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M13

ejwwest

By ejwwest
in Imaging - Deep Sky

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ejwwest

ejwwest

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Hi,

Really nice image there's something special about M13

could you tell me your setup.

Thankyou BigBlueOne.

The scope is a Celestron CGEM EdgeHD 925 f/10. I have a Moonlite Crayford focuser and used a Bahtinov mask to get a good focus on Vega. The camera is a Canon 40D DSLR and exposure was 1 minute at ISO 1600. I'd polar aligned according to the CGEM alignment procedure which has normally been about 45-60s before trailing occurs but must have fortuitously been rather longer. I used the long exposure and high ISO noise reduction settings on the Canon.

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ejwwest

ejwwest

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I had'nt realised how big your F/L was on your scope, also do you notice a big reduction in your noise

with the iso at 1600 and the reduction set on.

Thankyou BigBlueOne.

The main benefit of the long exposure noise reduction is saving the problem of taking a dark frame and subtracting it. For individual shots that's ok, but taking a large number of subframes it's better to take individual dark frames and letting the stacking software subtract them. I can't say I notice much improvement with the high ISO reduction: it still looks grainy and stripey!

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Anweniel

Anweniel

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Lovely M13 that :)

The scope is a Celestron CGEM EdgeHD 925 f/10. I have a Moonlite Crayford focuser and used a Bahtinov mask to get a good focus on Vega. The camera is a Canon 40D DSLR and exposure was 1 minute at ISO 1600. I'd polar aligned according to the CGEM alignment procedure which has normally been about 45-60s before trailing occurs but must have fortuitously been rather longer. I used the long exposure and high ISO noise reduction settings on the Canon.

Initially felt this seemed very low for the CGEM then realised the FL you were imaging at! Don't think this target requires a high exposure length anyway and the 60s has given you plenty enough detail :cool2:

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ejwwest

ejwwest

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Whats your choice of software for stacking you dont mention it, Plus I,ve been to flickr to view your Images

which I enjoyed very much.

Thankyou BigBlueOne.

This was a single frame. Last Summer I took a series of 30s exposures of M13 with dark frames and stacked them with DSS but don't think the result was as good as this, which suggests a longer exposure (if you can track reliably) is probably a better tradeoff. The problem is getting the tracking close enough and whether I was merely lucky with my setup on Saturday!

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BigBlueOne

BigBlueOne

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It seems that sometimes when Im out nothing can go wrong align with eqmod guides no worries, another

time I could,nt track a bus down a cul de sac so your not the only one.

But isnt great when it all does come together.

BigBlueOne.

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BigBlueOne

BigBlueOne

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Im glad its not just me Gina, but it can be so frustrating sometimes

I,ve had to actually think what to do next.

On other occasions you could be speedy gonzales slewing before

I knew what to slew at, my only regret is not doing this 20 years ago.

BigBlueOne.

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ejwwest

ejwwest

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It seems that sometimes when Im out nothing can go wrong align with eqmod guides no worries, another

time I could,nt track a bus down a cul de sac so your not the only one.

But isnt great when it all does come together.

BigBlueOne.

I set my scope up last night and concluded that as well as a good polar alignment the balance of the counter weights makes a big difference. I had to rebalance and then recalibrate.

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