it was 16 bit data in the TIFF. I think the program was struggling from my lack of RAM in the Windows VM.

I tried again with only 4 images and had much better success.

You have done a very nice job here Bryan.
Thank you for investing in this way in all of us.
Bravo !

I just completed my first real moon picture - only 1 image (100 stacked images) - - no composite. Yesterday I tried to do this - but left out the Registax section. It was ok. Today I added the sharpening, etc and followed your procedures. Stunning! Thank you for the tutorial. Now I have something to do when the moon is wiping out the stars.

Hey Bryan I know this is an old thread but WOW!!! Recently ordered a new lunar/planetary camera & Powermate, looking forward to giving this a go. Thank you sir!

Mike

chartram wrote: ↑Wed May 13, 2020 11:29 pm Hey Bryan I know this is an old thread but WOW!!! Recently ordered a new lunar/planetary camera & Powermate, looking forward to giving this a go. Thank you sir!

Mike

Thanks, Mike! I'll be looking forward to your results!

Thanks Bryan for putting in all the work required to produce such a complete tutorial.

Your final mosaic image is stunning. Well done.

Steve

Fantastic explanation, I’ll give it a full read later - my ASI224MC is winging its way to me. Of course the sky is now full of clouds clouds

Grrrr.

Just going back through the archives and saw this post again. Thanks for sharing your experience and knowledge on creating lunar mosaics, Bryan. Lunar imaging is not my thing at the moment, but I may want to seriously expand outward into this venture in the next year or so.

May get clear skies tonight, so will see what I can image as a start.