NGC3372 - Eta Carina Nebula

[jase]

Well... it’s been sometime since I've submitted an image to the forum.

I've been spending most (if not all) of the nights fine tuning my mount, in particular periodic error (PE). My Titan out of the box had a peak-to-peak (+/-) 5.3 arcsec error in RA. Dec was around 1.5 arcsecs (not an issue). After running PEMPro for 7 worm cycles, analysing the data, building a curve and re-programming PEC, RA is now down to 1.8 arcsecs. A significant improvement to the original worm error. I originally thought that PEC and auto-guiding would work against each other. I was amazed at reduction in auto-guider corrections required after reprogramming the PEC data. I think I should be about to squeeze a little more performance out of the mount yet. Astronomical "seeing" where the observatory is located does not often get below 2 arcsecs, so for the time being the PE of 1.8 arcsecs suffice.




Some info on the attached image:
Exposure time: 80 minutes (Subs: 7 x 10min/ 2 x 5min)
Taken: 03/02/07 @ 23:30 (local) - 12:30 UTC
Optics: C11 @ ~F/5.5 (~1540mm F/L)
Mount: Losmandy Titan

Camera: STL11k :temp -20 :selfguided :bin 1x1 (1.2 arcsec per pixel)

Filters: None - Full wavelength spectrum including UV and IR

Processing: Calibration: master DF removal in MaximDL/CCD - no Flat removal. No further processing such as DDP or unsharp masks.


Notes: Battled with glare of the full moon so sky glow was relatively high. On reflection, a 2x2 bin (2.4 arcsecs per pixel) would have delivered a better image as seeing wasn’t steady. Imaging with a CCD with no filters is not desirable as they are sensitive to IR and UV noise. A narrow band filter would work better on this target but while still in the testing/fine tuning stages I didn’t bother. More 5 min subs would bring out improved detail around Eta and the gaseous cloud and globes. Stars at the edge of the field are elongated – the Lumicon GEG doesn’t handle the large format CCD very well.


Thanks for looking. :P

[Striker]

Nice to see you have got a start Jase.

How did you find Pempro...was it easy to use.

The image looks severly clipped but you probably had to do this due to the reasons you have mentioned.

looking forward to some more images with the STL11000 from you.

[jase]

Hi Tony,
PEMPro is intuitive to use, but does take some time to get things set up. Tweaking the PE curve I found was trial and error, though I'm getting rather proficient at it. I could probably squeeze a little more from the Titan mount. I thought about going the Titan 50 and changing the gear ratio, but this will not improve the tracking accuracy. The '50 simply adds more torque. However, if you power the standard Titan with 18v (instead of 12v) you'll find you have plenty of torque (I certainly do anyway). I did some screen dumps of before and after PE results, but left them on the computer in the observatory (which is 160km away from where I am now). I can PM you with them when I get a chance. Your AP mount comes with PEMPro. I highly recommend you use it.

Yes. The image is clipped, somewhat on purpose to bring out the faint stars. I was checking for elongation and other optical anomalies. Seriously, I spent less than two minutes stretching the image. If I get time, I'll process the image again. Also, I processed the image on a laptop which has not been calibrated - this wouldn't help.:D

Hmmm. The STL11K.... I'm having doubts about this camera. I'm a little disappointed by its sensitivity around the 650nm. I think I should have spent the extra $5k or more and get the STL6303. I’ll wait until I get hold of the FSQ-106ED in early April, before I do something about it. Are you looking to buy?:P I see the C2 offer is on again. Check atscope website.

[Striker]

Already have the STL11000C2 it's been replaced....yes the STL6303 is a far more sensative camera but it was out of my price range plus I wanted Anti blooming where by the 6303 is not.

yes send me the graphs when you get a chance..I am in no hurry.

[Striker]

Jase

Just on the STL11000C2 special yes it still on but around $1800 AUD more expensive then before.

It was $5795 USD it's now $6995USD on special from retail at $7995

[iceman]

Beautiful image, Jase! Look forward to more when the mount issues are all sorted.

Lovely contrast and detail.

[jase]

Cheers Mike. The previously posted image wasn't meant to be visually pleasing, just thought I'd post it.:P

Anyway, here is a version that I spent some more time processing.

Processed in MaximDL/CCD 4.5 - PS CS2:
Recalibrated with DF. Non-linear stretch with no DDP to obtain initial levels. Removed 100 pedestal value to avoid clipping. 2 deconvolution runs of L-R method. Final curve adjustments. Saved from FIT to TIFF16. Loaded into PS, set white output balance to 200 to avoid white point clipping introduced in next step. Full unsharp mask - Amount 40% - pixels 250. Re-adjusted levels. Minor unsharp masks around key features - amount 10% - pixels 50.

Didn't want to over use the unsharp mask. Its tempting, but I like images to look natural and not heavily processed. More data is required for this object - 80 minutes is too short for a luminance channel in my opinion. Still processed on a laptop. LOL

[Striker]

Thats looking much better Jase.

[EzyStyles]

great shot jase! the second pic is really nice. i'll drillll to have your camera :)

[Phil]

great work Jase good to see you taking photos. Cant wait to see some more.
I went out tonight but the clouds rolled in. Its been cloudy up here for about 3 weeks. It sucks.
Phil

[jase]

Thanks Tony, Eric and Phil.:)