IC4592 to Rho Ophiuchus

[Rex]

Hi everyone, I've been really busy lately so took me a while to get around to processing this photo. Was taken a couple of months ago on the new moon. I realise this is not a fantastic photo of this region but I am a firm believer in jumping in with both feet, so had a crack at it. I really struggled with the stars in this one. Any pointers are welcome and in fact encouraged. Thanks for looking.

Canon 1100D unmodded
70-300mm kit lense at 100mm
3hrs 45min x 5min subs
ISO800 f5.6
Stacked in DSS processed in Paint Shop Pro V7

[LewisM]

WOW

I gots to try me some of that Rho Ophiuchus

[rmuhlack]

Very nice Rex, especially from Townsville - my recollection is that there is definite light pollution there, especially from the inner suburbs (where my wife's parents live). Out past Mt Louise i guess it would be darker. Still a great result, especially with an unmodded camera and the basic 75-300 zoom (which I also own but have never used for astro work) - you should be very happy :)

Just for comparison, I had a quick play with your image in PixInsight (hope you don't mind...) - I applied some noise reduction, removed the green colour cast and tweaked the colour and luminance curves and saturation.

:)

[Gem]

Exactly. I do the same. Interesting region to image. Plenty of data there if you imaged for that period. I have only cracked 2hrs on two occassions.

[Rex]

Thanks Lewis, it is a beautiful area.

Thanks Richard, I am reasonably happy with it, although i think my lack of processing skills has let it down somewhat. I don't mind at all that you made some adjustments, you've done a fine job of it. I would like if you have some time for you to elaborate further on exactly which adjustemnts you made and what the settings were. I really struggle to know when to stop and when to go a bit further, so any help you can give me would be appreciated.

Thanks Grant it is a very interesting area. It has been one of my favourites ever since I first saw a pic of it, so this year I decided that good or bad I was going to have a go at it. Only way you learn is to try for yourself and ask questions about how to do it better.

[rcheshire]

Hi Rex. I like this area too. It's a challenge. There is a lot of detail to be strained out. However, I have found that the expansive reflection nebula and dust fields tend to show up acquisition issues too readily. Particularly, if images are not adequately offset one from the other.

I found this very useful in my attempts at Rho Oph - Berry and Burnell in their Handbook of Astronomical Image Processing recommend spacing images by 10 or 12 pixels - dithering. This is not the super accurate dither technique used by high end/scientific gear, just a crude but very effective way of avoiding multiplying the effects of artifacts across the sensor - reducing noise, increasing SNR, improving flat fielding, sub pixel sampling and so on.


Not all gear is set up to dither - it can be as basic as pausing guiding/tracking for a few seconds between images.