Saturday, 15 September 2018

M57 - The Ring Nebula and Dealing With Hypercam Noise

M57 - The Ring Nebula, and the story behind the image.

Every image has a story.  Be it about the subject itself, the location or how the image was obtained.  This image represents for me 2 things.  Firstly, proof that not all astrophotography images are about full frame objects, or targets cropped within nanometres of their boarders.  An impressive planetary nebula nestled in amongst a field of view littered with stars, M57 is amongst the smallest targets out there to image, so getting any detail in it at all can take some effort.  Secondly though, the image has taught me a lesson.  One that I hope will now significantly improve all my future images taken with the Hypercam 183c.  More on that in a moment.
My last post set out the process I go through to collect the data for my images.  Whilst getting the screen shots for that post, I imaged M57 - The Ring Nebula.  I have now had the time to go through the steps of stacking and processing the data to produce the final image.  You see many images of this target because of it's apparent brightness, but more often than not, the images will be cropped or enlarged to see the Nebula in as much detail as possible.  Indeed, I have done this before myself.  This time however, I wanted to add a sense of scale to the image, so only cropped the image where absolutely necessary to remove the rough edges of the final image after the stacking process.

Almost lost in a myriad of stars, M57 is a popular visual target.
The details behind the image:-
  • 25 x 180sec light frames
  • 25 x 180sec dark frames
  • 31 x 90ms flat frames
  • Stacked and processed in PixInsight and GIMP
So, what of the one big learning aspect of this image in particular?  Well, I have already divulged that secret!  Ever since I started using the Hypercam, I have struggled with the anomaly of noise from the sensor encroaching the righe side of every image.  To be clear, this in itself is perfectly normal.  It is behaviour (though undesirable) of the Sony sensor used in the cameras, and it is found in every camera using that particular sensor chip.  Time after time, I have been told that correct use of calibration files (darks and flats) will get rid of the noise in the final stacked image.  To illustrate this noise, as well as the amp glow from the chip, here is a single 3 minutes sub frame, stretched, but not debayered.  Notice the amp glow across the top and bottom edges, but in particular the additional noise on the right edge which looks like some sort of extravagant starburst effect from a bright star just out of frame.

As more and more of these images are stacked up, the noise become more and more prevalent, and up until now, I have struggled to get rid of it during the stacking and calibration process.  This has meant that many of my images have been significantly cropped to cut out the noise.
I think I managed an imaging run once earlier this year where I successfully produce a stacked image without the noise on it, but I have failed to remember how I did it.
After much more thought and reading, I understood that the dark frames should be removing this sort of anomaly, so I started wondering if I just wasn't producing enough information in the master dark file to take care of this noise.  So, that left me with one option.  To increase the number of dark frames I was taking.  I have never found a definitive ratio for the number of light frames to dark frames to flat frames to obtain for each image.  Sometimes it has been 60 light frames and 20 darks.  Other times 20 light frames and 10 darks.  For this image in particular, I went with the approach that if I took one dark frame for every light frame, then I would be able to experiment by changing the ratio each time.  This is when I seemed to have struck gold.  
This is what the final stacked image looked like when PixInsight had finished the stacking process.  Remember that the image has had not been cropped at this point, has had no processing done to it, but has been stretched to show the detail available.


Notice that the noise and a majority of the amp glow has now been dealt with successfully, allowing me to make far better use of the whole frame, instead of cropping out any interference, and loosing about 1/3 of the image in the process.

So there you go, one image and 2 stories.  Now it's just a question of making sure that this is repeatable.  It all come down to the fact in this instance that I simply didn't have enough dark calibration frames.  All I need to do is get out there on the next clear night and repeat.
I hope this helps other owners of the Altair Hypercam 183c series of cameras.  I see it raised regularly in various forums and groups, but no-one as far as I can see has been able to say definitively what they do to combat the problems.
Thanks for reading, and clear skies! 

Thursday, 13 September 2018

Data Capture Workflow - Astrophotography and the Hypercam 183c

Altair Hypercam 183c Workflow

Hello!  After discussing with various people, the topic of how I go about preparing for and collecting my data for my images, I thought it would be useful to put together a workflow for others to consider using as a basis for their own imaging process.  I haven't gone into too much detail with settings in each of the steps.  These settings will be different for each person and each combination of kit, but it will be a good starting point.  So, before I proceed, this is a list of what I use for my own imaging.
  • SkyWatcher EQ6-R Pro mount.
  • Starwave 80 ED-R telescope.
  • Starwave 50mm guidescope.
  • GPCAM Mono guide camera.
  • Altair Hypercam 183c colour CMOS imaging camera.
  • Altair CCD light pollution filter.
  • LED artists tracing light board.
In terms of software, this is what I use.
  • Sharpcap Pro 3.1
  • Fits Liberator
  • Cartes du Ciel
  • PHD2

Polar Alignment

Every article I read about imaging and using an EQ mount always talks about polar alignment.  As I have found out, there are numerous ways of achieving polar alignment by using all sorts of different gadgets or software to aid the process.  The EQ6-R Pro comes with it's own polar scope, but as yet, I haven't used it.  Instead, I start off by ensuring my guide scope and main scope are aligned fairly well to true north, and the latitude is set correctly for my location (approximately 51.9 degrees north).  It doesn't have to be exact, but personally, I like to get things as accurate as I can.
My personal preference for achieving a good polar alignment is to use Sharpcap.  In Sharpcap Pro, there is an in built polar alignment tool which connects to your guide camera.  You need to have your mount aligned roughly to start off with, give or take 5 degrees or so.  Sharpcap can then plate solve the stars it sees through the guide camera and guide scope, before then giving you directions for adjusting your mount.  I took this screenshot showing what I saw during the process.

Polar alignment routine in Sharpcap Pro

3 Star Alignment

Once the mount is polar aligned, I go through the process of performing a 3 star alignment of the mount.  This process allows the mount to learn where given star are in the night sky, and can be incredibly accurate.  To carry out this alignment, I use an illuminated reticule in the telescope's eyepiece holder.  This reticule given me a crosshair target in the eyepiece meaning I can be sure that the stars used during the 3 Star Alignment routing are perfectly in the centre of the field of view.  
The alignment is carried out following prompts and instructions on the handset of the mount.  Once alignment is complete, the scope itself is ready to use, and it's time to move onto preparing the specific imaging hardware.

Fit and Focus the Hypercam

Once the scope is aligned, I remove the diagonal and reticule eyepiece, fit the 80mm extender, filter and camera and once again, return to Sharpcap.  The next part of my workflow is to get the Hypercam focussed as best I can.  I don't have a motorised auto focuser, so this is an important step that I need to get right first time.  If I need to make significant changes to the focus during the imaging run, I run the risk of making too much of a change and possibly stopping the latter process of stacking and image integration from running smoothly.
To achieve focus, in Sharpcap, I point the scope at a bright star, and then fit a bhatinov mask.  I used the zoom feature in Sharpcap and then turn the focus knob accordingly.  The idea is that the diffraction spikes caused by the mask are equally spaced when good focus is achieved.  The screenshot below shows the exposure time and gain used during the process of focusing, and the equally space diffraction spikes.

Equally spaced diffraction spikes showing good focus.

Choosing a Target

I am now ready to slew the telescope to a chosen target.  To do this, I used planetarium software called Cartes du Ciel.  I could just use the hand controller connected to the telescope, but for ease of use, I prefer the software.  For this particular night, I decided to image the Ring Nebula, or M57.  Once the mount is connected to the laptop and the software is launched, I can select a target and allow the mount to slew the telescope to the target.
M57 selected in Cartes du Ciel.

Framing the Target

Even the most accurate of go to mounts will still require the finest of adjustments if you plan on imaging a target.  This is especially important when imaging either very small, or very large targets.  You want to be sure that you fit as much of the target in the frame, and get it as central as possible.  To do this, I switch back to Sharpcap and adjust the exposure and gain settings to give me some sort of idea of where the target is.  M57 is actually quite bright, so it's fairly straight forward.  However, for dimmer targets, it can take a bit of time to get things framed accurately.  Sharpcap has a crosshair tool to help framing objects accurately.
In this screen shot, you can make out the shape of M57 near the centre of the crosshairs.  You can also see the scope controls available within Sharpcap which allow you to make fine adjustments to frame the target exactly how you want it.

Moving M57 into the centre of the frame using the crosshairs and mount controls in Sharpcap.

PHD2 - Guiding Calibration

So far, all the work has been done to get the mount slewing to targets as accurately as possible, and the target selected, framed and put into focus.  However, for prolonged exposures of more than around 60 seconds, it is necessary to run guiding software to improve the accuracy of the mount. In essence, guiding locks onto a star via the guide camera, tracks it as it moves through the sky and then issues adjustment commands to the mount to keep the guide star in the same location relative to the field of view.  
In PHD2, the guide camera is connected to the software, and as best practice, I use the Guiding Calibration feature in the software to 'teach' it how the mount is currently reacting to commands.  A guide star is selected and then commands are issued to move the star North, South, East and West during which time, PHD2 takes measurements of how much the mount has to move to move the star the required amount of steps.  The process is fully automated once started.  Once complete, guiding starts automatically.  If you want, you can leave it guiding from there.  However, I chose to perform some additional steps.
This screen shot shows the calibration steps being carried out.

PHD2 Calibration steps.

PHD2 - Guiding Assist

There are many settings in PHD2 which can be changed to try and improve performance.  To be perfectly honest, I don't understand most of them, but they all seem to be important.  So, to help me put the correct values in all these places, I use the Guiding Assist tool in PHD2.  Guiding Assist stops any guiding that is taking place and just measures the movement of the selected star.  From these measurements, the software can measure the increments in which guide commands need to be issued, and also if selected, the backlash of the mount.
Guiding Assist is left to run for around 2 minutes so it can make all the measurements it needs to.  Once completed, it then allows you to adopt the suggested settings and automatically enters them into the appropriate fields.
This screenshot shows the measurements that are taken and the different information it provides, and the second screenshot shows the results at the end of the process.  Remember that this changes from night to night and needs to be done every time everything is set up.

PHD2 Guiding Assist in progress.
PHD2 Guiding Assist results.
Once the settings have been adopted, PHD2 then starts guiding.  Before I carry on, I prefer to leave the guiding process run for a few minutes and watch the graph in the software,  Theoretically, the flatter the lines in the graph, the better guiding is working, and the better the mount is set up.

The difference in the graph shows the point when PHD2 Guide Assist stops taking measurements, and then starts guiding.

Starting the Imaging Run

At last, I'm ready to start turning my attention to capturing my images.  There are a final few calibration steps I carry out before starting the image capturing.  Back in the Sharpcap software, I have recently started making use of the Smart Histogram.  The feature analyses the sky conditions, and with some input from me about such things as how long I want the total exposure to come to, and the shortest and longest individual exposures I am willing to use.  For example, if I know I only have 3 hours total to spend, I can tell Smart Histogram that I want to collect 90 minutes worth of data in total.  Smart Histogram is then able to give me the optimum gain and exposure length to use for the parameters I set.  Again, this process can take a bit of time because Sharpcap actually takes a range of individual frames of differing lengths and gains to build up it's graph.  The remaining time left out of the 3 hours I can use to collect calibration frames for use during image processing.
This screenshot shows the histogram analysis in action.  Once the results are displayed, you can input them into Sharpcap ready to start the imaging run.

Smart Histogram calibration steps.

The Capture

Now it's time to start the data capture process.  The mount is set up, the software is configured, guiding is running and I now know the optimum settings to apply to the Hypercam in Sharpcap.  All I need to do is set the imaging run off within Sharcap.  I can set the imaging run to either take a fixed number of exposures, to run for a certain total amount of time, or take pre-configured numbers of exposures.  Using the information from the Smart Histogram tool, I usually know by this point how long or how many frames I need to take.  It's just a question of applying the settings and setting the process off.
Each frame is displayed in Sharpcap so you can see what's going on.  You can also see how much time is left in the run and how many frames have been taken.

Hypercam settings used for imaging M57
It's important to keep an eye on the PHD2 graph throughout the imaging run.  Normally, just keeping an eye on the graph is sufficient.  However, PHD2 does give an audio and visual alarm if it loses contact with the selected guide start because of cloud or dew.  To monitor this, I tend to have both the PHD2 window and the Sharpcap window open at the same time.

Monitoring the data capture of M52, and PHD2's guiding performance.

Capturing Dark Calibration Frames.

Once the main imaging run is complete, and all the light data is collected, my last job of the night is to collect the Dark calibration frames.  These are simply additional images taken using exactly the same parameters as the lights at the same focus and camera orientation.  The only difference is having the cap on the end of the telescope.
This screenshot is of Sharpcap taking the Dark calibration frames.

Collecting Dark Calibration frames.

Flats and Fits Liberator

This is usually the last task of the night.  The following morning, I will then take my flat images, but they can be done at anytime providing the focus and camera orientation are maintained throughout.  This is really important, so usually, I take the scope off the mount at night, put it onto a flat surface and don't touch anything until the flat frames have been acquired.
From reading up on various forums, and asking questions about obtaining flat frames, I have settled on the routine of:
  • Stretching a white T shirt over the end of the telescope.
  • Use an LED tracing/drawing board to give an even light covering over the end of the scope.
When I first got my Hypercam 183c, I joined the Altair Astro Google Group.  On there, I made contact with RobinG (who I think is the writer of the Sharpcap software), and he offered the following piece of information on taking flat files with the Hypercam 183c, and how to work out the correct exposure etc.

Mean flat values to aim for in Fits Liberator
Taking this on board, I then set about experimenting taking single flat files and opening them in Fits Liberator until I achieved the desired values.  It's important to note that I leave the gain settings the same, and purely work with exposure length.  It's also important to note that the optical train remains exactly the same.  In other words, if all the images are taken using a certain filter, then that filter remains in place for the flats.
This is a screen shot of Fits Liberator showing where to find the mean values to aim for.

Fits liberator is free software available to download and use.  The image statistics highlighted in yellow is where to look for your flat files values.

So that's my workflow for a typical night's imaging.  It seemed quite daunting at first, but once I got used to it, I found that I can get through everything in about 30 minutes.  Many of these steps will be redundant in a permanent set up in an observatory.  That would be ideal.
Anyway, thanks for reading, and I hope you find it useful.
Cheers!

Tuesday, 11 September 2018

Astrocamp XIII - Cwmdu we had no problem.

Astrocamp XIII - I Was There.
A highlight to the year for many people.  The anticipation.  The constant checking of weather apps.  The buzz.  The laughs.  The astronomy.  The traditional post camp hangover.  This weekend, we returned to the familiar surroundings of Cwmdu campsite, and attended Awesome Astronomy's Astrocamp.  It was said that in all the camps so far, nothing had gone particularly wrong, and that if it ever will, it was bound to happen at Astrocamp 13.  A rather odd expression given that the whole event promotes evidence based science and rational thinking!  Quite amusing.

Arrivals T-1 day...
On the run up to camp, I had put forward the idea of having kind of a popup Astro DIY workshop and encouraged people to come along and show off their DIY modifications and projects.  I mentioned the idea on the camp Facebook page and was really pleased to find it well received.  Throughout the weekend, a variety of people stopped around where we were set up on the campsite and were keen to check out each others ideas.  Indeed, only this morning, I have been out and bought components and materials for my next DIY project.  More on that in future posts!
I decided to turn up a day early to give myself as much opportunity as possible to get some observing done.  This proved to be a good idea given the forecast for the main arrival day was for rain on and off throughout the day and evening.  With this in mind, I had packed plenty of different kit in the van which would keep me occupied for the weekend.  Boxes of electrical components, ongoing DIY projects, books and even the guitar made a rare trip out of the house.  I managed to get some observing in on the Friday evening and was pleased to observe the Great Cluster in Hercules, the Ring Nebula and Mars.  This was the first time I had chance to observe Mars for some years, so I must have spent 20 minutes or so looking at it alone.  Clouds came and went, but eventually covered the sky.

Arrivals Day...
Arrivals day at camp is brilliant.  A chance to catch up with friends from past camps, and just as important, to make new friends. This year, next to my pitch, I was fortunate to be joined by Raoul.  A first timer to camp, but not new to the hobby.  He brought with him various DIY projects including an array of Arduino based ideas that he was working on.  Perhaps the most impressive of his projects, and the one which I would consider trying myself, is a meteor detector which can detect the passing of meteors through the atmosphere regardless of weather or day light.  He demonstrated what was possible, showing us some recent recordings captured during the Perseid meteor shower.  Showers and cloud allowed me time to work on one of my own projects, and to solve an issue of dew bands not heating up when used with my DIY dew band controllers.  So, it was out with the pliers, screwdriver and soldering iron in the tent as the rain pattered down onto the tent roof. 


Day 2...
Sunday morning started early for me.  Not being able to train my body clock to simply allow me to have a lay in, I was up and about at around 6.30.  After the previous days rain showers and cloud, I was greeted by occasional patches of blue sky and some warm sunshine during breakfast.



Sunday is always a day I look forward to the most at camp.  It's the day when everyone moves down to the local village hall, and to the pop up pub 'The Spiral Arms'.  It's also the venue for the much anticipated pub quizzes and talks which are always popular and never disappoint.  This camp, the guest speaker was Libby Jackson who spoke about women who work in space.  Libby is author of 'A Galaxy of Her Own: Amazing Stories of Women in Space''.  A collection of stories about women who have made massive and significant contributions to space science and space travel throughout history.  It wasn't until Libby started talking about her research and her book that it hit me exactly how under recognised these women have been by the history books.  Her talk was incredibly enlightening, and now that I have returned from camp, I look forward to reading her book to learn more.  There are so many events that have happened in human space history that would never have been achieved without some significant and important contributions by these women, that it baffles me why they don't get the recognition they rightly deserve.  Libby's talk was by far the highlight of my camp and one that I will remember.



Back in 1973, the famous Welsh poet, singer and writer, Max Boyce wrote a poem about a legendary event in Welsh rugby history when Llanelli beat New Zealand 9-3.  But the event wasn't entirely about the win itself, but more that the pubs ran dry!  Well, at Astrocamp 13, Welsh history was to repeat itself once again, as indeed, the pub ran dry.  It made the final quiz of the day, dubbed 'The Masters Of The Universe' quiz all the more important as entrants were playing for a case of beer!
During the day on Sunday, a wave of optimism washed through camp as rumours spread of a window of clear sky that evening.  As people headed back to the campsite from the Spiral Arms, attentions turned to getting prepared for the potential of an evening of Astronomy.  I decided to set up my refractor and imaging equipment.  At first, given the forecast window of clear sky was quite short, it might have seemed a bit of a waste of time.  However, as readers of my previous posts might know, I have recently bought a new mount and I wanted to get some more use out of it.  I seemed to have had a good run of luck with regards to guiding and setting this mount up for imaging runs, so I wanted to confirm to myself that this wasn't by some sort of accident.  So, the only way to prove that my recent results haven't been down to pure luck is to ensure that everything is repeatable.  So, it was pleasing to see that once again, I was able to achieve a good guiding graph using PHD2.  But, perhaps even better, I was please to be able to demonstrate to some fellow campers the ability to polar align using Sharpcap Software, the ability to slew the scope to various targets using Cartes du Ciel and finally, to set up an imaging run.  My luck soon ran out though.  By the time I had achieved everything I needed to do and I was ready to start imaging, I only managed a single 2 minute exposure of Andromeda before the clouds rolled back in bringing proceedings for the evening to a close.  I'll still chalk that one up as a success though.

Should I Stay or Should I Go???
Monday is the hardest day of camp for me.  Knowing that the end of camp on Tuesday is approaching, almost straight away, me and many other Astrocampers look to the weather.  The thoughts of the pending journey home.  This year, the forecast for the last night of camp was for very little observing opportunity because of cloud, and the potential of rain coming through during the early hours of Tuesday.  The possibility of dropping a bone dry tent and dry kit and then not have the problems of needing to dry everything out always makes the choice a tricky one.  Monday is the day of high tea on the common area of the campsite.  Everyone from camp gathers together to enjoy their last afternoon together.  It's a point in camp that I look forward to, but alas one that I did not attend this time around.  I made the tricky decision to bring my stay at Astrocamp to an early close.  Not that I rushed to get packed away at all.  I don't have much of a journey home.  So, at a leisurely pace, I set about getting everything cleaned up and helped out others where I could before loading the last of my kit in the van before heading home.  It's always sad to leave, but leave we all eventually must.

Looking forwards...
April 27th 2019 will see Astrocampers gather once again in Cwmdu.  With bookings due to open in around a months time, it's already a date put into the calendar.  This camp, I had a walk around the site, looking at the sky from different pitches to ones that I would normally consider.  On a small site such as the campsite in Cwmdu, you don't have a lot of choice, so it's often a race to get to the prime pace you want to, but I will be there, finger on the button and ready to book.  Already, I'm looking forwards to seeing my friends again, making new ones and swapping stories about what we have been up to over the Winter.
This camp has been a great reminder of what I missed back in the Spring, but at the same time, it's like I never left.  Putting on events such as this takes a team of very dedicated people, and it's only right that they be appreciated.  So, firstly, my thanks to Libby Jackson for coming to speak to us, and for providing me with my highlight of the whole camp.  My thanks of course has to go to the team at Awesome Astronomy, Ralph, Paul, John, Damien and Jen.  Every camp means another brilliant and memorable time to be had.  My thanks also to my friends and neighbours, old and new at Astrocamp 13.  You put up with me and always have time for me, which is truly appreciated.

Why I'll be at Astrocamp 14...
Many comparisons are made during various star parties between organising groups and venues.  Some of these opinions are formed on the experience and views of others by people who have never been.  I have always said that I intend to visit a selection of different events around the country.  Earlier this year, I attended the Spring Kelling Heath star party in Norfolk.  That is a huge event with hundreds of attendees spread across a very flat and well appointed site, with generous sized pitches.  Being in the East side of the country, it could also be argued that there is a better chance of having more observable nights, with slightly better weather than is experienced in the mountains and hills of Wales.  So why not return?  The reasons are numerous.  What Astrocamp brings to the table is what many perceive to be a much more friendly atmosphere.  I went to my first Astrocamp on my own several years ago, not knowing anyone.  By the end of that first camp, I had made friends for life and had been left with no doubt that I would return.  Undoubtedly, the key reasons for this were the smaller site which makes the whole event more intimate, the Sunday in the Spiral Arms and perhaps more than any other, the common area in the middle of camp.  This is the place to meet, to share stories and views through the eyepiece, and in the event of a cloudy evening, chew the fat over a couple of lemonades.  Would I go back to Kelling?  Not for a star party, no.  Astrocamp however is a completely different experience.

Thanks for reading!
 

Tuesday, 21 August 2018

NGC 6888 - The Crescent Nebula

NGC 6888 - The Crescent Nebula

A couple of weeks after the first outing of the EQ6-R Pro, I had a short window of opportunity to use it again.  Really encouraged by my first experience with the new mount, I chose a target for evening from one of my astrophotography books and set about getting everything ready.  It was going to have to be another short session because it was a school night, but the forecast was clear and that was good enough for me.
After polar alignment and 3 star alignment, I came across a problem with PHD2 where during the calibration steps, the selected guide star wasn't moving.  I was about to throw a paddy and jack it all in for the night when I come across a little nugget of information on one of the forums.  It all come down to the ST4 cable in the guide camera not being pushed in quite far enough.  I thought it had clicked into place, and indeed, it wouldn't pull out easily, but it needed an extra push.  With the cable pushed in correctly this time, PHD2 sprang into life and calibrated first time.  Once calibrated, I run Guiding Assistant for a few minutes, accepted it's recommendations and started guiding.
The last time I was out, for the first time I used the smart histogram feature in Sharpcap Pro.  This time, I didn't want to use up anymore valuable time because of the delay with the ST4 cable earlier on.  So, I loaded the same settings that I used before, achieved a good focus and set the imaging run off.  I only had time for an hour of imaging, so set everything up for 20 exposures of 3 minutes each.  After sitting for a while making sure everything was working OK, I came back in to get a drink, but when I returned I found that my laptop had rebooted itself mid-run thanks to Windows updates.  A lesson learnt there - change the hours to when things can get rebooted!  I checked how may frames I had captured, but I only had half the frames I wanted.  Guiding had stopped, as well as the data collection during the reboot, but the mount had kept tracking.  I didn't want to waste the data I had already collected, so I decided to set up for another run of 10 images.  This meant I finished later than I wanted to.  I still had to collect my calibration frames, but contrary to good practice, I decided to leave that for the following day.  I made sure I kept the focus and orientation of the camera in the scope, and covered everything up for the night.
Fast forward to stacking, and PixInsight dealt well with the stacking process given that it was now stacking two different sets of data on the same target.  Somewhere in the stacking and processing steps, I have forgotten, or at least missed out steps to counter the glow effect from the sony 183 sensor, but fortunately in this case, the nebula was quite central to the frame so I managed to crop most of the glow out.  It's definitely something I need to master though, especially when it comes to imaging larger targets which fill the frame more.
So, here's the final image from the positive, but disrupted session.  NGC 6888 - The Crescent Nebula.


Altair Hypercam 183c v1
SkyWatcher EQ6-R Pro
Altair 80ED-R
21 x 180sec subs
10 x flats
10 x darks
Stacked and processed in Pixinsight
Processed a bit more in GIMP

Thanks for reading!

Tuesday, 7 August 2018

EQ6-R Pro First Light And A Bubble

First Light

Always exciting! A few weeks ago, I took delivery of my new SkyWatcher EQ6-R Pro mount.  Recently, I posted a quick video of the unboxing and my first thoughts.  Since then, I've installed the SkyWatcher Ascom drivers on my computers, done a couple of test runs with controlling the telescope from Cartes de Ciel and updated my license for Sharpcap Pro.  Perhaps I will do a more thorough post in the future showing the exact steps I've taken.
Back to the present. Over the last weekend, the forecast was excellent, and with no work to worry about, I was able to get a quality late night out with the new mount.  I didn't really know what to expect, so I went ahead with a plan of polar alignment, 3 star alignment, slewing to and locking onto a target, guiding and eventually, if there was time left, some imaging.
I put the mount together in daylight and was able to check level and balance.  With no 'zero' positions on the SkyWatcher mount like I am used to with the AVX, it was a best endeavours type approach with getting it set up.  There are setting circles on both axis which can be used, but looking briefly through the manual, I'm not sure will need to use these.
Another feature of the SkyWatcher is the included polar scope.  While the principles of this are very straight forward, it appears that it does take some time to calibrate, but I do have an alternative when it comes to polar alignment.  Sharpcap Pro comes with a really useful polar alignment tool which I have used nearly every time I set up.
So, mount polar aligned, and the 3 star alignment procedure complete, it was time to test it's accuracy.  A quick trip around some targets confirmed all was accurate in that department.  One of the main drivers behind me upgrading to the SkyWatcher mount was to try to improve my guiding to achieve longer exposures in my imaging.  I was pleasantly surprised on how easy the next part went.
I opened up PHD2 and connected it to my guide camera and mount.  Over the last year or so, I have read up a lot on the calibration and the guide assistant of.  Even though some say you should run the calibration steps in PHD2 first, I went straight to guide assistant and let PHD2 go through it's routine.  It came back with a couple of suggestions, saying that polar alignment could be a little better and that I might need to consider guiding in one axis.  Nevertheless, I applied the suggested settings and then forced calibration.  Once all had been completed, PHD2 started guiding, and to be honest, the graph was looking pretty good.


So far so good.  Since the guiding was looking pretty good, I thought I would get some imaging time.  With my AVX mount, the longest exposures I managed were around 60 seconds. To be fair, my results sticking to those parameters have been really good, but it's time to up my game.  I turned to Sharpcap Pro once again.
One of the biggest developments in this piece of software in recent times has been the inclusion of the Smart Histogram.  It's a great feature that requires you to input how long you want your imaging run to last for.  It then analyses the sky using your imaging camera before displaying a graph showing you the optimum exposure time and gain settings to use during your imaging process.  It takes a lot of guesswork out of the process.  It's the first time I had used the feature in anger, so I left it with 1 hour total imaging time, for which it suggested using 20 3 minutes exposures at 400 gain.  I have neve shot at 400 gain before, usually imaging with 1500 gain.  This was to be the proof of the pudding.  A first test of a 3 minute sub and a check for any form of star trails showed no signs of any, so I let the software run off 60 minutes of light frames.
So excited was I to have achieved all this at the first time of asking, I actually forgot to take my calibration frames, other than a handful of dark frames.  But the point of the whole evening wasn't to take an awesome image straight off, it was to test my processes of data capture  And I achieved that with flying colours!
That's not the end of the story though.  I had collected some data, but missing flats and bias frames meant that whatever come out wasn't going to be as good as it could be.  But I went ahead and did the processing anyway with the data I had.  An hour or so of work in PixInsight allowed me to pull this image out of the data.  This is the Bubble Nebula.  NGC 7653, a magnitude 10 nebula in the constellation of Cassiopeia.

I can't wait to get back out and do it all again!  Thanks for reading.

Tuesday, 31 July 2018

A New Mount, Another DIY Project

For my last post, I created a video of the unboxing process of the Skywatcher EQ6-R Pro mount and gave my first thoughts on it.  I have still yet to give first light to the mount, but in the meantime, I've been busy planning the next DIY project.
A few years ago when I took delivery of my Celestron AVX mount, I needed to create a pier adapter which would allow the AVX to sit on top of my pier in the back garden.  As different mount models from different manufacturers all have different sized bases to their mounts, each fitting into proprietary tripods, it means that I need to redesign my pier adapter.  So, it's time for another video following the steps and thought process behind my solution.
Hope you enjoy!
MMM


Wednesday, 18 July 2018

Introducing the Skywatcher EQ6-R Pro GEM

Good day to you.
This is my first post for quite a while, and it's only going to be a short one.  I recently bought a new mount as an upgrade to my existing Celestron AVX.  I've put together a short unboxing type video with some thoughts and comments.  It's my first attempt at such a video, but it wen OK.  I might do more video based posts in the future.  We will have to see.
Anyway, see what you think!
Clear Skies :-)


Thursday, 12 April 2018

For Dad


For Dad

I can trace my interest in astronomy back to when I was growing up in my earliest years.  I remember Dad’s refractor telescope set up in the spare bedroom of our house in Swansea.  At the time, it intrigued me, but unfortunately, I don’t remember ever spending time at the eyepiece with him.
Living in a city didn’t really lend itself to astronomy or observing too much, and back in those days, it was still relatively inaccessible as a hobby.  Not like these days where it’s more affordable, and the quality of the optics are generally excellent.  I bought my first telescope about 4 or 5 years ago after much deliberating and research.  It felt like the biggest purchase I had made at the time and at last, I was able to fully understand why Dad had enjoyed his telescope all those years ago.
Around 3 years ago, Dad was diagnosed with cancer, and I don’t know why, but it spurred me on to get involve with astrophotography.  Looking back, I think it was a way that I finally could share my view from the eyepiece with my family and friends, but especially with Dad.  From the beginnings using my DSLR camera, to my current set up using a one shot colour CMOS camera, I’ve been able to produce more images to show him as time has gone on. 
This Christmas, Dad and my step mum contributed significantly to the cost of a license to the processing software, PixInsight which I had come across follow an Astro imaging course.  This software helped me raise my imaging game by allowing me to make even more of the data that I was managing to collect.  It was something that Dad was able to see the results of almost straight away.  I was able to rework some old data, and had a couple of opportunities to collect new.  I was able to show Dad images of Orion, the Flame Nebula, and The Elephant’s Trunk Nebula along with The Crab Nebula.  He really liked them, and later, I found that he would happily be telling his friends of my interest and my results.
This winter has been particularly poor for astronomy, but I did seize the opportunity one night in early February to get out and collect data on 3 targets.  One of those targets was the spiral galaxy M33, but I had a problem.  For some reason, I was getting some sort of light interference on the sub frames, which showed up significantly on the final image.  After trying to figure it out for myself, I did a bit of reading up, asked a few questions on some forums and got some things to try.  By this point, several weeks had passed by, but I managed to get some of my best final images from that data, that I have produced so far. 
Soon after, Dad was admitted to hospital.  He had contracted an infection which on its own was easily treatable with antibiotics.  However, Dad’s cancer had also become more aggressive, and by the time the infection was under control Dad was incredibly ill.  Dad lost his fight with cancer on 27th March 2018 and died at home.
Sadly, I never got chance to show him my latest images particularly this one of M33.  I appreciate that there are probably much better or clearer images out there of it, but this one is mine and I am very proud of it.  This image will always mean more to me than any other that I have taken in the past, or will take in the future.  Dad, this one is for you.
Antony x



Monday, 15 January 2018

M1 - The Crab Nebula in Hypercamvision

M1 - The Crab Nebula

Setting Up

This Christmas gave me a small opportunity to get out under the stars.  I took that opportunity with both hands.  Thanks to friends and family, I've also been lucky to receive some Astro gifts that I was itching to get stuck into.  During recent weeks, I noticed an astro friends image of M1 taken with a CCD camera.  I found it really impressive, and incredibly detailed.  It inspired me to see what the Hypercam would make of it.
So, on the night, I set up out the back garden, got the mount polar aligned and fulfilled the 2 star alignment process with 2 calibration stars, fitted the Hypercam with my new LP filter and connected everything up in the obsy shed ready to go.  I was pleased to see that my alignment routines were spot on as I turned up the image gain and saw the outline of the Crab Nebula almost dead centre of the screen in my initial test frames.
My previous uses of the Hypercam have concentrated on getting around an hour of exposures on each target.  I have asked myself what difference a longer exposure period would make in my previous sessions, so I decided to dedicate the whole night to just imaging this one target.  So, with that in mind, I set Sharpcap Pro up to take 60 second exposures at 1500 gain and set the time for 3 hours.  This would give me plenty of data to work with, along with sufficient time to collect bias, flat and dark frames too.
With a longer session planned, I also set up remote access to the kit outside from the comfort of the living room allowing me to keep a real-time eye on the data being collected.

Data Collected

There wasn't much more to the night.  I just sat back and let the camera and scope do the work,  I backed the data up straight away and brought a copy indoors before calling it a night.  The following day, I counted up the total number of frames I captured which reached 176 x 1 minute exposures. 
Also this Christmas, I was fortunate enough to be able to use some Christmas money to put towards a license for PixInsight, and a book to accompany it.  PixInsight is initially quite daunting.  There are so many tools and scripts to use within it, but with some previous experience using it under a trial license, things start to make a bit more sense.  One very useful process I have found recently is Blink.  This allows you to load up all the frames into one viewer, and then skip through them quickly, allowing you to identify frames for rejection that might have meteor trails, satellite trails, or aircraft trails streaking through them.  I easily identified 3 or 4 frames for rejection and deleted them from the list.
One day, I'll post more in depth about my work flow in PixInsight, but I don't know anywhere near enough about how it works yet.  I'm still learning!  Nevertheless, the remaining frames were stacked and calibrated with the dark, flat and bias frames too.  I've used a workflow compiled from a few sources that seems to work well for nebulae.  In fact, I attempted the stacking process and processing process twice.  My first attempt was in the more familiar Deep Sky Stacker with processing in PixInsight and CS2, but this was a slightly rushed job.  The second attempt was completed almost completely within PixInsight with a small final tweak in The GIMP 2.9

The Results

Two attempts and two quite different images.  Both these are using the same amount of light and calibration frames, but processed differently.

Though presenting more colour and perhaps a little more detail, the first attempt was cropped a little too tight.  I think it lost a little something, but still and impressive demonstration of what the Hypercam 183c is capable of.

My second attempt.  This one is not cropped so close, and a little brighter albeit at the sacrifice of some colour.  Nevertheless, I think that this attempt is a little closer to what you might see through a large aperture reflector telescope.

Saturday, 30 December 2017

Hypercam 183c - The Boxing Day Marathon

Hypercam 183c - The Boxing Day Marathon

In what is probably going to be my final post of 2017, it's time for an update on my latest exploits with the Starwave 80 ED-R and the Altair Hypercam 183c.  Christmas has once again been kind to me with a lovely selection of Astro gifts from family, and for once, the new astro toys didn't bring on the traditional onslaught of crappy weather for days on end.  At least, not straight away anyway.  That part was delayed by a day or so which give me an ideal opportunity to get out under some great skies.
Boxing Day night 2017 and the forecast was for freezing cold, clear and still conditions from sunset to sunrise.  I set up my imaging kit and gave first light to my new Light Pollution filter and first use to my new case for the hand controller of the AVX mount.  

Objectives

My objectives for the night were to image the Iris Nebula, the Flame and Horsehead Nebulae and the Orion Nebula.  Outside of these targets, I was happy to just fill in any spare time with a couple of other targets.  At the moment, I have to wait for Orion to rise above the rooftops to allow me to get them into the telescope's field of view.  That doesn't happen until about 11.30pm, so first target was to be the Iris Nebula.
While capturing images of my targets, I also wanted to use a variety of different settings within Sharpcap pro.  I've included the settings with each of the images.

Tools For The Job

  • Celestron AVX Mount (unguided)
  • Altair Starwave 80 ED-R
  • Altair Hypercam 183c
  • 2" Light Pollution Filter
  • Sharpcap Pro
  • PixInsight
  • Photoshop CS2
  • GIMP 2.9

The Iris Nebula - NGC 7023/Caldwell 4

The Iris Nebula is a reflection nebula found in the constellation of Cepheus.  At around 1300 light years away, it's comparatively close to us.  When you trawl the internet looking for images of the nebula, it's often presented as a lovely blue colour with much darker grey or black nebulous clouds of dust and gas around it.  My hope was to at least be able to capture some of the blue colour, and possibly a little bit of detail within the dust clouds.  In reality, I think I achieved both these things with some success for a first try.  
This image is made up of:
  • 90 x 60s  exposures
  • 1500 analogue gain in Sharpcap
  • Bias, flats and dark frames processed and calibrated in PixInsight


The Elephant's Trunk Nebula - IC 1396

Another target in Cepheus was next on the list.  This time an emission nebula known as The Elephant's Trunk.  This is quite a tricky target to image, especially as it is very red in colour.  There are many clear images taken by CCD cameras all over the web, but I think that to expect that level of detail would be unwise.  So, for this image, I was happy to just find out what I could obtain with a comparability short total exposure time with a CMOS sensor.  Once I had stacked the image and performed the initial image stretch of the stack, it was obvious though that I was slightly off target.  Nevertheless, I was pleased to find that I could make out some detail of the trunk and also other areas of dark nebulousness.
This image is made up of:
  • 90 x 60s exposures
  • 2000 analogue gain in Sharpcap
  • Bias, flats and dark frames processed and calibrated in PixInsight

Open Cluster Messier 35

With 2 targets down already for the evening, Orion still hadn't risen high enough in the sky to allow me to image it through the telescope from it's position on my garden pillar.  Looking around the constellations that were visible, I decided to try a different type of target.  I chose M35 which is an Open Cluster in the constellation of Gemini.  Open clusters tend to show up well in refactor telescopes, displaying good levels of colour in the final image.  M35 is in close proximity to another cluster NGC 2158.  This was out of the field of view of the final image, with M35 comfortably filling the sensors image frame.  In the final processed image, though you can see some yellow and white stars, I failed to get anything in the blue colour.  I think this might be down to my processing skills more than the quality of the data.
This image is made up of:
  • 60 x 60s exposures
  • 2000 analogue gain in SharpCap
  • Bias, flats and dark frames processed and calibrated in PixInsight

Horsehead Nebula and Flame Nebula - Barnard 33/NGC 2023 & NGC 2024

At last, the constellation of Orion was high enough over the rooftops to bring it into view.  The next pair of targets are very easy to find.  The appear either side of the star Alnitak in the belt of Orion.  I have managed to capture some detail of these nebulae with a DSLR before, but only a single shot.  Those results were promising, so the target was high on the agenda of features to return to.  Easy to find, but quite tricky to image if you want to get both features in the same field of view.  I didn't realise until after stacking and the initial histogram stretch that my alignment was slightly off, only capturing a portion of the Horsehead.  What I think makes it tricky is that you have a bright star Alnitak somewhere near the centre of the frame, the Flame which shows up well in CMOS sensors and the very red area around the Horsehead, traditionally the subject of CCD images.  The Hypercam dealt with it all incredibly well though.  If only I had the image aligned to get more of the Horsehead in it though!
This image is made up of:
  • 60 x 60s exposures
  • 2000 analogue gain in SharpCap
  • Bias, flats and dark frames processed and calibrated in PixInsight

The Orion Nebula - M42

This is the target that seemingly everyone attempts to image at one point or another.  The Orion Nebula is very bright and shows up very will in all sorts of different photographs.  Though this was the target I wanted to image the most, I had to leave it until last.  Bloody rooftops!  So, as the ice was forming freely on the scope and mount, the dew band were doing their job very well and the optics of the scope were being kept crystal clear.  The internet is adorned with thousands of different images of this fantastic nebula, each representing the owners personal interpretations of the target.  I wanted to add mine to that list.  My previous attempts with my DSLR have been poor, so I was apprehensive as to how this was going to turn out.  Looking through various forums, plenty of people seem to be having great results with the Hypercam.
This image is made up of:
  • 60 x 60s exposures
  • 1500 analogue gain in SharpCap
  • Bias, flats and dark frames processed and calibrated in PixInsight

Summary

At the end of nearly 9 hours outside, occasionally nodding off in the shed in front of the fan heater with the cricket commentary on the radio, I managed to get data on 5 targets, each with their own challenges.  My first thing to work on though is the framing of the target.  I need to get used to taking some images and stretching the histogram on the sub frames to make sure I can get all the target in the field of view.
I feel as if I am now getting to grips with the process of collecting the data within SharpCap and this is now becoming a little more routine.  Images will improve in quality with more data on each target.  Next time, I'll stick with only one or two objects for the evening.  In total, it would be great to get 2 to 3 hours on each target.
My biggest improvement at this stage of the hobby will be in processing.  The use of PixInsight has brought on my processing to the next level, and there is a huge amount to learn about this software and it's routines.  I am now a fully paid up license holder of the software so I am determined to make it work to the best of my ability.
So, that's 2017 all wrapped up for me astronomy wise.  The forecast for the next couple of nights is rubbish, and the moon phase is approaching full moon.  If 2018 proves to be as productive and pleasing as 2017, I will be really pleased.  I have my first star party at Kelling Heath booked for 2018 and look forward to experiencing a different location and new circle of people.  That does mean that AstroCamp will take a back seat in Spring because the dates clash.  Nevertheless, I'm sure the dark sky of rural Norfolk will more than make up for it.
Finally, I would like to thank anyone who spends a few minutes reading my posts.  I have no idea how popular or unpopular these pages are, but I have always maintained that the primary reason for the blog is a method for me to keep track on my hobby.  If others find it interesting, great!  Bonus!
Wishing you all the best for 2018.