Horsehead 28/30 Jan

[JohnP]

Thks Mark - Surprising clean image for a single 30 sec sub. Have to say it is amazing when you put that single sub & the final image side-by-side. Once again you need to make sure you get an A2 print of this done - John

[The Thing]

A few of years ago I'd have been happy to have that sub as a finished image!

[RobertM]

Pretty impressive skies, I'd say it would take me at least 10-20 subs to get to the same  quality as that single frame.

Robert

[Carole]

Yes, agree with all the above comments. 

Carole

[Fay]

Great image Mark, as ever

[MarkS]

I forgot to mention one very important benefit of using short exposures on the C11.  It completely removes the issue of star trailing caused by slight shifts in the primary mirror as the scope tracks across the sky. 

The usual way of avoiding this problem is to use an OAG (off-axis guider) but using short exposures is an excellent alternative.

Of course you need a camera with very low read noise - the Sony A7S at high ISO is perfect for this

Mark

[Carole]

That is indeed a bonus.

Carole