Martin Meredith

Jocular: A tool for astronomical observing with a camera I'm pleased to announce the first release of Jocular, an open-source, cross-platform application for doing EEVA-like things. I'd like to acknowledge the sterling work done by SGL members Bill S, London_David, AKB and RobertI for testing the tool and providing some great suggestions. Thank you! Features observation planning via an extensive DSO database DSO/session/equipment logging management of incoming observations reloading of earlier observations live stacking many stretch functions several stack combination methods inverse (‘negative’) view automatic black point estimation gradient removal bad pixel removal & mapping full access to, editing and animation of the stack and its constituent subs support for constructing and automatic deployment of a calibration library (darks/flats/bias) annotated snapshot captures save as FITS interoperability with other tools through open formats a recompute philosophy throughout which enables all decisions to be reversed on the spot Important caveats Jocular requires an external capture engine and supports mono only at present for FITS with under 2M pixels. Jocular is a source-code distribution and requires a Python 3 system plus the installation of a few dependencies (first-time-only). Downloading user guide with installation instructions (3.1M) userguide.pdf jocular (0.18M) jocv001.zip DSO database (1.3M) dsos.json.zip Arp 145 to practise on (9.2M) Arp 145.zip Getting help The best way to get help in the first instance is to PM me and I will summarise any issues of general import on this thread. Videos Search for 'martin meredith jocular' on youtube (the interface has changed a little since those were made but not much).

SNR is theoretically independent of gain In practice, if read noise is different at different gains then that will affect SNR -- though not by very much in the scheme of things. But SNR itself is independent of gain. Some of the strategies employed on CMOS are ways to get around limitations of low full well capacities and should not be seen as boosting CMOS performance above the level of other types of sensors that don't have these limitations to start with. Of course, CCDs have their own disadvantages, but I think it is important not to oversell what gain actually is, which is just a simple multiplier dressed up to look like something else. To give an audio analogy, gain is recording level. If you use a cheap sound card (say 8-bits per sample), you need to worry about setting the recording level high enough to capture faint sounds (plus noise!) but low enough to avoid clipping. If on the other hand you use a 24-bit sound card you can probably leave recording level fixed and still capture faint sounds and loud sounds without clipping. Martin

If my Lodestar failed I would definitely consider getting another -- probably immediately! Or maybe an Ultrastar mono. I'm not convinced that the Lodestar has been superseded for EAA use, at least for the kind of objects I like to observe. I presented some data on theoretical SNRs achieved after a fixed exposure (either with 30s subs or 10s subs) at the link below and the Lodestar wins out due to a combination of larger pixels and high QE. I hear what you say David re binning which can of course make up effective 'super pixels' to catch up with the Lodestar's performance, but the Lodestar is still a very competitive option for those of us that that like simplicity (no gain no pain) and sensitivity. And SX service is excellent, I can attest personally, even from over here in Spain. Chris, I don't see them coming up second hand very often (which tells its own story) but they are well worth snapping up when they do. Anyway, the key thing is to be happy with one's kit! We have a lot of choices and the 290 looks like a good option in the sensible number of pixels stakes ? s

I imagine at some point quite soon we will have devices that fit into the drawtube that we will look through but that are in fact sensors + compute + screen, in an eyepiece-style package (fortunately the bar is pretty low in terms of miniaturisation given the size of some TeleVue eyepieces). Then the debate will begin again in earnest about whether we are observing or not. Off-topic, but I've found adding a little random 'scintillation' to a near live EEVA image is really quite compelling in promoting a live feel. Also, one can do things like progressive stacking (adding in a portion of the last sub at say .5s intervals), which has a similar effect. Its all fakery (well, not quite; as Vlaiv said, our visual system does a lot of processing too, trading off noise suppression against sensitivity to the disadvantage of visual astronomers), but can satisfy the live urge for those that require it. For me, EEVA is all about seeing deeper. Last night I was observing Arps in Leo and came across some real gems with incredibly faint but long tails, and I am fortunate to be able to do that with a mere 8" scope from a SQM 19.5 location in mediocre seeing rather than having to lug an 18" out to a dark site on a night of pristine skies. The idea that one is either observing or imaging seems to be a false dichotomy. Let's not forget that there is a good reason why astrophysicists like Arp used sensors, and that was not to produce great astrophotography. It is only on astronomy forums that this debate exists. I will choose to observe these fascinating objects in whatever way I feel is appropriate. Martin

I welcome this development and hope that it will see NV and other electronically-assisted observers getting together to discuss DSO observations. And I also hope that traditional visual observers will feel welcome to chime in with their observations too! Perhaps we can set up some monthly challenge objects and compare notes. Just for clarification: I'm assuming that the Discussion sub-forum (this one) will be the place for discussion of equipment, software, observing techniques etc, and the Reports sub-forum will be limited to observational reports (as opposed to reports on say a new bit of kit)? Martin

That's a very interesting chart, and I'm sure will grace any wall it is hung on and bring much pleasure studying it. I can see something that might be Cassiopeia and Cepheus, but the scale seems wrong. One of the things that strikes me looking at this chart and at others of the time is how crowded with stars they are (and hence it is not surprising that there are so many different asterism interpretations). This might be puzzling to those of us used to poor skies these days, but it brings to mind one of my most memorable astronomical experiences when I stopped my hire car in the middle of nowhere in Utah a few years back and looked up at an almost totally unfamiliar sky. Even the good old plough was a bit hard to spot amongst all the other much-brighter-than-usual stars. Martin

Hi I'm not sure about the Evolution mount. Mine is the AzEQ6 mount and I don't have a problem with clearance at any point as you can see. While the scope is bottom heavy, by the time you take the focuser, camera and filter wheel (and dew shield) into account, it is surprisingly evenly-balanced anyway. The Quattro is quite short too being f4. I can't resist sending this one to show just how small the 8" Quattro is (and not a matter of perspective). ? But it does indicate where the balance point is. Yes, the EAA software will be available to anyone who wants it. Martin

I'm still here! I've been a little busy lately (mainly coding up a new tool for EAA which will be ready soon). Anyway, fire away! The Quattro + alt/az is still my main scope. Martin

I read in the papers this morning that it has rained or snowed (the latter 16 times) here in my part of 'sunny' Spain for 78 out the first 100 days of 2018..... I did manage a couple of sessions in January though. Nothing since. Martin

Messing around with different stretch functions I came across one that gives a very direct visual meaning to stacking subs. This is exactly like the pile of acetates I used to prepare my classes on... Interesting to see that a median stack destroys the effect completely: It makes sense when you think about it, but all the same I was quite surprised at the difference in information content between these two ways of combined subs (at least at the edges where it is most noticeable since the number of subs contributing varies).

I've been mainly working on the stack inspector this week. The idea is to be able to quickly inspect the entire stack, rejecting bad subs (this also applies to calibration frames, though fuller support for calibration is the main task for next week). The stack inspector also allows animation of the subs and/or stack, making it easy to diagnose tracking issues etc. There's the option to restack based on an arbitrary sub in case the keyframe chosen isn't too good. One thing I'm finding a great surprise when going back through some of my old captures is the proportion of 'bad' subs that nevertheless get stacked into something reasonable.

Thanks Stub & Bruce!

Thanks, and sure, this is the best place to ask. I'm using Kivy from kivy.org Whether you could call it suitable for rapid development is another matter. The learning curve is quite high I found and some layout aspects are not very logical, but it is very powerful in terms of designing one's own widgets etc and I think well worth the initial effort. The beauty is that it is cross-platform and based around touchscreen ideas, so quite easy to build more natural interfaces.

Since shortly before xmas I've been developing a piece of software to support electronically-assisted astronomy (EAA). Realistically it is still some months away from release, but the main design elements are getting close to being fixed so I think now is a good time to document what I'm doing in the hope that any comments or suggestions might be taken on board before the thing fossilises too much. The tool -- codenamed Jocular -- aims at promoting observation, but getting the most out of the limited number of photons we EAA-ers typically collect for each object we observe. The interface will be kept as simple as possible, but in spite of this I'm planning to implement a fair bit of AP-like functionality, adapted to the EAA use case where nearly all processes have to be handled semi- or fully-automatically. In a sense the tool was motivated by a desire to experiment with just what is possible to accomplish in near real-time and minimal user intervention. So there will be support for a full calibration scheme but operating silently where possible, as well as various luminance-chrominance manipulations, gradient removal and advanced stacking and stretching options. I'm attempting to operate by the principle of least commitment, which is especially important for EAAers, whereby it shouldn't be necessary to take decisions in advance that limit later options and potentially waste photons. For example, it will be possible to reject subs from any earlier point in the stack, or change the stacking mode, or choose a different key frame for star registration, or re-assign incorrect subs to the appropriate type or to a different object -- at any point during the observation of that object. Currently, live mode operates via a 'watched folder' approach in which an arbitrary capture program dumps .fits into that folder. These can be darks, bias frames, flats or lights, or short captures used for FAFing (focus-alignment-framing); a user-defined naming template enables the program to sort out the type of each sub. However, I am one small step away from complete integration with Nebulosity, which will enable capture control for any cameras/filterwheels supported by Nebulosity, but all done via a simple interface. The Nebulosity option will also allow scripted captures, again heavily simplified e.g. click RGB to have the program capture N subs of duration D from each of RGB, rinse-and-repeat (assuming the user has an electronic filter wheel). I hope to support INDI-based capture/control at some point and would like to track down some compatible open-source capture options as this is one area I really don't have the time or inclination to work on. It is possible to use the tool both live and offline in much the same way. The tool will provide easy access to previous observing sessions, enabling a user to revisit and re-process the data in a 'what if' fashion. It will support observation planning and logging as well as image annotation. The program is being written in Python. In principle it can be ported to all OSs, including iOS and Android, but I'm developing first and foremost for the Mac where there is a shortage of EAA tools. The software will be open source. Here's a shot of the current interface during a recent test session observing the polar ring galaxy NGC 660 in Pisces.

Per ardua ad astra could equally well be the motto of the amateur astronomer... Personally, I've never flown anything. I do love reaching the tops of mountains though, so maybe the common factor is a subconscious desire to get above the clouds? Martin

No, you can't zoom in selectively. These are literally just individual 1-page pdfs with hyperlinks and so are limited to what you would expect to do with a normal pdf document. There is an illusion of something more in e.g. the charts where clicking on a column appears to sort it, but in reality it is just calling up another pdf document.....

I'd be interested in any feedback on which pdf viewer works best. There is some discussion from a while back earlier in the thread. For me at least Adobe Reader v 11 works well on the Mac, but Acrobat DC is a pain. Dave in Vermont recommended Sumatra, but I can't test it on the Mac. It is strange that not all viewers are capable of handling local hyperlinks in a pdf document, something that is needed to make the maps remotely useable. Martin

Update: Astrojedi has kindly hosted the complete distribution here for the foreseeable future https://www.amazon.com/clouddrive/share/rPeOakPlJbjyMe64hF0TwngYysTiOUi6pFtOE3wVbIC Martin

I just checked index.zip and those 2 pdfs are present, so it must be a dropbox/incomplete download issue of some kind. Looks like you've managed to get them now, but do let me know if there are any others that you don't have and I'll attach them to this thread. Martin

Just to mention that I got an email from Dropbox saying that on 1st September 2017 they are discontinuing the use of the Public folder mechanism which I've been using to host the Pretty Deep Maps (I guess they consider hosting websites via Dropbox to be some kind of unforeseen usage and hence are killing off the possibility?). Since the distribution is very large it may be some time before I find an alternative host so if anyone wants the charts it is best to download in the next 7 days! I do have a new version planned but since it involves a major rewrite in Python it is still some months away. https://dl.dropboxusercontent.com/u/14005918/index.htm Martin

Glad they're of use. Excellent image too! I'll be constructing a new release at some point this year so any comments welcome. Meanwhile, I'm planning to produce a 'lite' version which goes down to mag 16 to support EAA in smaller scopes of the 80mm class. I need to do some more on-screen star/galaxy hopping first to see what is required. Martin

Yes, that's the right one. Be sure to check out the technical document (which does say v0.3 ) Martin

Chuck, I just wanted to check that you have v0.3, since you mention the finder which was a v0.2 concept that I no longer use. Or by finder do you mean the index? Martin

I was excited about Sumatra until I saw it only works with Windows ;-) You're right, the most recent Acrobat is not the best. I suggest not using the DC version, in part because it takes up too much screen space with its own icons (which are tedious to remove). Martin

Hi Chuck Some suggestions: You need to ensure that all the pdfs (indexes and charts) are in a single directory. Are you using Acrobat Reader to open them? Not all PDF readers operate correctly with links. Martin