Still New To Mono But Getting There!

[Budgie1]

Since getting an Atik 428EX camera & SHO filters from a fellow SGL member + filter wheel and LRGB filters to go with it, I haven't had many clear nights to work with. So practice with the mono setup has been limited.

I started with an SHO image of the centre of the Heart Nebula, so I decided my second project would be a broadband target and chose M33. I started this on the 15th December and managed a good set of Luminance subs (20x 180s), then the 25th December I got 20x 180s Red filter and 4x 180s Green. On the 31st December I managed another 9x 180s Green, with 4 more on the 17th January and finally finished the project on the 18th Jan with 3 more green and 10x blue. None of the nights was perfect, with passing clouds or thin high cloud, but this is what I ended up with and I may add more blue data to it, just even things up.

It's alright, but I'm not overly impressed.

Next was NGC7635, The Bubble Nebula, where I went back to SHO and managed to get three hours in total over a couple of nights.

I'm still working on this one but I'm pleased with what I've got to date.

Finally, IC434, The Horsehead. Now that I have the observatory to image from, it's also meant that I get a better view of Orion at this time of year. Before I was lucky to get a couple of hours between trees on the South side of the garden. With the pier in the observatory, the scope is higher and slightly further West, so I get about 3.5 hours per night now.

Sadly, I've only managed 50 minutes of Ha data so far, but I went ahead and processed it anyway.

These were all using the Atik 428EX connected to a Sky Watcher 80ED DS Pro with 0.85 FF/FR on the HEQ5. Stacked & processed in PI.

C's & C's welcomed, as always.

 

[wimvb]

That's a very nice set of images.

10 hours ago, Budgie1 said:

It's alright, but I'm not overly impressed.

Regarding LRGB imaging with a classic ccd camera, the general idea is to shoot RGB binned x2 to help get the noise and total integration time down. L at bin 1 with something like double the integration time of RGB to get the detail. This is different from LRGB CMOS imaging, where there isn't as much benefit from binning the RGB, and everything is captured at the same bin level. In your case, you captured 1 hour R, 1 hour G, 30 mins B, and 1 hour L. If you captured everythung at the same bin level, you could try combining the 4 masters into a composite synthetic L in order to get the noise down. Just use image integration with weight 1 and no pixel rejection. Then process the RGB master for maximized colour, and the L for maximized detail before LRGB combination.

[newbie alert]

Nice set of images

Why aren't you impressed

It would be better with more data, 20x3 mins of luminance is an hour, and I'd double the luminance to the rgb

I'd be doing 5 min subs instead of 3 for the RGB and I'd be doing 10 mins on the Ha 

With any camera a few hours of integration the data is far easier to work with than just 1

 

[Budgie1]

4 hours ago, wimvb said:

That's a very nice set of images.

Regarding LRGB imaging with a classic ccd camera, the general idea is to shoot RGB binned x2 to help get the noise and total integration time down. L at bin 1 with something like double the integration time of RGB to get the detail. This is different from LRGB CMOS imaging, where there isn't as much benefit from binning the RGB, and everything is captured at the same bin level. In your case, you captured 1 hour R, 1 hour G, 30 mins B, and 1 hour L. If you captured everythung at the same bin level, you could try combining the 4 masters into a composite synthetic L in order to get the noise down. Just use image integration with weight 1 and no pixel rejection. Then process the RGB master for maximized colour, and the L for maximized detail before LRGB combination.

Thanks Wim,

I knew about making the luminance about double the RGB, but not about using bin 2x2 for teh RGB, so everything was captured at bin 1x1. But now I know for next time.

I had a go with the synthetic Lum and trying to boost the RGB. There's a green hue right of centre but it looks a little better. 

This was my first LRGB image, so I learn a little each time.

[Budgie1]

3 hours ago, newbie alert said:

Nice set of images

Why aren't you impressed

It would be better with more data, 20x3 mins of luminance is an hour, and I'd double the luminance to the rgb

I'd be doing 5 min subs instead of 3 for the RGB and I'd be doing 10 mins on the Ha 

With any camera a few hours of integration the data is far easier to work with than just 1

 

It's only the M33 image I'm not that taken with. Thanks to Wim's suggestions, I know how I may improve it next time and thinking about it, some of the issue may be with the cheap ZWO LRGB filter set I got, so I'm on the lookout for a better quality set.

The issue with the integration time was mainly weather related and rushing to get something in the bag. M33 was an experiment to see what to do with mono LRGB data but it took much longer than intended to get any data. Dodging clouds and nights when I get 3 or 4 images and then it clouds over gets frustrating and I wanted to move on to another NB target when I did have the chance of a good session. So this one wasn't taken seriously and was rushed.

Taking 3 minute subs meant I wasn't throwing away too many due to clouds for the LRGB image. On the Ha image, I was using 5 minute subs because the sky was clearer, I just didn't have enough time on the target before the trees go in the way. I will got more on this one, now I know I can see it better.

I'll also have to try using 10 minute subs and see how I get on with it. Thanks for the tips.

[wimvb]

3 hours ago, Budgie1 said:

I'll also have to try using 10 minute subs and see how I get on with it. Thanks for the tips.

Before the days of Starlink, ccd imagers could get away with just capturing a handful of 30 minutes exposures, if the mount allowed it. But I think that is not practical anymore. Just make sure your exposures clear the read noise floor, and collect more and shorter ones. That way you can remove any that have too many satellite trails.