NA and pelican through a 200mm lens

[rocketandroll]

Hi folks

Thought I;d have another stab at this with the new 500D.

I actually spent most of the night imaging Sadr but for some reason the 70 minutes I have on that looks awful and the 12 minutes I have on NGC7000 looks great?

Much as with the Lagoon/Triffid pic last weekend... it seems as if 10 - 15 minutes at f2.8 is some kind of sweet spot for getting a nice well balanced image of nebulae with this lens/camera combo?

Longer than that seems to just result in burnt out stars that dominate it and take away most of the detail in the nebula.

Anyway, here it is, as I said, just 12 minutes or so of data with 10 mins of darks and 20 flats applied. Imaged through the 200mm L series f2.8 lens on the modded 500D on a (suddenly very temperamental) HEQ5-Pro, unguided in 2 min subs.

Ben

[rocketandroll]

The pic was looking a bit out of focus on the large image, so thought I'd post some close ups too...

I'm quite impressed with the clarity it's achieved on the miriad of tiny blue and white stars in the nebula...

seems much clearer than past pics I've taken with this lens.

Ben

[rocketandroll]

Sorry, clogging up my own thread now :-)

I just dug out my first attempt at this target through the same lens earlier this year.

Now I don't know if my processing has just improved a lot (I don't think it has)... or if it's just down to the camera... but...

Here's my first pic of the NA alongside the new one. Both are taken through the 200mm L series lens, the old one with my 350D and the new one with my 500D, both are astro-modded. Both images taken at f2.8 and 800ISO. The old one had the dissadvantage of no LP filter, but the advantage of being over 40 minutes of data in 2 minute subs. The new one is just 12 minutes of data in 2 minute subs.

Erm.... why is the new one so much better and less noisy?

Everything suggests it should be the other way round?

Ben