Help Making Mosaic Of The Sun

[Daniel_Reardon]

Hi all,

As you all no, tomorrow is the day of the Venus transit. I've come here for tips on making a mosaic of the sun. I would love a full disk image while Venus is moving across, but I only have a Coronado PST and a DMK21 camera. I need to use a 2x barlow to achieve focus at all, which makes the final image quite small. So to get a full-disk image, my only option is a mosaic. The problem is, there is too much variability in the focus and gain needed. If I leave it on auto, it gives me good result all around but then doesn't match up with other areas. Then, if I manage to get a good gain and focus, there's still the matter of processing all of the images in the same manner and getting them all to match up well. Any tips would be appreciated.

Cheers,

- Daniel

[Photosbykev]

remove the C/CS thread ring from the front of the DMK21 and use a short shoulderless nosepiece that allows the front of the camera case to touch the top of the PST eyepiece tube. This will let you obtain focus with only the DMK21. Shoot a mosaic of short 30 second videos at 60fps with the exposure manually set, make sure you have plenty of overlap between frames 30-40% this will help remove the gradients that naturally occur at the edges of the final images.

Batch process the avis through Registax 6 or AviStack2 and save the resulting images as Tif files, then use some thing like AutoPano Giga2 or Microsoft ICE to make the final mosaic.

IF the weather behaves I plan on shooting the transit through an 1100mm scope with a DMK21 without making a mosaic, without the x2 barlow on the 400mm PST I think you would be ok with a single set of images rather than trying to make a mosaic which will be difficult with Venus moving over the surface.