Martin Meredith

This is one from last week in EEVA-mode (ie live-stacked and LRGB'd at the scope). Its a long exposure by my standards, but then the galaxy pulled me in and held me. I'm not getting anything like the resolution or depth of Alacant's image of course but I was happy to catch a little of the outer halo. I can't fit M106 and NGC 4217 in my 0.34 x 0.44 degree FOV, but here's a separate image of NGC 4217 and friend from the same session: Martin

Excellent results Tony, and glad to see you posting again! Martin

Great animations, Paul & Bill. Every time I think about doing something similar, I ask myself whether I have the patience to return the scope to exactly the same position every 10 minutes so as not to waste the intervening session. Once I have the Pi controlling the mount maybe I will set up some kind of automated sequencing... Martin

Marvin, I love your description of this thread! Here's my NGC 4217 which started out in mono but as is often the case when I see an interesting star field ended up in colour (not that these stars are anything but yellow...). I was able to get a slightly wider view than Mike so the crab-like galaxy NGC 4226 (early barred spiral, SBa) creeps in too. What makes this field for me is the conjunction of the stars and galaxies. If you took the galaxies away we have a loose open cluster (not sure if they are in any way related though). Thanks Mike for pointing out the kink in the dust lane.

Here are some that are well-placed and good in colour as well as being bright galaxies M106 in CVN (lovely in colour) NGC 3718 in UMA (lots going on in this field) NGC 3726 in UMA (face on spiral) NGC 4217 in CVN (galaxy in excellent star field) planetary nebulae M97 in UMA (see if you can get Hickson 50 in the shot as it contains a mag 20 galaxy that is useful for checking your reach!) NGC 1501 cam (ring with structure) NGC 2392 gem (beautiful colour contrast in the nebula) NGC 2371 gem (interesting structure/colour with faint outer parts) cheers Martin

Some really remarkable galaxies there. UGC 6309 is so unusual -- very hard to get my head around that. I can't find what the ^ means and I have trawled through the entire N page table in the most recent galaxy classification I could find...You've really been able to pull a lot of detail out of Arp 336, with the helter-skelter trails and the bomb-shaped outer envelope -- wonderful shot. The 3 Arp ring galaxies I think I have visited (146-148). I'm looking forward to both observing some of these and seeing what other shots get posted in this thread. Martin

It seems we posted at the same time. It would be a shame to lose those so here's a link to Mike's recent post:

So to get the ball rolling, here's one from very early yesterday, the final observation from a long session during which I observed 20-odd galaxies in a small region of the sky in and around Ursa Major and Draco. This is the galaxy NGC 3726, a late-stage spiral (spiral arms quite loose) which is seen almost face on. Apart from the bright core and knot-laden arms, this one stands out for its large and relatively bright halo. Two of the arms show interesting features: at the right hand side the arm appears to split into a tuning fork, while at the base there is a twig-like branching which seems quite unnatural to my eyes. No doubt high-resolution images will show what is going on, but part of the fun is trying to work it out without seeing the Hubble view. I'll see if I can find out more and add to the thread later. Since getting the local plate-solving and annotation side going I've been enjoying seeing what else is in the field. I have the one million quasar catalogue loaded so inevitably in most fields there are a few quasars, but often they are too faint for my setup. Unusually, on this occasion there are 6 that I think I have just about caught a few photons from. Their magnitudes (mainly blue) and redshifts are shown. In fields with lots of quasars, detecting the faint points of light is an interesting pastime to see how deep your setup can reach on a given night. I tend to max out at around 20 most nights (at least for short exposures -- I never use long exposures so I can't say what my real limit is), but last night I might just have reached a little further than this (though the evidence for the mag 20.4 quasar is not very strong...). cheers Martin

Galaxy season is upon us and we have threads collecting together galaxy groupings e.g. Arps, VVs, Shakhbazians, WBLs etc, but none for EEVA-style observations of isolated galaxies, so I propose to start one here. Exemplars might include the well-known Messier galaxies, members of the NGC or IC catalogues, ultra-thin or face-on spirals, or indeed any galaxy that stands out for any reason. It might be embedded in an interesting star field, possess some astrophysical peculiarity or historical relevance, or simply be plain good-looking! All observations or comments welcome Martin

Thanks Paul. I'm definitely not a hard or even soft core imager either. If it can't be done at the scope then I don't do it. That isn't to say that I don't enjoy 're'-observing by reloading the sequence the next day or in the future and messing around with it, but anything that takes more than a few seconds of adjustment isn't for me. I'm mainly interested in seeing what I missed during the near-live experience... One thing we've being trying to do is group things into threads by catalogue or object type so that things are easier to find in the future. I think we need one for interesting NGC galaxies as there are so many. Martin

Managed to observe this field last night. First, a 'wide' (well, 0.44 degrees) field shot that also captures the lenticular galaxy NGC 4386. Then a close up. I stretched this to bring out the lower arm, which wraps around and fades out. The elliptical is blindingly bright when viewed like this. I let this run for a bit as there was a lot to see. Diameter info appears wrong -- will look into it. This was one of the several highlights of a night where I was fortunate enough to be able to observe nearly 30 objects -- mainly galaxies -- in a 4 hour session. cheers Martin

Hi I'm going to resist suggesting any sensors without knowing what kind of objects are you mainly going to be observing. If large nebulae, you'll need a larger sensor than if mainly galaxies, for instance, where a small sensor is going to be fine. If planetary then the answer will be different again. Whether you want to see things in colour will also influence your decision e.g. a main interest in galaxies typically would point towards mono. (I use mono + filters to produce colour when I need it). Check out some of the threads in the EEA observations section to see what is possible. As a general consideration, for most EEVA objects you'll need a sensor with a high QE and either large pixels or the ability to bin smaller pixels to create large effective pixels. I suggest you use the FOV and CCD suitability calculators at astronomy.tools to see which cameras produce a reasonable arcsec/pixel in the range 1-2 say for your scope with its 1000mm focal length. Bear in mind that the objects that are used in these tools to check field of view are typically quite large. My position is that you really don't need a huge sensor unless your main interest is in nebulae and open clusters. I personally use a 0.4M pixel guide camera on my 8" f/4 scope running in alt-az on an EQ6 class mount. There are other reasons why some prefer larger sensors, such as being able to find objects (not such a big issue these days with platesolving), or having enough stars in the field for alignment during live stacking, or indeed for platesolving itself. You should certainly avoid choosing a FOV that is too small. Mine covers 0.44 x 0.33 degrees which works fine for stacking/platesolving but I wouldn't go a whole lot smaller than this. I hope others will chime in too! cheers Martin

Beautiful shot and very interesting description, thanks. I'd agree it looks like it has a ring so a classic case of a SB(r) and a late one given those far flung arms. I imagine you've checked that the bright spot is not a supernova 😉 If I get a chance I'd like to look at this tonight or tomorrow. Martin

There are at least two ways into INDI that I know of for Python (if anyone knows of others I'm all ears): 1. https://github.com/geehalel/pyindi-client which is a set of SWIG-generated bindings to the C++ code 2. via the Dbus interface exposed by Kstars/EKOS (thanks to SGL member @KP82 for alerting me to this and showing me the way). More details: https://www.indilib.org/support/tutorials/148-dbus-scripting-with-kstars-python.html A bit of context: I have a cross-platform, 100% Python near-live observing application called Jocular (that a few of us use in the EEVA section) and my plan is to write a simple two-way asynchronous communication system (also in Python at both ends) that will allow Jocular to use high-level requests (set filter to X, exposure 3s, goto NGC 2403 kind of thing) which will be picked up on the PI side and converted into INDI requests and use one of the two mechanisms -- most likely PyIndi as it avoids the EKOS layer altogether -- to get the job done. This way, the client remains pure Python and there is a (hopefully small) server sitting on the Pi handling the requests and communicating the results. I'm currently looking at Open Sound Control as the communication protocol as it is simple and handles large objects, but this is very preliminary. cheers Martin

Thanks to you both. I've let Radek know in any case but if it is just GPS then it won't affect me. Now I'm keen to turn my Python app into an INDI-client 🙂 Martin

I ordered a RPi4 (4G mem, 64G SD card) yesterday afternoon, it arrived around midday today, and a couple of hours later I have what appears to be a working Astroberry-based system, so I'm pretty happy! My camera (SX Lodestar) and electronic filterwheel (also SX) are up and running via EKOS and I'm just waiting for the Lynx cable to be delivered so I can connect the Pi to my AZ-EQ6 mount and get rid of the Synscan hand controller once and for all. Having never used any of the tech before, nor EKOS, I followed this great video which goes through the entire process from scratch and I would highly recommend it to anyone installing Astroberry for the first time. I did come across one issue (nothing to do with the instructions in the video). After installation, I followed the instructions on the astroberry.io site to update the system by running sudo apt update && sudo apt upgrade && sudo apt dist-upgrade in a terminal window. This all seemed to go well but at the end I received the following message: Errors were encountered while processing: gpsd astroberry-server -sysmod E: Sub-process /usr/bin/dpkg returned an error code (1) Everything seems to be working fine, though now of course I wish I'd ignored the update instruction. Has anyone else come across this? Cheers Martin

I was looking at/enthusing over this beautiful galaxy last week in EEVA mode and it is great to see what it actually looks like! Apart from the core, I found it a challenging object and I think its family resemblance in your excellent image to the likes of M101 or M61 might give the impression that it is quite a bright galaxy, whereas the spiral arms are actually quite faint. Martin

Some great observations there Mike. Love the edge-on in the penultimate picture. Although your FOV is quite small, it gives the appearance of a much wider field, I think because of the different galactic sizes on view providing a sense of perspective. Some of them may have been observed only once or twice before! (I was going to add 'or never', as they were discovered using an algorithm, but I'm pretty sure they would have been carefully checked!). I remember reading some years ago that the criteria for choosing compact groups placed a limit on the magnitude difference between the bright and faintest members considered to be part of the group and there will have been other criteria (compactness too, of course), so the existence of other galaxies in the region may well indicate physical proximity yet escaping being considered members of the group for purely algorithmic reasons. Also, I think they excluded one of the two overlapping groups if they algorithm came up with such sets. The PCGs were apparently collected to extend out to greater distances the kind of catalogue Hickson represents. Martin

I love seeing open clusters like this, especially in a wider context. I'm afraid I can't match your FOV as the Lodestar is my main and only camera, but this is an observation of the 'core' from last year from near Vitoria. You may be aware that there are quite a few galaxies in the M67 field, and that was what I was mainly interested in pulling out. I've marked three of them but there are plenty more. The middle one is mag 18.3, the others a little brighter. cheers Martin

Thanks for digging these out. I certainly wouldn't like to live in a highy irregular Magellanic galaxy based on that description ... I did a quick search in the Jocular planning tool and there are 155 galaxies whose type contains an 'm' out of the 12488 listed (basically just the M/NGC/IC/FGC), 112 of which are above dec -20, so plenty to look for. However, the classifications are all Sm, SBm or SABm (note no SAm), so I will see if I can find a list of more detailed classifications to include in the next version of the tool, because it would be fun to contruct an observing programme around finding good exemplars of each type. Martin

Hi Philip If you're happy to use scikit-image and Python I have some relatively brief code that performs star extraction. It currently runs as part of a larger OS-independent application but should be easy enough to turn into a command line tool, if that is what you need. Martin

Thanks for posting. I read more of my de Vaucouleurs atlas to see if I could find the (m) in parentheses and so far no luck. There is a m subscript that signifies 'massive arms', and there is there is the m type that stands for Magellanic (as in, irregular but of the Magellanic Clouds variety -- I think this is what you are referring to?). However, this designation doesn't appear in parentheses but at the end e.g. SABm. Maybe it is just simply that the brackets were used to separate the m from the 'pec' part. Looking at that galaxy again I can see that the presence of so many knots could lead to it being seen as Magellanic type, though I would have been hard-pushed to say so without seeing the class beforehand! Martin

This observation from earlier in the week is a case of 2-for-1 or even 3-in-1 as it contains Arp 313 and VV 523 just above and to the right, and the group is also known as WBL 366. The Arp designation is simply 'galaxy group' -- what's so peculiar about that? The larger galaxy in the Arp pair is NGC 3995, and its companion is NGC 3994. Both are spirals: NGC 3995 is classed as SA(m)pec in the Arp Atlas and SABm by LEDA. I'm not sure what the m in parentheses refers to. Any ideas? NGC 3994 is SA(r)c pec, the 'r' indicating a ring-like structure, or just Sc by LEDA. Just above NGC 3995 is a bit of material that seems to me to be part of the disrupted upper spiral arm. Just to the right of the bright star is another dim slash of fuzz which is down as a mag 17.3 galaxy. The star is pretty bright, just about naked eye, at mag 6.4, and varies over a period of 17 hours, but nothing to get too excited about because the vairation is just 7 millimags. The galaxies are worth looking at in detail. Here I've tried to bring out the series of knots that run down the crinkled 'leading edge' to both sides of the brighter nucleus in the main galaxy of the Arp pair. Is this the result of a recent interaction with its neighbour(s)? The three galaxies in this figure are at a similar distance of 155-160 million light years. To the upper right of the image is VV 523, identified as the galaxy NGC 3991, classified as I-type (Irregular, I assume) but there may be 2 galaxies, the other being UGC 6933. The close up shows something quite unusual and it would be good to see if anyone can get a more detailed shot of this. Is is a pair of galaxies that are in the middle of an interaction but happen to be edge-on to our viewpoint? Or is it a single galaxy with several prominent knots that are obscuring the rest? One might imagine it being similar to NGC 3995 but edge on except there is no clear central core. So yes, a galaxy group, but quite satisfyingly peculiar!

Another Saturn galaxy! For the purpose of anyone wanting to compare different setups, this is what I was able to get, oriented/framed to appear like yours. The additional focal length and slightly smaller pixels provide a clear benefit in your setup in terms of the clarity of the gap between the core and 'ring' in the main galaxy and of course the blocky stars in my case. (Assuming seeing etc the same, quite an assumption...)

To be honest, the colour version looks a lot better on my screen than in the image here where it isn't very bright. I hope you get a chance to visit it with your 15" as there is a lot of structure to be seen. Martin