Ha Omega and Lagoon Nebulae

[Farooq]

For the first time in a month got an almost cloud free sky, however lots of light pollution so decided to do an hours worth of imaging just to get used to the new SBIG ST8300m and imaging with a mono.

Attached is a single 10min Ha exposure of the Lagoon Nebula and 6x10min Ha of the Omega Nebula. Images acquired and calibrated using MaximDL, Mono images converted to false Ha using PS.

Guiding was very poor, DEC line on PHD graph was going down off the graph due to my ankle weight around the dew shield not being very secure with the velcro tape.

I will need to get a longer dovetail plate and somehow attach a weight to it to balance the OTA and CCD/FW. Any suggestions on balancing the OTA would be really welcome.

[Gina]

Just WOW!! Fabulous

[Farooq]

Thanks, Gina...

I'm really getting hooked into just doing Ha imaging, simply because of the light pollution where I live and the limited imaging time window I have for any particular object. I'm amazed with what can be captured under bad skies with a single 10min exposure.

[SJJ]

Two really nice images.

[Spikey]

Really, really nice images for the exposure time Farooq. Are you using Noels actions to ive the Ha false colour? I found dropping the saturation down and adjusting the hue slightly gave the image better contrast.

A bit like this;

[Farooq]

Yes Spikey, I used Noels actions. Looks much better after your tweaks, i'll bear that in mind next time. Cheers!

[Quatermass]

That is really good looks like a fire in the sky, I must try Ha imaging everytime I see Ha images it tempts me further, great job.

[Gina]

That is really good looks like a fire in the sky, I must try Ha imaging everytime I see Ha images it tempts me further, great job.

Same here

[Farooq]

Ha imaging is easy, only one filter, longer exposures at least 10mins (depending target and conditions). I have yet to make the transition to LRGB yet. The complexity of it seems to be daunting. Especially knowing the ratio of exposures (L: RGB) and the respective lengths of exposures.

[Farooq]

Here's my first go at LRGB. The objective was not to produce a nice image but to try and get my head around LRGB image acquisition and processing.

Image consists of only 3x180 Lum, 1x120 RGB (no flats, library darks at -5degC, mid to heavy light pollution)

Process used was:

1. Used MaximDL to calibrate and produce individual LRGB fits.

2. Align and colour combine RGB fits files in MaximDL. I also tried PS with Noels actions and FITS liberator to produce RGB image. I think the PS result was a bit better.

3. Resize RGB (2xbinned) in MaximDL so same as L

4. Use PS to combine L + RGB image and tried to tweak the final result.

The problems I found was finding any tutorials on Maxim DL5 which cover LRGB processing, plenty around on v4.

I wish someone would produce a tutorial on LRGB, and HA LRGB, and HaRGB etc. processing using the latest version of MaximDL5 and not old versions (eg. version 4 etc).

I had a problem determining the optimum length of exposure and RGB ratios. I used Starizona exposure calculator and according to that for my CCD and the background reading of my individual exposures, the L should have been around 150secs, but the R should have been 30secs only and GB should have been 45secs only !!! ??.

From the histograms, Red was saturated (towards the rhs of the histogram), green needed more exposure (LHS of histogram), and blue was in the centre (just about right).

Any advice from experienced guys most welcome.

[Gina]

Well you've got an image of M20 - that's a good start I can't offer any advice as I haven't tried any of this myself yet.