Wednesday, 29 April 2020

M13 and M102 - A fine pair

M13 and M102 - A fine pair

Finally, I have got to the end of the glut of data I have acquired over the recent weeks.  Also, this will be the final instalment of the recent glut of astronomy blogs, for I have eventually caught up with all things Astro blogging on my list.  Yippee I hear you cry!  For this post, I look at two targets I imaged around a week ago.  In a break from galaxies, I look at M13, a globular cluster before moving onto M102.  A galaxy with a dubious past.
No matter what time of season it is (as in, right now, we call this time of year Galaxy Season because of the number of galaxies that can be observed and imaged with relative ease) I always keep an eye on what's next coming over the horizon.  It won't be long before we lose astronomical darkness overnight, which will mean imaging time of any use will be taken from us in the weeks either side of the Summer solstice.  So, over the next couple of months, while darkness is at a premium, we will say goodbye to Leo, Virgo and the likes, but hello to the Summer constellations of Lyra, Cygnus and Hercules amongst others.  In fact, these constellations are already putting in an appearance after midnight as they creep up above the Eastern horizon.  Hercules is the first of these to put in an appearance, rising high enough to observe and image slightly before midnight, and it is here that I looked for my next imaging target.

M13 - The Great Globular Cluster in Hercules

A favourite at star parties for observers new and old, M13 is a magnificent site in any telescope or suitable binoculars.  It's brightness and location make it easy to spot.  But, I have found that imaging this target raises it's own difficulties.  Being made of nothing but countless stars mean that focus is everything.  When we observe M13, rather than just being satisfied that we've seen a condensed blob of stars, we spend time at the eyepiece to try to visually resolve those stars.  Only then I find can we gain a true appreciation of this cluster.  The same goes for taking a picture of it.  Slightly out of focus, and you could tell what the image is of, but instead of being able to resolve as many stars as possible in the globular core of the cluster, you could end up with a blurred white spot with a few speckles of other stars around it.  However, accomplishing a good focus is harder that it sounds, especially when having to rely on manual focusing without the aid of an auto focuser adjusting itself throughout the imaging session, keeping everything as optimum as possible.
I first tried this target before I had a dedicated astronomy camera, instead using my DSLR and though back then I was happy just to get any result, I have since changed to a refractor telescope which makes focussing much better.
Can you spot at least one other galaxy in the image?

M13 in Hercules is a wonderous site at high magnification when observed through a telescope.

M102 in Draco

M102, or should that be NGC 5866?  If you take a look at the Wikipedia page for this galaxy, you will be referred to several other galaxies, including M101.  To get a partial understanding of why we have confusion, we need to have a very quick history lesson...
The targets we observe and image all have designations, or names given to them.  Targets starting with the letter M were first catalogued by Charles Messier as he went about searching the skies for comets in the 18th century.  When he identified a target, but determined it wasn't a comet, he described it, gave it a catalogue number and a position and then left it at that.  The point being that he knew if he came across this object again in the future, that he had already observed it, and therefor could just get on with the rest of his observations.
Then, along come another astronomer, Pierre Machain, who used to share observation information with Charles Messier, but he determined M102 to actually be a duplication of M101 and therefor, you could say not to exist.  Though limited because of the quality of the equipment of the day, the confusion for sets in because visually, they are very different targets.  Though both galaxies, M101 is a face on spiral galaxy, and the supposed M102 is an edge on galaxy.  It has also been suggested that M102 is actually a duplicate of one of several other galaxies listed in the NGC (New General Catalogue).  Over the years, other astronomers and professional bodies have had their own interpretation of what M102 actually was when it was first catalogued, but it's now come to be generally accepted that it was indeed different to M101, and is more likely to be what is now catalogued also as NGC 5866.
Whichever way you look at it, and whatever name you wish to give it, it provides a good challenge to image.  On images using a longer focal length which allow you to get much higher magnification, you can see the galaxy edge on, but also make out a thin dark line running through the edge of the galaxy.  While I could just about make out this line early on, unfortunately during the processing stages, I seem to have lost this detail while trying brighten the galaxy overall.

The wider field view of the galaxy.
The image below is an enlarged crop from the original hi-res image in which you can just about make out the notable feature of this galaxy.  It's still quite tricky to spot though...

Finally from me, thanks for sticking with me through this recent splurge of Astro posts.  I have finally come to the end of my backlog.  Hurrah!  There are a couple of opportunities to get outside observing and imaging again in the coming few days, but the weather has generally deteriorated somewhat compared to recent weeks.  It's back to snatching half chances to get out under dark skies when I can.  For the moment though, thanks for reading, and stay safe 😊.

Tuesday, 28 April 2020

Astrocamp Spring 2020 - The one that got away.

Astrocamp Spring 2020 - The one that got away.

Regular readers will know that after ever Astrocamp, I like to sum up the long weekend with a regular blog post.  Well, how the bloody hell am I going to pad this one out????  So, what do you do when you can't all meet up for the main event of the Spring?  Well, as it turns out, you do what every other human on the planet seems to be doing at the moment, and shift it online.

Day 1.  Arrival!

On a day where I, and people across the land, should have been arriving at camp, and setting up our tents and scopes, we were all sat at home, under lockdown conditions just like we have for over a month.  It has become the new norm.  And people seem to be coping with it in different ways.  Some better than others, but we get by.  In this particular situation, I could sit back, look at what we were all missing, and get generally down in the dumps about it all.  Or, I could pick myself up, and try to make something of it, and join a whole bunch of other people trying to make the most of a pretty glum situation.  I chose the latter!
I decided to replicate my pitch out in the back garden, and so hauled all sorts of kit out into the back garden and set it up.  OK, I admit, I had plenty of time on my hands!  In a rather bizarre way, it at least felt like camp had started.  Being surrounded by everything from a toilet tent and telescope to a water carrier, stove and slow cooker.  Mind you, I do look back at this and wonder what exactly I was trying to achieve, but it kept me amused for a while...

Over the last couple of camps, I have taken my bike with me, so I can go out for a ride during arrivals day.  A great chance to get out and usually see some of the Brecon Beacons and Black Mountains.  Indeed, this time last year, I went off on 70km ride starting and finishing at camp.  This year, I wanted to replicate this.  Fortunately, one of the few reasons we can currently leave the house is for a period of daily exercise.  So, with the Sun up and the sky blue, it was time to replicate that part of camp too!

Night 1, and people were posting images of themselves setting up their scopes in their own gardens to take advantage of some fantastic weather and clear sky.  It seems that everyone was determined to take part in some way or other, and was great to see.  For me though, the local forecast started off good, but cloud was soon to come in and obscure the stars for the rest of the night.  Unfortunate, but typical of camp on so many occasions!

Day 2. Setting the scene.

When I woke at home for the second day of my sudo Astrocamp, I thought back to how things typically look after a good night at camp.  There are relatively few things needed to make a classic night at camp.  1.  Awesome people.  2.  Clear sky.  3.  Let's call it 'socialising'...
There are certain things you will generally see at camp if you are up and about early enough.  Telescope tents covering telescopes, camping chairs, and socialising leftovers. It was time for another re-creation in the back garden, and even the customary barrel of Astrocamp ale made an appearence!

Quite what the neighbours might have been thinking , I don't know, but it was time to carry on with the rest of day 2. And that means only one thing. A trip to the café for a cooked breakfast. Yep, I re-created that too...

Day 3. Quiz time!

The highlight for many an Astrocamper is the afternoon spent at the Spiral Arms where we would usually have talks and quizzes.  We could not let the weekend go without at least having a quiz, and it also turned out to be a brilliant opportunity to catch up with everyone via the power of Zoom!  For me, this was both the best bit, and the saddest bit of the whole weekend.  Finally a chance to see everyone, and talk to everyone.  This is the part of the whole event I missed most.  A big shout out to John for putting himself forward to organise the quiz.  Such a  great way of bringing everyone together, and the uptake was brilliant.  So many familiar faces and voices.  It was just awesome to be involved.

Day 4. Time to head home, from the back garden.

The day where everyone wakes and knows the inevitable can't be delayed any further.  Time to go home.  In a scene often witnessed at camp, people start the tradition of tent wrestling as they try to get it all packed down and fitted into the bag.  Yep, I had a go a recreating this too...

Wrapping up.

When things improve.  When we get back to normal.  Two phrases that we have all heard with increasing regularity during the last couple of months.  By our very nature, we are social creatures.  We like spending time together be it in large groups or small.  The circumstances we find ourselves in at the moment are unprecedented in our lifetimes.  While we can leave the politicians try to make out that they know what they're doing, and that their course of action is the best one in the world to take, the truth is that it is down to us as individuals to look after ourselves, our families and our friends.  This weekend has shown me that in some situations, we only have ourselves to turn to, but in other situations, if we pull together, we can make the best of many things.  It's easy to become totally isolated because we don't get the physical company we like as humans, but by rolling up our sleeves and immersing ourselves in things that we can control, we can come out all the better for it.  Having contact with so many regular Astrocampers over the last weekend has been really good for the mental health and re-affirms what a brilliant bunch of people they all are.  
In years to come, I expect we will be able to read back to this blog post and wonder how we coped with it all.  It's been the weirdest, hardest and possibly most pointless and worst blog post I've ever written, but as I have always maintained, it's my way of just recording what I get up to in my astronomy activities, and if anyone else wants a nosey and a read, then great.  
Finally, when news broke that this Astrocamp had to be cancelled, everyone who had paid for their pitch had an option of either claiming a full refund, or donating the money to local business that would otherwise benefited in some way by the event taking place.  During the Zoom quiz, John announced that together, we had donated well over £2000 which was being split between the campsite at Cwmdu, the local pub The Farmers Arms and the local café and tea rooms.  A fantastic gesture by a great bunch of people which I should go a little way to supporting those businesses.
Here's to the next Astrocamp!  Stay Safe.

Monday, 27 April 2020

Welcome To My Observatory

Welcome To My Observatory

Hello, and welcome to another lockdown blog post.  Clearing the backlog generated by the opportunity to do a shed load of astronomy due to the lockdown measures coinciding with some brilliant observing and imaging weather conditions.
Back in October last year, I had my observatory built, and now I've had plenty of time to get settled into using it.  All my kit has been moved in, and I've been able to knock out images more regularly that I have ever have done before.  Actually, let me rephrase that.  I've managed to take advantage of minimum set up times, and every weather opportunity presented.  That's probably more accurate.
Anyway.  I've posted a couple of pictures here and there of the observatory, but nothing that really takes a close look at it.  So, here by no popular demand whatsoever (actually, two requests), I've taken a step into the world of YouTube and put together a quick video tour of the finished product.

Keeping, this post short and sweet, that's a wrap for this one!  I'm off to start processing more data which I have gathered in the last month or so.  The backlog of posts is finally diminishing, but I'll keep going until I'm all done and I have to wait for the next batch of good weather so I can start astronomising once again.  Still to come this week, I'll be posting about a couple more images I've taken of a couple of Messier objects, and also Astrocamp on Lockdown!
Stay safe everyone!

Sunday, 26 April 2020

M51 - Snatched From The Jaws Of Defeat

M51 - Snatched From The Jaws Of Defeat

Welcome to the latest in this series of catch up blog posts.  I've managed to cram in so much astronomy this Spring that the topics I feel that are worthy enough to write a few lines about, are stacking up!  So, let's continue through this backlog and get on with today's post.
This post hails back from a week ago, when I snatched another chance to get the observatory roof open and do a bit more astrophotography.

Target Acquired...

It had been quite a while since I last tried to image M51, AKA The Whirlpool Galaxy.  In fact, looking back through my archive, I see that it was circa August 2016 when I last collected the photons travelling from this popular target.  Back then, I was using a completely different set of equipment and techniques.  I was using a DSLR and Backyard EOS to capture my data.  The mount I used back then was a Celestron AVX mount set up in the back garden of our old house.  Processing was carried out predominantly in Deep Sky Stacker and GIMP.
I've come on a bit since then, and now use an astro dedicated OSC camera on a Skywatcher EQ6-R Pro mount permanently set up in the observatory.  All the data is captured with SharpCap Pro and processed in PixInsight.
That's enough of the tech jargon, let's move on.

Data Acquired and Processed...

Originally, I wanted to collect between 3 and 3.5 hours of light data of M51, and then all the relevant dark and flat calibration frames on top of that.  In fact, that is precisely what I did, but I did seem to hit a big issue.  As part of the processing, I look at each individual frame to see if there are any anomalies which could affect the final results.  I found loads.  Out of approximately 36 frames, 8 of them had satellite trails going through them, so I removed them from the stack.  Only after I finished this image did I learn that there are techniques within PixInsight which can deal with satellite trails to some degree.  But that's a whole new topic for another day!
Onto the stacking and calibration, where for some reason, PixInsight failed to calibrate another bunch of the remaining frames.  I tried several different ways using different settings, but not making much difference.  In the end, I had to call it quits, and just run with the frames I could use.  I was now down to a total of 11 light frames, roughly 1/3 of the total I was originally hoping for.  Things weren't looking good and to be honest, I wasn't expecting much at all.  I was staring a completely wasted night in the face.

Victory Snatched...

Even though I didn't expect much from this set of data, I wanted to persevere through to the end result.  After all, you don't learn anything by giving up half way through if something doesn't work out.  Somehow, and I'm not sure how, I managed to salvage a very reasonable picture (in my opinion anyway) of M51, and when compared to my attempt from 4 years ago, I'm particularly heartened to see how far I have come.  So, without further delay, my most recent effort on M51 - The Whirlpool Galaxy.

M51 - The Whirlpool Galaxy.  11 x 5 minute light frames + approximately 25 flat frames and 30 dark frames for calibration.
Just to compare the difference, here's my attempt from back in August 2016.  It's a significant difference.

For comparison, my first attempt at M51 from August 2016
Time to wrap this post up.  Still to come over the next few days, I will look at the results of another couple of imaging sessions (although I haven't processed the data from those yet), a tour of the home observatory and the traditional blog post for Astrocamp, with a difference.
All the very best.  Stay safe!

Saturday, 25 April 2020

Astro Live Streaming

Astro Live Streaming

In today's catch up blog post, the latest in the backlog which I want to get sorted, I look at how the current social distancing measures are affecting astronomy hobbyists outside of their own back garden.  Numerous events around the world are being postponed or cancelled because of the ban on gatherings of groups of people.  This means families, friends and organisations across the lands are turning to live streaming in an effort to avoid missing out completely.  In the last week or so, I've taken part in two live stream discussions with more in the pipeline.  The great thing is that if you don't get chance to take part, you can at least catch up with these events at a later date because inevitably, they get uploaded to YouTube.  Happy days!

Awesome Astronomy does Live Streaming

I'm a subscriber to the Awesome Astronomy podcast.  A fortnightly (ish) podcast on space and astronomy put together by the same team of people who organise Astrocamp, a twice yearly star party in the foothills of the Brecon Beacons national park.  This year, the organisers had to cancel the event, which as it happened, should be starting today, 25th April.  Rather than just kicking back, and just knocking out the podcasts, the Martian overlords have stepped up to the plate, and put together their first live streamed version of their podcast.  In this episode they had some special guest appearances and contributors who were all on hand to answer any questions put to them.
Though we are all missing Astrocamp this Spring, seeing these friends and having the chance to interact with all the regular attendees has been brilliant and uplifting.  Take a look at the recording, and subscribe to the channel.  There are more in the pipeline with the next episode due to be streamed on Monday 27th April at 8PM UK time (BST).

The Blackrock Castle Observatory, Cork does Live Streaming

I come across this event via someone I follow on Instagram.  She works at the observatory, but obviously is also subjected to current restrictions.  However, that didn't stop her from putting together a live Q and A with one of the astronomers based at the observatory and streaming it on their YouTube channel.  The topic of this Q and A session covered something which has received a huge amount of press and social media coverage in the current weeks, and that is Starlink, the satellite mega consolation currently being produce by SpaceX with the aim of providing global superfast broadband coverage.  I have my own views on this, but during the Q and A, plenty of questions were being asked covering all sorts of aspects of Starlink including what will happen to the satellites if they fail, if they collide, if they come to the end of their useful life.  Also covered were such things as the ethics of launching these satellites into space and who has the final say as to who has the legal right to allow companies to carry out these launches.
This channel is really worth subscribing too.  Since doing this Q and A sessions, another live stream was put together to celebrate the 30th birthday of the Hubble Space Telescope.

These are just two notable outlets of astro related content that in my opinion, is worth spending some time watching.  That's it for this blog post.  I just wanted to bring these brilliant channels to peoples attention.  Coming soon from me, I will be returning to my own astronomy experiences and looking at some imaging sessions which I recently carried out, and also take a look at a video I have put together giving a tour of my home observatory.
Until next time, thanks for reading and stay safe!

Friday, 24 April 2020

ISS Solar Transit Captured

ISS Solar Transit Captured

This is the third instalment in a batch of blog posts which I'm putting out.  This time, I'm looking at imaging the ISS.
Since I've been interested in astronomy, I've held subscriptions to some astronomy magazine and my favourite part, regardless of which publication, is generally the section when people can submit their own images.  You can always find a great mix of targets.  Galaxies, lunar, solar, nebulae the list goes on.  I remember being stunned when I first saw a picture of the ISS taken through amateur equipment.  At first, I couldn't believe that you could photograph the ISS, and show anything more than a streak of light in the night sky as it passes overhead.
Soon though, I come to learn and understand how these things pan out and I grew a greater appreciation of the techniques needed to get these images.  For some years since, I have always fancied giving it a go.  It seemed all I needed was to be in the right place, at the right time, with the right kit in the right weather conditions.  That's a lot of 'right' things needing to be in place all at the same time.  Mmm, this could be the hardest part.

When do transits happen?

The type of image I wanted to capture was a transit image.  Either of the ISS transiting the moon, or the sun.  Either would do for me.  Logic kind of says a solar transit is more likely given that the phase of the moon is always changing whereas the sun is always present.  You just have the great British weather to contend with.  Then up steps the internet, and a plethora of sites and apps that are designed to help you determine when a visible transit might be due.  I found to be most helpful when it comes to predicting solar transits.  You can enter your location, a time frame within which you want to check and how far from your position you are willing to travel to see the transit.  The site then takes that information, checks the latest ISS orbit data, and plots any relevant times and dates onto a map, showing the area where a transit will be visible from.
Let's not underestimate all the things that need to come together for this to happen.  The sky on a global scale is massive.  The Sun in comparison to the area of the sky visible from the whole planet is pretty small.  The ISS from the perspective of being on the surface of the Earth is tiny.  What you are waiting for is for your position on the surface of the Earth, the ISS (moving at a rate of 17,130mph) and the Sun to all line up at the same time.  The margins are tight to say the least.
Now imagine my excitement as I entered in my details into the ISS tracking website, only to find out that over a 2 week period, the ISS would be visible passing in front of the Sun (transiting) not once, not twice, but 3 times and all visible from my back garden.  A transit will last anything from under one second to around 2 to 3 seconds.  There's no messing.  That's all the time you've got to get that image.

Capturing that image... and failing.

My first opportunity came around the 13th April late on in the evening.  The sun was no longer visible from within the observatory, so, I took a spare mount and tripod into the garden, took my refractor off the mount in the observatory, and set everything up connected to my laptop.  It is at this point I need to put out the usual warning, but it would be somewhat remiss of me if I didn't give this a mention.  
Under no circumstances look directly at the sun, be it with the naked eye, or with any sort of optics such as a telescope or binoculars.  It will hurt.  It will blind you.  You will suffer irreversible damage.  Not even a pair of posh expensive sunglasses will protect your eyes.  Don't do it.  Just don't.  The only way it is possible to look at, or image the sun is by using specifically made filters or equipment that severely cut down the amount of light allowed through the device.
I used a white light filter specifically made to fit snuggly over the end of my refractor telescope.  Only when that was fitted was I able to turn the telescope in the direction of the sun, and start preparing to take pictures.  Anyway, back to the first attempt.
With everything set up and working, I took a couple of test frames and managed to frame the Sun pretty well in the centre the camera's field of view.  Then, up steps the wonderful British weather.  A single, although large cloud crept along the surface of the Sun, obscuring it from view.  This is where the problem started.  Not being a regular solar imager, I needed some time to test my camera settings.  Getting the sun in focus is one thing.  Getting the correct exposure times and gain settings is something else, requiring plenty of experience, or at least, time for trial and error.  Do you know, that single cloud hung around as long as it possibly could?  I watched my countdown to the time when the transit was due to happen.  I was running out of time.  I wanted to take 1 minute worth of exposures, approximately 30 seconds either side of the transit time, to make sure I caught it.  The cloud cleared the Sun with about 90 seconds left to go, and I simply ran out of any testing time.  I could only go with what I had.  I failed.  Miserably.  However, I have got a nice collection of around 200 frames of a bright white circle to show for my efforts.  There's no doubt the ISS did transit the Sun as it was predicted to.  My camera settings were hopelessly over exposing the images though.  I had nothing.

Capturing that image... and succeeding.

I would need to wait another week for my next chance.  Time I could spend gathering more information, and learning a bit more about the techniques required to get the image.  I decided to change tac slightly, and instead of taking a rapid series of still images, I read up on how I could use my equipment to capture a movie clip in .avi or .ser format.  I could then use some free software called PIPP which is designed for solar and planetary imaging, to take that video, break it down into component frames and safe them as .tif pictures.  There is a bunch of other clever stuff this PIPP software can do, but that would be enough for me, and would get the result I wanted.
So, come the morning of 21st April, I checked the weather, checked the transit website and verified that all was good.  This time, I didn't need to remove anything from the observatory as the Sun was gong to be high enough for me to see directly from inside the observatory.  This transit was scheduled to last around 0.8 seconds.  No third chance for at least another week.  After that, no more foreseeable chances for perhaps many months, even years.  At least, not from my position in the back garden.
I had the mount set up and tracking the Sun.  This time, not a cloud in the sky, so nothing was going to get in the way.  I was also able to run a few tests, and bring down the settings to allow me to see some features on the solar surface.
My plan of attack this time was to capture 1 minute of video, in the middle of which would be 0.8 seconds of transit time.  And that is what I did.  The countdown clock came to zero, I pressed the capture button, and waited, staring at the screen for any sign of the ISS passing in front of the Sun.  I didn't see it.  The video clip finished and was saved to hard drive.  I had no idea if things had worked.  All that preparation, and everything was over in a flash.  Quite literally the blinking of an eye.  Next I needed to copy the captured video from the observatory computer to my laptop, where I could start searching the footage.  It was only then, I realised that with my camera, and the resolution and frame rate it was recording at, that one minute of video footage took up around 21GB in size.  Positively massive when compared to your regular HD 150 minute classic Disney film!


So, PIPP did it's thing, produced hundreds of .tif files, debayered them and made them ready to view.  I started my search, getting rid of all the images I didn't need until I struck gold.  A sequence of around 8 or 10 images taken from the video where the ISS could clearly be seen passing in front of the Sun.  How excited was I?  Really excited.  Pleased as punch, made up, stoked.  Generally, quite happy.
Since I took these images, I have done two things.  I have arranged them in a short video, which shows the transit, slowed down to around 5 seconds.  I've also taken one of the images and introduced some false colour to bring the more expected, yellow colour of the Sun.

The ISS passing in front of the sun.  This transit passed in front of the sun on it's left edge.  This image is from approximately half way through the transit.

There is a third opportunity for me to try for another image, although the next chance in a few days time a quite early in the morning, possibly before the sun has made it up above surrounding roof tops, trees and fences.  I don't think I will try to image that one, but instead, start the search for an ISS transit of the moon.
Stay safe everyone!  Cheers.

34 Observations

34 Observations

In this second post of the present glut of posts, I wanted to go back to the days when my astro hobby was purely visual.  With the weather being very kind recently, I've been able to set the imaging equipment up, but also set up the SBT in the back garden so while the imaging rig is running for 3 or 4 hours at a time, I've been able to get outside and use the Mk. 1 eyeball.  It's been brilliant!  It's been part of the hobby that doesn't get revisited too often, but boy is it rewarding!

13th April 2020

There's a familiar buzz when everything set up and you can't wait to get going.  All you need to do is wait for darkness.  The anticipation of seeing things which you don't get to observe very often is great.  It's different to imaging, where, to be honest, you get a very different experience of what you're observing.  Images very rarely, if ever, resemble anything that you see from the eyepiece.  Observations are often just very dim smudges of light, and it becomes a bit of an art tracking them down and then picking out the detail as you spend your time at the eyepiece.  It requires a lot more skill to locate them and observe, rather than just pushing a few buttons and performing a few mouse clicks on the computerised GoTO mount I have in the observatory.  You could liken it to navigating in the mountains by traditional map, versus opening your phone, and using it as a GPS on a pre-planned route.  Fortunately, I don't think visual observing with manual mounts is a dying art, unlike more traditional navigation techniques.
The SBT 12" dob set up in the garden waiting for darkness with the observatory in the background all prepped and ready to go.
It's galaxy season, and with the excellent light gathering capabilities of the dob, I'm able to go off hunting for targets up to mag 11 or 12 from my position at home.  With only minor light pollution in this area, it's challenging observing objects of this magnitude, but it is possible.  It is also where your skill comes into it, knowing how to locate, and then positively identify what you're looking at.  This particular night, I was looking forward to getting stuck into the likes of Leo, Canes Venatici and Virgo, which are home to so many galaxies and galaxy clusters.  I concentrated on the Messier objects for this first evening, and managed to observe 23 different targets.  The problem isn't necessarily finding some of these galaxies, but distinguishing them from all the others in the same area of sky.  It's a massive eye opener that makes you realise what is out there in the night sky, which under any other circumstance, you would only ever get chance to read about in books (remember them?) or on the internet.  Seeing them for yourself will never be surpassed in my opinion though.

15th April

The weather during the day had been dry, warm and settled.  No real cloud to speak of and relatively low humidity.  It was all set up for a night of excellent conditions with local sky conditions as good as they will get.  Having concentrated on the Messier objects, and galaxies in particular, for this second session, I wanted to observe some of the less popular objects.  With the added bonus of moonless nights, the sky was truly dark at the moment.

Observing in full flow, using the red torch for picking through my star charts.
The Broken Heart Cluster, The Spindle Galaxy and NGC 2403 were a few of the 11 targets I observed during the evening.  Some of them harder to locate, and needing the use of a UHC filter to pick them out from the background sky meant that the tick list for the evening wasn't as long as the previous session, but in no means any less rewarding.
To finish the evening off, a reminder that the astronomical sky is ever changing.  It only seems like a couple of weeks since we were welcoming galaxy season into our night sky, but now, by the time it gets dark truly dark, Leo is already touching the meridian and Virgo is well up in the sky.  A sign that the sky never stands still.  By the time I called it a night, Cygnus and Lyra were well up over the horizon giving a tantalising glimpse of what is to come.  Unfortunately, in the coming couple of months, we will start to lose true astronomical darkness as we approach periods of the longest day light.  It will mean that imaging sessions will be limited, and observing sessions short and possible for only a couple of hours very late into the night.  Then, it will be time to step back for a month or so, until darkness returns.  Who knows what the world will look like by July or August, but by then Leo and Virgo will be heading under the horizon by the time is gets dark, and Cygnus will be in prime position.
For me, during this quiet time, it will be the start of a maintenance period.  There will be eyepieces to clean and service, mirrors to assess and if required, cleaned and the mount will be taken off the pier and cleaned up.  It will also be the first period of maintenance for the observatory,  All the wood will be treated and the inside will get a good clean out, ready for when darkness returns.
Thanks for reading.  Next up, ISS solar transit imaging!

Thursday, 23 April 2020

Whales and Hockey Sticks

Whales and Hockey Sticks

Good evening (as I type this anyway!).  This will be the first in a glut of posts, for astro life has been busy and fruitful.  To bring you up to speed.  The current situation of not being able to work for several weeks has also timed itself with a good settled spell of weather, meaning that there has been lots of action in the observatory at nights, resulting in the rather pleasing backlog of data to be processed, and the even larger backlog of blogs posts to write.  Rather than knocking out one long blog post, I'm going to split them up into more manageable chunks.  As well as imaging, I've knocked together a new video, taken part in live Q and A's and had some brilliant observing nights out in the back garden.
So, where were we?  Oh yes.  At the end of my last post, I was somewhat lamenting the noisy images which I seemed to be creating, along with anomalies appearing which really ought to have been addressed with the flat frames thrown into the mix.  I finished up by having a rethink on what I could do to help tidy up the data I've been collecting, be it changing exposure times, gain settings etc.  I then had a rethink on the rethink and decided that the data I was collecting was actually OK, and perhaps my calibration frames needed more attention.  The result of this thinking about rethinking resulted in me creating new libraries for the dark and flat frame libraries.  It's kind of helped!
We are right in the middle of galaxy season with Leo, Coma Berenices, Virgo and Ursa Major amongst other constellations, putting on their best displays.  It's been tricky to decide what to image each night.  Keeping an eye on when the target crosses the meridian each night, trying to avoid having to perform a meridian flip along with mount versus pier clash have all played their part.

NGC 4656 - The Hockey Stick Galaxy

The first target in this mini collection is NGC 4656 in the constellation of Canes Venatici.  This galaxy is often imaged with it's near neighbour, the Whale galaxy, but I wanted to image it in it's own right, and give it it's own place in my collection.  So, the main thing to remember with this image is that the light frames (the ones actually taken of the target itself) are using exactly the same settings and equipment as those in the previous posts.  It's the calibration frames which are different.  I have included more dark frames and more flat frames in the creation of the master calibration frames.
I'm quite pleased and encouraged with the results.  A little more work may need to be done, but the target galaxy is in the centre of the image, with the Whale galaxy photobombing on the edge of the image, as if to say 'what about me????'
Can you guess why NGC 4565 is also dubbed The Hockey Stick galaxy?

NGC 4631 - The Whale Galaxy

The second image in this brace of images look at the photobombing Whale galaxy.  This galaxy has an apparent smaller companion galaxy, designated NGC 4627.  Depending on the orientation of the image, it could be said that this companion galaxy forms the spout of the Whale as it exhales, or, if flipped 180 degrees, the pectoral fin of the Whale.  The fact that I have it turned at 90 degrees in my image may result in a degree of confusion as heads are tilted from one direction to another in and effort to see what I'm talking about.  Either way, it's a stunning galaxy to image, and with a nice big dob, looks very nice in the eyepiece, along with NGC 4656.
This image was taken the night after NGC 4656, and took somewhere in the region of 3 hours of light frame collection, along with around 2.5 hours of dark frames and approximately 40 flat frames to throw into the calibration mix.

So, that's it for this mini post.  More to come as I try to cover off more imaging, a guide to the observatory video, visual sessions and live streamed Q and A's.
All the best.  Say safe.

Saturday, 11 April 2020

Salvation in the Observatory.

Wow.  Just, wow.

Well, this is all a bit weird.  I'm going to mention it once at the start, and then not mention it again.  Promise.  Bloody Covid-19 virus.  It's turned the whole globe inside out.  (Note, not upside-down.  That would be playing into the hands of another bunch of nut-job flearther conspiracy theorists).  Our current situation.  
1.  Furloughed from work until the end of May at the earliest.  Furloughed. A word I'd not even heard of until a month ago!  And now, all of a sudden, everyone knows about it.  
2.  So much unexpected time on our hands with no work, and being on social distancing measures like the rest of the world.  
3.  Along with No. 1, come the mental stress, anxiety, worry or call it what you will.  The medium term prospects of being able to retain our jobs with the happening at the same time as the 2 year anniversary of the loss of Dad to cancer.  With all the crap and fake news doing the rounds, I decided to take a break from my social media accounts.  It's just not what I need right now, and I'm glad to say, I feel better for it.  In a way, thankfully No. 2 has played a part and given me a chance to step back from everything to focus on and appreciate what's good in life.
4.  My planned trip for Astrocamp has been cancelled, replaced by a live Q and A which the organisers have very kindly put together and will be streamed on YouTube.  

The Positives.

It's good to get that off my chest.  Rant over, and time to concentrate on the positives.  The unexpected time off along with some of the clearest weather for many months has meant that I've been able to get out under the clear sky, albeit with a near full moon but with the added bonus of not having to wake up for the alarm for each morning.  I've managed to produce a set of 4 images, in this, the start of my Galaxy Season.  So, it's time to present the set of results.  First thing to remember about these images is the calibration.  I've got, or rather had, a massive dust bunny on the chip cover which resulted in a rather large blob on images.  This should have been dealt with by using flat frames.  The problem was that I took all the calibration frames as I went along, but didn't process any of the data  until much later.  In fact, not until after I had removed and cleaned the camera, meaning that it was too late to take a new set after finding that the original set was rubbish.
I could probably sort out the image defects in GIMP if I had the inclination to do so, but for now, I'll leave the images as they are.  I can always come back to them at a later date, and lets face it, I seem to have plenty of time on my hands at the moment.
Generally, these images are made up of 3 to 3.5 hours exposures of 5 minute subs.

M106.  Intermediate spiral galaxy in Canes Venatici.

I really like this image and the potential it shows.  If you look carefully, there are a handful of other galaxies in the background, but the main galaxy shows some good structure with a hint of more structure to be revealed on the outer edges.

NGC 4236.  Barred galaxy in Draco.

This is quite a noisy image, which I think is down to the longer 5 minute exposure.  However, the galaxy is still well defined and would benefit from more data and better calibration frames.

M63.  The Sunflower Galaxy in Canes Venatici.

When I processed this image, I was pleasantly surprised at the amount of detail in the core of the galaxy.  I've managed to preserve some of the colour of the surrounding stars too.  Again, a couple of other galaxies can be picked out in the background.

M109. Barred spiral galaxy in Ursa Major.

This is perhaps my favourite image out of the 4, and is certainly a galaxy I will return to image again.  A little noisy, but the spiral arms of this galaxy are so well defined, it's stunning.  Also, the surrounding galaxies visible just shown how rich this region of the sky is.

Where next?

As I alluded to earlier, these images, though pleasing, are noisy.  I have struggled to deal with the background noise throughout the processing stages.  Some of this can be accounted for with the quality of the calibration frames.  However, I can't help but think that 5 minute are pushing the limits of SharpCap and the 183c Hypercam.  My intention now is to carry out another analysis using the auto histogram function in SharpCap, but limit the exposure length to 3 minutes.  I will still aim for 3 to 3.5 hours total per image.  It will be interesting to see where that gets me, along with better quality calibration frames.
I've just re-polar aligned the mount and have started a new imaging session on another target.  There are a couple more opportunities in the coming evenings, so I'm going to make the most of the current circumstances and see what I get.  Until next time, clear skies!