MartinB

Dave, as Tim says, I have used an SX AO unit a fair bit and my experience is that it tightens stars and also enhances resolution. This is when used with a 10" Meade ACF typically in conjunction with a focal reducer and working at a focal length of around 1800mm. As a minimum I have found that you really need 4 guide corrections and 10 corrections per second is better still. With my lodestar 1 this requires a mag 8 star or brighter. You set it up pretty much like any OAG but with additonal cables to the computer and, in my case, the mount. It helps to plan in advance. I use Sky 6 and have an FOV indicator showing the position of both chips which helps me work out the framing. I use Maxim but presume there are drivers available for other capture software. Other than the extra layer of complexity the main problem I have encountered is a bit of tilt as a result of the long image train. I do think it is effective system even in good seeing but there are a lot of targets without a suitable guide star.

A very lean year for me. Away a lot and also spending more time on night time landscape photos. Need to get my dome automated!

Yes, I've given up with osc from my light polluted site. This wasn't based on theory as much as what I end up with from a given amount of imaging time. I would be interested to hear from anyone who has found osc outperforming lrgb, esp with regard to signal to noise ratio

That will have queues forming at any star party you choose to go. Fantastic set up.

Ideally your dark exposure times should match those of your lights. When this is the case they will also subtract the bias so you shouldn't use bias frames. If your darks are shorter than you lights you can multiply them to match your lights but you must subtract the bias from the darks before doing this. You do then need bias frames for your lights. Hope that makes sense, it gets a bit confusing especially if you then start doing darks for your flats!

Any updates Brian? The problem with finding things is the combination field inversion combined with the equatorial axis shift. However, an equatorial mount is just an alt az mount on a 50 degree slope! If you can adopt this mindset, with a bit of practice things start to fall into place. Turn Left at Orion is a great book for developing your star hopping finding skills. I would also recommend either a red dot finder or it's more sophisticated big brother a Telrad. I once tried to help someone through the procedure of using the polar scope It's harder to describe it than to use it!

Wonderful as the HST image is the question for me is, what would the image be like if all that SII time have been spent on more Ha and SII? I'm still liking that bicolour!

Magpie Mine is an old lead mine in the Peak District between Sheldon and Monyash. Canon 6D with Samyang 14mm lens

Passed this spot several times whilst out on my bike and thought it a good place to come with camera and tripod one night Canon 6D with Samyang 14mm lens

Thank you Ian, Piero and Paul

Thanks a lot Barry. Hope to keep the mn190 in service for years to come!

Not having to do meridian flips would be wonderful!

Thanks Stu!

Is the problem occurring in all 4 channels? Are you using curves to stretch? This target like many others contains 2 or 3 very bright stars which will tend to saturate during the process but yours do look very harsh.

You are likely to get quite a lot of reflected light unless the shield is well flocked