Category Archives: galaxies

M101 – Pinwheel Galaxy

Field centered at: RA: 14h 03m 12.6s, Dec: +54° 21′ 16.7″
Up: 178 E of N.

(plate solve from nova.astrometry.net)

The Pinwheel Galaxy, M101 is located in Ursa Major, and I found this a surprisingly tricky object to image – it has low surface brightness, with a lot of faint outlying regions. I also appeared to have some small issues with the flat fielding process here – there are a couple of very large dust bunnies in the raw data that haven’t quite been subtracted away and there’s a touch of clipping to deal with this. Add to this some faint colour gradients (attempted to sort out gradients!) and a couple of bright stars in the field and it became something very tricky to try and get right (and I’m still not 100% convinced that it’s truly there yet…).

The fainter galaxy to the right (east) of M101 is NGC5477, which is a dwarf galaxy at about the same distance (~20MLy). There are lots of fainter objects in the image as well: the brighter galaxy to the upper left of M101 for example is MCG+09-23-25, and there are also loads of other faint galaxies, galaxy groups and QSOs lurking in there. Using a solved fits file in Aladin is very instructive here!

I used fairly long exposure lengths (I was using the FLT110 at f7 here, a shorter focal length would be a major bonus in truth – at f4-5 this would be a much deeper image!). Exposure details are as follows:

WO FLT110 @ f7 on Losmandy Titan, ST2000XM cooled to -20C (images on 18 & 19-Apr-2015)
L: 4.5hrs (1×1)
R: 70min (2×2 binned)
G: 48min (2×2 binned)
B: 48min (2×2 binned)

The Luminance for the image was processed using a Lucy-Richardson deconvolution (3 iterations) using CCDSharp.

M101 - Pinwheel Galaxy in UMa (Luminance)

 

M101 - Pinwheel Galaxy in UMa (LLRGB)

M65, M66, NGC3628 – The Leo Triplet

RA: 11h 19m, Dec: 13°15′ (approx. centre)m65_m66_ngc3628_20061221.jpg
The famous Leo Triplet is a small group of three spiral galaxies (namely, M65 (NGC3623 – bottom-left), M66 (NGC3627 – top-left) and NGC3628 (right)) that is located about 35 million light years away between Theta and Iota Leonis. All three galaxies are readily visible in a small telescope, though NGC3628 tends to be the hardest of the three to spot. Additionally, the smaller galaxy NGC 3593 (not shown) may also be a member of this group.

This image was taken from the dark skies of Mid-Wales on December 21st, 2006 as a “quickie” before sunrise after a run on imaging the Cone Nebula (to follow in a later post) – it’s only about an hour of total exposure. A much longer imaging run would allow the faint surrounds of M66 and the “tidal tail” of NGC3628 to be brought out, but unfortunately, as is so often the case with imaging in the UK, the clouds came in for the next 5 nights leaving the telescope ready to go, but unable to actually take an image…

M81 & M82 – Bode’s Nebula and The Cigar Galaxy

Image centred at:  RA: 09h 55m 34.7s, Dec: +69°19′ 52″
Up is 89 degrees E of N
(Plate solve from nova.astrometry.net)

M81 and M82 in Ursa majorM81 and M82 in Ursa Major are two of the brightest members of the M81 group of galaxies. M81 (often called Bode’s Nebula after being discovered by Johann Elert Bode in 1774) is a large bright spiral approximately 12 million light-years distant, whilst M82 (the “Cigar Galaxy”) is an irregular starburst galaxy, highly disturbed by gravitational interaction with other members of the group.

This was taken from Kelling Heath at the 2007 Spring Star Party on an excellent night after we had been fogged out for the previous two nights! I’m hoping to go again this year to do some more imaging…

m81_m82_mandel_wilson_3-20070415.jpgIn the region of M81 and M82 (and across large parts of the northern sky), there is a large faint nebular complex associated with dust and gas expelled from the plane of the galaxy. The region here is part of MW3 (Mandel-Wilson Catalog of Unexplored Nebulae) and the faint dusty areas show up faintly in a strongly stretched image of the region. This has been refered to as an “Integrated Flux Nebula” since it reflects the galaxy’s light rather than that of a single star. Also visible is Holmberg IX (below M81) which is a small, faint blue irregular galaxy also in the M81 Group.

M31 (NGC 224) – The Andromeda Galaxy

RA: 00h 42m 44.3s, Dec: +41°16′ 9″m31_20060921.jpg
The Andromeda Galaxy is a naked eye object from a dark site, appearing as a small smudge in the sky. Long exposures reveal it’s true extent (over three degrees in size!) as well as two smaller elliptical companion galaxies (M32 – top, and M110 – bottom edge partially off frame). It is a member of the Local Group of galaxies, and is actually moving towards us at a rate of about 300km/s. Taken from Abingdon, UK on the evening of September 21st, 2006.

This picture was chosen as Anacortes Telescope & Wild Bird picture of the day on 6th Nov 2006.

Additionally, it was chosen as Sky at Night Magazine Hotshots Picture of the Month, Feb 2007 and subsequently it was chosen as Sky at Night Magazine Hotshot of the Year, 2007. (Sky at Night Magazine). As part of the Sky at Night Hotshots competition, I won a 5x Astro Engineering barlow lens for the photo of the month, and a DMK41AF02.AS camera from The Imaging Source.

I’m very happy with this one – if anything, it needs a bit more data – especially in the colour channels – I’m tempted to have another go at this, maybe as a mosaic at a later date 🙂