The Flaming Star Burns Brighter in Hydrogen-α; Straton is fun!

For some reason the name "Flaming Star Nebula" has always been attractive to me, and the object itself is beautiful: it's a combination of a lot of hydrogen emission with some delicate blue reflection, in some ways a lot like the Orion Nebula. I suspected it would look good in Hα so when it moved high enough in my sky I turned my telescope in its direction. I had intermittent high clouds. My chiller was broken so I didn't cool the camera, but the night was cool enough. I had trouble plate solving (it's a lot harder in Hα due to fewer stars), but found β Tau OK and used the PicGoto from there. #!%!!??! Windows did an automatic update on me and killed the session early, but the mount was about to bump and it also looked like the clouds were coming back about then anyway. I've disabled the automatic update "feature" now, I hope. Regardless, the Flaming Star looks very nice in Hα. Here is the Hα image; a lot of emission and detail is visible. This is an animated GIF alternating between grayscale and false color.

Date: 6 Nov 2014

Subject: IC 405, Flaming Star Nebula

Scope: AT8IN + Antares 0.5x Telereducer

Filter: Baader Planetarium 7 nm Hα

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1k (Win 7 ASCOM)

Camera: DSI IIc no chiller 5-10 °C

Acquisition: Nebulosity 3.2.1, no dither

Exposure: 23x600 s

Stacking: Neb 3, bad pixel map, bias included, 35 flats, OSC extract R, normalize, trans+rot align, 1.5 SD stack.

Processing: StarTools 1.3.5.289 Crop; Develop 75.00%; HDR:Optimize; Life:Less=More; Deconvolute: 5.0 pix; Track 5.3 pix; Magic 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools Deep space noise reduction; Hα false color dark space; Astroframe; assemble animated GIF.

After seeing the Hα, I realized I really needed the blue reflection as well, so I waited for the Moon to move away and captured a long one-shot color data set. The night was very cold and clear. I synched from β Tau and easily acquired the target with the PicGoto; I used the markers in Nebulosity to align the shot to match my previous Hα image for later combining. The CCD ran from about 2.5 to -5.5 °C with no chiller (it's still broken). The tiniest bit of wind gave no guiding issues. I threw out about the first hour's worth of subs due to poor focus. I imaged up to the meridian, then did a meridian flip and took in a few Leonid meteors (I saw a bright one streak right across Orion, leaving a trail). I used Astrotortilla to resynch, reacquired with the PicGoto, realigned, and continued imaging until dawn. I think the image turned out really nice; you really do need to see the blue to get the full "flame" effect. Here it is:

Date: 17 Nov 2014

Subject: IC 405, Flaming Star Nebula

Scope: AT8IN + Antares 0.5x Telereducer

Filter: Baader Planetarium Fringe Killer

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1l (Win 7 ASCOM)

Camera: DSI IIc no chiller 2.5 to -5.5 °C

Acquisition: Nebulosity 3.2.1, no dither

Exposure: 78x300 s

Stacking: Neb 3, bad pixel map, bias included, 35 flats, normalize, deBayer & square, trans+rot align, 1.5 SD stack.

Processing: StarTools 1.3.5.289 Crop; Wipe: Aggressiveness 85%, Corner aggressiveness 163%, Drop off point 85%; Develop 82.53%; HDR:Optimize; Color:Scientific, 235%;  Life:Moderate; Deconvolute: 1.8 pix; Track 5.3 pix; Magic 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools healing brush; Increase star color; Levels; Astroframe.

I did these two images with the intent of combining them to make an HαRRGB image, but my first few attempts using my previous methods were unsatisfactory, usually because using the Hα for the red channel or for luminance always left the stars looking blue. The red channel in the RGB is quite bright. So I set this aside for a day or two, then I ran across some references to Straton, a piece of Windows software that does beautiful automatic star removal, image subtraction, and similar things. At 15 euros, it falls within the realm of "inexpensive" (notice I did not say "cheap"); this works out to about $20 at current exchange rates. I played with the free trial and then bought Straton; it works fine under Windows 7/VMWare on my Macbook. Straton allowed me to remove the stars from the Hα image, and to make a "stars only" version I could use as a layer mask in Photoshop. I combined Hα without stars plus about 50% of the stars added back in, with the R channel from the RGB, and I used the same combination for luminance but layered the original RGB on top of that with a "hide all" layer mask allowing only the stars to show to preserve the original star color. I like this result, but I’m still learning so I might learn to do better. Here it is:

This shows a lot more detail in the emission. The stars still look a bit blue, but not too bad. Straton was definitely worth my $20, and I plan to play with it some more.

Catching Tadpoles

When I was little, I used to catch tadpoles from the pond and watch them metamorphose into frogs. So I was intrigued a few years back when I saw images of the Tadpole Nebula in 100 Best Astrophotography Targets. It has two pillar structures that very much resemble the little immature amphibians. I tried several times to image the nebula, but could never really see the tadpoles, and concluded that they were just beyond the ability of my gear. Well, it wasn't my gear. With the Hα filter performing well on emission nebulae like this one I've been anxious to try it on IC 410, the Tadpole Nebula. Sure enough, the tadpoles were easily visible in my subframes. The full moon was quite near during this session, and probably hurt the contrast in the image a bit. I'm only intermittently able to get Astrotorilla plate solves when using the Hα filter, and this session was no exception to that. I initially synched on β Tau, did the goto, and imaged up to the meridian. After doing a meridian flip, I tried to use Astrotortilla to resynch and reacquire, and it just kept driving the scope farther and farther AWAY from the target. I wasted about an hour of sleep time messing with it, then finally went back out and manually aimed at β Tau, synched, and went right to the target. My chiller is still broken, but CCD temperatures started at 10 °C and fell as the night wore on. The tadpoles are easily visible in the stacked Hα image at the upper left, "swimming" toward the core of the nebula. I've been having fun working out how best to present Hα data, and finally settled on what you see here, an animated GIF that alternates between greyscale, which I think shows a bit more detail, and Hα false color, which is close to the true color emitted.

Date: 7 Nov 2014

Subject: IC 410, Tadpole Nebula

Scope: AT8IN + Antares 0.5x Telereducer

Filter: Baader Planetarium 7 nm Hα

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1k (Win 7 ASCOM)

Camera: DSI IIc no chiller 5-10 °C

Acquisition: Nebulosity 3.2.1, no dither

Exposure: 41x600 s

Stacking: Neb 3, bad pixel map, bias included, no flats, OSC extract R, normalize, trans+rot align, 1.5 SD stack resize 2x.

Processing: StarTools 1.3.5.289 Crop; Develop 60.00%; HDR:Optimize; Deconvolute: 5.0 pix; Track 5.1 pix; Magic 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools Hα false color dark space; Astroframe; assemble animated GIF by pasting uncolorized layer on top of false colored layer and manually aligning then making frame animation.

Encouraged by this result, I decided to dig up some older RGB data that were obtained at the same imaging scale and make a composite image. The RGB data are really pretty lousy (the subframes were not exposed long enough, and I probably should have used the UHC-S filter to improve the contrast). I had some trouble aligning the layers even though I pre-aligned them using Nebulosity. The red channel is 25% from the RGB and 75% from the Hα, and the Luminance came from Hα with 80% opacity. I was quite pleased with how the composite turned out, especially given how bad the RGB looked.

California Dreaming

I've wanted to image the California Nebula for some time, but always assumed it was out of my reach because it is too large for my optics and its surface brightness is too low (I thought). My wife and daughter are both native California girls so California has a special place in my heart. Realizing this nebula is a hydrogen-α emission region, I decided to give it a try with the Hα filter. Since the Moon is bright again, it was time to make the attempt. To maximize my field of view, I decided to go with my ST80 telescope with a focal reducer.

I've been using my AT8IN Newtonian reflector recently, so I needed to switch telescopes. In the past this has been a pain because I'd have to move my finder/guider and my Telrad sight from one scope to the other, then realign all the optics. This time I decided to try the switch to the ST80 scope "cold turkey": I just mounted the finder/guider on the ST80 without changing any alignment and didn't even bother to take the Telrad sight off my AT8IN reflector, so I'm not using anything to aim the ST80 scope other than bare eyeballs along the optical tube. I did look at the Moon first to make sure the ST80 was focused. Anyway, the plan was to rely on Astrotortilla to find the target. It didn't work at first, until I realized I was setting Astrotortilla to the field of view of the AT8IN, not the wider field of the ST80. It's a little challenging to do Astrotortilla plate solves with the Hα filter in place (because the filter drastically cuts down the number of stars visible in the image), and to top it off, my Peltier cooler failed big time while I was doing this and just got hot instead of cooling. The CCD temperature got up into the 40's (Centigrade) before I realized something was wrong and numerous hot pixels masqueraded as stars, competing for Astrotortilla's attention. Fortunately the weather has turned cold, so the CCD was down below 5 °C once I really got the session rolling. Eventually, I did get plate solving to work after setting the field of view correctly and taking longer exposures. The California Nebula was quite easy to find once I got the scope aimed at the star ε Per; the thing is HUGE! I shot 2 sections of a mosaic, but *!#*! Windows decided to shut itself down for updating in the middle of the second session. I need to figure out how to shut off that autoupdate "feature." So much for staying up half the night to perform a meridian flip; my California Dream was a bit interrupted!

I've mentioned before that I'm a bit undecided about whether to present these Hα images in grayscale or in false color. I think maybe you can see more contrast in grayscale, but I like false color and the algorithm I'm using to do it (from Noel Carboni's Astronomy Tools suite in Photoshop) does a nice job. So this time I decided to have the best of both worlds and make an animated GIF that fades between the two views. I was a bit surprised at how many "likes" this got on Astrobin; it's an OK image, but I think it could be better.

One last aside: while I can see a resemblance to the state of California, I think this nebula looks more like a squid. The head is to the left, a dark eye is in the middle, and the tentacles trail to the right.

Date: 3-4 Nov, 2014

Subject: NGC 1499, California Nebula

Scope: Orion ST80 + Antares 0.5x telereducer

Filter: Baader Hα

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.3.1k (Win 7 ASCOM)

Camera: DSI IIc no cooling

Acquisition: Nebulosity 3.2.1, no dither

Exposure: 22+9x600 s (2 panels)

Stacking: Neb 3, bad pixel map, bias included, flats, OSC extract R, normalize, square, trans+rot align, 1.5 SD stack resize 2x.

Processing: StarTools 1.3.5.289 Crop; Develop 50%; HDR:Optimize; Life:Less=More; Deconvolute: 3.0 pix; Track 5.0 pix; Magic 1 pix. Photoshop CC 2014 + Carboni Astronomy Tools Layer mask align & combine; Levels to match backgrounds; Hα false color black background in one panel; Astroframe.