Mosaic Tutorial

 Moon, Tutorials  Comments Off on Mosaic Tutorial
Jan 102015

This tutorial shows how to use DFM and DSSR to automatically capture lunar (and solar) mosaics and how to process them into a final image.  I used a Nexstar 4SE OTA on a HEQ5 Pro with a DMK21 camera for this tutorial.

First off, set up your scope and mount and make sure that DSSR has the correct FOV values in its telescope settings page. Let your scope cool down to ambient and then focus using DFM. Then capture your mosaics using DSSR as shown. DSSR will generate a preview image for each mosaic like this one below.

M 20150103183125 X1 preview

The blue tiles were dark sky which DSSR automatically skipped but you can see some tiles which are totally black or just have a sliver of Moon on them. We need to remove these before the next processing stage or they will crash the stacking programme. You could do this manually but this is very time consuming, especially for very large numbers of videos.

Luckily, Andrew Cool of SkippySky has produced a great app called AS2_Cull_Movies which will do this for you. You tell it where your videos are stored and what percentage of each video should be above a certain brightness threshold. I used 20% and a brightness threshold of 5. The app then checks each video and moves any rejects into a separate folder (or optionally changes their file extension). You can then move onto the video processing stage.

I use AviStack to process my videos into very sharp images. First, load all the videos from your DSSR video folder and select one of them with prominent features like craters or mountains. Change your settings to Processing>All automatic (except post processing) and Update display>None. Adjust the wavelets and other settings to give the best and sharpest image and process that single video. Remove that video using the red cross and press the Batch Processing button. AviStack will then run through all your remaining videos and produce an image from each.

Finally, open Microsoft ICE and drag all your images onto it. ICE will then stitch your mosaic together and you can then export it to disk. A final edit in your image editor of choice (I use GIMP) will give you an image like below. Compare this image with the shimmering videos in the video above.

Click for full size mosaic.

Click for full size mosaic.

 Posted by at 2:37 pm

Mosaic Preview Finally Fixed

 Moon, Tutorials  Comments Off on Mosaic Preview Finally Fixed
Dec 302014

DSSR has a cool mosaic module that automatically captures videos for making lunar and solar mosaics. Part of this module is a mosaic preview image that shows the progress of the capture process. This was a bit hit and miss in older versions but I just tried out version 4.7 and I think I have finally got it.

Note that my mount is very roughly aligned so I set the mosaic size to 0.8×1.0 degrees to make sure I got the Moon. First up was a mosaic with the scope west of the pier. This took 22min with each video at 10sec and the mosaic started in the top right tile. The blue tiles are sky which DSSR automatically skips using the Exposures module.

M 20141229182748 X1 preview

Next up I did a meridian flip and tried again. Continue reading »

 Posted by at 1:56 pm

First Winter DSSR Lunar Mosaic

 Moon  Comments Off on First Winter DSSR Lunar Mosaic
Dec 072014

I have now dusted down my winter observatory and I did a quick test mosaic using DSSR. This comprised about 100x 10sec videos which my HEQ5 zipped thru in about 15 minutes. The videos were batch processed in AviStack 2 and merged in Microsoft ICE. Click on image for full size.

Click for full size image

 Posted by at 1:48 pm

Canon A810 Moon

 CHDK AstroKam, Moon  Comments Off on Canon A810 Moon
May 032013

I have been trying out my £50 Canon A810 camera for astro work. An early trial was to connect it to my Nexstar 4SE scope with a Skywatcher digiscoping bracket and the results were pretty good.

Here is a sample and you can see more of the image by clicking on it.

Click for full size image

 Posted by at 12:21 pm