Advice on NGC 3372

[davelrkn]

Hi All

Just new to the forum and new to DSLR imaging and would like an opinion of this image of NGC 3372 and I do realize it has a classic example of Coma.I am in the process of purchasing a Baader MPCC for my setup.

I am not sure if I have the colour balance correct (am slightly colour blind) as it was originally more to the Cyan and has been shifted to the red.I have also made adjustments in levels and curves from hints and tips from this forum.

The image was taken with a Canon 450D using Raws,in camera NR, no filters 4min singleshot,Autoguided with 80mm guide scope through Skywatcher 254mm(10'') F/4.7 EQ6 pro under light poluted skies.

Any advise would be welcomed

Regards

Dave

[roundycat]

three days and no answers? I would suggest you carry on doing what you are doing. I am not familiar with the object but the colour looks sound. Just maybe back off a bit on the contrast.

Dennis

[jcm]

Is this the Eta Carina Neb ?

You have done well and captured a great deal of detail.

The sky is very black , which indicates clipping at that end of the histogram. Taking several images and stacking them will reduce noise.

The colours are pretty good a bit over processed for my tastes but this a personal view.

A light pollution filter is a must , CLS or IDAS seem to be most popular.

John

[davelrkn]

Hi Dennis & John

Thanks guys for your replys

Yes John it is the Eta Carina Neb or also known as the Keyhole Neb

It is considered to be the showpiece object of the Southern Hemisphere.I would like to take a series of images of this NEb but on the night, could only manage a single shot as there was cloud streaming accross most of the night.

John do you think I need to tone the processing down a little to make it a little more natural looking.When you say clipping do you mind telling me what you mean by that as I am very new to the processinng side of things.

I do have a light polution filter coming with the Coma Corrector

Thanks again

Cheers

Dave

[steppenwolf]

You have captured an amazing amount of detail but I too feel that it has been overcooked a little in the processing - more subdued brightness and contrast would, I feel give a more natural and pleasing result but remember, beauty is in the eye of the beholder and your colour blindness may mean that this image is attractive for you and that is the most important issue.

On a secondary point, I have the same 10" Reflector as you (although mine has the R & P focus whereas yours may be a lower profile Crayford and may have different fixings for the 2" eyepiece holder) and I also have an MPCC. If you have the older style focus unit, you will not be able to achieve focus with the MPCC in that 'scope because there will not be sufficient inwards travel using the standard Skywatcher supplied adapters.

If your focus mechanism looks like the following (this is my 8" but it is identical to the 10"), let me know and I can probably advise you on a work-around.

[jcm]

Hi Dave,

If you load the image into most software - Photoshop , MaximDL , AstroArt , Images Plus or the program you used to take the image - look for the histogram display button.( often looks like a little graph ). Most displays have black on the left , check the curve on the display does not stop abruptly on the left hand side but comes down ( fairly steeply ) to hit the horizontal axis. Faint image data ( hidden in the lost black area ) would be lost if this happens.

John

[davelrkn]

Hi Steve

Thanks for your reply

Yes I have the old style rack and pinoin but did have the crayford on the 8'' before I sold it for the upgrade to the 10'''. Do you believe I will have an inward focus issue as they state in the specs that the MPCC adds about 10mm outward focus and could it be different with the fact i am using a 450d

Cheers

Dave

[davelrkn]

Hi John and Steve

Thank you both for your input I will take on board your advise and make my adjustments a little more subdued in the contrast and brightness areas and John will have a look at the histogram a little more closley now I know what to look for as this is all part of the learning curve.

Thanks again guys for your time and sharing your expertise too a newby in imaging

Cheers

Dave

[steppenwolf]

Do you believe I will have an inward focus issue as they state in the specs that the MPCC adds about 10mm outward focus and could it be different with the fact i am using a 450d

Whilst it is true that the MPCC gives 10mm of effective inwards travel, the problem is as follows:-

The MPCC has a 2" barrel and thus forms its own nosepiece which is great BUT to get a 2" pushfit on your focus tube you have to put the supplied 2" adapter into the non-standard throat (57mm dia. approx) of the focus tube and this extends out by 36mm whereas the 'T' thread adapter that is exposed when you unscrew the 1.25" EP holder is flush with the end of the focus tube. 36.0 - 10.0 means that you have extended the system by 26.0mm and therein lies the problem as I doubt that you have an additional 26mm of inwards focus travel on top of what you currently use?

[davelrkn]

Hi Steve

Thanks for the info

Looks like I could have an issue here will let you know how I go as I expect the Corrector to arrive Monday or Tuesday.

Does the probable work around you mention in your original Email involve moving the mirror up the tube as I have thought of that and will not be an easy task as the Skywatcher tube has the mirror cell fixed around the end of the tube and would have to cut some off the end of the tube.The last time I moved a mirror cell was fairly easy as the cell was fixed inside the tube and no fitting around the end of tube assy if you can understand what I mean.

Cheers

Dave

[steppenwolf]

Does the probable work around you mention in your original Email involve moving the mirror up the tube

No, it is a custom adapter that you can get a machine shop to make up for.

See how you get on and keep me posted - don't worry, it is resolvable

[davelrkn]

Hi Steve

I will wait for the Corrector to arrive and check if I have a focusing issue.If I then need to have an adaptor machined up, have a mate who is also an amatuer who would be able to machined one up on his lathe.

Will keep you posted.

Thanks Steve for your support.

Cheers

Dave

[davelrkn]

Hi Steve

Not sure if I keep the tread going here or repost new thread as its been a few days for an update

I picked up the adaptor which was the standard 2'' eyepiece one that is supplied with the Skywatcher after having it machined down to about 5mm which was enough for the locking screws to hold the mpcc in place and was able to achieve focus.

Works well as the Camera is positioned fairly close to the OTA.

I have another question if you can help. I used the mpcc with a Orion Skyglow filter and have found that when checking the histogram I do not have the same range of adjustment as without the filter and after checking other images it has cut the Red channel sensitivity.The Histogram is now displaying a very thin black line around two to three mm to the left

Is there a setting that I am not adjusting correctl

I have tried all types of programs Photo Shop ,Max Lm ect too no avail.

It would help a lot if I knew what I was doing

Cheers

Dave