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By Ken Mitchell
For a long time I wanted to shoot this frame, probably from the early days of my astrophotography adventure.
Finally after all these years I managed to get a decent result of the 'stuff' between these two beautiful nebulae. Fairly happy with the image but always looking for improvement.
I hope one day to redo this all with a mono camera and filters.
Apart from NGC1499 , M45 and the Baby Eagle Nebula no idea what else is in the picture. If you happen to have an idea feel free to educate me.
Some info on image and capturing:
Widefield Pleiades to California.
Taken over 2 nights with a total of 11hrs 25min integration.
With a stock Nikon d610 and Nikkor 85mm 1.8 objective.
Tracking was done with the Skywatcher Star Adventurer.
Lights and all calibrations frames were stacked in DSS.
Processing was done in Adobe Photoshop CC using Adobe Raw, GradientXterminator plugin, HLVG plugin, Nik software plugins and Photokemi action set.
By Martin Meredith
Is it possible in near real-time observing to capture photons that set out in the first billion years of the life of the universe? Under current estimates of the age of the universe and its expansion, any such object will have a redshift of at least 5.7.
While preparing the indices that will accompany the forthcoming deep maps release, I spotted a possibility listed in the Veron catalogue , which goes under the unromantic name of SPIT J17210+6017 after the Spitzer First Look Survey. This quasar has an estimated redshift of just a fraction under 5.8, corresponding to light seen from a universe just 0.97 billion years old. A listed V magnitude of 20.6 makes it a very challenging target for my alt-az mounted 8" scope.This object lies in the rich galaxy fields in the centre of Draco, more or less equidistant between NGC 6361 (Arp 124) and VV 1840, the former being my starting off point last night before hopping down to identify the correct field for the quasar. With a sky of SQM 20.3 I went for 30 second subs.With some wishful thinking, the quasar started to appear after live stacking of 6 or 7 subs, but by 10 it was reasonably certain:I continued stacking just to be sure. Here are closeups at 10, 16 and 28 subs, compared to the DSS image.There are even more distant quasars listed (this doesn't quite make the top 20 in the Veron catalogue) but most are significantly fainter (but still worth hunting down!).Thanks for looking, and a big thanks to Paul for the robust live stacking in LodestarLive that makes this kind of thing so much fun.Martin Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010), accessed as Table VII_258_vv10 on VizieR.
By Martin Meredith
Here are some bright nebulae I observed last week, all using 15s subs live stacked in LodestarLive. Filters are probably necessary to get the best views of some (or all) of these objects, but I wanted to see what the unfiltered mono camera was capable of producing.
First, NGC6888, the Crescent nebula. I was happy to capture at least part of the nebulosity but was fighting a 75% moon which didn't set for 2-3 hours after this shot (SQM 19.3 skies). But what struck me most watching it build up is that the beauty of this field is not simply the wraith of nebulosity embedded in a rich star field, but the 4 or 5 brighter foreground stars, of which 3 appear as doubles. Two are catalogued in the Washington Double Star list. OS401 (Otto Struve) has components with mags 7.2 and 10.7, separated by 13.8". The pair SLE 955 has mags 8 and 13 with a 14.9" separation. Also labelled are a couple of other members discovered by SLE (anyone know who this is?). Pair 956 is an almost equal pair (11.9, 12.8) separated by 9.9", while pair 965 is an equal pair of mag 12.5 stars with a 7.5" separation. V1770 Cyg is variable but not listed as a double.
Taken a couple of days earlier with a setting moon, this is a shot of the Cocoon, the first time I've seen this object and not the last. It really is a spectacular sight with its inner sanctum revealing one bright and many faint stars. It appears to be surrounded by obscuring dust too. Also marked is an unexpected find: a faint background galaxy (PGC 167593 mag 18.2). It must surely be quite rare to see a galaxy in this part of the sky given the density of stars and dust?
Next, part of the Western segment of the great Veil supernova remnant. I've observed this visually with an O-III filter and it looks superb, so I was interested to know what an unfiltered view looks like with the Lodestar. Both arcsinh and x^0.25 scaling produced good views of the Veil.
Next, some nebulosity surrounding two pairs of bright stars (looks like a cat's face to me) and an open cluster, Dolidze 8, in Cygnus. These are known as Van den Bergh 132 and 131.
Here's part of the "War and Peace" nebula (NGC 6357) in Scorpius. I was really struggling with this low target to bring out the fainter extensions while keeping the stars from too much bloat, and haven't really succeeded. I think it is worth a visit with a filter and a wider FOV at some point.
Finally, M17, the Omega Nebula in Sagittarius. This is a full 4 magnitudes brighter than War and Peace, and it shows! This reminds me of a cloud underlit by significant light pollution.
Note that in many cases these are quite long stacks, but they accurately represent the end product of a real-time observing experience during which the image continually improves with 15s updates. For me nowadays "total exposure length" is almost unimportant: I observe for as long as I like (usually 15-20 mins per target including finding and framing). None of this would be possible without robust live stacking.
thanks for looking
By Martin Meredith
SHK 10 is the second most galaxy-rich of the 377 Shakhbazian compact groups (*), packing an astonishing 32 galaxies into a space of little over 6 minutes of declination. On the other hand it is rather faint: its brightest member shines at mag 17.7 from a distance of around 1.7 billion light years. SHK 10 can be found centred at [14 10' 56.1" +46 15' 54.7"] a degree or so from mag 4.2 lambda Bootis heading towards the border with Canes Venatici (chart BOO/5769 in the Pretty Deep Maps collection). Here's a screenshot showing the locations of the galaxies, numbered using Shakhbazian's scheme.
For me, the challenge of the Shakhbazian groups is seeing how many members can be pulled out using near live viewing techniques -- literally seeing more and more of them appear on the screen as live stacking does its magic. To give a flavour of the live experience, I've prepared a cropped animated gif showing the progress as more subs come in: 1, 2, 4, 8, 16, 32 and 64 in total. This was also a test of fast stacking so the subs themselves are short, at 10s. Note that this is all live stacked in LodestarLive v0.12 and not post-processed in any way apart from rotation to match the chart. I retained the same brightness and contrast settings throughout, and used the ^0.25 compression mode. The group is in the central third of the shot.[Edit: animation appears not to work yet … here's a temporary dropbox link (0.5M)]Noise is greatly reduced by stacking, revealing the galaxies.Here's the last frame (64x10s stack) in full. Note the super-thin galaxy at top-right. This is mag 16.3 UGC 9066 at a distance of nearly 400 million LYs. Here I've blown up the central portion and labelled the constituents. There are a few obvious stars amongst this group and also some interlopers -- things that look like galaxies but are not listed by Shakhbazian. Checking the SDSS image using Aladin these are definitely galaxies. Whether all belong to the same physical cluster is another question. As recently as 2012 there were only 13 spectroscopically-confirmed members.The ones I've failed to split are 19/20 and 8/24, though the latter actually appears to be a single edge-on galaxy in the SDSS image.Details: SQM 20.2, windless, no moon, around 50 degrees up. Skywatcher Quattro 8" f/4, Lodestar mono X2, LodestarLive v0.12, no filters, AZ-EQ6 mount in alt-az mode. CheersMartin(*) The title goes to SHK 40 in Pisces, a relatively-bright 60-member group also known as Abell 193.
By Martin Meredith
Here's a couple more shots from Monday's session. First, the rather faint Hickson compact group 34 in Orion, a chain of 4 galaxies in the centre of the image. The brightest is NGC 1875 at mag 14.6 and looks stellar. The other three are falling off to the west/south-west and range in magnitude from 17.5 to 18.4 as shown in the figure. The sensitivity of the X2 mono is evident here.Second, something that has been on my hitlist for a while: Abell Galaxy Cluster 539 a few degrees away from the Hickson group. This 50-strong cluster at around 470 M light years is doubly interesting since it contains a lovely galaxy chain, VV161, at its centre. The accompanying pdf provides details of all the galaxies and the wider field. The VV161 galaxies are numbered. Abell 539_leda.pdfThis chart is part of a new project I've been working on during the overcast nights of the last few months: developing from scratch a new deep atlas suitable for EAA. I hope to release a first version in early March (probably focusing on Virgo and Coma) in time for galaxy season.cheersMartin