alan4908

Thanks for the comment Bryan. Yes - lots of stars, so I spent a bit of time trying to bring out their various colours. I always find this a bit of a challenge, particularly when you have blue stars embedded in red nebulosity. Alan

Thanks for the comment Laurin. Yes, the NSG script is definitely impressive and it will now form part of my standard processing in PI. Alan

The Tulip Nebula (aka Sh2-101) is about 6000 light years away in Cygnus and consists of a collection of hydrogen, oxygen and sulphur gases. Ultraviolet light from nearby young stars ionise the gas creating red, green and blue colours, making it a popular narrowband target. In particular, the very bright blue/white star HDE 227018 shown near the centre of the image creates a bluish/violet bubble within the nebula. Since I prefer natural colours, I decided to image using LRGB techniques but to enhance details and contrast, I also decided to capture HII emissions via an Ha filter which I subsequently blended into the red and luminescence channels. The result is below represents 19 hours integration time and was taken with my Esprit 150. For those that may be interested: after watching Adam Blocks tutorials on the Pixinsight script Normalize Scale Gradient www.adamblockstudios.com/categories/PixInsight - this is my first image using this script – it really does appear to give more realistic sub frame weightings and facilitates easier removal of light gradients. Alan LIGHTS: L:21, R:17,G:15,B:13 x 600, Ha: 16 x 1800s; BIAS:100; FLATS:40; DARKS:30 all at -20C.

Yes, I also use Aladin, which I find to be an excellent program but mainly to identify background objects within the field of view. Alan

Thanks I shall explore that one. FYI I normally use CCDNavigator for selecting my targets, I mainly use this since it is also communicates ACP Expert, allowing a new target to be programmed with just a mouse click. Alan

Thanks Peter Thanks - Yes, it definitely is a colourful object, so it is a little surprising that it doesn’t often appear on SGL, perhaps this is due to it’s small apparent size. Alan

Thanks Michael.

Thanks - yes, the Ha filter definitely makes the star forming regions stand out (nice pic by the way) I will have to try this should I ever revisit this target.

Yes, given the relatively good UK seeing conditions from my site I did wonder if going below 0.7 arc seconds/pixel would bring any additional resolution to my images, however, I subsequently convinced myself that I was at the limit for my system + site. Alan

Thanks - yes, it is well worth the effort of imaging but take note that it has a small apparent size. I was at 0.7 arc seconds per pixel and still decided to crop it. Alan

NGC3184, also known as the Little Pinwheel Galaxy, is located in Ursa Major at the border with Leo Minor and is about 40 million light years distant. Since it is only 20 degrees inclined from face on, its distinct spiral structure is clearly visible. The yellowish core contains old mature stars, while the spiral arms show star forming HII regions scattered amongst mainly blue stars. A dim gaseous disc surrounds the galaxy which has been found to contain over 1000 compact star clusters. To the right of the image you can also see a red giant star. A few much more distant galaxies are also visible in the background. This LRGB image was taken with my Esprit 150 and represents just over 12 hours integration time. LIGHTS: L:25, R:16, G:17, B:15 x 600s, DARKS:30, BIAS:100, FLATS:40 all at -20C. Alan

Thanks for the comment Peter Alan

Located in Cygnus, I could only find a handful of images of this relatively bright nebula, so it appears quite a neglected target. What I particularly like are how the blue stars add colour contrast to the deep red of the emission cloud. This close up also reveals the dark structure in the central region. This LRGB image has an Ha blend into the red channel and represents 23 hours integration time, it was taken with my Esprit 150. Alan LIGHTS: L:27, R:21, G:20, B:20 x 600s; Ha: 17 x 1800s. FLATS:40, DARKS:20, BIAS:100 all at -20C.

I also have the same weather sensor but use it in conjunction with ACP Expert. The Hitec Astro Weather has an ASCOM weather service object ID with the name HitecWeather.Weather - in order to set this up in ACP you simply tell it the ASCOM ID of the weather server and it then knows the state of the weather (Safe or Unsafe). Although I'm not familiar with Voyager, I'd have thought you be able to perform a similar set up. FYI - given the variability of the UK weather I use 20 mins before starting things again. Alan

Thanks - I agree with your point on the detail, that's why I went for an imaging set up with the highest resolution I thought was practical for Deep Sky imaging given my local conditions - 0.7 arc seconds per pixel. Alan

Thanks for the comment. On the tidal tail - I was expecting this to go all the way to the galaxy but it hit my noise floor quite a way out. I presume it still exists here but it must be much dimmer in this region. Thanks. Yes, I too really like how those HII regions have come out on the final image. Good luck with your future capture ! Thanks Peter. Thanks, I'm glad you liked it ! Alan

Thanks for the comment Yes - that faint band of light to the left of the galaxy is the very long tidal tale . It doesn't often appear on images, probably because it is is very faint. As explained above, it was probably created c800 million years ago when M66 passed by and ripped stars and gas out of NGC 3628. Thanks - yes, I agree - I've often looked at images at this galaxy but never really paid as much attention to the amount of detail before. Alan

Located in the Leo constellation, NGC 3628 is relatively bright, edge on spiral galaxy about 35 million light years away. Notable features are a broad equatorial dust band, which obscures the central region, and a very faint, 300,000 light years long, tidal tale of stars. It is also known as the Hamburger galaxy. The neighbourhood also contains two other large galaxies, M65 and M66, which together with NGC 3628 form the Leo triplet. Gravitational interactions with these galaxies are believed to be responsible for the warped disk and tidal tale. Spectroscopic analysis indicates that the stars in NGC 3628’s disk orbit in the opposite direction to the gas, which was probably caused by a close encounter with M66 800 million years ago, which is also thought to have also created the vast tidal tail. The LRGB image below was taken with my Esprit 150 and represents 9.5 hours integration time. Apart from the galaxy features described above, if you look closely at the image you can see that I’ve also managed to capture some pinkish/red HII star forming regions in the central region of the galaxy. Alan NGC 3628 NGC 3628 (annotated) LIGHTS: L:17, R:14, G:14, B:12, x 600s; DARKS: 30, FLATS:40, BIAS:100 all at -20C.

If you zoom in to a high degree on the unbinned (first) image you can see that all the stars suffer a severe elongation. You can also see that the noise is quite high and that the RGB colours and not quite correct. I suspect that the non-round stars are due to the fact that your guiding was not working and so the lack of roundness is simply a manifestation of your mounts tracking inaccuracy. If you look at the binned image, where you have decreased the overall resolution of the image, they appear more round. You can also fix this effect to a large degree in post processing - I'd suggest Photoshop - take the image, duplicate the layer. Set the top layer to Darken and then apply the offset filter to the top layer (this moves the top layer by fractions of a pixel with respect to the bottom layer), until you get rounder stars. To improve your RGB star colours I'd suggest you separate the result into an RGB and a luminescence image and process these separately. This relies on the fact that almost all the detail comes from the luminescence rather than the RGB image. So, take the RGB image and blur it until all the stars look quite blurry. You might also want to increase the colour saturation slightly. Then recombine if with the lum image. On the noise front - I'd make the background less dark - in Photoshop I'd suggest a background level of between 18 and 24, your image is currently around 3 to 5. I then suggest you look at the image and see where the main sources are, in general I'd always suggest applying any noise reduction scheme in conjunction with an object mask so that it is targeted where it is most needed. Hope this helps. Alan