First go at astro HDR with a DSLR - LMC and Orion widefields

[rmuhlack]

Having a play with the HDR composition feature of PixInsight. Am curious to see whether this approach will improve the dynamic range potential of my images on my old 12-bit modded 400D

First is the LMC, comprising 20 calibrated 4min frames @ ISO400, and 26 calibrated 4min frames @ ISO1600, captured with BackyardEOS using a modified Canon 400D and Nikkor 135mm AI prime @ f5.6.
larger image here: http://www.astrobin.com/24411/C/

Second is the Orion region, this time with 20 calibrated frames of each of the following: 30sec subs @ ISO400, 4min subs @ ISO400, 4min subs @ ISO1600. Again captured with BackyardEOS using a modified Canon 400D and Nikkor 135mm AI prime @ f5.6
larger version here: http://www.astrobin.com/24508/

Am not convinced I'm getting the most out of this data, but I still have my training wheels on with PixInsight.

Constructive criticism welcomed. :)

[Larryp]

They look pretty good to me, Richard.

[rcheshire]

They are both good images Richard. You could try different exposure times and same ISO and take long dark frames for scaling, as an alternative. Saves separate bias and dark frames for the different ISO.

[irwjager]

Hi Richard,

Thanks for sharing your experiment and results!
Personally, I've never been convinced that HDR photography has much of a place in astrophotography, except for the very brightest of DSOs (M42 comes to mind). Interestingly enough, your M42, which theoretically would benefit the most, still seems to have a blown out core.
I think that your 400D has a pretty good well- and bit-depth, with a low native ISO starting at 100 and therefore an ability to capture a good dynamic range without requiring different exposure times to counter overexposure. That said, I'm getting more and more of an armchair photographer these days, so someone else may want to chime in on this... :P

[rmuhlack]

thanks for the feedback :) I must admit that HDR is not striking me (yet) as the magic silver bullet i was hoping for. However, the blown out core of M42 is probably more related to my inexperienced processing skills through rather than the HDR method though, as I was focused on chasing the faint nebulosity. This is one of my other versions with the core more under control.

[rcheshire]

The PI HDR tool is useful for composing images from different telescopes that wouldn't ordinarily work with the usual integration tools etc. Ivo makes a very good point regarding dynamic range and lower ISO.

As far as the core is concerned a number of short exposures, just enough to get the stars in the Trapezium, will solve the blow out. HDR is useful for combining these. If the exposures are too short you might have difficulties with PI.

[LewisM]

The StarTools HDR is pretty good,and I am not just saying that because Ivo is here :)

Having said that, I have found the Nix Photoshop plugins SUPERB for astrophotography, and their HDR is pretty good, and HIGHLY customisable. Nix also has colour cast removers, contrast enhancers etc - all designed for regular photography but work superbly for astro.

I also highly recommend the Topaz plugins, but not sure if they do HDR.

I have used HDR on myM42 images (see my reflector vs refractor versions) and find that you have to be VERY minimal at best, otherwise it looks, simply put, crap!

Only thing I dislike about HDR is how it handles highlights. The first image shown to me emphasises this, as M42's core highlights look grey and washed out. The second repro is much better.

Great shot by the way - hoping to do the same with my R200SS when it finally fines up here.

[AstroJason]

Wow Richard, great shots you have there! I really like them

[ourkind]

:thumbsup: Very nice :thumbsup:

I love the bar structure in the LMC really well captured. Very well applied HDR!

[jakob]

:thumbsup::thumbsup:
I love the framing of the belt and sword!
To see the horse head together with M42 is fantastic. Well done.