alan4908

NGC4631 is a starburst galaxy that is viewed edge on from Earth and interacts tidally with the dwarf galaxy NGC4627, forming a "light bridge" between the two objects. It has also very vibrant star forming regions along its length. Due to its shape it is commonly known as the Whale and Companion. The image below is an LRGB image and represents about 7 hours integration and was taken with my Esprit 150.

A reprocessed image of SH2-140 completed in June 2018. The original image can also be found in this album. For this reprocess I was attempting to get better star colours of the bright stars. I achieved this by stretching them must less than the main image and then blending the result with my original attempt.

An LRGB image of the Iris Nebula, representing about 11 hours integration time and taken with my Esprit 150. The Iris is a reflection nebula in the constellation Cepheus. The light from the very bright central star is scattered by the surrounding dust giving it a distinctive blue colour. Although not designated as an emission nebula, you can also see reddish regions close to the central star which indicate the presence of ionized hydrogen. Also present is an open star cluster, which can be best seen through the triangular clearing of dust to the left of the bright central star.

An LRGB attempt of the galaxy NGC5907 representing just over 11 hours integration time. This spiral galaxy is about 50million light years from Earth and appears "edge on". It is also know as the knife edge or splinter galaxy and was taken with my Esprit 150.

In order to maximize my imaging time during clear skies, I've recently started to capture bright star clusters when the moon is too bright for any other deep space object. My latest LRGB attempt is below, the globular cluster M92. Apart from the inevitable light pollution gradients, removed during post processing, the effects of the moon light pollution appear to be minimal. The image was taken with my Esprit 150 and represents about 3.6 hours integration time. To maximise star colour I gave the Lum data three different DDP stretches within CCDstack (high, medium and very low) and then blended the scaled images within PS. This approach tries to get the Lum data below 200 (when measured in 8 bits) to ensure that star colour can be obtained. On the acquisition front: I have an automated set up that is controlled by ACP Expert. So, if I believe that an object can be imaged during any phase of the moon, then I set this objects priority as very low. This means that image capture will only be attempted if it is not possible to capture any LRGB or narrowband data on any other objects. Using this approach my imaging time is automatically maximized since ACP monitors the moon's phase and periodically works out if LRGB or narrowband data can be collected based on the angular distance of the object from the moon and type of data to be collected.

A LRGB image of M106 with an Ha blend into the red channel. Along with the main galaxy (M106) and NGC4248 (bottom right), quite a few very distant galaxies can also be seen in the background. M106 is quite bright in Ha, so I decided to blend 6.5 hours into the red channel to obtain a more structural detail. The total image integration time was just under 16 hours and was taken with my Esprit 150.

The image below illustrates what happens when two spiral galaxies crash into one another..... They are now somewhat less spiral shaped than before the crunch and you can also see the debris trail between them. Apparently, they are now heading away from each other. The larger galaxy is NGC4490 (aka the Cocoon Galaxy) and the smaller one NGC4485. Whilst this is an LRGB image, I was quite pleased to see some Ha regions clearly visible. The image represents just over 12 hours integration time and was taken with my Esprit 150.

An LRGB image of the open cluster M67. I selected 300s sub exposures, down from my normal 600s, to avoid excessive star bloat. To maximize star colour, I also decided to process the image using two different DDP stretches of the Lum, a high one, targeting the dim objects and one low, targeting the bright stars. The result image was then blended together in PS with an appropriate mask. The cluster is unusual in that it is incredible ancient (c3billion years), somehow, it has resisted the gravitational forces which tend to disperse most open clusters over several hundred million years. As a consequence, M67 has more yellow/red and less blue stars than younger open clusters.

An annotated version of the Galactic grouping image.

An LRGB image of a galaxy grouping in Leo illustrating various galaxy types and a featureless nebula. The various objects are annotated in a separate image in this gallery. About 12 hours integration time. LIGHTS: L: 17, R:17, G:18, B:18 x 600s, DARKS:20, BIAS:100, FLATS:40 all at -20C.

First go with my Esprit 150 at M63. I particular like the galaxy colours and I was pleased to capture some of the surrounding nebulosity. The image is an LRGB and represents about 10 hours integration time. A corresponding image within my Deep Sky II album was taken with my ED 80. LIGHTS: L:11, R:19, G:15. B:17 x 600s, DARKS:30, FLATS:40, BIAS:100 all at -20C.

An HaLRGB image of M97 aka the Owl Nebula. This is an example of one of the few green coloured objects in astronomy. I found that attempting to blend Ha into the red channel destroyed the green colour, so I opted for a very strong black clipped Ha into the Lum channel which increased detail. LIGHTS:L:15, R:9. G:11, B:13 x 600s, Ha: 28x1800s, DARKS:30, BIAS:100, FLATS:40 all at -20C.

An LRGB image with an Ha blend into the Lum and Red channels. Taking into account this was captured in non-ideal conditions (c25 degree elevation) due to tree obstructions and about 1hour visibility per night, I was quite impressed by the amount of detail which the narrowband subs generated.I normally take 30mins Ha subs but decided to reduce these to 10mins since I was uncertain how many usable subs I'd get due to the combination of the UK weather and the relatively short imaging window per night. In the end, it took 3 months to gather the data.....it is at times like this when I'm thankful for an automated imaging setup ! LIGHTS: L:14, R:11, G:8, B:9 x 300s, Ha:14 x 600s, DARKS:30, BIAS:100, FLATS:40 all at -20C.

I've begun to capture star clusters when it's inadvisable to image fainter objects due to moon light pollution. I also quite like them since they provide a very good basis for practicing star field processing, which I find quite challenging. For this open cluster I used 600s subs which caused my camera to enter its non-linear, whilst this did not create saturated stars it can distort colours. I therefore decided to use the Pixinsight script Repaired HSV separation which may be used to repair non-linear data - it attempts to put the correct colour back into the star cores by examination of the surrounding pixels. I also shot sum Lum data in order to create the "glowing" star effect that I like which to me also looks more natural. LIGHTS: L:5, R:10, G:9, B:8 x 600s. DARKS:30, FLATS:40, BIAS:100 all at -20C.

An LRGB image and my first attempt at this galaxy with my Esprit 150. I decided to capture more than my usual amount of Lum subs with the objective of boosting detail. I was very happy with the resultant galaxy details and colours. LIGHTS: L: 34, R:11, G:20, B:21 x 600s. DARKS:30, BIAS:100, FLATS:40 all at -20C.

The Medusa Nebula is a faint planetary nebula that was only discovered in 1955, presumably due to faint nature of the object ! The image is an LRGB with an Ha blend into both the L and Red channels. To get a reasonable looking deep red colour, I only blended a small percentage of the Ha into the L channel. The faintness of this object, makes this a very difficult to process. While the Ha yielded some details but I think it would be improved by adding some OIII narrowband data. I will therefore attempt a bi-colour (Ha/OIII) at some point. LIGHTS: L:6, R:8; G:12;B:8 x 600s, Ha:14 x 1800s. DARKS:30, BIAS:100, FLATS:40 all at -20C.

A reprocessed attempt on NGC891. The starfield was processed separately from the main galaxy in an attempt to reduce the impact of the bright red/yellow stars. I was very happy with the amount of detail displayed in the main galaxy. LIGHTS: L:21, R:17, G: 15, B: 17 x 600s. BIAS:100, DARKS:30, FLATS:40 all at -20C.

An RGB image with a synthetic Lum layer. I decided to try taking a close up of M45 since I was interested in revealing the details of the nebula. I like the details and the star colours, however, I think I prefer a wider field of view. LIGHTS: R:25, G:14,B:49 x 120s, DARKS:30, FLATS:40, BIAS:100