Paul Hughes Astroimaging: Blog

M31 Reprocess with hydrogen alpha

Sat, 23 Nov 2019 21:31:50 GMT

I always felt my original M31 from 2016 was over-processed. I decided to give it another go and incorporate some hydrogen alpha data to bring out the nebulosity and star-forming regions in the spiral arms. I've therefore added a further 3 hours of data captured earlier this week over two nights. The final image total exposure was 17 hours

NGC 281: Pacman Nebula

Tue, 29 Oct 2019 15:56:02 GMT

Bicolour Ha:sGr:OIII, total exposure 9.75 hours

Cornish Weather doing its thing

Tue, 29 Oct 2019 10:39:45 GMT

Been a while since the last post but hopefully November onwards will bring some better opportunities for astroimaging. Last week I captured 4.75 hours of OIII data for NGC 281. This was over 3 nights as the weather was a little unpredictable. Two evenings, the ST-8300 CCD was running at -25 degrees and the other evening -22 degrees. Fortunately I had captured sufficient dark, bias and flat frames to calibrate the light frames.

The EM-200 was tracking and autoguiding well, with RMS down to 0.5 arc seconds. Occasionally the guiding would deteriorate but it soon settled and I didn't have to drop any 15 minute subframes. The FG-Temma 2Z model is a great upgrade over my original USD3 mount allowing for ASCOM pulse guiding and an accurate GOTO system using the Sky X software.

The TS-Optics tube rings and dovetail fixing configuration appears much more stable than the Takahashi tube clamp. The FS-102 is quite a long tube length and I found I was experiencing flexure problems.

Looking at the OIII subframes, I think my focus could have been a little tighter, but CCDSoft @Focus seems to make a good job of things.

The latest bicolour image of NGC 281 appears more natural and less aggressive than the Ha:RGB image from 2016. My aim is to capture S-II data to generate a Hubble Palette image of this fantastic deep sky object. That is, if the clouds go away!

IC 5070: Pelican Nebula

Tue, 29 Oct 2019 00:25:49 GMT

Bicolour image Ha:sGr:OIII. Reprocess

01/01/17: Image Processing Update

Sun, 01 Jan 2017 16:08:29 GMT

Finally processed my image of M45 The Pleiades -LRGB 90:120:120:120, total exposure time 7.5 hours. This was really difficult to process. There were a number of light pollution gradients and internal reflections to contend with. I was trying to achieve an image that doesn't look over processed or too blue!

After several attempts I finalised the new image. I would have liked more star colour but that will be one of the next steps on the LRGB learning curve. M45 The Pleiades LRGB

04/11/16: Update

Fri, 04 Nov 2016 23:58:38 GMT

I finished processing the NGC 281 image this evening. This is a HaRGB image (300:120:180:120), total exposure time 12 hours

I used Robert Gendler's technique of blending the hydrogen alpha data with the red filtered data to use for the RGB image, then layering in the main hydrogen alpha data. It results in less washed-out reds in the nebula

01/11/16: Update

Tue, 01 Nov 2016 22:23:09 GMT

A busy couple of nights

Yesterday I managed to get two hours of blue data for NGC 281 and then once it had crossed the meridian I switched to M45 and captured nearly two hours of blue data.

This evening with it being cloudy, the camera has been taking dark frames

Progress update:

NGC 281

Hydrogen alpha - 5.5 hours

Red - still to shoot - aim for 2 hours

Green - 3 hours

Blue - 2 hours

M45 Pleiades

Luminance - 1.5 hours

Red - still to shoot - aim for 1.5 hours

Green - still to shoot - aim for 1.5 hours

Blue - 1.75 hours

30/10/16: Imaging update

Sun, 30 Oct 2016 23:55:42 GMT

Unexpected clear skies this evening so decided to gather some more NGC 281 data. I acquired 3 hours through the green filter before the scope cables hit the mount. I then decided to capture some luminance data for M45 The Pleiades; another target I'm interested in.

As I have been using 5 minute subframes I will need some 5 minute darks at -22 degrees

RGB and Hydrogen alpha flats captures at twilight this evening.

Guiding performance was good, especially in declination due to the better polar alignment

27/10/16: Update

Thu, 27 Oct 2016 21:21:40 GMT

Last night I managed another 2.5 hours of NGC-281 in hydrogen alpha. I spent a little longer than usual setting up as I'm still getting to grips with PHD2 and the need to optimise the polar alignment for best results.

Autoguiding performance was very good, with good RMS values for both RA and Dec. Sub-pixel guiding was achieved ensuring round stars in all 15 minute subframes.

This evening the CCD is busy capturing dark frames and I'll run the Bias frames later.

22/10/16: A new imaging season begins

Sun, 23 Oct 2016 22:42:23 GMT

After some disappointing weather over the last 12 months, I've taken my first proper deep sky image again in 2016. NGC 281, The Pac-Man Nebula is a nice easy target in Cassiopeia. This latest image is simply 2.5 hours of hydrogen alpha data, no darks, flats or bias frames. Naturally the image will be reprocessed when these calibration frames are available. I also want to add another evening's worth of data when the weather allows it.

NGC 281 will be my project focus over the nest few sessions. Firstly I will create a HaRGB image, then shoot O-III and S-II data to create a Hubble Palette image. The narrowband data will need to be several hours per filter to achieve a good image. I will be aiming for at least 5-6 hours per channel.

I am now using PHD2 autoguiding software with its added features. In order to improve guiding performance I have started using the polar align assistant which allows even greater polar alignment accuracy than the Takahashi EM-200 polar alignment scope does. Given the declination backlash which unfortunately plagues the EM-200, a very accurate polar alignment will reduce much of the declination drift and any necessary corrections. Guiding performance was very good last night despite the wind. Polar alignment was accurate and declination guiding corrections kept to a minimum. Sub-pixel guiding was still achieved with round stars in each of the subframes.

30/09/14: Imaging Update-NGC-7380 Hubble Palette

Wed, 01 Oct 2014 18:54:53 GMT

Well I finally managed a Hubble Palette image of NGC 7380 after gathering 4.25 hours of S-II data over a couple of evenings. This one took a lot of processing but I found the chapter on narrowband imaging in 'Lessons from the Masters' very useful. One of the main challenges was getting the colour balance right-the H-a data can really swamp the image. The addition of the super-luminance layer also really helped to preserve some fine detail.

De-saturation helped get rid of the strong magenta in the star colours.

On with the next target.....

22/09/14: Imaging Update

Mon, 22 Sep 2014 20:58:35 GMT

Well the nights have started to draw in a bit now which means that the new imaging season can start. I've decided to continue with Hubble Palette narrowband imaging this year so look forward to getting some decent images!

My latest image is a bicolour (Ha:sG:OIII) process of NGC 7380-The Wizard Nebula, a large nebula in Cepheus. Total exposure time - 3.5 hours hydrogen alpha (from 2011) and 4 hour of oxygen-III. Although the skies have been clear, the seeing hasn't been great and individual 15 minute O-III subframes have shown little nebulosity. Despite this I hope I've managed to come up with a decent image. The next plan will be to add some S-II data to develop a Hubble Palette image

28/06/14: Update

Sat, 28 Jun 2014 10:43:50 GMT

Well the shorter nights have made deep sky imaging pretty much impossible when you have to be up early in the morning! I have however just uploaded a shot of the Leo Triplet from some data captured back in February. Since I last had a go at this object I have discovered how to process the data without burning out the galaxy cores. This meant that the detail in the galaxy arms has been preserved. Obviously some RGB data would be nice but that will have to wait.

Currently the cameras are off the scopes and I have spent a few evenings observing the planets Saturn and Mars. I'd forgotten just how sharp my Takahashi FS-102 was on planets. Saturn looked stunning in particular.

Looking forward to the nights drawing in a bit so I can get some imaging done at reasonable hours! Still deciding on a target but I'm keen to try some more tricolour narrowband imaging in the next few months

14/03/14: Update

Fri, 14 Mar 2014 22:06:19 GMT

It has certainly been a better week this week for astronomy, although the Moon has been quite high in the sky for astroimaging. Nevertheless I managed an image of a beautiful spiral galaxy in Ursa Major. Galaxy season is now here, so I have decided to try LRGB imaging again as the evenings aren't dark enough at this time of year for the hours of exposure demanded by narrowband imaging. I've selected a number of galaxy groupings and star clusters to target over the next couple of months.

This week I also had to replace the desiccant within my CCD camera. I had started to notice a patch of condensation appearing on the images-a sign that the desiccant needed replacing. This is relatively straightforward although it does involve dismantling the camera and opening the CCD chamber itself. It was also a good opportunity to give the filters a clean in readiness for the galaxy imaging.

On the visual astronomy front, I have spent a couple of enjoyable sessions viewing Jupiter with the 8'' Newtonian. At high power, some detail is visible within the cloud bands. Earlier this week there was a shadow transit of Io which was great to see, as was the emergence of the moon itself from in front of the planetary disk. Last weekend I spent a couple of hours tracking down some galaxies in Leo and Ursa Major. The EQ-5 setting circles aren't bad and do seem to work! The Leo Triplet was nice to see, although quite washed out in the moonlight. This will certainly be one of my next targets. I did try it a couple of years ago, but was not happy with the result. Now being more familiar with the CCD and image processing I look forward to giving it another go.

21/02/14: Update

Fri, 21 Feb 2014 21:46:14 GMT

Well it has been a couple of months since my last blog post. As many will know, the weather in the UK has been particularly bad for many weeks now. Deep sky imaging has been virtually impossible, with not a single clear usable moonless night. I've finally managed to generate a six hour hydrogen alpha exposure of IC 410, 'The Tadpoles' in Auriga. I'm not sure when I will get the OIII or SII data!

On the visual astronomy front, the Tolcarn Observatory Astronomy Group has had a couple of clear club nights, albeit with the moon in the sky. Last week we had the opportunity to test a mate's new scope; a William Optics GT-102 triplet refractor. The build quality on this scope is excellent, with a feathertouch focuser and integrated camera angle adjuster. We had some cracking views of Jupiter at high magnification. That night was also the first time I've seen the 14'' Meade LX200 show what it can really do. At 280x magnification we detected structure in the bands and the Great Red Spot itself. I've never seen Jupiter so clear. I'm looking forward to some galaxy hunts with this light bucket! The Takahashi TSA-120 also did not disappoint, with clear crisp views of the planet.

24/12/13: Merry Christmas

Tue, 24 Dec 2013 18:01:31 GMT

Unfortunately the weather has not made it possible to do any imaging for the last few weeks. However, Xmas is here again. Can I have some clear skies please??!!

Merry Christmas all, here's to a productive year in 2014!

10/12/13: Image Processing

Tue, 10 Dec 2013 22:21:15 GMT

I was keen to see the results of the 3.5 hours of hydrogen alpha data of IC 410/IC1893. I therefore processed the image using Zone System principles, with micro curves adjustment finishing with high pass filtering. Once I can capture another 3 hours of H-alpha, I'll have another go before starting on the OIII data capture.

08/12/13: Imaging Update

Sun, 08 Dec 2013 23:23:54 GMT

This week I finally managed to process my first image using the Hubble Palette (SII:Ha:OIII). Although it only comprised two hours of hydrogen alpha data, the end result was satisfactory. I followed the instructions from the book 'Lessons from the Masters' by Rob Gendler after processing the individual filtered images separately using the Zone System approach. Getting the correct colour balance was important to generate an aesthetically pleasing image.

My next Hubble Palette project is another go at IC410, The Tadpole Nebula in Auriga. My plan is to aim for at least 6 hours per filter. I will shoot the H-alpha data first then the OIII which can then be combined in a bicolour image to begin with, then finish with the SII to generate the Hubble palette image.

Tonight turned out clear in the end so I managed to gather 3.5 hours of H-alpha data (14 x 15min subframes). This will be processed later this week once I have taken a new batch of dark frames.

30/11/13: Tolcarn Observatory Opening

Sat, 30 Nov 2013 23:24:00 GMT

The weather couldn't have been better today for the opening event of the Tolcarn Research and Education Observatory. It was a great opportunity to give the Polarie a run and capture a couple of widefield images of the stars over the observatory buildings.

24/10/13: Imaging Update

Thu, 24 Oct 2013 20:41:23 GMT

Although I was generally pleased with the bicolour image of the Crescent Nebula, it just highlights how much exposure you need when working with narrowband filters. I've recently acquired an SII filter with the intention of creating images using the Hubble Palette (SII:Ha:OIII). Over the last couple of weeks I've managed three hours' worth of SII data. The weather hasn't exactly been friendly in this regard! Nevertheless, then next step will be to add some OIII data. I also plan to experiment with slightly longer subframes. I routinely image with 10 minute subs, but it's certainly worth trying 20 minute ones to see how it goes. This should improve the signal to noise ratio and the smoothness of the image. More to follow when I manage the OIII data!

29/08/13: Sadr Region imaging and processing

Thu, 29 Aug 2013 20:29:46 GMT

Well it has been a good couple of months since my last blog post. Lots happening, especially on the Tolcarn Observatory development front. We had a successful open weekend for the Perseids meteor shower earlier this month, and obtained a couple of promising images with the new Takahashi TSA-120 and SBIG STT 8300. As the days start to draw in, I'm sure there'll be more to follow. This week I managed a couple of hour's worth of hydrogen alpha data on the region surrounding the star Gamma Cygni 'Sadr'. Unfortunately my dark frames collected on subsequent evenings weren't great so I had a lot of image clear-up to do. Despite this, everything else worked well and the guiding was spot on. After calibrating and combining the images I used the NewAstro Zone System technique to process the image. I was pleased with the final result.

26/06/13: New Astro Zone System Processing

Wed, 26 Jun 2013 21:04:41 GMT

I've been fortunate to acquire a copy of Ron Wodaski's book 'The New Astro Zone System for Astroimaging'. My plan is to work through the processing principles and techniques and spend some time redoing older images. My first go was a re-process of the Rosette Nebula in H-alpha. I was really impressed with the result, which I believe to be a significant improvement over my original image. I've saved the image in a new folder called 'Zone System Processing'. More to follow.....

26/05/13: Planetary Comjunction: Closest approach

Sun, 26 May 2013 22:42:08 GMT

Another clear night and the opportunity to image the trio of planets low in the western sky. I managed to capture the image on the way back from a friends barbeque after finding a spot with a clear horizon. Had to be quick as wife and kids in the car obviously wanting to get back home to warm up!

25/05/13: Planetary Conjunction

Sat, 25 May 2013 22:42:55 GMT

Tonight was a fantastic opportunity to hunt down Jupiter, Venus and Mercury in the western sky after sunset. These three planets will form a tight triangle tomorrow on the 26th May so I'll try this all over again! The planets were low in the sky and starting to disappear into the cloud but a nice image was still possible. I also snapped a couple of images of the moon on my way back home.

19/04/13: Viewing Session

Sat, 20 Apr 2013 19:38:06 GMT

I wasn't expecting good results tonight on the imaging front as the moon was high in the sky. Therefore I decided to take the cameras off the scopes and have a bit of a viewing session with a mate of mine. I put the kettle on and we made a start!

The first target was the moon and we managed to get some clean crisp views of the visible lunar surface. We explored some of the features along the terminator at high power. Unfortunately I'm not familiar with names but the craters looked nice!

We then began a hunt for some deep sky objects. I knew galaxies would be a challenge in the bright moonlit sky, but I managed to locate several nice globular clusters; M3, M53, M13 and M92. The constellation Lyra had just risen but I located M57 The Ring Nebula without a problem. Saturn cleared the roof at around 2230 so we had a quick look at the brilliant ringed planet before calling it a night.

07/04/13: Imaging Update

Sun, 07 Apr 2013 21:37:32 GMT

It was good to get the toys out on Friday and Saturday night. Galaxy season is upon us and I decided to delve into the constellations Leo and Coma Berenices and see what I could find.

I do like widefield galaxy imaging as it gives a sense of scale, and reminds you of the vastness of the cosmos. Both images taken this weekend (M100, M105 etc) contain a large number of faint background galaxies that would be far beyond what could be observed visually through an amateur telescope. Maybe at some point I'll add some colour data, but I find RGB imaging quite labour intensive and the rewards don't justify the effort, for me anyway. There are many imagers who do make it work and I've still got a lot of learning to do! So the monochrome images will suffice for now.

31/03/13: Comet Pan-STARRS

Sun, 31 Mar 2013 12:21:18 GMT

After five failed attempts at spotting it, I finally got a look at Comet Pan-STARRS last night. A binocular sweep of the western sky from a layby on top of the clay works outside St Austell revealed the comet, and a small tail. Just above was the faint smudge of the Andromeda Galaxy M31. My estimate of the comet's current brightness is magnitude 4. I couldn't make it out as a naked eye object so it has dimmed considerably since it first appeared a couple of weeks ago. Luckily some have managed to get some really good images of this icy visitor to our skies. I had to settle with a few quick snaps before my camera battery decided to give up due to the cold! Anyhow, my favourite shot was one which appeared to include three meteor trails as well as the comet; certainly a lucky shot! I also managed a shot which showed M31 as well as the comet. I finished off with some telephoto shots at 75-300mm, but the focus wasn't great so they weren't worth displaying.

Roll on Comet ISON!

Clear skies all

27/01/13: Observatory Update

Sun, 27 Jan 2013 22:58:55 GMT

Well things have been pretty quiet since returning home from Mozambique. The weather continues to scupper any attempts at deep sky astrophotography but hopefully things will improve soon.

Reflecting on my Mozambique trip, the astrophotography side was a real disappointment. Unfortunately the moon was around for most of the trip and then the rainy season kicked in several days before we left. Whilst I had the opportunity to take a few tracked shots with the Polarie, I didn't feel they were anything special.

Anyway, the kit is all ready for the next clear night. I hope to continue with narrowband imaging this year but also develop my processing skills further in particular.

Work continues on the new observatory site outside St Austell that I am involved with. Unfortunately things have slowed down a bit, mainly due to the weather but also down to the significant delay in the main observatory being built. I won't name the company responsible for this, I just wish they would get the job done so we can get on with things!

Anyway, roll on the clear nights, I'm beginning to forget what stars look like!

29/12/12: Mozambique Update

Sat, 29 Dec 2012 16:26:59 GMT

Currently having a fantastic time in Mozambique with the family. The trip has corresponding with an ever brightening moon in the sky which has limited deep sky photography with the Vixen Polarie, but I have added a couple of scenic shots to the website.

I have taken the opportunity however to get some practice in with the Polarie. Unlike the Northern Hemisphere polar alignment is more difficult as there is no Pole Star! I've also found the Polarie compass to be inaccurate which is a bit of a disappointment. On the nights it has been clear, I have managed 2-3 minute exposures before trailing, but the moonlight has washed out any decent deep sky stuff.

On a recent hunting trip, I did see the Milky Way stretching from horizon to horizon which was amazing, but to photograph it I would have needed to put down the shotgun!

Anyway, with still another week to go I hope to get some deep sky stuff. Watch this space!

05/12/12: DSLR Imaging and Jupiter observation

Wed, 05 Dec 2012 23:19:39 GMT

Well the sky finally cleared properly at about 2100 so I set up the 8'' Newtonian for a look at Jupiter. I also decided to give the Polarie a test run in preparation for my trip to Mozambique.

The Jupiter Great Red Spot was visible after about 2200, but the best view of it was at approximately 2240 when it had crossed the centre of the planet. The Newt also revealed some amazing detail within the bands.

Once set up the Polarie worked brilliantly. I've put a sample image on the site of the constellation of Auriga. In just a 3 minute exposure the image included a number of Messier objects. Due to the cold however, the camera batteries needed replacing frequently.

Looking forward to astronomy in shorts again!

04/12/12: DSLR Imaging

Tue, 04 Dec 2012 21:11:19 GMT

I captured another DSLR image of the planetary conjunction this morning. I was particularly pleased with this one, as the image showed a number of background stars.

At the weekend I attended Ian King's advanced CCD imaging course at Herstmonceux Observatory. It was a great day and I picked up a number of useful tips to improve my image processing. Nik Szymanek was also on hand to offer expert advice on RGB colour and bicolour narrowband imaging. If you haven't attended one of Ian's courses before, I'd certainly recommend it.

The telescopes at Herstmonceux Observatory are well worth a visit. It's a shame that they appear to sit dormant most of the time. I was fortunate to view the moon through the 10-inch refractor at an open evening last year. It was fantastic. These beautiful pieces of kit should be looking at the heavens every clear night!

28/11/12: DSLR Imaging

Wed, 28 Nov 2012 22:32:48 GMT

Well it has been a good couple of months since I did any CCD imaging. The weather hasn't exactly been great but I took the opportunity this morning to get a quick shot of the planetary conjunction involving Saturn, Venus, and Mercury.

I will be away in Mozambique for Xmas and New Year, so hopefully I should get some great opportunities to view some southern gems and get a few more images. The sky is very different to the last time I went so I hope to get a good look at some other constellations and deep sky objects. I'll be limited to DSLR imaging, but I hope my new Vixen Polarie is up for the challenge!

04/11/12: Update on activities

Sun, 04 Nov 2012 18:43:29 GMT

Since a quick monochrome image of M33 several weeks ago, the weather has been disappointing to say the least. Clear moonless nights have been very scarce. Nevertheless I've managed to get a little time in with some observational astronomy with some friends. A few weeks back I spent three hours just exploring the constellation Cygnus, hunting down deep sky objects in the Messier, Caldwell, Hidden Treasures, and Secret Deep object catalogues. I have found the books by James O'Meara to be a fantastic resource; his observing style demonstrating the need to take your time with each object. In addition they make fantastic armchair astronomy books, but don't worry I'm not quite at that stage yet!!

Hopefully we'll get some clear skies again soon so I can get my toys out to play.

20/09/12: Imaging and processing review

Thu, 20 Sep 2012 20:46:33 GMT

It has been a busy couple of weeks on the imaging front with a number of clear nights on offer. I've decided that bi-colour imaging using H-alpha and Oxygen-III data is the way to go at the moment. Imaging vast nebulae is perfectly suited to my refractor and I feel that colour adds an additional layer of depth to H-alpha images. Going forward my plan will be to acquire O-III data for objects that I already have H-alpha data for from the last couple of years, and turn them into bi-colour images. Not only will this enhance my image portfolio, but also it will allow me more time to practice my image processing.

My first attempt at bi-colour imaging was with NGC 7000. Following instructions from a couple of fantastic imagers' websites (Steve Cannistra and Salvatore Grasso), I constructed what I thought was a bi-colour image. It turned out however that I had misunderstood the Photoshop steps and only colourised the H-alpha data! Whilst I think the result looked quite nice I realised what I had done wrong and had another go. This time I managed a decent bi-colour image with plenty of colour and contrast. Now I knew what I was doing I had a go at IC 5070, and another nice image was the result.

My latest image is a shot of the Elephant Trunk nebula in the constellation Cepheus. This feature is part of a much larger nebula complex which requires a shorter focal length scope and wider field to capture in totality. Obviously I hope to image the same object through the O-III filter to generate a bicolour image.

09/09/12: Image processing

Sun, 09 Sep 2012 20:52:20 GMT

This evening I attempted to generate a bi-colour image of NGC 7000 from the hydrogen alpha and O-III data. There are a number of websites explaining this processing method, but all seem to imply that the user is a whizz at Photoshop! After a couple of hours I managed to process a coloured image. It's not great, but then I knew the O-III data from the other night wasn't optimal. If I have time I might give it another go, but process the hydrogen alpha data a little more prior to generating the bi-colour image.

Nevertheless, it can only get better!

08/09/12: Imaging session

Sun, 09 Sep 2012 20:45:22 GMT

A late start this evening but I decided to acquire some hydrogen alpha data for the Pelican Nebula (IC 5070). Like NGC 7000 this huge emission nebula responds well to hydrogen alpha imaging and I was pleased with the result.

06/09/12: Imaging session

Sun, 09 Sep 2012 20:41:07 GMT

The seeing wasn't great this evening but I decided to gather some O-III data for NGC 7000, that I could use to generate a bi-colour image. I shot 12x10 minute subs. Having processed the O-III image, the results weren't great but it was something to work with.

Towards the end of the imaging session I noticed that the dew controller had switched off and the optics had consequently fogged up. This obviously did not help!

05/09/12: Imaging session

Thu, 06 Sep 2012 21:22:46 GMT

This evening was the first real imaging session as the nights are starting to draw in again now. I decided to have a go at the North American Nebula NGC 7000 in the constellation Cygnus. This is an extremely large emission nebula and a good target for hydrogen alpha imaging. The weather was good and I shot two hours worth of subframes before calling it a night when the target began approaching the meridian.

I have processed the image with a focus on sharpening the 'wall' to bring out detail within the nebulosity. This involved using the unsharp masking function within Photoshop. I'm pleased with the result and hopefully aim to add some OIII data in order to generate a bi-colour image.

07/05/12-08/05/12: Image processing

Tue, 08 May 2012 20:52:28 GMT

Well the weather this past month hasn't exactly been great for imaging down here in Cornwall, but then it's too light now anyway! This last couple of day I decided to revisit the processing of a couple of my images this year. I've spent a bit of time looking at the imaging processing fundamentals in a bit more detail so I was keen to see if I could drag a half decent image out of the data that I had gathered. I started with M81 where I had got some RGB data, but felt that it wasn't very good. Having spent an evening colour combining and luminence layering I did get an image I was pleased with. There were some tricky light pollution gradients and uncorrected flat field issues but it seemed to turn out OK. After this and another go at M101 I have learnt that for good LRGB imaging I definately need to bin the RGB channels 2x2, and ensure good focus and calibration frames. Going forward I need to get some more data and keep practising!

It would be good to gather some RGB data for M51 if we get a clear night. After the summer I aim to acquire RGB data for some of my H-alpha images, and try filtered luminence layering.

07/04/12: Viewing session at the Roseland Observatory

Mon, 09 Apr 2012 11:58:45 GMT

As it was looking to be a clear evening, and the moon wasn't due to rise until about 2200, I took my 8' Newtonian along to the Roseland Observatory, Court Farm, St Stephen for a quick viewing session with colleagues. Fortunately I was able to mount the scope on their EQ5 mount which meant I didn't need to take the EM-200.

The session was fantastic and there was the opportunity to share the views with several campers who had arrived for the weekend. Views through the 30mm Tak eyepiece of the Pleiades were stunning, with pinpoint stars. Venus showed a small crescent under a 15mm eyepiece with polarising filter. Jupiter was descending very quickly but we saw the main Gallilean satellites. There was hint of Syrtis Major on Mars with the 6.4mm eyepiece but I was a little disappointed with the view compared to that a couple of views ago with the Tak FS-102 where we detected a polar icecap and a nice contrastly surface feature. The view of Saturn was good, although the planet was very low in the eastern sky. The Moon was fantastic, although being full did not display the level of surface detail assocaied with a crescent or gibbous phase.

A fun session therefore, and a nice reminder of the rewards of visual astronomy!

The activities of the Roseland Observatory can be viewed here: www.roselandobservatory.com. I'd thoroughly recommend a visit!

03/04/12 Venus among the Pleiades

Mon, 09 Apr 2012 11:45:17 GMT

I was fortunate to get a shot in between the clouds of the planet Venus in conjunction with the open star cluster the Pleiades. I needed to get the exposure right for this; not too short that no detail is detected, but then not to long so the planet over-exposes and the stars of the Pleiades begins to trail. It was good result!

30/03/12: Imaging session review

Fri, 30 Mar 2012 22:00:40 GMT

The weather has been fantastic this week and I was able to take a few images. Obviously with the clocks going forward this has meant some later nights and consequently some difficult mornings!

The latest additions to the site have been monochrome inages of the Whirlpool Galaxy M51 and the large spiral galaxy M106. The seeing wasn't too bad and I was really pleased with the resultant images. There is a clear improvement over my DSLR image of M51 and the image shows significantly more detail within the spiral arms.

I've always liked being able to detect faint background galaxies in my images and the latest two are no exception! The M106 image is full of them, with several fantastic spirals; one with a clear dust lane. Hopefully at some point I'll add the RGB data to produce colour versions but I'm pleased with these for now.

The moon is now high in the sky that will obviously make imaging a little difficult for a couple of weeks, but the next targets will most likely be in Virgo....

25/03/12: Evening Conjunction

Sun, 25 Mar 2012 20:31:29 GMT

Great view of Venus, Jupiter and the thin crescent Moon this evening. It made a nice image!

23/03/12: Imaging session

Sun, 25 Mar 2012 20:29:38 GMT

This evening I decided to have a go at imaging M101 The Pinwheel Galaxy in Ursa Major. I was keen to see the difference between my DSLR image and that with a CCD camera. I managed 24x5 min luminence data with 6x5min each for RGB. Total exposure time was 3.5 hours. The mount tracked perfectly as usual. Unfortunately the green and blue images weren't tightly focussed even through I had moved the focuser to the xpected focal point. Considering the speed at whivh @focus works, I will just run this between filter changes in future.

I processed the data a couple of days later. I was disappointed with the result, mainly due to the fact that I had to remove a significant light pollution gradient which had a detrimental effect on the colour balance. In addition, I didn't seem to pick up as much detail as I was expecting. The sky wasn't great on the imaging night though and the Pinwheel can be a trickly target.

Anyway, seeing as the clocks have now gone forward it's going to be difficult to get the hours in, but I'll keep going!

18/03/12: Imaging Session

Wed, 21 Mar 2012 19:53:04 GMT

A clear night tonight, I decided to grab the RGB data for my M81 and M82 image. I took 6x5 minute exposures of each channel binned 2x2. M81 and M82 were about to cross the meridian at this point so I decided to image the Hickson 44 Galaxy Group in the constellation Leo. I've wanted to image this galaxy grouping for a while due to the diversity of the galaxy types. I took 15x5 minute luminence exposures and managed to get a decent image abeit a large field of view. I therefore cropped the image around the galaxy group to show the detail. These galaxies lie 60 million lightyears away.

A couple of days later I attempted to do something with the RGB data I had gathered for the M81/M82 image. Unfortunately I'd overexposed the galaxies and there was a significant light pollution gradient which made processing very difficult. I therefore decided to leave the luminence image as it is and have another go next time!

11/03/12: Imaging Session

Mon, 12 Mar 2012 22:17:04 GMT

It turned out clear on Sunday night, so there was an opportunity to start imaging some galaxies. I therefore chose M81 and M82 to start with. I managed to acquire two hours of luminence data with the intention of adding RGB data at a later date. The sky started to get a little hazy as the evening went on, but I was still gathering good data. The mount tracked perfectly, at times averaging a periodic error of 0.3 arc seconds with the QHY guider. I processed the final image the following evening after acquiring some dark frames for image calibration. I was pleased with the result, but look forward to adding some RGB data at some point.

07/03/12: Planets in the evening sky

Wed, 07 Mar 2012 22:14:08 GMT

Not strictly imaging I know, but it's been fantastic over the last few nights to see Jupiter and Venus in the western sky, with Mars and the Moon rising in the East. This evening was really clear but on nights like this it's just great to see the planets rather than trying to image anything. Another week or so and the Moon will not affect things.

19/02/12: CCD Focussing

Mon, 20 Feb 2012 20:23:36 GMT

One of the reasons for using a Lakeside focuser is the ability to focus accurately automatically using computer software. I find that using the focuser with the @Focus functionality of CCDSoft works particularly well. Seeing as this evening was again thwarted by low level cloud, I decided to write off an imaging session and spend a little time assessing the abiliy of @Focus to focus accurately. I also wanted to establish the degree of focus shift between the LRGB filters. The Tak FS-102 is good for a doublet apochromatic refractor, but I have noticed a slight shift in the past with my LRGB imaging. I therefore ran a few @Focus routines for each filter and determined that the average shift from Red to Green and Blue was 23 units on the Lakeside Focuser. This corresponds to a focus shift of approx 138 microns. Knowing this, my intention is to try a little more LRGB imaging, moving the focus manually by this amount for the green and blue subs. I can still run an @Focus routine at the beginning of the evening to check my focus is good at the start. Obviously temperature changes come into it, but it's a start!

I've found that I've tended to concentrate more on the hydrogen alpha imaging lately due to the simplicity of monochrome imaging. Come galaxy season however I want to be LRGB imaging a lot more.

18/02/12: Imaging session

Sat, 18 Feb 2012 23:37:37 GMT

The forecast looked good for tonight and I'd set everything up with the intention of getting at least four hours exposure of NGC 2264. Unfortunately there was a lot of drifting cloud which ended the imaging session just after 2200. I was pleased with the 70mins of data I obtained and managed a half decent image. Now for a quick look at Mars through the 8'' Newt before some much needed sleep!