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My first 30 minute sub


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To continue the 'my first....' theme, last night I successfully captured my first 1800s (30 minute) narrowband sub. This was after 16 1200s (20 minute) subs and the heart was approaching the meridien, and I needed to go to bed, and as the clouds / rain were coming in, I stopped after this and closed the roof / shutdown.

The attached has had an automatic STF applied and nothing more (so no calibration of any kind), saved as a reduced resolution png to view on here, but the attached .tif is full scale.

I'm incredibly pleased with this as I can't see any field rotation, so from now on I will forget 20 minute subs and go on to 30 minutes for narrowband only.

Imaging scale is 3.18"pp, with a WO Star 71 II and Moravian G2-8300, using a Baader 7nm Ha filter, on an AZ-EQ6.

SGP solved and centered, autofocused using SharpSky, guided with PHD2.


Heart Nebula_1800sec_1x1__frame10-20C.tif

Edited by Jonk
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Good! Now the thing about deep subs is that you have strong signal at the bottom end of the brightness range. To exploit this I prefer to go for an aggressive stretch in Curves, hauling out the contrasts in the faint signal.


This horrifies some people but I'd at least give it a try.


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It’s a great idea in principle, I’ve been doin* it for some time, however in the uk; it’s really fraught with difficult our weather doesn’t lend self to long subs, our average seeing is pants due to the moisture that lingers so good conditions are rare.

but...it is worth it and I’ll continue to do it, you just have to have patience and don’t get eager to accept subs that just aren’t good enough because they are long.

thats a great sub and well done.


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Thanks all, nice to hear no-one has said 'very good, however...'!

I agree that the weather is one of the biggest enemies in this game, but to be perfectly honest, we weren't even meant to have clear skies here last night, and I suspect there was lots of thin high level cloud floating through all night.

I'm very happy with it, as it proves that I sort of know what I'm doing and the kit is behaving as best I can get it to.

Also this is only 1 untouched sub....if I can get many more 30 minute subs, then calibrate and stack properly, I'll post it back here and who knows, the next stage is colour from Ha, SII and OIII.

Baby steps and all that first though!

Edited by Jonk
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