Several firsts ... so be gentle with me!

[Demonperformer]

This is my first attempt at imaging a globular cluster and, just to be different, I selected M5.

Unfortunately I was later getting out this morning than I planned and so the sky was a bit bright (NTS: must set the alarm for 3 instead of 4 in future). Focussing leaves a bit to be desired (NTS: must produce bhatinov mask before much longer).

This is also the first time I have tried imaging using sharpcap software (developed by Robin 'rwg') so had a little bit of fun at the start (just getting used to it).

Took 3 avi's on the mintron + 1 with the lens cap on [df] + 1 unfocussed on a clear patch of sky [uf]. Then sky was far too bright to do anything. When processed using uf as a dark frame, none of the data avi's showed anything:(. So processed using df as a dark frame and this is the best of a bad bunch.

Technical details:

102SLT on SE [alt-az] mount

264 sec of capture at 128x sensitivity [2.56 sec of data per frame]

Registax5 selected 18 out of 103 frames, so total data time 46.08 sec

Wavelet adjustments: layers 1, 2 & 3 each set to 30.4

Contrast set to 200

Brightness set to -10

Opinions/thoughts welcome, but please be gentle - I'm learning as fast as I can.

Thanks.

[Deneb]

Not bad at all, just remember to take your time when imaging & go at your own pace.

Nadeem..

[Taff]

Hi' Weldone with your capture of the glob cluster.Don't worry we all got to start with a camera and scope if you want to do astrophotography' way to go.M3' M13' are nice to go for Good Luck.Mark

[themos]

Is this a 100% image or is it reduced? If it's the full thing, I don't see anything wrong with the focusing. As always, more exposure time helps. I think df must stand for dark frame so you should be using that for dark subtraction. That's a whole lot better than my first effort, for sure!

[Demonperformer]

Thanks for your encouragement, guys.

Themos: The image you get when you click on the thumbnail is the full size. And yes, 'df' is the avi I took with the lens cap on. There was a thread on sgl a while back where someone was saying that you can use an image that has been taken of a blank bit of sky nearby, unfocussed, as this removes any background glow as well. I have tried it on a few images and found it gives less in the finished image [presumably because you are subtracting a greater amount from each frame]. Think I will stick to the standard 'lens cap on' dark frames in future (at least until I have a bit more idea what I am doing and why)

Am currently wondering, as I have three images from this morning's efforts [one from each avi], whether it would be worth putting them into DSS to see what it comes up with. As they are already dark-frame adjusted, presumably I would just need to put the three data images into it and let it do its own thing .... mmmm ...

[themos]

The blank bit of sky shot is for "flat-fielding", not dark subtraction. You do a different arithmetic operation with it. Here's a rough explanation:

Digital Imaging - Flats and Darks Explained! - IceInSpace

[Demonperformer]

Thank you so much for that, Themos.

I have now reprocessed the original avi using both the proper dark frame and the flat field frame [which i was calling uf in the original post]. Tweaking the sliders [layers to 50.0, contrast to 309 and brightness to -20] has brought out somewhat more detail.

The other two avi's also produce much better results, so I am even more tempted to download a copy of DSS and see what it can make of the three together [which would be a whole 92.16 sec of data! ].

[Demonperformer]

OK, tried that. Eventually got DSS to stack 2/3 of the photos. Not sure that it is an improvement. Several funny straight lines. But then, I suppose this is not really how DSS was designed to operate. Have had to convert to jgp as tif is too big. Hopefully I will have the chance to try it with some of my DSLR images shortly ...