May 30, 2008

NGC3372 HaRGB (finally!)

After having a few issues with Rob Gendler’s method for HaRGB, someone pointed me at Russell Croman’s solution, which appears to be a lot easier and more flexible (at least for a newbie to it like me).

Global Rent-A-Scope
Remote System: Global Rent-A-Scope GRAS-012 (TAK FSQ 106, SBIG STL-11000M)
Images: Ha 36 x 300s , Lum 24 x 300s, RGB 9 x 45 2xbin (for each channel)
Stacked: DeepSky Stacker
Post Process: Images Plus + PSCS2 + Noels Astro Tools

(Click on image for larger version)

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May 30, 2008

NGC3372 Ha rework

Just spent rather a lot of time on this reprocess of the new Ha data (without the autoguder induced trailing visible n the previous large version). I have to say that I have learned quite a lot from this one. I could bring the detail out in the nebula but had horrible noise issues in the darker areas, so have learned a lot about the color range, expand, feather options, as wel as how to manually make a star mask.

So, as reference, this was the original:

and this is the new version (click on image for the HUGE version)

Far more subtle, far more detail, zero dark rings around stars from deconvolution… I`m really quite pleased with this rework, and have learned some new techniques along the way that I can use in future processing sessions.

I now also have a lot of Luminance and RGB data to play with for his target, but as a OSC imager, I`m finding this hard to combine without it looking utterly pants.

The huge Ha version is going off to Pixum to get printed out as a 30″ x 20″ poster 🙂

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May 22, 2008

NGC3372 Eta Carinae in Ha (GRAS012)

“Variety is the spice of life” or something… whatever…. anyway, I thought I`d try something a bit different this time, and mix it up a bit. Not only did I choose a target that I will never see from the UK, but I also used GRAS while I was at work (instead of over breakfast like the last time 🙂 ).

(Note: This image has been reprocessed and updated since this post was first creqated).

Global Rent-A-Scope
Remote System: Global Rent-A-Scope GRAS-012 (TAK FSQ 106, SBIG STL-11000M)
Images: 21 x 300s, Ha filter, unguided
Stacked: DeepSky Stacker
Post Process: Images Plus + PSCS2 + Noels Astro Tools

(Click on image for larger version)

With a lot of my processing, if there is any movement in the subs at all over the imaging run, I tend to 2 x drizzle and then software 2 x bin to raise the Signal to Noise ratio. Well, with this one, I did the 2 x drizzle… and it was still so smooth that I worked on that image! The master for this is 8000 x 5200 (or thereabouts).

The GRAS system did “lose” 3-4 subs in the automated upload procedure, which were found and sent to me by the GRAS support team. I will add these new ones into the stack and reprocess ovre the weekend, just to see if those extra subs make any difference at all. I can see a great 20″ x 30″ poster of this coming up soon (orders being taken shortly…. 🙂 ), along with my M16 from the other day. I need a bigger house to gain wall space for the amazing images that keep getting spat out of my machines.

The GRAS system will empty your bank balance very very quickly if you are not careful, but being astronomers, we all know that problem with the temptation of buying new kit. I will attempt to limit my use to ONLY objects I`ll never see from the UK from now on… but expect that promise to go out the window after 3 weeks of constant cloud, or the upcoming “no dark” nights.

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May 19, 2008

M16 Ha taken via GRAS

This image was taken over the weekend while I was down in Selsey, working on Sir Patrick Moore’s Observatory/Roll-Off-Roof shed project.

10 x 600s, Ha Filter, TAK TOA-150, SBIG ST-10XME

(Click on image for larger version)

It was quite difficult to get this image… it was daylight in Selsey, and I was stuffing myself with a lush bacon and fried bread breakfast at the time 🙂
OK, so I rented some scope time from Global Rent-A-Scope (GRAS) last week, and finally got to use it on Sunday morning. GRAS is all web based, so I logged in, chose the rig I wanted to use (GRAS003, located in New Mexico), chose the target, the filter, the number and length of the subs, and set it going. After the imaging run had completed, I downloaded my FITs light files, and the pre-created darks/bias/flats, and then stacked and post processed. Yes, it really was that easy.

My own thoughts on this:

Did I actually learn anything or progress my own experience by using GRAS? No

Will I be using it again? Yes, definitely!

Under what circumstances would I use it again?

  • Southern Hemisphere Targets
  • If its been cloudy for weeks and weeks and I`m getting stir crazy!
  • UK summer meaning longer days and short (or non-existant) dark nights
  • Target/Mosaic investigation for future imaging runs of my own at home (mostly stuff in the East that I am unable to see for several months yet, due to the house blocking the sky almost up to the Zenith)

I am also curious to see what come up with when that goes live very shortly.

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May 13, 2008

USA Dark Clear skies

Just thought I`d post some of the better astro related shots I managed to take while away in the USA for 2 weeks. These were all taken with my unmodded 350d on a normal camera tripod, so excuse any trails that you might see

OK, for starters, this was how clear the sky was in Death Valley (the sun is hiding behind my fingers), and it was a bit hazy that day.


When the sun went down, the sky was black… and I do mean completely black! This following image was made up from a few 15 second exposures stacked together, but absolutely no light pollution or gradient removal has been applied… and this was taken from the middle of the lawn area at hotel complex at Stove Pipe Wells.

(Click on image for larger version)

(Click on image for larger version)

The image below was supposed to be a single “star trail” image at ISO100 for 20 minutes, but had to be cut short when the lawn sprinklers fired off at 11pm and I had to retreat rapidly with the camera and tripod

Later in the trip, we stopped at Sedona (Arizona). Again, no light pollution or gradient removal is applied.

(Click on image for larger version)

and then this one, also from Sedona, needed a little light pollution and gradient removal, but only because of the location of the bright light in the image causing some issues:

(Click on image for larger version)

Of the 14 nights I had over there, only 3 were cloudy, and one of those was at Las Vegas and the sky was orange anyway! I was also pleased to see that even as we march onto towards the summer months, sunset was early due to their more southerly location… sunset at 7.15-8.00pm (depending on location), and “astrodark” in 90 minutes or so. Then I come back to the UK and get a nasty shock when I find out just how late it gets dark here

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