Brain Function and Narrow Band

Somewhere to ask questions about the best way to use SharpCap
MrAstroBen
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Joined: Fri Mar 16, 2018 12:19 pm

Re: Brain Function and Narrow Band

Post by MrAstroBen » Fri Jan 11, 2019 12:40 pm

I understand your limits here as I am also in the UK.

Easy to get caught out with cloud hitting and no blue channel aquired.

I now set my filter sequencer to get 2 or 3 of each filter. My focus is close enough on each not to worry.
then repeat as opposed to trying say 10+10+10+10

Other option is time your L&B for when the object is high in the sky.

As a rough guide i do one test image on each filter at the same exposure. Blue is usually weakest. So estimate x number more of these to help balance.

It can change though so no hard rule.

Rob

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turfpit
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Re: Brain Function and Narrow Band

Post by turfpit » Fri Jan 11, 2019 9:29 pm

Nick

I looked up your scope - very nice piece of kit. It looks like it is an f/6 scope. An f/2 scope would be around 10x faster than an f/6. This roughly means that if you capture 60s of data with your scope then the f/2.8 lens that Roger Clark uses could capture the same amount of data in around 6s. That is why he can acquire stunning images with 30s exposures. The Canon 7D camera is the result of many years of development, hence the lack of requirement for dark frames. The internal electronics of the camera deal with darks & bias. A NASA space scientist with 40 years of photography experience - I certainly take notice of what he says and does on his website.

This is why people spend typically £1000+ on a Hyperstar conversion for a Celestron SCT scope. An f/10 scope becomes an f/2 scope and can capture data 20 times faster - see the Starizon website.

If I had stumbled across alternative information 2 years ago, my equipment today would look totally different and I would be able to walk with it all on my back. :cry:

Dave

nexusjeep
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Joined: Thu Oct 18, 2018 3:01 pm

Re: Brain Function and Narrow Band

Post by nexusjeep » Fri Jan 11, 2019 10:33 pm

Hi Dave,
Mine is running F4.5 as I currently have the 0.75x reducer / flattener in as opposed to the straight 1.0x flattener when I am using it at the native F6 still not F2.8 though. It is a nice bit of kit if we ever get the skies to give it a major work out we were originally going to go for something midway in cost but then decided if we did that we would probably wish we had bought it or end up deciding to upgrade in the future so we bought it with the intention that it is the last refractor we will buy as it is big enough but still reasonably easy to move.

Cheers
Nick

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oopfan
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Re: Brain Function and Narrow Band

Post by oopfan » Fri Jan 11, 2019 10:55 pm

Now that the tension has subsided a bit please allow me to inject a bit of humor...

Several posts ago Nick began with "But surely..."

The adolescent in me could barely resist replying "Don't call be Shirley" but the adult had the upper-hand.

So now from the movie "Airplane":

https://www.youtube.com/watch?v=NSL4buk0OmY

Brian

nexusjeep
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Joined: Thu Oct 18, 2018 3:01 pm

Re: Brain Function and Narrow Band

Post by nexusjeep » Fri Jan 11, 2019 11:01 pm

ooh the memories of Airplane / Police Squad and the Naked Gun :D

Showing my age now.

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oopfan
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Re: Brain Function and Narrow Band

Post by oopfan » Fri Jan 11, 2019 11:33 pm

Don't get me started with Police Squad:

https://www.youtube.com/watch?v=het1kl-A8qw
:lol:

Brian

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