1st Light PST and DMK41 CCD

[Photosbykev]

my new camera arrived today from FLO, the Imaging Source DMK41 usb CCD and even more amazing the sun didn't scurry off to hide under a cloud.

A few notes on using the DMK41 CCD with the PST. The camera does not reach focus even with a short c-mount nose piece. If I machine off a slight lip on the nose piece it will allow the CCD to get another 4mm closer to the PST which maybe enough? I'll try that on Monday when I get back in the office.

Putting a 2.5x Powermate into the optical path of the camera does work very nicely. The photograph above is an uncropped full size image made from a 30 second avi in Registax v6.

The DMK41 was received in a fully sealed package and it still had dust spots on the CCD which was very disappointing and means I need to spend some time cleaning the sensor before I can capture some of the surface detail.

[DrRobin]

Hi Kev,

Great photo. I have a PST and a DFK31. I also read that you can use a short nose piece and ordered one from FLO, but like yours it doesn't reach focus. I will need to try a Barlow next time.

I also have an Xbox camera and have used that but whilst the sun looks fine in an eyepiece, in the camera only about 1/4 of the centre frame is illuminated with everything else badly illuminated. Is this normal or does it point towards a problem?

I also get the dreaded parallel lines with the DFK, I have seen others report them, but don't know what causes them.

Finally how do you get a black disc? Mine is over-exposed.

Any help would be appreciated.

[JamesF]

That's a gorgeous picture. Very atmospheric with the black disc of the sun. I want to know how you did it too

James

[WayBig]

Nice, all the more impressive given the amount of sun we get at the moment. Normally solar observing helps with the light summer evenings....normally...

[JamesF]

I also get the dreaded parallel lines with the DFK, I have seen others report them, but don't know what causes them.

There was some discussion about this a while back. I don't recall if you were one of the posters. I think the "resolution" (and I use the term in its loosest possible sense) was that it's a firmware issue that Imaging Source either can't or won't fix and the way around it was to use a different frame rate. Shame, as one of their cameras would have been on my shopping list at some point.

James

[JamesF]

Finally how do you get a black disc? Mine is over-exposed.

Actually it's just struck me that if it's massively over-exposed you can probably replace the range of colours across the disc of the sun (which probably won't appear anywhere else) with black in Photoshop or something.

James

[GreatAttractor]

I also get the dreaded parallel lines with the DFK, I have seen others report them, but don't know what causes them.

Do you mean Newton rings, like these http://moonglowtech....tor/index.shtml? From what I've read rotating and/or tilting optical elements (including the camera) might help. Perhaps DFK is more susceptible than DMKs as it has the built-in IR-cut filter.

[Zakalwe]

There was some discussion about this a while back. I don't recall if you were one of the posters. I think the "resolution" (and I use the term in its loosest possible sense) was that it's a firmware issue that Imaging Source either can't or won't fix and the way around it was to use a different frame rate. Shame, as one of their cameras would have been on my shopping list at some point.

James

The parallel lines problem is different than Newton's rings.

I think I remember seeing on the Imaging Source forum that it can be cured with a firmware upgrade. You have to PM one of the mods IIRC.

[DrRobin]

Hi,

Thanks for all the replies. It does look like some sort of diffraction issue, so I will first try a different shutter speed and then try to see if there is updated firmware for the DFK31. I am also not achieving focus, but found a AE 1.25" 1.6x screw in Barlow which should do the trick. I am a bit reluctant to start modifying the PST, until I know that it can't be fixed any other way.

I have guessed what you have to do to get the prominances (flares) and the surface detail, you have to expose twice, once over-expossed for the prominances and then again for the surface detail, possibly adjusting the Etalon in between exposures, then merge the two final pictures together.

[JamesF]

I didn't mean Newton's rings, but I may have misinterpreted Robin's posting.

James

[JB80]

Actually it's just struck me that if it's massively over-exposed you can probably replace the range of colours across the disc of the sun (which probably won't appear anywhere else) with black in Photoshop or something.

James

It's pretty easy really, you can use the magic wand to try and select just the disc but not the proms and then fill the colour black or just use the circular area select tool and manually adjust in free transform(or transform selection, I get them mixed up) and again fill colour black.

[JamesF]

It's so easy when you know how

James

[DrRobin]

Hi,

Yes, could just fill the disc that way. Still trying to get to grips with HA imaging, but already quite keen on it.

[Photosbykev]

This is an old thread

I used the circular select tool and used the shift key to force it to be circle and then just feathered the edge and filled with black

Sent from my iPhone using Tapatalk. Blame Apple for the typos and me for the content