Improving - M47, M46 and NGC2438

[iceman]

Hi all

This image of M47 (left side), M46 (right side) and NGC2438 (planetary nebula in M46) was taken on Sunday morning, about 3am.

Transparency and seeing were both very good. My polar alignment wasn't great so I couldn't go 120s exposures, but 90s worked ok with minimal trailing.
The sky was getting brighter and I wanted to image Mars, so I only took 10x 90s exposures.

This image is a big improvement over my previous ones through the ED80, but it's not so much the way i'm capturing the images (that's the same as before) - I think my processing has improved using ImagesPlus. I still can't get the "automated" image processing to work with good results, but if I convert the RAW's to TIF's first, stack the darks to create a master dark, calibrate the lights with the darks separately, and then align/combine the calibrated lights, the images comes out well.
I must be doing something wrong with the settings in the "automated" routine, because they just come out too dark with no detail.

So anyway, details:
- EQ6 + ED80 + unmodded 350D
- 10x 90s lights (unguided), 10x 90s darks all at ISO1600
- Calibrated, aligned and stacked in ImagesPlus
- DDP in ImagesPlus, noise-reduction and curves in Photoshop.

Once I get my 0.8x WO reducer (should be here in a week or two), the field will be flatter. I really need to work on my drft alignment too (ie: not be so lazy).

Anyway it's slowly getting there. I'm happy with this double-cluster image, my first of this region of sky.

[Garyh]

Now thats very nice Mike!
composition is great and stars look pretty good as well!
A lovely image, well done :thumbsup:

[[1ponders]]

Nice Mike :thumbsup: NGC2438 is one of my favourites.

Dark results from automated processing in Images Plus is pretty standard for me as well. And understandable if you consider that the 16 bit fits or tiff files are stretched to their full 0 - 65535 tonal scale. If you save them as tiffs and then open them into PS you then raise your black point with levels to just to the left of the histogram and then use curves to stretch the dark to mid range. If you do this a couple of times (using levels in between to raise the black point to keep it just to the left of the histogram) you will see the detail come out.

[iceman]

Thanks Gary and Paul.
I'm happy to have some star colour there but I feel there's still not enough blue and yellow/red stars.

You could be right about the levels, Paul. I'll give it a go next time. It certainly would be much easier and quicker than having to convert them to TIF first.

[[1ponders]]

I still convert my fits to tiffs in IP. I prefer to work with tiffs in PS than fits for some reason. Just a personal preference I guess.

The other thing too is that you are only using 90sec exposures. You might try using the add combine option instead of an average or median combine. That would give you more dynamic range to work with.

[xelasnave]

Another wonderful image Mike... congratualtions.
Please try my method of taking an exposure with the scope in home pos. so as to get some trails and adjust so they center... if nothing else it is fast..if it works for you that is.

Also have you considered a permanent pier?
I was thinking you could have a pier with the mount set on it permanet and throw a garbage bin over it... something a bit more imaginative but you get my drift ( oh no a pun sort of) ... I was going to do that initially and build a mini dome to cover the pier and just the mount something that just lifted off and then add the scope... I think you will fast approach the level where getting polar is a frustration simply because of the time taken when you could be cooking at the scope.

In addition you can refine it each night... I am so happy that I dont have to worry that much about polar now... I am getting hand guided runs of 9 minutes..nine minutes because I train the PE and take a photo at the same time ..the buzzer is a great timer for me as I dont have that sort of software in place.. and I add that it is only the RA running a little slow that I correct... if nothing else my recent Horse with a 1170 second run says polar is not bad.

Anyways great work you are doing fantastic captures.

alex

[[1ponders]]

These two images will show you what I mean.

The first is a median combine of 6/600sec ISO800 shots.

The second is a straight add of only 3/600sec ISO800 shots.

You can see the second one is much brighter and contains more obvious details but if you look at the histogram the stars have already started to clip on the right of the histogram. I could have used an adaptive add or some form of sigma adding to prevent the clipping if I'd really wanted to do that. Unfortunately with using that sort of technique you often don't have a lot of control over what is rejected to prevent the clipping. IP has an adaptive add but I've not used it much as I prefer either median or averaging 'cos I can take nice long shots and don't need it.

[Ric]

A lovely image Mike, everything is nice and sharp and you have some nice colour throughout as well.

Well done.

[Alchemy]

youre moving along fine. you could try stacking in deep sky stacker version 3.0.1 and see if theres a better result.... i went from AIP to this program and found a better colour balance and finer detail, you do have to save the image as the version of the final stacked that apears on the screen at completion is brighter than it saves as . this program automates the whole routine easily....and its free.

when you get to the auto guiding your dmk will work with PHD

just try increasing the saturation to improve star variety on this image

[iceman]

Thanks guys.

Paul - I often do use the Adaptive Add in IP for stacking, because as you said my exposures aren't long enough so that averaging usually ends up with the result too dim. Obviously the result of the add is a bit noisier than the avg because it's going to be adding the noise as well.

Auto-guiding is my next step (my GPUSB kit arrived yesterday), but I just need to figure out how to mount my 2 refractors together securely and still be able to balance them properly.

[[1ponders]]

You should end up with less noise when adding compared to averaging and median combining (not sure about adaptive add though). It's controlling the clipping that makes it so difficult to use.