Martin Meredith

Thanks. The FITs is actually fine (good news). It fails because it contains 3D data and I'm currently only handling 2D. I can handle 2D FITs that need debayering but not those that have already been debayered and saved in a single 3D FITs. It isn't hard to do and I'll add it to the next version -- just that this is the first time I've come across it. Meanwhile, is there an option in Altair Capture to save un-debayered? Martin

Could you send me a FITs file so I can check what is going on? ignore = non-FITs files that end up in that directory unused = any FITs that haven't been processed when the app closes invalid = any FITs whose reading throws some kind of exception Thanks Martin

No, it doesn't lock it. BTW What OS are you using? There is a way to change the path in the next version but not currently. I've had reports that some capture software (ASILive) doesn't write FITs directly to a specific folder but creates a subfolder within it. I wonder if this is happening here? If you have a FITs file, you can test things out by just dragging them into the watched folder and Jocular should respond by loading them and displaying the image (assuming the FITs is well-formed). Martin

Here it is wall-to-wall sun 🙂 (plus moon soon) but all my friends in the UK are complaining about rain... BTW the next version which will be out in a month or so will contain support for ASCOM cameras, filterwheels (and perhaps mounts), in case that is of any use to you. I recently acquired a Windows machine and a RPi to test this stuff on so now I am utterly confused by different OSs and keyboard layouts.... I'm also hoping to support ASI cameras natively but don't have one to test. Martin

Hi Greg If you have python installed already then pip install jocular will do the trick. More info here: https://transpy.eu.pythonanywhere.com/jocular/ cheers Martin

I'm surprised Acrobat 'Reader' is a paid app. The full Adobe Acrobat yes, but the reader is usually free.

On a tablet, for 'click' read 'touch' ie the same way you would open a link on a website. The left hand part (i.e. everything that is not part of the chart itself) consists entirely of hyperlinks. So instructions like "click on a constellation code" simple means click (or touch) the 3-letter code representing the constellation at the top left of the chart. Likewise for object types. Maybe you are not seeing them for some reason related to the browser/ipad? Have you explored them on your laptop? I would recommend doing that first so you can see how the maps are meant to behave, because I can't work out whether the problems you're having are iPad-related. You have to use a browser that supports hyperlinks (e.g. Acrobat Reader), and it is best to choose one that supports loading pdfs into the *same* window. There is an earlier thread on preferences for Acrobat to support this. I don't know of any other browsers that support hyperlinks properly and support reloading in the same window, but the experience using Acrobat is very smooth. Having said that, I have no idea what the iPad implementation of Acrobat Reader is like.

This is an old topic but it appears to crop up occasionally, and having run into it myself during some code development which involved reading the data off the SX ASCOM driver, I am almost certain that this is due to a problem with the SX ASCOM driver emitting the odd and even rows in the wrong order with no option provided to swap them. If I swap the rows in software the image is perfect; if I don't, I get the double stars. Binning 2x2 'solves' it, but only by default because the order of the rows is rendered irrelevant by binning with an even number. This solution doesn't help anyone who wishes to preserve resolution (as I do). I leave this here in case it helps anyone (although the only solution at present is to bin, or to use a different driver). I've contacted the driver developer to check if this really is the case. Meanwhile, for anyone using the SX ASCOM driver with the Lodestar I'd be interested in seeing your unbinned images to see how widespread an issue it is. It may be that some software knows about the issue and provides a 'silent' fix. This is the kind of thing you see. Left is corrected, right is swapped odd/even rows. Top is stellar, lower is a capture of a straight edge. The effect is quite substantial. Martin

Is this an issue with zips in general for the iPad, just large zips I wonder. In any case, I've created a small zip of a few charts in Octans here for you to try: testpdm.zip Just one other thought: when I recently upgraded my laptop I noticed that the browser settings (Safari) were such that by default it didn't download without me explicitly giving permissions (this was an issue for all websites with zips, not just Zenodo). Quite frustrating until I figured it out (Firefox was fine). Have you tried with a different browser? Martin

I really appreciate what you're doing here. Label placement is a tricky problem and quite a lot of the code (Matlab, ugh!) I wrote to generate my charts was devoted to it. I ended up computing bounding rectangles of all labels and defining a set of possible locations for each label (steps around a circle mainly, but for constellation names etc the bounds were quite flexible). I then used an iterative approach (simulated annealing) to find the label placements with the least overall overlap (weighted by importance). Often it would take 1000s of iterations but of course that compute cost doesn't really matter for printed final copy (or pdfs). Good luck! Martin

Most fields I annotate have dozens of quasars marked (not all captured by any means!), and that's in a 0.4x0.3 degree field of view, such are the sizes of the quasar databases these days. For those hunting very deep, here's a list of distant quasars under mag 22, ordered by decreasing redshift. These come from the MilliQuas dataset (Million Quasars, but actually just shy of 2 million these days). A couple of things to bear in mind * I'm not showing the filter that these magnitudes come from. Mag 20 in the B filter is very different from mag 20 in the I or K band... (I've made this mistake a few times looking for distant quasars) * Many quasars have a certainty attached which is less than 100%. A few years ago I set out to observe a z=6 quasar and managed to get some photons above the noise in the right place, but checking a year later it turned out to be a false alarm (either not a quasar, or quasar with a much reduced redshift) You can check both of these factors by accessing the MilliQuas database directly in Vizier https://vizier.u-strasbg.fr/viz-bin/VizieR?-source=VII/280 Martin

NIce work Tiago. I hope you manage to inspire more people to consider the EQ platform approach. When I first started I did actually think about a platform but wasn't sure it would work with my dob which is quite heavy (it also has a focal length of over 2m so not ideal!), but you're showing that for a medium size dob it can work well. I bet you'll get some great results with the planetary nebulae that are coming our way soon... Martin

I'm afraid I can't help with the specific question but you might get more luck posting in one of the main imaging forums here as this one is mainly for EEVA equipment and not so many people appear to use filter wheels for EEVA. Martin

That's a great image from your location. I once captured it from near Cadiz, so at a similar latitude to you, and you're right, it is very low above the horizon and needs to be clear of the murk. (I recall that I had a lighthouse beam swinging round every few seconds to deal with!) It has a surprisingly elliptical shape compared to the other big globs. Martin

Hi Peter Thanks for providing the sub. That doesn't look like coma to me, and neither does it look like tracking. Is it possible that the camera has rotated slightly during the exposure? The doubled star images suggest that it made a sudden rotation. Martin

Hi Peter As Mike says, short exposures work well for bright globulars. I'd say with my 8" f4 Newt, something around 5s is more than enough. If you have the choice in the software you're using, choose a nonlinear stretch of some kind (I find log worked well with globs). A Bahtinov mask was one of my most valuable purchases. My scope/sensor combination provides a slightly larger field of view but there are 1000s of interesting targets for your FOV so long as you can get enough stars for alignment and can place the target on or near the sensor with your goto (plus local platesolving perhaps). Re the elongated star, it would interesting to see the full field. I sometimes see the odd oval star but it turns out to be a close double! Always worth checking. Stacking actually covers up a range of sins (eg tracking issues) so it is worth looking an individual subs too. Cheers Martin

Indeed Olly, it is definitely worth restating this often, because the idea that a fast focal ratio is a necessary condition for EAA has become perhaps too firmly embedded (*). We typically make this compromise in the interests of getting a bright image of the target quickly enough to tell ourselves that we are observing in near real-time, but other tradeoffs are possible e.g. binning at the native focal ratio, which might be preferable in some situations. I don't think we explore these alternatives nearly enough. As you say, we are indeed aperture-limited and its just a matter of how we want to sprinkle the photons we collect. Martin (*) speaking as one who has spent half the afternoon recollimating his f4 Newt....

I couldn't resist a look at Abell 2065 in Corona Borealis last night. This has the reputation of being a challenge for visual observers with the brightest galaxy at around about mag 16, but for EEVA the full beauty of this dense cluster is more easily attained. With a listed diameter of about 25 arcmins, this fits nicely on to the Lodestar. Apparently this cluster contains ~400 galaxies and lies at around 1100 million light years distance. Apologies for the coma -- I spotted that my secondary needed the merest tweak and I seem to have ended up with it right out of kilter, secondary adjustment being the beast that it is, at least on my Newt. The galaxies are pretty forgiving though. Martin

Really interesting capture and information -- thanks! Its amazing to thing that light takes 11000 years to pass from one core to the other. It really puts the distance into some kind of perspective. [BTW I will try to sort out the exposure not getting recorded in the next release!] Martin

Sorry, I meant two related but different things but didn't express it too well: (1) The nebulae seem to stand out more than the stars compared to "non-NV with a camera" ie better nebula contrast (2) The stars themselves seem tighter than "non-NV with a camera" Both of these could be down to seeing conditions, equipment/tracking etc, but those are my first impressions comparing to what I typically get with EEVA. I haven't got any 1s shots of these objects handy for a proper comparison but I'm inspired to collect some.

Agreed, very interesting to get a feel for the experience. The mount sound adds a lot to the 'live-ness'. Given you've set the exposure to 1s, it made me wonder what the kind of non-NV based EEVA stuff I do would look like at 1s exposures for these objects. There is a qualitative difference between the kind of image produced in this way and those from an astro camera without NV -- different kind of noise for one thing, and a different nebula vs star balance, the latter much tighter in NV it seems. Please do post more of these when you can.

Just checked my observations and I don't have either of those listed, but they're both real beauties. The 'far' arm in NGC 3646 appears to be rippled. It just shows that nearly every galaxy has something new and distinct to offer (except for most of the ellipticals 😉) NGC 3821 is a great example of a ring, almost perfectly face on. And the galaxy partly obscured by the star to its right makes for an interesting field. I hope I'll get a chance to look at these with the moon out of the way. Thanks for posting Martin

Sorry! I use the white background theme so it looks great to me 🙂 Guessing this is just an issue with cut & paste of code... BTW yours is now white-on-white for me 😉 As a non-linux user I think I prefer your solution. Thanks for alerting me! Martin

Ah, yes you're right. I forgot I had to do that too. RPi now resting for the day... but I think this is what did the trick update-alternatives --install /usr/bin/python python /usr/bin/python3.7 1 from here: https://linuxconfig.org/change-default-python-version-on-raspbian-gnu-linux Thanks for trying it out Andy. BTW I'm just working on native support for ASI cameras and ASCOM so hope to have some news on that soonish. Martin

Not that anyone in their right mind would want to, but if you do want to use Jocular on the Raspberry Pi it is possible. As I have recently got hold of the RPi4 and Astroberry, I tried it out. First thing is to note that the default on the RPi4 is python2, so it is necessary to do the install using python3 -m pip install jocular Then, there are some additional steps to handle the GUI toolkit which you can either read about here https://kivy.org/doc/stable/installation/installation-rpi.html#install-source-rpi or just do the following: sudo apt update sudo apt install pkg-config libgl1-mesa-dev libgles2-mesa-dev \ libgstreamer1.0-dev \ gstreamer1.0-plugins-{bad,base,good,ugly} \ gstreamer1.0-{omx,alsa} libmtdev-dev \ xclip xsel libjpeg-dev sudo apt install libsdl2-dev libsdl2-image-dev libsdl2-mixer-dev libsdl2-ttf-dev Finally, you need to add this to your .profile file in your home directory PATH="/home/astroberry/.local/bin:$PATH" (this last step shouldn't be necessary but apparently is...). Martin