DSLR use with Solar Scopes

[Martin Pugh]

So here is a question for the seasoned solar imagers.

Why wouldnt a DSLR (a Canon 550D in this case) which has a HD video mode, be a good camera choice for imaging through a solar scope?

thanks
Martin

[Merlin66]

Yes, it will work, but the Bayer matrix still doesn't give the same resolution as a mono camera.

[jjjnettie]

I have used the HD video on the 550d to image the moon.
Registax won't recognise the .mov format though. You have to convert it, and I found all that lovely resolution was lost in the process.
Since then, I've stuck to taking tons of hi res jpgs and stacking them instead.
But if you can find a good converter to use. I say go for it.

[Martin Pugh]

Thanks both.
I am finding that I am getting better results with the simpler Phillips Toucam Pro.

I have also been looking at the PGR Flea3 v Lumnera Skynx. Thoughts?

JJ - I have actually done a lot of testing with a few of the programs you can get to convert the MOV files.

There is a limtation on Registax and AVISTACK on which codecs they recognise also. Otherwise, Quicktime Pro allows you to export to AVI.

So, I have found the freeware by Pazera called movtoavi, does a good job without loss of resolution. Choose Motion JPEG option and you will find it is okay.

cheers
Martin

[jjjnettie]

Cheers Martin.

[Phil Hart]

StreamClip is a great free program for converting video files. You also need the quicktime alternative that they talk about on their website.

Would be interested to see your results with an SLR Martin!

Phil

[Paul Haese]

Well because the light from a solar scope is monochrome and a DSLR is bayer matrix. You will be capturing one third of the available light. It will require lots of work to get an image at one third the resolution. Buy a DMK41 or simlar mono camera and get the best possible images. Don't waste your time on DSLR images with this format. If you don't believe me check out the web and you will see all the great images are from monochrome cameras. :);)

[Peter Ward]

While there are some heroic efforts with DSLR's....go mono. Bigger chips are a two edged sword. Bigger slabs of Sol but slower frame rates... Then again port speeds ( USB 3.0) are getting quicker.... Decisions decisions :)

[Martin Pugh]

Thanks all

Paul - I completely agree. The images taken through my DS90 and the 550D have been nothing but disappointing.

So I will have to consider a mono camera - perhaps the PGR Flea3

cheers
Martin

[gregbradley]

I'd like to hear a comparison of DMK41 and PGR Flea 3 also.

Then there is the Skynyx as well.

Is the Fleas 3 more suited to planets?

Greg.

[Paul Haese]

I'd steer away from 640 x 480 sized chips for doing this sort of imaging. Mosaic work is an enormous task. Even covering a large active region will take a lot of mosaic panels. Another thing to look out for is Newtons rings. In mono light with high mag these beasts show up.

If you go with the point grey flea3, take a look at the largest sensor. That will give you real estate and perhaps even a faster frame rate than the DMK41.

To answer Gregs questions; the skynyx is a bit outdated now. The frame rate is high but it suffers badly from Newtons rings and is very noisey. That means a lot of processing to try and correct for the problem.

The 640 x 480 flea is best on planets and does require an powered adapter and well not suited for solar work. Perhaps look into the camera Peter has too. That is a Lumenera but not the skynyx variety.

[gregbradley]

Thanks Paul.

Greg.

[Peter Ward]

Que?

I use a Lumenera and it is a *Skynyx* 2-2. Never noticed any rings. Noise is well controlled provided you keep the gain low. It typically delivers 12FPS at 1600 x 1200 res. Can't say I seen significantly better specs elsewhere at that res... but must admit to having adpoted a
"if it ain't broke, don't fix it " approach to new gear of late :)

[Paul Haese]

Yep Peter, Newtons rings abound with the 2-0 version I have. Seen here the rings are running from top left to bottom right. I have done considerable work to eliminate the problem. It gets worse the more magnification I apply.

[Peter Ward]

No Link? But to re-iterate, none that I've seen on the Skynyx 2-2 hence making me wonder, apart from chip size, what may be different between the two.

[Paul Haese]

Sorry here (http://paulhaese.net/AR987,%20988,%20989%2028%20March%20 2008.html) is the link.

Newtons rings are primarily caused from monochrome light passing between two optical surfaces that are very close together. I have similar problems with the DMK41 too. There is a glass cover plate over the top of the sensor which causes the problem on both cameras.

[Merlin66]

I've also experienced the Newton's Rings with both the DMK21 and the DMK41 cameras I use.
Do you think there's any correlation between focal ratio and the generations of these artifacts? - Steeper light cone = better/worse rings??

[Paul Haese]

Yes, I think the longer the focal length (which could be a steeper light cone) the worse the rings get. If I use a 5x powermate it can be quite severe. Although the detail is pretty nice overall. It can be overcome by doing a flat, but that is even more trouble.

[Poita]

Would these new cameras be of any use for solar work, the 340fps rate sounds promising?
http://www.cmosis.com/products/standard_products/cmv2000