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Going to start CCD imaging... Help please


AlexxxAA
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I've doing some imaging with my 500D. However the SEVERE smog and light pollution here in Los Angeles gives me problems with iso settings. I actually have to image at ISO 100 so that I don't pic up the skyglow of the city, even with the CLS clip and the Baader Skyglow...

I've read that dedicated CCD cameras are good against some light pollution.. I'm about to buy Meade DSI II in order to start getting into CCD imaging... Will this new camera combined with my baader skyglow give me better resulting subs than the unmodded dslr???

(i will post my latest example in a little while)

Thanks to everyone in advance :)

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I think the problem you have is really down to the mass of different wavelengths that cause the light pollution around LA. :)

The problem is that the CCD would pick up the glow too and as it's more sensitive, it's likely to end up over-saturating the CCD pixels with the background noise very quickly.

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Thanks for the help guys ;)

Nick: yea I called a dealer and they told me something similar. They said that dslr is simpler and somewhat better here in the city.

Olly: I'm patiently waiting for something bright to capture in Ha since I have the filter already. But the Rosette is already to low for due to trees in the neighborhood. And the early night sky only has galaxies right now. I'm waiting for sagittarius, scorpius, and the summer triangle so that there brighter things to practice with :eek:

So far I have an example up with my dslr. Its pretty dull, but I sill wanted to share it. You guys can find it in the Deep Sky section.

Clear skies!!! :)

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Hello Alex.

That's a fine M101 considering where you're imaging from!

TBH, I think you should invest in a monochrome CCD and some 6 or 7nm narrowband filters. I've seen some great images done from downtown LA in narrowband, but I reckon you're going to have problems with RGB imaging, espoecially with a DSLR.

Cheers

Rob

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Hi Rob. I was still thinking about that. Considering that some basic CCD cameras are very affordable.

For the time being, i wanted to image some Ha with my dslr and then just make the image monochrome.

I also have an OIII filter. Is it harder to combine Narrowband images coming from a DSLR rather than CCD images???

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For the time being, i wanted to image some Ha with my dslr and then just make the image monochrome.

Aaah :)

It won't work.....the Ha wavelengths that your filter lets through won't make it through the DSLR filtering due to it being unmodded, and having a cutoff point higher than the Ha wavelengths.

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Ohhh darn! Oh well. Atleast you are helping to convince me about the CCD LOL. I will most likely start off with an inexpensive one like the DSI II.

Thanks for the help Olly and Rob :)

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Ohhh darn! Oh well. Atleast you are helping to convince me about the CCD LOL. I will most likely start off with an inexpensive one like the DSI II.

Thanks for the help Olly and Rob :)

Have a look around for a guide scope. I got mine secondhand and that works perfectly as a imaging CCD. Later it can be moved to guiding duties.

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whoa whoa whoa! hold up a second! lol

You guys lost me there lol still a noob here.

I have my Zenithstar and Nexguider both guiding. but i guess thats not what you mean? Nick can you give me an example of the product you are talking about, or the one that you own???

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I think they meant a guide camera Alex :)

Actually, a DSI2 is capable of good results, and will make a great guide cam later on, plus, you should be able to pick one up pretty cheaply I would have thought.

Edited by RobH
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Ahhh ok lol :)

Yea that's kinda what I figured.

I will definitely get my hands on a ccd. But again, the ccd won't really help me with DSO's here in the city right? It will be strictly for narrowband? :eek:

Also, do you know where I can read up on how to stack or combine narrowband images? For the future when I try to combine Ha + O3? And then + S2 in the long run ;)

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Hehe, late reply but I see you're in good hands! Yes - guide camera.

As the light pollution is a wider spectrum than the normal sodium light pollution, you will need to select narrow spectrums that aren't on the same wavelength as the LP.

So if you used RGB you'd have a wider spectrum for each component (red for example) and the impact of LP in the red spectrum (neon) would be apparent.

CCDs and DSLR CCDs only register the luminosity for the light allowed to pass through by the filter (DSLRs have a colour filter attached to the CCD). This means the CCD will not be able to differentiate between the wide spectrum of red and the spectrum of neon in LP for example.

The narrowband filter would block everything out but the specific spectrum of the Ha or OIII for example and as there's no LP that produces light at these wavelengths, all you get is the light from the sky object rather than LP.

The emphasis is on the filter rather than the CCD. The problem with DSLRs is that the DSLR CCD has filters already attached to the CCD - UV/IR and RGB for creating the bayer matrix. Secondly DSLR CCDs are usually less accurate (8 or 12 bit vs 16 bit of a cooled CCD).

Edited by NickK
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