Return of the Lion

May 2, 2020 by grahamrob in AstroBin, Deep Sky Objects, Galaxy, Narrowband and tagged Leo, M65, M66, NGC 3628 | 2 Comments

Leo LRGB RotateX denoise2 (Medium)

The period between March and May provides an excellent opportunity to see and image objects in and around the constellation of Leo. Located close to the ecliptic, this area of the sky is packed with galaxies and can therefore be seen from most parts of the northern and southern hemispheres. Located to the east of the Leo 1 Group is perhaps the best known of these M65, M66 and NGC 3628, also known as the Leo Triplet.

Leo Constellation

I last imaged this attractive group of galaxies shortly after changing to a CMOS mono camera in March 2017. Unfortunately on that occasion it was only a test with just 45 minutes integration time at 300-gain, so a more serious attempt to image these three beauties was obviously long overdue. On this occasion imaging over three nights during late March and then finally again in April produced well over 7-hours of integration time.

Whilst the earlier test image showed promise, each of these objects is small and certainly push my equipment it to the limit. However, the benefit of much longer time and imaging at unity settings is self-evident. I’m very pleased with the final LRGB image, which shows good detail and colour for all three galaxies. Furthermore, the advantage of a wider view using the William Optics GT81 and ZWO ASI1600MM-Cool camera combination, has also captured numerous other colorful stars and even smaller galaxies, thereby providing a more interesting background for the main show – the Leo Triplet (see below).

Leo LRGB Final (Large)

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Each of the galaxies that make up the Leo Triplet is tilted at different angles relative to the view from Earth, thereby producing a variety of form and perspective in the image (cropped & adjusted to accurate orientation @ top-of-the-page). In addition, various distortions of the galactic discs and other effects demonstrate that the three galaxies in the M66 Group have all been affected by gravitational interactions with each other. Seen edge-on, the unbarred spiral galaxy NGC 3628 clearly shows a broad band of dust stretching along its outer edge, thus obscuring young stars within the galaxy’s spiral arms. NGC 3628 seems to be the most affected by the said intergalactic forces which, moreover, has drawn out a tidal tail from the eastern side of the galaxy spanning some 300,000 light years; unfortunately the aforesaid tail is very faint and does not often appear in images – something for another day and a larger telescope!

	IMAGING DETAILS
Objects	The Leo Triplet or M66 Group: M65, M66, NGC 628 AKA the Hamburger or Sarah’s Galaxy
Constellation	Leo
Distance	35 million light-years
Size	M65 = 8.71’ x 2.45’ M66 = 9.1’ x 4.2’ NGC 3628 = 15.0’ x 3.6’
Apparent Magnitude	M65 +10.3 M66 +9.97 NGC 3628 +9.4

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control & Cartes du Ciel
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 camera & PHD2 guiding
Camera	ZWO1600MM-Cool mono CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWOx8 + ZWO LRGB & Ha OIII SII 7nm filters
Capture & Processing	Astro Photography Tool + PHD2 + Deep Sky Stacker & Photoshop CS3
Image Location & Orientation	Original Subs: Centre RA 11h 19’ 44.95” DEC +13^o 19’ 06.48” Main Image Top = East + Cropped Image Top = North
Exposures	180 sec x 42 L Ha, x37 RGB = 153subs Total Integration Time 7hr 39min
	@ 139 Gain 21 Offset @ -20^oC
Calibration	10 x 180 sec Darks 20 x 1/4000 sec Bias 10 x LRGB Flats @ ADU 25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5-6
Date & Time	x4 nights: 18^th + 29^th + 31^st March + 26^th April 2020 @ +21.00h
Weather	Approx. 2 – 8^oC RH 60 -75% 🌙 19 – 43% waxing

Spinning Plates

May 12, 2018 by grahamrob in Equipment, Imaging, Software and tagged Leo, Plate Solving | Leave a comment

65 Comp Lgx Crop

Much of life is about meeting and dealing with challenges. Who hasn’t put off a task in the hope either that it will go away, somebody else will deal with it or an easier solution might be found? Whatever anybody says to the contrary, astrophotography is not easy and throws up many such challenges from the very beginning, which will usually have to be dealt with if progress is to be made. Amongst such challenges a few have the potential to transform the process and / or outcome of imaging but can also irrationally at first appear as a stumbling block rather than an opportunity and, as a result, get put aside until another day.

My list of such obstacles so far confronted consists of:

Achieving polar alignment – in my case made much more difficult as Polaris is completely obscured by my house
Moving to synchronised computer control of the mount, telescope and image capture
Autoguiding using PHD2
Mono-camera imaging

I have experienced many other challenges but excluding processing itself – which is another story – overcoming these four tasks has each time had a material positive impact on my astrophotography.

It’s fair to say that with technology, problems and life in general, wherever possible I like to adopt the KISS principle (Keep It Simple Stupid). Unfortunately such a philosophy is often difficult, if not impossible to follow with astrophotography and most of the time there is just no alternative but to work through the unavoidable difficulties step-by-step in every excruciating detail, which usually requires lots of patience, perseverance and time. In understanding and finding a solution the almost endless and invaluable online help from others should not be overlooked, without which I would probably still be back at the proverbial square one. The availability of such friendly help and the extensive free but still excellent software is surely one of the defining characteristics of astronomy and astrophotography, which not only makes it easier but more enjoyable.

Notwithstanding, when I look back at the aforementioned list of tasks which took me months or even years to address and solve, I wonder now why I had been so daunted beforehand. Once I found the courage to work through the problems, I discovered that I too was able to set-up and carry out such techniques that hitherto I’d thought beyond my abilities. It was very satisfying but, more to the point, each such breakthrough took me to another level of imaging.

Ever since moving on from DSLR to using the ZWO1600mm-Cool mono camera and EFW, I realised that if I was ever going to truly master astrophotography I would need to achieve much longer integration times, which could only mean one thing – the apparently black art of plate solving. I had read about plate solving and understood the principle but at first was too busy learning the new camera and then either just kept putting it off or, with so much bad weather, used the rare clear night just to enjoy imaging. Notwithstanding, an all too brief warm and clear spell recently occurred and I decided to give it a try.

Aside from the innate underlying complexity of such techniques I am first put off by the instructions. I do read them but as always with technical items they appear to have been written by an alien – poorly written, idiosyncratic and altogether difficult to understand. In this case I chose to use PlaneWave’s PlateSolve2 software incorporated within the excellent image capture software Astro Photography Tool (APT) as Point Craft and to be fair, the author’s (Ivo from Hungary) instructions are comprehensive but still difficult to understand; thankfully the related APT Forum helps enormously to resolve resulting difficulties and misunderstandings. However, like riding a bike you will not learn by reading a book but need to get on and do it!

Having installed the necessary software and star catalogues for plate solving my first night was for various reasons a disaster, thankfully the good weather continued for the subsequent two evenings and I was therefore able to continue. To learn the technique I needed a suitable target and at this time of the year the Leo Triplet formed an easily recognisable composition that met the bill, though the detail of each galaxy remains difficult to resolve with my set-up. My approach was first to verify I could Solve an image i.e. identify the exact RA and DEC position of the image (location and orientation) using the plate solving software and then using this image and solved data:

Re-position the camera exactly over the target in the same part of the sky
Do the same but after a Meridian flip, and finally…
Do the same using the original image but over two nights

APT PointCraft input screen: After connecting the scope, solving the image (upper box) and framing the image (lower box), the GoTo++ function can be used to return the scope and imaging location to the originally solved and framed position in order to resume imaging.

I’m not going to say I’ve cracked it but I did achieve all the above tasks and am now confident that I’m on my way to obtaining longer integration times with the help of plate solving. After some failures I was finally able to realign the camera to within 2 pixels, which is quite amazing accuracy achieved by the software. I was even pleased with the resulting test images, which however emphasised the aforementioned need for much greater integration times; top-of-the page image from separate image sets on 19th April, image below from image sets on 20th April. Of course increased times will also require clear skies and a return to more suitable targets.

Picture saved with settings embedded. Despite my aversion towards much of the so-called modern world I am not a technophobe, I embrace and often enjoy many of today’s technical developments. However, I am of the opinion that many of the problems with such technology arise at the interface between the technology and mankind – technology is now (mostly) digital and we are analogue i.e. incompatible. Furthermore, such difficulties are often compounded by the lack of intuitive operation and inability of those creating such devices or software to explain to normal human beings how to use them – surely altogether a limiting factor for the ultimate development of the modern world itself? Notwithstanding and somewhat ironically, my experience indicates astrophotography may also be a metaphor for life. Often working in the unknown, difficult, complex and frustrating but at times very rewarding – a bit like spinning plates really? And so on to my next plate – watch this space!

Leo

	IMAGING DETAILS
Object	The Leo Triplet M65 + M66 + NGC 3628
Constellation	Leo
Distance	35 million light-years
Size	M65 8.7’ x 2.45’ M66 9.1’ x4.2’ NGC 3628 15.1’ x 3.6’
Apparent Magnitude	M65 +10.25 M66 + 8.9 NGC 3628 + 10.2

Scope	William Optics GT81 + Focal Reducer FL 382mm f4.72
Mount	SW AZ-EQ6 GT + EQASCOM computer control
Guiding	William Optics 50mm guide scope
	+ Starlight Xpress Lodestar X2 guide camera & PHD2 control
Camera	ZWO1600MM-Cool (mono) CMOS sensor
	FOV 2.65^o x 2.0^o Resolution 2.05”/pix Max. image size 4,656 x 3,520 pix
EFW	ZWOx8 + ZWO LRGB & Ha OIII SII 7nm filters
Capture & Processing	Astro Photography Tool + PS2, Deep Sky Stacker & Photoshop CS2
Image Location	Centre RA 11:19:59 DEC 13:31:01
Exposures	1.Main image 60 sec x35* LRGB (Total time: 100 minutes) *15 East & 10 West 2. Second image 180 sec x 5 LRGB (Total time: 60 minutes)
	@ 300 Gain 50 Offset @ -20^oC
Calibration	1. 15 x 60 sec Darks 20 x 1/4000 sec Bias 10 x Flats LRGB @ ADU 25,000 2. 10 x 60 sec Darks 20 x 1/4000 sec Bias 10 x Flats LRGB @ ADU25,000
Location & Darkness	Fairvale Observatory – Redhill – Surrey – UK Typically Bortle 5
Date & Time	19^th & 20^th February 2018 @ 22.00h approx.

Spring’s Playground

May 12, 2015 by grahamrob in Deep Sky Objects and tagged Coma Berenices, Galaxies, Leo, Virgo | 1 Comment

The night sky has been full of surprises for me this Spring, in particular the very extensive presence of galaxies. Their occurrence has been mostly associated with the constellations of Leo and Virgo but also less well known (to me) Coma Berenices, located between the two aforementioned constellations. Despite being the 42^nd constellation by size and relatively small with few bright stars, Coma Berenices is nonetheless something of a little gem and every bit as interesting as it’s more famous neighbours.

Previously part of the Leo Constellation, Coma Berenices was promoted to a constellation in the 16^th Century and named after Queen Berenice II of Egypt; the asterism was previously considered to be the tuft of hair at the end of the lion’s (Leo) tail, which has now become the ‘Queens Hair’. Though small, Coma Berenices contains eight Messier objects, several globular clusters and is rich in galaxies – including the northern part of the Virgo cluster – also with the North Galactic Pole located within its boundaries. All-in-all the constellation forms an impressive and interesting part of the sky at this time of the year.

Notable objects are: M53 (NGC 5024), M85 (NGC 4382), M88 (NGC 4501), M91 (NGC 4548), M98 (NGC 4192), M99 (NGC 4254), and M100 (NGC 4321). Whilst amongst the more famous features of the Coma Berenices is the Black Eye Galaxy (M64), the Needle Galaxy (NGC 4565) and the Coma Cluster of galaxies.

M64, AKA Black Eye Galaxy, Evil Eye Galaxy or the Sleeping Beauty Galaxy is the brightest in Coma Berenices and gets its name from the dark (black) dust band that obscures the stars in its bright core.

M64 Black Eye Galaxy
WO GT81 & Canon 550D (modded) + FF | 10 x 180 secs @ ISO 1,600 | 11th April 2015

NGC 4565 or the Needle Eye Galaxy is considered one of the finest examples of an edge-on galaxy, thus producing a slender, needle-like profile. Located 40 million light years away, almost directly above the North Galactic Pol, this giant barred spiral galaxy is about one third larger than the Milky Way and is more luminous that Andromeda.

NGC 4565 Needle Eye Galaxy
WO GT81 & Canon 550D (modded) + FF | 10 x 180 secs @ ISO 1,600 | 11th April 2015

Some 60 million light-years away, M88 is located in the lower area of Coma Berenices, is over 100,000 light years diameter and one of the brightest galaxies of the Virgo Cluster.

M88 with other galaxies of the Virgo Cluster nearby.
WO GT81 + Canon 550D (modded) + FF | 20 x 180 secs @ ISO 1,600 | 25th March 2015

Apart from a few occasional opportunities since obtaining my new equipment last Summer, I have been yearning for more galaxies to image and have thoroughly enjoyed Spring’s veritable playground of galaxies that have filled the sky in their hundreds and sometimes thousands since February. Notwithstanding, my 81mm refractor though good struggles to obtain the detail of these magnificent, mind-blowing Deep Sky Objects and I can only look forward to the day of owning a larger aperture telescope and have mastered the art of long-exposure tracking, which I am still working on. In the meantime, I now await the development of the Summer sky and another crack at objects first encountered last year.

The one that got away

April 14, 2015 by grahamrob in Deep Sky Objects and tagged DSO Imaging, Galaxies, Leo | Leave a comment

At the end of February the appearance of the Leo constellation marks the end of the winter sky and the transition to Spring. After previously succeeding in imaging the Leo Triplet and M96 group, there remained one feature I still wanted to capture and, after a long period of difficult seeing conditions, I finally got my chance much later in March.

Just west of the lion’s head, south of the star Alterf (Lambda Leonis) is the 10^th magnitude barred spiral galaxy NGC 2903, discovered by no less than William Herschel in 1784. At 12.6’ x 6.0’ (80,000 ly) NGC 2903 is a little smaller than the Milky Way and too small for my equipment to show much detail but it is possible to see the spiral arms and the bright core, which is known to exhibit an exceptional rate of star formation. However, the galaxy’s main notoriety is that this significant feature should have been overlooked by Messier though, to be fair, he did well with 103 other wonderful objects that I’m still working through.

NGC 2903
WO GT81 + Canon 550D & FF | 10 x 180 sec @ ISO 1,600 | 25th March 2015

Big Cat Hunting

February 26, 2015 by grahamrob in Deep Sky Objects, General Astronomy, Imaging and tagged DSO Imaging, Galaxies, Leo | 1 Comment

As we move closer to the Spring Equinox, the winter sky is already rapidly disappearing towards the western horizon and I have been left wondering what next? I was concerned that after successfully imaging the Orion constellation and all its spectacular parts over the past four months, it would be a difficult act to follow, I needn’t have worried. Already starting to appear from late-evening, a series of constellations are about to proceed across the night sky over the next few months which will provide an equally spectacular but different kind of show to Orion.

First of these is the constellation Leo, the celestial Lion, which it turns out is packed with galaxies and double stars. The asterism of Leo is in the shape of a lion which, being dominated by various groups of galaxies holds much imaging promise, with my 81mm telescope providing an ideal field of view.

Located behind Leo’s rear ‘leg’ is the best of these, known as the Leo Triplet or M66 Group, which consists of three galaxies: M66, M65 and NGC 3628. Evidence suggests that these are linked in a gravitational dance with each other which, in the case of NGC 3628, has created a disturbed, unbarred galaxy with a faint 300,000 light-year star to the east. M66 is an intermediate spiral galaxy, with a diameter of about 95,000 light-years and is the largest and brightest of the trio. M65 is a smaller, barred intermediate galaxy. The field of view has also captured other galaxies as well as the orange giant star 73 N Leonis. All-in-all a wonderful image which I hope to return to in order to achieve even better detail using longer exposures, guiding and hopefully a larger telescope one day.

Leo Triplet: M66, M65 & NGC 3628
WO GT81 + modded Canon 550D & FF | 10 x 180 secs + calibration @ ISO1,600 | 21st February 2015

To the west of the Leo Triplet, in the direction of Leo’s dominant star Regulus, is another triple collection of galaxies called the M96 Group. While a little fainter that the Leo Triplet, the M96 Group nonetheless makes a wonderful image accompanied, as it is, by numerous other galaxies and stars. Of the latter, the giant orange 52 K Leonis star dominates the scene.

M69 Group: M105, NGC 3373 & NGC 3371 + other galaxies and orange giant 52 K Leonis WO GT81 + modded Canin 550D & FF | 10 x 180 secs & calibration @ ISO 1,600 @ 21st February 2015

M96 Group: M95, M96, M105, NGC 3373 & NGC 3371 + other galaxies and orange giant 52 K Leonis
WO GT81 + modded Canon 550D & FF | 10 x 180 secs & calibration @ ISO 1,600 @ 21st February 2015

It’s fair to say that the results of my big cat hunting around the constellation Leo have been a pleasant and successful surprise, with further promise still to come as Spring develops. Watch this space!