Subscribe to Flamsteed via Email

Enter your email address to subscribe to this website and receive notifications of new posts by email.

Join 1,746 other subscribers

Home Forums Observing and Imaging Group Solar images by Tej

Viewing 15 posts - 1 through 15 (of 17 total)
  • Author
    Posts
  • #6204
    Mike Meynell
    Moderator
    Topics: 119
    Replies: 756

    I’ve added a couple of images of the Sun, taken by Flamsteed member Tej Dyal, to our solar viewing gallery. See here.

    I think they are fantastic, particularly as the Coronado PST is very difficult to image with, and Tej has only just started solar imaging… and, to top it all, they were taken from his bedroom window in Peckham!!

    Certainly shows what it’s possible to do, even in London.

    #6207
    Andy Sawers
    Moderator
    Topics: 128
    Replies: 602

    Stunning! Jaw-droppingly good!

    #6210
    Tej
    Participant
    Topics: 39
    Replies: 597

    Thanks for your encouraging words, guys!

    Perhaps I should comment on a few things related to my beginner’s endeavour in HA solar imaging with a dslr and PST. BTW, I did start solar imaging of the sun several months ago but in white light…again from bedroom and living room windows!

    I know its not ideal to be planetary/solar observing/imaging through a house window due to the extra atmospheric haze and heat emanating from walls etc but for those of us with limited options, its still a worthwhile endeavour/exercise and there is plenty to achieve from doing that whenever one craves for it and cannot take the telescope outside often enough. I guess its largely thanks to the wonderful stacking software available. The one I use of course is the very popular free to use Registax. Even in bad atmospheric turbulences, there are still moments of split second clarity and its these moments that the software try to extract and layer together to give a significantly more coherent image. Of course the number of good frames would be more if the telescope was taken outside in the same atmospheric conditions…at least I think so in theory, right?

    Another reason for observing/imaging indoors is that you may capture moments that you may otherwise miss if you wait for an outdoor opportunity. I had one glory accidental moment when I captured a plane and its jet stream transiting the sun. It didnt matter about the sharpness or quality of the image, capturing the moment itself was the big thing. Having a better quality and focussed capture would simply be a bonus…though still most desirable and always worth putting that extra effort into achieving of course. With HA Solar imaging, there are many more “moments” to capture given its dynamic changes with prominences, flares, sunspots etc.

    As Mike mentioned, imaging specifically on a Coronado PST is an extra challenge regardless of where you are using it and that is in achieving focus with any imaging camera. The worst being a dslr because the sensor chip is so far in its housing that its beyond the PST’s very short focal travel. The same problem applies with most other dedicated planetary cameras.

    There are solutions on the internet involving hacking the PST! That’s a no-go for me, no way am I risking hacking at a device that is built to protect my eyes from harmful sun radiation! Another much safer solution on the internet involves using variable photo adapters combined with a particular type of Barlow (so far only GSOs) in which you unscrew the chassis and then slot the shortened barlow lens into the variable photo adapter. This sounded like a solution I may have gone for but I would have to buy both the variable photo adapter and the barlow and I hate the idea of buying yet another barlow of the same magnitude and less quality than what I already own! So first, I wanted to see if I can achieve the focussing problem with the telescopic/imaging accessories that I already own. I experimented with different things and eventually found this combo to be the neatest solution for me.

    The key element is a Televue (TV) 2.5X Powermate and a special TV imaging T_ring adaptor. I had purchased the powermate for its superior optics to a normal barlow simply for enjoying sharper views during stargazing sessions and producing more detailed planetary astrophotos. It was worth its fairly higher price tag as the difference is considerable. The TV T-Ring adapter was needed for using the powermate in planetary imaging with my DSLR. So I had these two components already.

    The Powermate’s eyepiece barrel can be unscrewed and replaced with the TV t-ring which in turn screws unto the T-ring specific to my Canon DSLR. So its a 4 piece chain. My Canon DSLR, the Canon specific T-Ring adaptor, the Televue Powermate specific T-Ring adapter and the Powermate itself (sans eyepiece barrel). This chain brings the Canon’s sensor chip closer to the Powermate’s lens and so just about within the PST’s focal range. This chain I could use for both close up and full sun images and that is thanks to the Canon’s great 5X Live View record feature which I can toggle the 5X magnification to capture either full sun or close up on prominences as I’ve done here. Of course, a monochrome astro camera will etch out far superior details but for some reason, with my DSLR, I can capture both surface detail and prominences in one single shoot, whereas with a monochrome camera, one has to shoot prominences separately to a surface detail shoot (by varying the exposure levels) and then either layer them together in post processing or simply keep the two images separately…at least as far as I am aware, please do correct me if any of you have seen or achieved otherwise.

    Anyway, I will be moving on to imaging with a Mono QHY5L-II next which I had just bought. I’ll see what I can manage with that. There appears to be new challenges to face with this camera on a PST. One is the Newtonian ring effect, hear. On first attempt, tt seems to be a sort of strobing effect, I will report my experience and any solutions I find on this, soon.

    • This reply was modified 5 years, 7 months ago by Tej.
    #6216
    Mike Meynell
    Moderator
    Topics: 119
    Replies: 756

    Thanks Tej, that’s a very interesting and informative summary of how you’ve achieved these images.

    It will be interesting to see what you can achieve with the QHY camera. This “Newton’s Rings” effect that you are seeing is an interference pattern. I believe it can be prevented by tilting the CCD chip very slightly. There are adapters available that enable you to adjust the light angle and eliminate the interference pattern… though others are probably better placed to offer you advice on this!

    #6219
    Tej
    Participant
    Topics: 39
    Replies: 597

    Ah thanks for correcting me, “Newton’s Rings”, got it. It does indeed look like an interference pattern now that you describe it that way. Interesting that I have to tilt the CCD chip as one solution…that sounds a bit awkward! I will research on the light angle adjuster adapter you mentioned.

    Here is the initial test I made to see what issues I have to deal with. So focus is obviously one hurdle which I am positive can be solved easily because the neat thing about the QHY is that it has the format of an eyepiece barrel so the actual sensor is at an eyepiece lens distance. So I should really have been able to focus it better than this from the word go…but I was just making a prelimnary test.

    The interference pattern is the other issue which we already discussed.

    ….but wait, what the hell is that blotch…that aint no sunspot…no, it cant be…I got dirt on my sensor already?!? I only just bought the damn thing! How that get there, must have been sold to me that way! Grrr.

    • This reply was modified 5 years, 7 months ago by Tej.
    • This reply was modified 5 years, 7 months ago by Tej.
    • This reply was modified 5 years, 7 months ago by Tej.
    #6233
    Astrograph
    Participant
    Topics: 27
    Replies: 102

    Hi Tej

    The Newtons Rings effect is caused by the protective screen in front of the sensor and the surface of the sensor acting like an Etalon and bouncing light between the two surfaces. As Mike says this can be rectified by use of a special tilt adjuster.

    The Newtons rings effect is very camera dependent and also depends on focus. I normally image with PGR cameras and have seen the effect when out of focus but it then disappears when focused. I guess this must relate to the gap between sensor and protective cover from camera to camera.

    An interference eliminator is available from Daystar which ironically I have on order. These have T2 threads and cost a quite frightening £289.

    For focus you must also be aware that the limb focus and more central focus will be quite different. If you have focused on the limb then that may well be why the surface is soft and the rings have appeared. I tend to try and find something on the surface to focus on as prominences can be soft and still look OK. If you want sharp prominences and surface then you have to focus stack. There are lots of tutorials for focus stacking online.

    With any small planetary camera like this, your next purchase should be a can of air to blow the rubbish out of it. It gets everywhere. QHY don’t seem to have much of a clean room. All the QHY-5’s I have had, have all had some rubbish in them.

    With the QHY’s, try not to use there own EZ Planetary software. Its OK but there are a few things you need to turn off to get the camera to work at its best. This can add in all sorts of weird effects. Firecapture is much better but never connect or disconnect a QHY with Firecapture open. It hates that!

    Best

    Rupert

    #6251
    Tej
    Participant
    Topics: 39
    Replies: 597

    Oh that’s a wealth of great tips Astrograph. Thank you very much! Sounds like more of a challenge with this camera but the results hopefully will be worth it.

    The image I posted btw was one frame of a video. Not a stacked one, I never bothered once I saw that ugly blotch!

    Will use fire capture as per you advice…and uh watch out, I may be pestering you for more tips 😉

    #6354
    Tej
    Participant
    Topics: 39
    Replies: 597

    OK so I “cleaned” my webcam…and its even worse! Its like the one big blob has now split into many little ones 🙁 its a bloody new camera, surely sensors should be clean when bought new?! I used a lens air pump, what else to try?

    I used Sharpcap btw simply because I am more familiar with the software from my previous planetary imagings. However, during this first session, I hadnt realise how huge the files were. Each of my 30sec shoot are 1GB in length. My problem however, is not the storage but it seems that registax cant handle 1gb AVI. Any ideas of how I can stack my existing 1GB AVis? Even though there is dirt on these shoots but I still want to see how much detail I can extract from these (qhy5l-ii cam) compared to my DSLR. I can already see there is a lot more detail on the raw AVI then on my processed DSLR images which is exciting me. I also managed to adjust the frequency and to get a little of the prominences on show too although, I had to do a seperate higher gain shoot to see more of the prominences but completely losing the “surface” detail.

    So this is just a still frame of my AVIs. Two problems to solve…How to properly get rid of the damn dirt off the sensor (I did use an lens air pump). And how to stack my 1gb AVIs.

    And this is my DSLR shoot of the same event, processed to look like a piece of grapefruit (naturally not my intention 🙂 ).

    • This reply was modified 5 years, 7 months ago by Tej.
    #6360
    Tej
    Participant
    Topics: 39
    Replies: 597

    Sorry didnt upload the Dslr one and I decided to go back to the yellowish colour as the grapfruit one looked ridiculous!:

    Taken 13th June (this is just to compare to the QHY still frame unstacked image above)

    #6361
    Astrograph
    Participant
    Topics: 27
    Replies: 102

    Hi Tej

    If the sensor is this dirty then return the camera. I assume you got it from Bernard at Modern Astronomy as he is the distributor. He’s normally a reasonable man…

    When you see ‘air pump’ are you talking about those little plastic blower brushes? If so, waste of time. Go and get a can of compressed air from Maplins (about £12). That will blow the dirt off.

    When shooting planetary / solar don’t use AVI, its rubbish. Use SER.

    For the best results use the following software

    PIPP (Planetary Imaging Pre Processor) – This will tweak your files before alignment and stacking. It can also convert your files to SER but for future files make sure SER is the format used.

    Autostakkert – This is by far the best alignment and stacking software.

    Not needed for solar but after Autostakkert would come WinJUPOS for derotation. This needs SER files!

    Registax – Only use this for sharpening and personally I don’t use the sharpening by layer option. It should cope with the big files anyway as long as you are using registax 6.

    Generally for shooting have the gain turned right down. It will just add too much noise, particularly with a QHY. Use the histogram and make sure its fully illuminated. Don’t worry about FPS.

    The DSLR image will always look soft compared to the mono camera as its got 75% less active pixels. Unless its been modified it is also less sensitive to light at the 652nm wavelength.

    Best Regards

    Rupert

    • This reply was modified 5 years, 7 months ago by Astrograph.
    #6364
    Tej
    Participant
    Topics: 39
    Replies: 597

    So Astrograph = Rupert…doh, should’ve guessed!

    Brilliant tips, Rupert, you’ve made this page a priority bookmark for me, thank you!

    Yes indeed, I bought it from Bernard and he was very helpful and honest in pre-purchase, giving me the pros and cons of the QHY5L and specifically its performance for Solar imaging. So I knew the challenges…except for the dirt, lol. But I will get the aircan from Maplin and have another go before contacting Bernard (if still necessary).

    Just one question about the aircan, is there a danger of it spraying any kind of water droplets (condensation)?

    SER format, right got it…never heard of that format before!

    Well, I might well go back to my old planetary raw videos and have a go at re-processing a couple of them with your suggested software, PIPP and Autostakkert while I wait a while for a new opportunity to get my scope and camera out again to image the Sun (and other planets)

    #6365
    Astrograph
    Participant
    Topics: 27
    Replies: 102

    Hi Tej

    The SER format was introduced by Lumenera with their Skynyx cameras and has sort of become the defacto standard for video capture.

    With the air can, have a few test blasts with it first. If you shake the can or point it up or down while using it, it can blow the propellant straight out and cover the sensor with liquid. Its best to hold the can upright and move the camera to avoid this.

    I have to say, of the dozen or so QHY cameras I have had, most have had some muck on them but it usually blows off. I tend to check these things before sending them out, but its hard to eliminate the problem. You just have to be a bit more diligent in use and where you keep them. I had real problems not so long ago with a 24mm Panoptic eyepiece that seemed to be forever covered in dark bits across the field of view. I finally discovered it was foam from my eyepiece case getting inside it. I had a tendency to swap eyepieces and just sit them back in the case without putting the caps back on. Lesson learnt!

    Are you coming to Blackheath for the Solar event? I may set a camera up while there. Its looking like we will hold the event on Saturday at the moment.

    Best Regards

    Rupert

    #6383
    Tej
    Participant
    Topics: 39
    Replies: 597

    I cant come to this Sunday’s one, unfortunately, Rupert. Summer is very limited for me as I only have Fridays and Saturdays free but that means I will be coming to all the Saturday Flamstead Solar observation events, though. Would be great to get an opportunity at some point to watch you in planetary imaging action.

    #6639
    Tej
    Participant
    Topics: 39
    Replies: 597

    Well, having been justifiably grounded for gross conduct by Star Trekking the forum, I refocused my attention back to getting to grips with my new, (and still dirt speckled) QHY5L-II camera 🙂

    I aircanned that sensor with half the can and still it has specs of dirt. So I scoured the net for tips and learnt a technique which has proven to be very effective through some trial and errors.

    Yesterday morning, I had a great solar observation session. There was a quadrant that showed a nice little prominence accompanied by some large plages surrounding some sunspots and a decent size filament to boot. So I focussed my newly learned technique to imaging this.

    So basically, I have two inherent problems in using the QHY5L-II. Firstly the dirt, secondly, the newton rings. I suppose focus would have been the third problem for most other cameras but the beauty of the QHY5L-II is that it has an eyepiece barrel form in which the sensor can be placed at an “eyepiece” level thus easily achieving focus with any barlow or even without. So at least I didnt have that to contend with.

    The trick to eliminating both unwelcomed artefacts is to first, video my target regions with a slight drift. Then after my video sessions at the one setting for gain and exposure, I drive the scope to the middle of the sun surface and bring it out of focus until all the dust particles and newton rings stand out against a pure white unfocussed background.

    After the imaging session, I then run Autostakkert 2 stacking software. But before I stack the target videos, I load up the unfocused video that highlights the newton rings and dirt to convert as a Master Flat tif file. This is then used to mask out the dirt and newton rings on my main video frames stacking. It doesnt always work but the addition of the drift in images help to negate the newton rings.

    So here is a typical flat I used to mask the dirt and sometimes newton rings off. I think I need to get the whiteness more uniform next time for better results.

    So here is my first “proper” (for my humble standard) Solar image using the new camera. I have more material I can work with, including some really interesting activities this morning which I cant wait to process (after I have written up a small little tiny article that was requested of me). I should have had more balck regions on the image to give that prominence some more room to breath. Still a fair bit to learn (of course!) but I think I am happy with this next step of progress and the new camera certainly abstracting more details than I had from my dslr. Just takes a bit more of work with this one…rewarding though!

    I have to say, I my cute little PST is delivering far more than I expected from it. Probably my most loved purchase since my first telescope!

    • This reply was modified 5 years, 6 months ago by Tej.
    #6648
    Mike Meynell
    Moderator
    Topics: 119
    Replies: 756

    So here is my first “proper” (for my humble standard) Solar image using the new camera.

    Very, very good, Tej. I’m hugely impressed with what you are achieving with the PST. I presume this picture is of the active region on the eastern limb of the Sun? There are a large number of sunspots at the moment, but most of them pretty small – apart from a group of spots near the eastern limb, which I think is what you picked up.

    Not much in the way of solar activity – certainly the Flamsteed VLF receiver hasn’t picked up anything much recently, as far as I can tell.

Viewing 15 posts - 1 through 15 (of 17 total)
  • You must be logged in to reply to this topic.