Live stacking with Barnard 104

[Martin Meredith]

Having spent much of the last month at latitudes between 56 and 63 deg N, it's a relief to return to some astronomical darkness here at 43 deg, notwithstanding the near-full moon. For some reason the skies at the moment have a nasty habit of clouding up around midnight but on Monday -- coinciding with the release of LodestarLive v0.9 -- they held off until around 1am, giving me just enough time to collect some darks, misalign a couple of times, explore live stacking on M4, before focusing on my main target for the session, Barnard 104.

This dark nebula required some camera-based star-hopping (from the Wild Duck Cluster, M11), but is pretty easy to find as it lies just 20' N of Beta Scutum (whose presence can be felt just at the mid-base of the image). B104 is variously known as the fish-hook, the number "7" or the number "1". Unlike Barnard 72 (The Snake) which I posted on a month or so ago, this object is easy prey for observers in more northerly parts, sitting around 40+ deg above the horizon when I observed it. 

The first image shows an unstacked 60s exposure while the second is the result of live-stacking 8 of them in mean mode. Even with the 90% moon in the vicinity, dark nebulae (the field is full of them) seem to stand out well. 

Usual setup: 80 mm f/6 achromat on alt-az mount, no filters, plenty of bloat ;-)

Concerning live stacking, I found that with an interesting object like this even 60s subs come in quite fast and I think in the end I observed this for a good 15 minutes with the 'picture quality' improving all the while. I imagine with much shorter exposures one's attention might be divided between checking the latest sub for accept/reject and actually observing!

Thanks for reading

Martin

[Paul81]

Nice shots and write-up Martin! I think it looks more like a 7 - its a fascinating object. You have certainly sparked my interest in hunting these dark nebulae down once the longer nights return.

With live stacking it almost feels more akin to visual - i.e. you observe objects for a period of time to tease more detail out with the eye. Its now similar but using the camera instead, whereas before I used to just grab a frame or two and move onto the next target I will now spend more time observing the target like I would visually to see what extra details might appear.

[Martin Meredith]

Thanks Paul. It definitely feels more like visual due to the changing image and at the same time the image is more stable -- the odd gust of wind or knocking the scope doesn't mean another X seconds of waiting for the next one. For that alone having the ability to stack and undo is worth it.

It's cause for celebration that the days are getting shorter now... (yet another reason people think amateur astronomers are weird...) 

Martin