M46 and NGC2438

[Viv]

Thought i'd try a cluster for my second DSO image - this was placed nicely in the sky / garden combo.

It's only 20 x 160 sec subs @ 400 iso

no darks, flats or lights (yes i do have a couple of bunnies)

Only basic editing, as it'll be at least next month before, I get any software,

thanks for looking.

PS - would like to add more subs to this, to get better detail.

PPS - Amazing when the moon is asleep what can be done !

[Woody]

Nice shot.

Like you say when you get some darks (and flats to get rid off dust bunnies?) it will come up better.

What software are you using for the basic editing?

[Viv]

Thanks much.

It's called professional photo editor, came with my camera.

Think I'm going to get Pixinsight. Also love that you can try it of 45 days, before buying !

[Jessun]

Nice image Scarlet! With some help I now find PI very powerful. I wouldn't say easy to use but can only recommend it anyways!

You can see a few hot pixels in your image and as the mount drifts slightly so do they, and looking closely you have a streaky look to the background and it's all aligned with the hot pixels, so the noise is now not so random anymore, it has formed a pattern caused by the drift.

I think if you can dither between the subs - the guide program moves the scope by a tiny bit in some random direction - then the streakyness will fade. At least that's what I found using a DSLR. Also give the camera a while to cool between each image. I don't have a number but say 20 seconds or so.

Then chuck some darks in the mix.

That should leave you with a much better bunch of subs to stack :-)

[Viv]

Jesper - thank you for that.

Some brilliant & very helpful info there.

Must admit did find alignment last night a bit troublesome, so I don't think that helped !

[Zul]

Nice shot!

[Shibby]

Very nice, Scarlet. Maybe it's just my monitor, but I don't see any dust bunnies??

It looks like the focus is a little bit out. Do you use a bahtinov mask to focus with? If not, I highly recommend. I used a homemade paper one until very recently!

[iwatkins]

Nice Scarlet. Looks like you have this guiding lark sorted (which was your problem before yes?).

You are using the 7D I think? Have you considered bumping the ISO up, to say 1600? You can get more detail more quickly and modern Canon DSLRs are good on noise even at ISO1600. And as Jessun suggests, stick a pause in between subs to allow the camera to cool a bit. I do go for 20 seconds usually.

i.e. using APT, each sub =

1. 5 sec pause between mirror lockup until shutter opens.

2. 60 sec sub then shutter closes

3. 20 pause for cooling (and image download over USB to laptop)

... then repeat.

At ISO1600 this seems to work well.

I've also been playing with the 7D these past few days and darks appear to be a must, aim for around at least 20% worth over the lights. E.g. 10 minutes worth of subs, then at least 2 mins worth of darks. Anymore than 40% darks and it doesn't seem to make things any better, 20% - 25% seems about right. (As you can probably tell, I spent most of the weekend trying all sorts of combinations in DSS).

Flats/bias if necessary. I personally couldn't see a lot of difference using them, but I will continue for a while before I do really stop using them.

In my case, this is a 7D on an Evostar 80ED with the dedicated flattener/reducer in place. Which incidentally gives a very solid imaging train as everything is screwed together.

Cheers

Ian

[Shibby]

...darks appear to be a must, aim for around at least 20% worth over the lights. E.g. 10 minutes worth of subs, then at least 2 mins worth of darks. Anymore than 40% darks and it doesn't seem to make things any better, 20% - 25% seems about right...

In theory, the amount of lights taken is irrelevant. The more darks the better; they add noise to each light sub you subtract them from, so the more subs you take the less noise they add. I always use at least 20.

[iwatkins]

That would make sense Shibby. Maybe my case only applies to the few targets I used in testing.

Ian

[Spikey]

You're off to a great start Scarlet, well done.

In theory, the amount of lights taken is irrelevant. The more darks the better; they add noise to each light sub you subtract them from, so the more subs you take the less noise they add. I always use at least 20.

I agree, go for as many darks as you can at least 10-15 but more like 20+. Flats make quite a big difference as well. I've never noticed much of a difference when applying BIAS frames but they take so little time to do and a set will last several months that I tend to use them anyway.

[Viv]

Guys - thank you for the kind comments.

Lewis - the bunnines are on the wide version - this is less than a quarter of the original full image.

Ian - that's awsome detail, thank you lots. My previous problem was the mount, EQ5 with battery motors just doesn't work for beginners (it's tough remembering everything else).

I know a few people do this already, but time to start logging, everything I do & what effect it had. I keep thining that DSO imaging is so much easier than planets !! Think it's about to kick me & a bit of realisation, that it's not