Author Topic: How much Ha is needed?  (Read 1950 times)

Offline tdgm

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How much Ha is needed?
« on: 2018 April 04 22:29:45 »
Hi Everyone

Iam planing on taking some wide field image of M 101 4 hrs luminance and 1 hour for each rgb channel. Question is how much Ha would i need to shoot as well????


Steve

Offline aworonow

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Re: How much Ha is needed?
« Reply #1 on: 2018 April 05 05:45:23 »
Because Ha is a narrow-filter, not all the red light gets through, obviously. One way to do Ha is to use the same number of exposures as for R, but double their exposure time. That works pretty well.