Dusty DMK

[matt]

Hi guys

Just got my DMK 21AF04.AS CCD cam today.

Just plugged it all in the for first time and I've about 6 or 7 full-on dust bunnies that won't come off with use of a simple bulb blower.

Any of you other guys with DMK's have the same problem when your cams arrived "brand new"?

[Dennis]

Hi Matt

What a bummer – not good news eh? Do you have an IR filter fitted? This is the first thing I did when I received mine.

I’ve only used my DMK with a x2.5 PowerMate and generally, dust bunnies don’t become visible in my optical train until I get to x5, so bearing that in mind, my DMK appears to be clean enough to get through the x2.5 test.

I’ve previously tried cleaning Meade LPI’s and ToUcam’s with puffers, blower brushes, lens cleaning brushes and lens cleaning tissue, but invariably ended up making things worse. I know that you didn’t want to hear that. Not only did I merely re-distribute the offending material but I usually introduced new stuff.

The only 100% successful procedure that has worked for me on my LPI, ST7, ToUcam and DSLR is the method outlined here (http://www.cleaningdigitalcameras.com/index.html). I made up the cleaning paddle from rubber tipped icing cake spatulas as described in the article - see the "How To Make Your Own" section.

I purchased the cleaning fluid and cleaning pads from here (http://www.qualitycamera.com.au/index.php?cPath=33&osCsid=76c4a5d527ce80474d8cc6c3d336 98c1). I used the Copperhill cleaning pads (Pec Pads) and Eclipse cleaning fluid and they have been very successful.

I only clean when RH < 65% otherwise there is a risk of leaving drying stains.

Good luck!

Cheers

Dennis

[[1ponders]]

Mine was pretty clean. I use an Arctic Butterfly 724 (http://www.dyxum.com/reviews/accessories/cleaning/visibledust/abutterfly724.asp)to clean my ccd chips on all cameras. From Aust you will find them a bit expensive but worth it.

Borge's Imaging (http://www.borge.com.au/product_info.php?products_id=12159&osCsid=aa16a6f0278e45e8779961cf0047 4fdd)

[iceman]

I've had to clean dust off my chip several times. A q-tip with distilled water is all I've used. It's clean now!

[Dennis]

Wow Paul - that is one funky looking device! So the brush spins which throws off any loose particles and also generates a static charge on the fibres so that when you apply it to the sensor, it attracts dust particles. Now that is hi-tec!

Cheers

Dennis

[[1ponders]]

Aye it is Dennis :)

The brush is meant for a Canon size chip but it works fine with the smaller chips.

[matt]

Thanks folks.

I used a q-tip with some de-miineralised water and it appears to have fixed the problem:thumbsup:

Still, a tad disappointing that it was in such a state when it was supposed to be new.

Ah well, them's the breaks sometimes with astro gear:whistle:

[RB]

Sorry to hear that Matt.
The other thing you need to check is that the camera has no "hot" pixels anywhere on the array.

[matt]

Thanks Andrew.

Dust is fixed now.

To your second point, how do I check for hot pixels?

Cheers

[RB]

If you look at the screen while exposing, you may notice a pixel that stays in the same (X,Y) position while you move the camera around a little.
If it's always in the same position, it's not a star but a "hot" pixel (faulty) on the array.

It may not be a big deal but I'd check to see if it's in a awkward position or if there's more than one.

:thumbsup:

[matt]

Cheers RB

Can I test that during the day???

What settings would I need to "crank" to reveal hot pixels???

Loads of gain? Long exposure?? etc

[[1ponders]]

You will probably find you will have one or two strange pixels somewhere on the chip if you look hard enough. If you didn't then you would be paying a lot more that the chip that is in your camera. It's the big obvious ones you want to avoid. I have 4 or 5 of them on my ToUcam, but it rarely causes any problems.