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The Cygnus wall is finished, at last

The last time I did any work on the ” Wall ” part of the North America nebula, NGC 7000 was way back in June, then I captured the Wall in Ha light, but now the nights are drawing in, the sky is getting much darker now as the sun goes deeper below the horizon ( Astronomical twilight is when the center of the Sun is 18° below the horizon ) so as last night was clear I managed to collect the OIII and SII data to finish the Wall. The seeing was good as Cygnus is nearly overhead when it gets dark.

NGC7000 North American nebula, The Wall - Cygnus
NGC7000 North American nebula, The Wall – Cygnus

I captured as many 300 second exposures in each of the two filters as I could, I also had to perform a Meridian flip part way through capturing the SII data, The Meridian is an imaginary line, running north to south, directly overhead, at your observing location. When using a German equatorial mount you run the risk of the telescope hitting the mount tripod or pier, if the telescope is allowed to continue past this meridian line on the West side of the mount and falling ( counter weights rising ), this can cause damage to the the drive motors and gears so a ” flip ” or a 180° about turn is performed before this happens to put the telescope on the East side of the mount and rising ( CW’s falling ). This also has the effect of inverting the image as the telescope and camera are now essentially upside down compared to before the flip occured, as both the R.A axis and DEC axis rotated 180° – so you have to double check the image Framing, the APT image capture software I use has a framing mask tool that can be flipped to help in this. I had to stop imaging at about 5am, as once again the clouds rolled back in.

Once the data was collected I then proccessed it through Deep Sky Stacker and Photoshop.

The Wall, Cygnus
The Wall, Cygnus

I think it turned out quite well, hopefully I’ll get some more clear nights as I will soon be able to continue my Rosette nebula project, also Orion season is back.

I was away camping week before last, at a small campsite in Bridgetown, Exmoor not far from Dunkery beacon. The campsite lies beside the river Exe, I took my DSLR with me this time and got a couple of nice shots of the night sky as well as the stunning views a round abouts, however the site sits in the bottom of a deep valley with tall trees on either side so the view of the sky is rather limited.

A truely beautiful dark sky, I really wish my observatory was under it, but on top of one of the hills would be best. 

 

Perseids, clouded out again for a second year.

I didn’t even mention the Perseids last year – because it was clouded over for the entire time, again for a second year the Perseid meteor shower, from my location has been hidden by clouds all week, this time with a yellow weather warning for thunder storms all week. Capturing a good thunder storm or two on the all sky camera would be great – if it actually happened, but I haven’t even heard the slightest rumble from where I live, what we have had this week is humidity at 90% and heat up in the 30’s, to say it’s been oppressive would be an understatement, the forecast for next week is much of the same, maybe next year ?.

Work, work and more work

It’s been a while since my last post, while a lot of people have found lots of time on their hands with this Corona virus pandemic and lockdown, I on the other hand have not stopped at all, work has gone mad and as a concrete mixer driver, working long days is not conducive to long nights in the observatory, While I’m not complaining, some people may not have a job to go back to – it does mean I’ve missed lots of opportunities for imaging and as a rule the weekends when I’ve not worked have been rubbish anyway.

As an example, when the lockdown restrictions were eased, my partner and I, like many others decided to go out in our camper for the weekend, just to get away from the same four walls, the weather forecast was for cloud and possible light rain ( so I didn’t take my portable imaging kit ) but that didn’t matter, we’re pretty much self contained in the camper, also we didn’t go far, just to Dunkery beacon near Minehead, Somerset – a wild, beautiful and secluded area, and the highest point in Exmoor. It became obvious as we pulled into a wide layby that the weather forecast was going to be utterly wrong, the clouds were going and a deep blue blanket of evening sky was replacing them, and my portable imaging kit was 30 miles away.

So we sat and enjoyed watching the stars come out one by one, I keep a pair of 10×50 binoculars in the van so all was not lost, binoculars are great especially from a dark sky reserve, Jupiter and Saturn shone brightly in the south east and the Milkyway reached from horizon to horizon, at home you can only see the Milkyway overhead due to light pollution, eventually we retired to bed as it became a bit chilly. 

At around 2am, I woke up and looked out of the window, I quickly got dressed as I could see comet Neowise and Noctilucent clouds, neither of which can be seen from home due to nearby houses and light pollution, all I had to try and capture this scene was my mobile phone so my appologies for the quality of the following picture.

noctilucent clouds and neowise
Noctilucent clouds and comet Neowise

You can just make out the comet as a light patch at top centre of the image.

Noctilucent clouds are the highest clouds in the Earths atmosphere,  located in the Mesosphere at altitudes of around 250,000 to 280,000 ft – They are too dim to be seen during the day and are only visible when illuminated by sunlight from below the horizon while the lower layers of the atmosphere are in the Earths shadow, they are visible only during summer months when conditions are right.

I have also been tinkering, I have made a new housing for my all sky camera as the one I had did not weather well and the plastic became brittle as it was not UV stable, the new housing is made from a waterproof outdoors electrical junction box and a circular dew heater from dewcontrol.com, total cost was less than £25. This camera will be put out when needed and not left to the elements, the camera and lens remain the same.

As the nights are now drawing in again – hopefully I’ll be able to get some more enjoyble work done.

NGC7000 and the Wall

On my last imaging session, I chose the North American nebula – NGC7000 as my target, this large nebulous region is in the constellation of Cygnus, very close to the star Alpha Cygni or Deneb

NGC7000 and Cygnus
NGC7000 and Cygnus

The relatively small field of view given by my 8inch RC telescope, means only a small portion of the nebula can be imaged, therefore I chose a bright area of the nebula called “The Wall” for the nights imaging run. using the Hydrogen Alpha filter, I captured 40 x 5 minute exposures or just over 3 1/2 hours worth, more than enough for stacking in DeepSky Stacker.

NGC7000 North American nebula, The Wall - Cygnus
NGC7000 North American nebula, The Wall – Cygnus

I plan on adding OIII and SII data to this, but for now the weather has turned unsettled for the moment, I have high hopes for next Friday or Saturday night to do this, fingers crossed.

IC1318, the Sadr region

IC1318, the Sadr region lies at the centre of the Cygnus constellation, close to the central star Sadr or Gamma Cygni – it contains many dark nebulae as well as diffuse emission nebulae. I chose to image this region as the contrast between light emission and dark areas are quite pronounced and a lot of detail can be easily discerned. 

However the amount of detail captured is very poor when imaged with an OIII filter, so I only used Ha and SII filters and combined them by putting the Ha data into the green channel and the SII data into both the red and blue channels in Photoshop to create the following SHS ( SII, Ha, SII ) colour image, also some tweaking of the contrast and highlights ( this is commonly known as messing about ).

IC1318
IC1318, Sadr region

Captured over two nights with an Altair Astro 8inch RC, Baader Ha and SII narrowband filters and a ZWO asi1600mm Pro mono camera, 40 x 300 seconds exposures with both filters.

below is a wider view, captured using a 72mm William Optics Megrez refractor and the same filters and camera.

IC1318 Cygnus Sadr region SHS WO72mm Megrez
IC1318 Cygnus Sadr region SHS WO72mm Megrez, Sadr bottom middle

Eta Aquarids no, Starlink yes

In my earler post, I said that I had set up my Canon EOS 600D DSLR camera some weeks ago to try and capture some Eta Aquarid meteors, now while I had transferred the image of Venus that I had taken, I had not looked at the rest of the images stored in the camera from that evening ( 21st April 2020 8.30pm ) – I had a look today and though I had not captured any meteors I did it seems, by chance capture these bleeding Starlink satellites. I had pointed the camera at an area of sky just below Ursa Major, the Great Bear, the Plough or if you prefer the Big Dipper, I had started to capture images just before 8.30pm and the sequence of 59 images that contain the satellites trails go on for 6 minutes, I had to adjust the tone of the individual images in Photoshop to make the trails stand out better, then reduced images to a quarter original size to allow me to make a GIF.

Below is a single image from the sequence, I have marked where the satellite trails are as its hard to see without enhancement.

Single image
Single image

Here’s the GIF of the Starlink pass, you can see the stars of the big dipper handle as well as some whispy clouds.

Starlink-Satellites
Starlink-Satellites

As these images were captured at dusk, you can see how bright they would of been had it been properly dark.

NGC 6888 ,the Crescent nebula, a matter of timing, and a late Venus

The Crescent nebula, NGC 6888Caldwell 27 or Sharpless 105 is an emission nebula in the constellation of Cygnus, that is some 5000 Ly away, formed by the stellar wind from WR136, a Wolf Rayet star – colliding with and energizing the slower moving wind ejected by the star when it became a red giant around 250,000 to 400,000 years ago.

Here is a spectrum of WR136 that I previously captured, note the bright emission lines.

WR 136 Cygnus ngc6888
WR 136, Cygnus, NGC6888

I decided to image this object as I already had data in Ha, OIII and SII, as long as your using the same set up, telescope, field flattener and camera, you can keep adding to the data, that’s the beauty of digital imaging, I added an extra 4 hours of exposure to the data and came up with this image.

Cresent nebula hubble palette
Cresent nebula Hubble palette, WR136 is the central star

As I mentioned in yesterdays post, I was going to try and capture these Starlink satellites with my allsky camera, they would pass over this morning at 3.48am GMT, the following comes from the Express website.

Space enthusiasts will be treated to two opportunities to spot the synthetic satellites this week, according to the Find Starlink website.

Wednesday, May 27 at 3.48am GMT: Starlink-6,7 will be visible travelling from southwest to east for around five minutes.

This starts at 13° from the horizon and the constellation will reach a maximum elevation of 51°.

Thursday, May 28 at 2.50am GMT: You have a second chance of spotting Starlink-6,7 while traverses from south to east for approximately three minutes, starting at an elevation of 25° and reaching 29°.

Well the allsky camera caught nothing. the problem lies with the information re-produced by the express science collumist, Tom Fish, who starts his post with the headline.

SpaceX Starlink: These are the exact dates and times to see Starlink from the UK this week

He reported the times in GMT ( Greenwich Mean Time ), the findstarlink.com website clearly states all times are in BST ( British Summer Time ) which is one hour ahead of GMT, so I was an hour late, now I challenge Tom Fish to see any satellite, unless it’s burning up in the atmosphere, at 17 minutes before sunrise.

I should of checked the findstarlink web site myself, lesson learned – tomorrow morning at 2.50am BST looks a better option. 

Here is an image of Venus from my backyard taken 3 weeks ago, I had my Canon EOS 600D on a timer hoping to capture some Eta Aquarid meteors so I took a quick shot of the planet before it started getting too low.

IMG_0005
Venus, the evening star

 

Chasing the Dark, Starlink and nearly giving up.

The days are long and the nights are short, at the moment there are about 4 hours of usable darkness for Deepsky imaging, fortunately since most of the aircraft have been grounded due to the Covid 19 pandemic, the skys have been much much clearer, this has happened before, I refer you to a previous post of mine about when the Icelandic volcano Eyjafjallajökull, erupted in April 2010, I’m even more convinced now that aircraft emmisions are the cause of so much bad weather and a huge contributor to global warming ( Aircraft operators can plant as many trees as they like, trees will not clean air 31000 to 38000 feet up ). Anyway back to topic, I have booked a weeks holiday to enjoy the weather, not going anywhere just relaxing at home and taking advantage of the clear ( night ) sky, I have done more imaging in the last two nights than i have for a long time, a total of 8 hours gathering narrowband data on IC1396 the Elephants Trunk Nebula in Cepheus, this was added to data that was captured in 2018 giving about 16 hours of exposure.

Elephant Trunk nebula Hubble palette
Elephant Trunk nebula Hubble palette

I must confess, I would have done some imaging a couple of weeks ago – but I had a moment where I seriously considered giving up astro imaging altogether, a couple of weeks ago I happened to be standing in the back garden looking up, when I noticed a satellite passing from west to east, ( nothing odd about this there are roughly 5000 in orbit, under 2000 of those are operational ) then another 30 seconds later following the same path, then another 30 seconds after that and so it went for about fifteen minutes, what I had seen was part of Elon Musks, SpaceX, Starlink satellite constellation, these satellites – when they cross the field of view of a telescope and camera, leave lines in the image as they pass.

starlink-trails
Starlink trails, Credit: Victoria Girgis/Lowell Observatory

I phoned a friend of mine, another amateur astronomer to have a look himself, we both agreed it was a sickening thing to see, many non astronomers do not realise the danger to our night sky these things pose, especially as they are already having an impact on the night sky with only 360 them, Mr Musk ( the very same guy who thought it a good idea, albeit an egotistical one to launch a Tesla Roadster, complete with a spacesuit clad dummy into space, from an astronomers point of view he would make an excellent Bond villain ) wants to launch 30,000 of them, to provide global broadband internet coverage.

By the year 2025 SpaceX plan to have 12,000 Starlinks in orbit distributed as follows

  • 7,500 at 340 km altitude
  • 1,600 at 550 km altitude
  • 5,800 at 710 km altitude, data courtesy of Union of Concerned Scientists.

But thats not all, there are other companys that want to launch their own satellite constellations, OneWeb with an initial 800 satellites, Amazon last year announced project Kuiper, with 30,000 satellites and Canadian company Telesat wish to do the same, although they have not as yet said how many satellites they will have.

I set my allsky camera up to see if I could capture some of these rudy things, but all I got was the ISS, at least when you see that, you can think to yourself, there’s people up there, the StarSTINK ( thanks for the name Ron ) satellites should pass over the UK on Wednesday, May 27 at 3.48am GMT, I’ll try again then.

MeteorDetect-0297_38_106
ISS, International Space Staion

The allsky camera works using software to compare one image with the next, any change such as a satellite or meteor triggers a capture sequence, imagine what it will be like when the sky is a moving net of satellites, it will be running a continuous capture sequence.

The issue of trails on deepsky images can be fixed with stacking software and Kappa Sigma Clipping algorithms, which ignore outliers such as satellite trails ( yet to be tested on a stack of badly trailed images ) and cosmic ray action on a camera sensor, but if you just want to lay back and look up at the spendour of the night sky, especially if you live under a dark non light polluted sky – then your view will be spoilt beyond doubt. 

That was why I was ready to give up the ghost, I do like to just stare up at the beauty of the heavens from time to time, is it’s not enough that we pollute the earth for greed, we now need to pollute the night sky as well.

Comet Atlas C/2019 Y4

A clear Saturday night ( shame about the moon ) had me gazing at a comet, this comet was discovered by the ATLAS ( Astronomers do love their acronyms – this one stands for, Asteroid Terrestrial-impact Last Alert System ) survey on December 28, 2019, and it was thought that it might reach naked eye brightness, however on around the 2nd April 2020 the comet underwent a fragmentation event, having thought to have split into at least four pieces, possibly due to outgasing causing an increase in centrifugal spin, this has caused the comet to dim considerably, however it does have a 3.3 million km long tail, more than twice the diameter of the sun.

Updating the comet elements in Cartes du Ciel ( CDC ) meant that once I had done a single star alignment and a quick plate solve of the star field, the telescope then slewed directly to the comet and put it squarely in the middle of the camera sensor, a hell of a lot easier than following a printed star chart and star hopping to the object. 

APT Comet Atlas
APT Comet Atlas

I captured 43 x 120 second exposures through the 8 inch RC and ZWO asi1600mm using a Baader 2 inch clear filter, the moon being three days from full – together with a bright sky glow did give some hard gradients, that were difficult to process out entirely.

Comet Atlas C/2019 Y4
Comet Atlas C/2019 Y4

Capturing so many images meant I could turn the images into a GIF to show the movement of the comet against the background stars. My appologies for the jump in the GIF, I had a go at tracking the comet instead of a star in PHD2 , I was hoping to get a clearer look at the tail, however the comet nucleus was too faint to keep a good lock on it, so I had to revert to star tracking. 

Comet Atlas C2019 Y4 2020-04-04
Comet Atlas C/2019 Y4 – 4th April 2020

Whether this comet holds together enough to brighten again as it approaches the sun, remains to be seen ( no pun intended ).