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MallinCam and Filters

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#1 Douglas

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Posted 08 January 2008 - 12:18 PM

I haven't seen anyone post any images using the MCHP and filters. I know you can loose a magnitude and sometimes more when using filters but on bright objects, the filters can really add to the image. Last night I used M42 to compare three filters. I tried an H-alpha, LPF, and NaHg (sodium and mercury) filter and here is what I found:

The H Alpha was the most impressive, and allowed me to capture the trap and nebulosity at the same time without overexposing the trap and loosing those stars.

I really like the black backround you get with the H Alpha.

There is no doubt that the NaHg (sodium and mercury) improved my images. It performed great and gave me more depth into the cloud structure and retained some nice color.

I like the LPF but didn't get quite the same color as I had hoped for.

Here they some images from last night comparing the filters:

M42 with no Filter

Posted Image

M42 with NaHg (mercury & sodium) Filter

Posted Image

M42 with H-Alpha

Posted Image

M42 - Another H Alpha

Posted Image

M42 with LPF Filter

Posted Image

- Doug Baum

#2 Alicatt

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Posted 08 January 2008 - 02:48 PM

Great pictures!
Your first pic (no filter) is what I got from my JVC 1460 just before the IR cut filter slides over the sensor. What settings were you using on the camera?

#3 Douglas

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Posted 08 January 2008 - 04:14 PM

I was using 7 second integrations with the following settings:

Sense x128
ALC, Shutter Off, Slider Full Right
BLC Off
AGC on Manual, Slider 1/3 from Left
W/B Manual with Blue +1 and Red -2
APC Settings right in the Middle for both

- Doug

#4 Alicatt

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Posted 08 January 2008 - 06:51 PM

Thanks, I will play around with the settings on mine and see what I can get.
Looks like I will have to do some surgery on my JVC and remove the IR filter from it.
That will have to do until I can get my name on Rock's waiting list :)

#5 prestonrich

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Posted 11 January 2008 - 11:28 AM

Basic question here...what does an "integration" represent when using the MCHC?

#6 Bowmoreman

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Posted 11 January 2008 - 01:43 PM

An integration is an internally summed up set of micro-exposures for the duration of the iteration...

so, for example 2.1 second integrationis a bunch of exposures (I believe each actual expose is 1/60th of a second) - in this case it is 128 exposures of 1/60th each, totally 2.1 seconds... then the circuitry generates a new screen update at the 2.1 second interval

And so forth... I may be wrong on this, but the math seems to work!

In any event, the "integration" specifies the length between screen updates AND the total exposure amount...

So in that sense it is very different than classic AP where you have exposures of many seconds or minutes and then have multipe "subs" of those exposures that you "stack"

MCHP does it all behind the scenes for you, and with much greater sensitivity...

clear enough skies

#7 Alicatt

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Posted 11 January 2008 - 04:53 PM

Think of it as like in photography, where as the light falls off you have to either increase the apature or increase the length of time the shutter is open.
The camera lets the charge on the CCD (Charge Coupled Device) build up without being refreshed and as Dave says it is "integrating" or combining multiple exposures to make one exposure which is then read out to the output.

#8 nytecam

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Posted 15 January 2008 - 06:05 AM

So in that sense it is very different than classic AP where you have exposures of many seconds or minutes and then have multipe "subs" of those exposures that you "stack"

MCHP does it all behind the scenes for you, and with much greater sensitivity.

So the 'subs' are of video frame duration before intergration - my [regular] SX CCD does the same in software and auto-stacks even on a moving comet thus. Obviously the subs and total exposure duration are longer than video but the principle is similar :rainbow:

#9 bkushner

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Posted 15 January 2008 - 11:13 PM

Where are you attaching these filters?

#10 Jack Huerkamp

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Posted 16 January 2008 - 07:37 AM

Brian,

Both the 1.25" adapter and the MFR-3 are threaded for filters. You can screw a filter onto either in front of the MallinCam.

Jack


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