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Can flats be bypassed if using narrowband filters?


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I'm playing around at the moment trying to generate & apply flats - not easy for a newbie that's for sure! I've scanned the threads and it's a repeated issue that keeps coming up.

Anyhow, my imaging at the moment is all narrowband work - and my question is whether flats are critical or not in this setting? My question is prompted by scanning the threads today about flats, and I came across the one below, where it was suggested that flats are not essential if you are using a H-alpha narrowband filter (see specifically the second post in the attached thread). Is this a general view and if so does it also apply to the OIII and SII narrowband filters?

Would make life a heck of a lot easier if true!

http://stargazerslounge.com/imaging-tips-tricks-techniques/119479-ha-flats.html

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You do need flats. Nice try but no shirking allowed!!!

Seriously, the uneven illumination and the presence of dust are no different in Ha or O111 than aywhere else. If you shoot in LP then you will have fewer gradients to worry about but flats are not about that.

It can be a faff getting a good Ha spectrum. My computer screen wouldn't give one so in the end I went for a Gerd Neumann panel and that gives good Ha flats, albeit far more slowly than in RGB.

Olly

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The simple answer to your question is no. Read what Olly said above. Regardless of the filters used (bandpass, colour, parfocality, make, price) they still pick up dirt and your camera chip will still exhibit fixed pattern noise. If you want good pictures there is no substitute for exposure or good flats.

You might wonder why, when bad technical advice is given it is not jumped on by the moderators.

Dennis

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You might wonder why, when bad technical advice is given it is not jumped on by the moderators.

Why? I don't think it's our job to correct potentially wrong advice, we could (and frequently do) give an alternate opinion if we see the particular thread as do other members, but with nearly 16,000 accounts registered, we'd need more mods than members!

Tony..

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You might wonder why, when bad technical advice is given it is not jumped on by the moderators.

Dennis

Why would moderators jump on technical advice given?

Moderators aren't always going to know if something is technically right or not, take me for example I know almost nothing about imaging or processing so it would be highly inappropriate for me to pull a thread or post.

What we are here for is to ensure that the forum runs well and to safeguard members as best we can from other members who seem to have trouble being civil to each other - like you Dennis! Just because you feel you know your stuff it doesn't mean you have a right to talk to people the way that your do. If you cannot be civil, then please go elsewhere!

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