M45 Guidance

[johnb 96]

So as I was packing up there was M45 so I got 30 mins worth of 300 sec exposures along with Darks and Flats, a quick process and the result is below, oh using the kit in my signature

Already I feel the stars are getting over exposed so can I solve this simply by taking shorter exposures but more of them to get the nebulosity or am I missing a process trick, I have heard of using star masks but im not sure if I fully understand how so use them (if they are the right answer)

Thanks in advance

Regards

John B

[Dann 10]

I think thats a nice image.

I was hoping to have a go at M45 this weekend, what ISO did you use? Would it be better to lower the ISO and stick to the long exposures?

[MjrTom 19]

Thats really nice.

All my attempts on this target never turn out that good. Local LP kills the nebulosity of Merope....

[johnb 96]

thanks for the feedback, I was using ISO of 800, maybe a lower ISO will do the trick, of course my other issue is that with my kit i cant get the complete M45 in my FOV so I will have to mosaic it - just oen thing after another.

Regards

John B

[Keiran 261]

That is a very nice image... As you said it may be slightly over exposed (you seem to have lost a little coulor in the stars)

I would be interested in what the settings were that you use for this? Expo time, ISO and amout of Expos

I like the shot you got, its different to the full M45 in a good way

Edited September 23, 2011 by Keiran

[johnb 96]

I would be interested in what the settings were that you use for this? Expo time, ISO and amout of Expos

I took 6 x 300 second exposures at ISO 800 and combined in DSS

Regards

John B

[jgs001 1,174]

I think that to get M45 and the stars is a tough challenge. You need the longer exposures to get the nebula to show up nicely, and you'll blow the stars in doing it. Perhaps taking a few shorter exposures (say 30 seconds) and blending a stack of those, for the stars over the nebula would work. I'm planning on having another go at M45 this year, and that's my intent.

[johnb 96]

blending a stack of those

Thanks, does one blend in the stacking or when processing ? Im using photoshop so any online tutorial would be great

Thanks

John B

[jgs001 1,174]

John, I plan to stack them separately and blend them in processing later. That's what I did with my Orion neb and trap last year.

[johnb 96]

thanks

John B

[Earl 1,283]

There is a lot more there than you think

[johnb 96]

Wow, tell me what I did not do. This is great. John b

[Earl 1,283]

Using Pixinsight I did a Dynamic Background extraction, which helped remove the gradient, then boosted the Luminosity with Curves.

Edited September 23, 2011 by Earl

[johnb 96]

Err right. I'm a photoshop person and I did a couple of iterations of levels just moving the black point a small amount each time time and then used curves a few time. I obviously need more practice. Thank for your explanation.

[mark7331 11]

John you can try adding shorter exposures but another technique is to make a star mask and then try stretching everything apart from the stars. You can pick up the nebulosity without blowing out the stars. Just be careful that you don't leave a dark halo round them.

I did this in PixInsight by creating a star mask and adding a range mask to it so the larger star halos are included. I'm sure you can do this in Photoshop.

Hope this helps.

Mark

[JimStan 11]

Don't you just LOVE all the different results you can get with the same data ? ? ? Just one of the MANY fascinating aspects of digital photography ! I LOVE that image in post #11 !

Jim S.