View Full Version here: : First night with a scope and camera, very grey.
28-05-2012, 08:40 PM
Hi all. I'm new at this. Very new. Bought a Celestron C8 and an EQ6 mount off two fellow forum members only 3 weeks ago.
Well my Nikon T ring finally arrived and I had my first night out this weekend. They may look a bit crap but I'm stoked at the result. After a LOT of photoshop work I managed to get something resembling M8, M20 and M83. I don't know how but my tracking was spot on, and M8 exposures were 17 seconds at ISO1250 on a Nikon D200.
For some reason though, the results look grey, and I mean very grey. They look far more grey after stacking in Deep Sky Stacker and bumping of saturation than the original frames looked out of the camera. So needless to say my processing techniques need a bit of work.
Deep Sky Stacker has a LOT of options and decent guides on how to use it (or process astrophotos in general) seem to be few and far between. Anyone know of any decent guides?
28-05-2012, 08:51 PM
For something you only had for three weeks they are a very good effort !
You get an elephant stamp
Can't help with processing though
Keep at it
28-05-2012, 09:04 PM
Your exposures are quite short which is probably why your colours are a bit gray.
But it's a great start for a three week run in period.
I know I couldn't get over 30 seconds until I got a wedge for my alt az -
can't help with the processing tutorials I'm afraid - unless you want to come down to Ormeau and see me.
PM me if you are close by
28-05-2012, 09:36 PM
:) You must be stoked to get that detail. :)
More data = more detail and colour.
29-05-2012, 09:27 AM
Your images are heavily processed. The lighter blob in the center of your screen is Vignetting - http://en.wikipedia.org/wiki/Vignetting
This can be "fixed" with flat files. Have a read of the Flat files section on this page for some details:
If your new to this, possibly forget flat files for now and read on.
A few things i would suggest:
Try some longer subs of M20, say 200seconds @ 1600. Take 10 to 20 subs and try stacking that. Should get a fair bit of color in your non-processed image. 17 seconds at 1250 ISO is a bit low and you will need to do heavy processing to bring out the detail.
If possible try your hand at M42 (orion) as you can get some decent shots of that with 30sec subs or so (ISO 800). Sadly M42 sets early at this time of the year so you will need to do it right when the sun goes down.
Also if using photoshop, what do you see in your levels for RGB? If possible, take a screenshot of your levels (histogram) window with no processing to the DSS stacked image and post it up here.
If the histogram for RGB or one channel is very small, or even just a line, then you don't have enough data, so see above.
29-05-2012, 06:40 PM
Thanks guys. I can correct for the vignetting quite easily, that's not really an issue.
However longer exposures are quite difficult. My first night out the alignment wasn't perfect so I only got around 5 second before startrails started. The second night I thought I did pretty well but from the looks of things I need to setup Periodic Error Correction before I go any further. Every 400 seconds or so I would end up with 3-4 frames which showed streaking, so a 200 second exposure may prove quite difficult presently.
Time to read up on autoguiders :)
13-06-2012, 10:31 PM
Ok did some re-processing. Giving the trial of Pixinsight a whirl. The result are quite good in my opinion. The noise is higher but M8 and M83 look far more true in both tone and colour to other examples I've seen. May have colour balanced M8 a bit too far to the purple but at least it's not a seasick green.
I have been around astronomy all my life, but imaging for only 6 months. You will keep finding little ways to improve and slowly improve.
If you can improve your tracking, you can start to increase your exposure times. Taking lots of bias and dark frames helps.
The better the tracking, the longer the exposure, the more light you have.
Here is an example of increase the number/amount of exposures on the same object with a scope similar to yours (C9.25).
14-06-2012, 10:15 AM
Yes indeed. I have a distinct feeling that my problem is I don't have enough detail to pull out of the darkness of the frame. Photoshop fails here as it is incapable of working on the 32bit stacked image that DSS produces.
I think I'll invest in an autoguider and then Pixinsight in that order :) At least if I had an autoguider and I could actually have longer exposures which gives Photoshop something to process.
15-06-2012, 10:18 AM
????? I do this all the time.
1) Photoshop can convert 32bit to 16bit so you can process. Select Image->Mode->16Bits/Channel
2) DSS can save as 16bit as well.
15-06-2012, 11:50 AM
:thumbsup: :thumbsup: :thumbsup:
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