alan4908

Hi Rodd Yes - the image is definitely cropped ! - I normally crop away until I get the prettiest picture. FYI the camera I'm using is the SX Trius 814. Alan

Thanks ! Hello and thanks for the comment. The image is LRGB, so I'm just using broadband filters. The object is quite rich in both Ha and OIII emissions, which is why you sometimes see narrow band images of this object using Ha and OIII filters. However, since Ha = Red and OIII = Blue you can also choose to image this with broadband filters, as I have done. Hopefully this makes sense. Thanks Rod. Yes, this was taken with my Esprit 150. I'm at an imaging scale of 0.7 arc seconds per pixel , so it's high resolution. In addition, I performed a high strength deconvolution on the lum data which revealed more detail. Alan

M76, which is also known as the the Little Dumbbell, Cork or Butterfly Nebula is a planetary nebula about 4.5 light years across and approx 4000 light years distant. It was formed about 10,000 years ago when the central dying star lost a huge amount of matter. The structure of the nebula has two inner lobes and two fainter outer ones. High Ha emissions are present along with OIII emissions which create a the teal (blue/green) cast. As for the title, the bright star reminded me of Sunrise on Earth, hence the name. (For the more literal among you, the bright star is HD10498 which has apparent magnitude of 6.6, so you'd probably be unable to see this with the naked eye. It's about 27x the size of our Sun and is approx 900 light years distant). The LRGB image below represents over 15 hours integration time and was taken with my Esprit 150. Alan LIGHTS: L:36, R:20, G:16, B:20 x 600s, DARKS:30, FLATS:40, BIAS:100 all at -20C.

Thanks for the comment gorann. It is interesting to compare the image from my Esprit 150 with that of your 14" Meade LX200R. Your image looks very nice by the way, particularly for only 5 hours integration time ! As you say, they do seem to give a similar level of detail - perhaps at one level that is not surprising since I'm at 0.7 arc seconds per pixel and you appear to be at 0.85. From my particular site, I've previously concluded that there's likely to be little benefit from a higher resolution DSO imaging set up. On the faint stuff - a possible explanation for less nebulosity in my image is that this consists of two blended images: galaxies and a star field. I deliberately stretched the star field much less than the galaxies to obtain better star colours and much less star bloat. Hopefully you cannot spot the join. Alan

Thanks Dave. Thanks Olly. No I hadn't considered that but it is a good idea to try, so thanks for the tip. It is a very interesting object to process due to the high dynamic range of both the galaxy and the surrounding stars, some of which are quite bright. Alan

Thanks Stuart Alan

Thanks for the comment. Thanks. It must be very frustrating for you, still you should have a nice observatory to look forward to soon. Alan

That is impressive. Alan

Thanks Dave - it took me rather a long time to acquire this, which wasn't particularly helped by the UK weather...... Good luck on your own rendition ! Thanks Peter.

The galaxy NGC7331 is located in Pegasus and is approximately 46 million light years distant. It's estimated to be be substantially larger than our own Milky Way with a transverse diameter of 140 000 light years. Some background galaxies can also be seen in the image (below), which are estimated to be c300 million light years distant Due to its high inclination of 77 degrees, part of the disc is blocked by dust lanes, although I was quite pleased with the amount of detail captured. The LRGB image represents 11.5 hours integration time and was taken with my Esprit 150. Alan LIGHTS: L: 16, R:17, G:17, B:19 x 600s. DARKS:30, FLATS:40, BIAS:100 all at -20C.

Very impressive Olly and nicely framed. Alan

Thanks. Yes, it's interesting what you can learn from this hobby. Alan

Thanks Rodd ! Thanks for the comment Olly. Yes, you can definitely see what appears to be a tidal tail emanating from NGC7320. However, I found this article on the subject from c10 years ago (http://chandra.harvard.edu/blog/node/150) which suggests it is an optical illusion. It states: Radio observations prove that the tail is unrelated to NGC7320 and is actually connected to the X-ray mission and the two spiral galaxies on the right (NGC7318a/b). The radio lets us see cold neutral hydrogen gas in the tails and trace the southern tail even where it passes behind NGC7320; there is no sign of disturbance in the gas or a connection to NGC7320, and the hydrogen is at the redshift of the other galaxies. Alan

Stephan's Quintet is located in the constellation of Pegasus and was discovered in 1876 by Edouard Stephan using a 80cm reflector. Originally, he perceived the close pair (NGC 7318 A/B) as a single galaxy, so originally it was perceived as a quartet. One of the galaxies (NGC 7320) is actually much closer to Earth (45m light years) than the rest which are much further away (287m to 310m light years). I thought a good challenge to have a go at the object since a search revealed that their are relatively few amateur images, probably because it is so tiny. The resultant LRGB image represents just over 12hours integration and was taken with my Esprit 150. I've also captured a few other galaxies in the image below which Pixinsight has annotated. The one near the top right wasn't picked up, however, a quick search on the free program Aladin informs me it is 2MFGC 17021. Alan LIGHTS: L:30, R:13, G:11, B:19 x 600s; DARKS:30, FLATS:40: BIAS: 100 Annotated version

Hi Olly Just to let you know that I've found the root cause - a little too strong application of Pixinsight's TGV Denoise. As I previously mentioned, I can see the effect when I zoom in but in posted image I cannot, which is why I missed this whilst processing. Many thanks again for your critique, hopefully this will allow me to improve. Alan

Thanks Alan

Olly Many thanks for the explanation. I must admit that I cannot see an issue in the areas you've marked on the posted image. However, when I zoomed in on the TIFF I can definitely see what I would describe as a soft focus effect in parts of the image. So if I zoom in on the fours corners and centre of the image I get this: If you look at the stars, the top left is most soft focus with the centre being the most sharp. Now that I can see this, I shall now explore where this came from. Alan

Thanks Alan

Many thanks for the tip Olly - I don't use the technique you describe but I shall give it a go. One final thing, would you mind indicating which parts of the nebula you believe have excessive noise reduction. I compared my image with a Adam Block reference ( http://www.caelumobservatory.com/gallery/ic5146.shtml) and I cannot see the issue. Alan

Thanks for the comment Olly. I'll go back to my processing to see if I've overdone something on the noise reduction front. I have to say that I find noise reduction very challenging to get good results. Currently, I'm hoping between Pixinsight, PS and NeatImage....... Alan

Thanks Stuart ! .....personally, I was a bit surprised to see the features of a Christmas Reindeer appear in the red nebulosity to the left of the very bright blue star in the center of the image Alan