If you have PixInsight and haven’t given AutoIntegrate a try with your Slooh, iTelescope.net, or other images, you should give it a try.

I write in detail about AutoIntegrate here; however, the summary is that it applies a number of automated processes to your image, often resulting in an excellent image with just a couple of clicks. AutoIntegrate produces very good results at its default settings, and its options allow you to customize what AutoIntegrate does to process your images.

There are times when AutoIntegrate does not produce an optimal result – that happens because AutoIntegrate relies on calculations PixInsight performs on your images, and PixInsight only knows about the pixels in your images: you are ultimately the best judge of your images.

If AutoIntegrate does not produce an optimal image, you still have options to improve the final image. In fact, you can even take over part of AutoIntegrate’s processes and let it continue processing from where you left off.

This article demonstrates what you can do with your images when the result from AutoIntegrate is not ideal, and I also explain how you can get even better results by taking over part of AutoIntegrate’s processes and allowing it to take over where you finished.

Sample Download

You can download a sample observation of Messier 51 – the same files I used to prepare this article. Download the sample FITS files here:

Download sample observation of M51

Sample Result

The following is the output of running AutoIntegrate on an observation of Messier 51 – the Whirlpool Galaxy:

I ran AutoIntegrate using its default settings. I noticed that the background sky was uneven, so I reran AutoIntegrate with the ‘Use ABE’ option checked and came up with the following result:

The background of this result is uneven, and the galaxy is somewhat overexposed.

Improving the Default Result

Fortunately, you can easily improve on the image with an adjustment using HistogramTransformation. From the menu, select Process – IntensityTransformations – HistogramTransformation; a new window pops-up.

From the bottom half of the HistogramTransformation window, where it says <No View Selected>, click the arrow next to it and select the image on your PixInsight desktop. Click the Reset button at the bottom-right of the HistogramTransformation window to reset the tool to its defaults.

Click the Real-Time Preview button (the third from the bottom-left side of the HistogramTransformation window).

Drag the mid-tones arrow to the right until the background sky becomes darker, and the galaxy is not as overexposed as before:

Next, click the ‘Auto clip shadows’ button, as shown in the following screenshot:

Your result will look something like the following:

Close the Real-Time Preview and make your changes permanent by dragging the New Instance icon of the HistogramTransformation window to your image as shown:

Save your image, and you can also export it to a format like PNG or TIF for sharing or further processing in something else like Photopea.com to add a logo or other information.

This is an excellent result. You could stop your processing here; however, you can get another result by taking over part of AutoIntegrate’s process and then using a feature called AutoContinue to allow it to process your image.

Advanced Use of AutoIntegrate

AutoIntegrate implements a feature called AutoContinue that allows you to process an image manually for some steps, and then have AutoIntegrate take over the rest of the processing workflow. The advantage here is that you can customize your processes and produce a better overall result. 

One reason you might want to customize the workflow is to reduce noise further than what AutoIntegrate does by default. You could reduce noise quite a bit and then let use AutoIntegrate to complete processing of your image.

Here is the result of processing manually and then using AutoIntegrate to complete the image:

The result between the completely automated version and this one is subtle and you’re ultimately the best judge of which image you prefer.

To use the AutoContinue feature, you create a luminance and RGB image which AutoIntegrate then uses as the basis for furhter automated processing.

AutoIntegrate creates several files as it runs – one set of files are the integrated L, R, G, and B images – these are respectively called Integration_L, Integration_R, Integration_G, and Integration_B and are located in the same folder as the FITS files from your last AutoIntegrate session.

You use each of these images to create a stretched version of both the luminance and RGB images. To create the RGB image, you use ChannelCombination to combine all three images and then use HistogramTransformation to stretch the image (you can use the STF Auto Stretch as the basis for your stretch). For the Luminance, you simply stretch the image using HistogramTransformation image (you can use the STF Auto Stretch as the basis for your stretch). In both cases, try making the background a little darker than the STF Auto Stretch suggests. Change the identifier of the luminance image to L_HT and the RGB image to RGB_HT. Ensure that only those two images are open on your desktop and click AutoContinue in AutoIntegrate.

AutoIntegrate applies noise reduction and some other processes to your image to produce the final result.

This approach allows you to customize how AutoIntegrate processes your image.

Conclusion

In this article, you learned about how to improve your AutoIntegrate-processed images and how to further customize the overall process.