Modded DSLR for solar

[Davey-T]

Inspired by Roger I've just been having a try at some WL between the clouds using 60Da and wondered if there's any advantage / disadvantage using a modded DSLR for solar.

Dave

[Steve Ward]

None that I can think of.

[David Smith]

Only if it were "modded" to remove the bayer "CFA" matrix, giving you a huge mono chip.

Not much to be gained from the "standard" astro mods as far as I can see.

[ArmyAirForce]

Detail in the Sun is best in the green part of the spectrum, so at least you have two green pixels for every red and blue!

Here's a test I did with a mono camera and filters.

[Pete Presland]

Interesting comparison there.

[ArmyAirForce]

The Baader Solar Continuum filter, used for enhancing white light surface granulation, looks in a small band of the green part of the spectrum, around 540nm.

This makes interesting reading too..... http://www.schursastrophotography.com/solar/Articles/solararticle3.html

[ArmyAirForce]

Here's a shot from yesterday, with a mono ASI120 camera, Solar Continuum and IR block filters.

I do use my Nikon D3200 ( not modified ) for solar, shooting video and processing it, but that of course is a lower resolution than a single RAW image.

Here's a Nikon solar image using an Evo80ED and x2 teleconverter.

As a comparison, here's a five panel Mosaic with the ASI120 and So Cont Filter, using the same scope at the native 600mm focal length.

[JamesF]

I did some messing about a while back on lunar images thoguh I can't recall if I tried it on the Sun.  I think the principle would be pretty much the same.  Basically I worked from the assumption that the image would be effectively monochrome (probably more true in the case of the Sun) and split the raw frames from the camera directly into separate their red, green and blue components (no processing of the colour mask at all), converted them into mono and recombined them to give a full resolution mono image.  I didn't have any idea whether it would work or not, but a side-by-side comparison with a standard colour image flattened to monochrome (derived from the same raw data) gave perhaps a little better definition in the image produced by the first method at the expense of a little noise.  The increased apparently noise isn't entirely a surprise as processing the raw frame to colour can smooth the image slightly.

James

[Herra Kuulapaa]

Only if it were "modded" to remove the bayer "CFA" matrix, giving you a huge mono chip.

Not much to be gained from the "standard" astro mods as far as I can see.

I did a test yesterday with monochrome Nikon D5100. Problem is that AS2 fails to process my dcraw true raw converted images if they're bigger than 2250x2236 pixels.

Here's a larger image:

http://www.kuulapaa.com/Solar/1872015_AG.jpg

[David Smith]

You can change the default max image size in AS!2. Just edit the appropriate lines in the ini file.

[Herra Kuulapaa]

You can change the default max image size in AS!2. Just edit the appropriate lines in the ini file.

It's not about the max value in this case. For some reason AS2 fails the alignment if I exceed that resolution..

[David Smith]

I see. How do you stack the image above? Generally I use registax 5 to stack my solar subs after they have been converted to tif in PIPP. Could you use PIPP to crop the frame as well so that it does not exceed the limit you mentioned?

[Herra Kuulapaa]

I take the images with firmware modded mono D5100 to avoid any raw data scaling. Then convert them true grayscale raw tiff without demosaicing, after that some levels and PIPP to crop the images. This results quite big files, but they should be pure representations of what sensor sees.

However both Registax and AS2 dislike the file format if resolution exceeds before mentioned limit, which is quite odd because dcraw is the standard. There must be something in the tiffs that results such behavior I think. Adobe raw converted debayered files have no such effect.