Grogfish

According to SkySafari, satellite Starlink-2044 passed through your field of view at that time. Direction of travel would have been from the horizon upwards towards zenith fairly close to vertical. Starlinks do zip past pretty quick though. Not sure what scope you used, but I think 15s sounds more likely. You don’t say what direction of travel of the object was but if it was pretty horizontal then I wouldn’t immediately rule out a distance plane or helicopter; it may not have been its lights you saw (too distant to its see red/green flashing lights) but just sun reflection which is why it looked like a space object. <I’ve edited this bit as a realise I was out 180degrees first time around!!!> From South London, there will be lots of flights going into Heathrow. Because they’re actually heading towards you they’ll appear to move relatively slowly horizontally in your field of view. Though guessing you’d be used to these. If you are really properly South then there was a flight from Vigo to Stanstead that was at 18’000ft over Cobham- which would have been going South-> North/ left-> right in a correct view scope This said you’re in some of the busiest airspace in the world and there were many flights going on. … just shows how busy the skies are…

Sounds like a good evening for Mercury! I got my first image of it - admittedly on my phone by hanging out of my son’s bedroom window (bright dot just over centre trees)😁

Thank you for sharing, I’d forgotten all about this!

That’s great news, so at least we know focus isn’t the problem 👍🏻 And you’ve got some eyepieces to try out. The smaller the eyepiece focal length, the more magnification you get, so worth doing some experimenting. mag= telescope focal length / eyepiece focal length. Your 8SE is 2032mm, so a 20mm eyepiece gives near enough x100 magnification. A 6mm is around x340. In my back garden I don’t usually go above x150 as I’m in a town and the atmosphere just isn’t stable enough ; see what works for you Your scope definitely gives you ability to see Jupiter’s detail, after all, Galileo and Cassini were spotting the moons of Jupiter, the gas clouds, red spot etc over 300 years ago with equipment that probably looked more like a Pringle’s tube😅 Jupiter is low in the sky at the moment though, so it’s not ideal conditions - and that could be your problem. Will be higher again come October. Mars is higher at the mo and you should be seeing its noticeable red-orange colour, but detail will be less obvious

If you are out of focus then stars and planets will appear as distinct discs, rather than points. Looking at the moon and getting focussed on that first might be worth a try, and will give you confidence you’re focussed However, as you say you’re seeing “points” I think you probably are in focus, and it might be worth checking a couple of things. First thought is you might not be using enough magnification (ie not zoomed in enough). What eyepiece have you been using and what planets have you been looking at? Uranus isn’t really going to appear as a disc (it’s just too distant without a lot of effort), but Venus, Jupiter, Mars (and Saturn when it’s around) should readily appear as discs (even through binoculars tbh). If you’ve been using a 25mm eyepiece I think you would have seen discs at least but perhaps not much more detail, however, perhaps try an eyepiece of 12mm (which will double your zoom) and see if that helps. My other thought is whether your tracking is inaccurate, and you’re not seeing the planet you think you are at all, but actually stars! Mars for example appears distinctly reddish-orange with the naked eye so through the scope you should definitely be seeing colour whatever eyepiece you use, and probably even if you’re out of focus. This may sound like a crazy suggestion but mounts are not perfect. My own experience with a 4SE is that it will be more accurate in some parts of the sky than others. When you’re looking at any of the bright planets, say Mars, you should see it dead centre of the red dot sight- if it’s off through that then you’re not seeing it through the telescope. Again, checking with the moon (when it’s around) might be worth a go too, as it’ll be obvious whether the mount has taken you to the right position or not.

That is pretty cool stuff! The neighbours will be talking for weeks! Errr is your kit mounted on a brakedisc?

+1 for the Ceres club! I remember an illustration in one of my dad’s old astro books of the solar system that shows Ceres in the planetary line up between Mars and Jupiter, as though it was “just another planet”. (And doesn’t show Pluto as it wasn’t yet discovered). So yes, I’ve also thought of it as a bit of a “forgotten child” of the solar system. Thank you for sharing the fascinating information about its incredible geology/ just goes to show how wonderful the universe is. I think the position at the moment is pretty good for observation; if the clouds ever lift!

I assume the 100Mly is a redshift distance for PGC49919. Inter galactic distances are really quite tough to measure especially for something as (apparently) far away as this. Sloan Digital Sky Survey III measured a redshift of z=0.00628. That translates as a comoving distance of 88Mly for Hubble Constant of 70, and you get 100Mly with a Hubble of 61 The Simbad service is great for this kind of info (https://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Pgc49919&submit=SIMBAD+search), although they’ve now added a horrible mobile interface that hides the good stuff so you have to force use of the desktop site if you’re viewing on a mobile!

I remember in Stevenage central library I once came across a telescope making book from the early 1980s. It included a wide range of very difficult builds including a 12” or so schiefspiegler… seemed a little.. niche! That said libraries aren’t just books, and they’re not just buildings these days. In Herts you can use the Libby magazine app for free with Library membership, and among many many mags it includes Sky at Night magazine. So every month I can read it for free without leaving the sofa😄 Worth checking what your library service offers!

@kuvik Fantastic way to help support your club, it looks like a great book too. Donation on its way to Vega👍

The Nexstar 4SE, focal length 1325mm. A couple of others have mentioned the Baader Classic Orthos. I’ve only got the 32mm, which I believe is actually a plossl not an ortho. It’s a decent eyepiece but how much of a difference you’d see compared to your Omni I’m not sure. The range comes in 32mm, 18mm, 10mm and 6mm; which isn’t as thorough as some sets but I think it assumes use of a Barlow to get the intermediate sizes.

It’s a little beyond your budget (~£90), but I find a 16mm Nirvana eyepiece works well in my 102Mak. As it’s 82degrees you get virtually the view of a 32mm plossl, but I’ve found the optics to be a big improvement and you get more magnification which helps on some objects. I found 10mm is around the highest power I can routinely use/ and for that I use a pretty old school Meade 4000, but works well for me.

This has been an interesting topic to read up on because I don’t remember ever hearing about this at uni - so it’s a nice new problem to think about. Given some of the very famous names to have looked at this, I think it’s a case of “only fools go where angels fear to tread”, but I’m game!! I’ve been wondering if some indirect methods might work to avoid the need to measure the round trip time. And it was interesting to see that Mossbauer appears to have experimented in this area, as I wondered if his effect might be useable. However, I suspect he would have investigated it himself if there is! A different idea that comes to mind is to consider the angular distribution of photon energies from bremmstralung radiation. If it could be shown that the energy distribution curve is the same at different angles then I think that would indirectly demonstrate the speed of light would have to be the same in different directions. In fact, it could be that you see the change in the shape of the energy curve at different angles particularly at low energies; as you’d effectively be measuring the average speed of c across small section of the electron travel path. / but I guess that would really depend on how c varies. I think in practice though it might be hard to get precise enough measurements to constrain the variability of c as much as would be nice. And may be the Achilles heel of this method would be finding a conceivable energy detector that itself wouldn’t be effected by the same change in light speed along the same vector? Any thoughts on this? Am I barking up the wrong tree?

Just seen your update - yes a 0.5x focal reducer is cheap as chips and well worth a go- I still use one. Be aware they don’t always give exactly 0.5x, depends a bit on the device itself and your set up. Mine actually gives me 0.63x. Also, thinking a bit more about your camera, it may only be able to save video output (AVI) rather than still images. The usual starting programme people use to stack images (which massively helps to reduce background noise/graininess - and I didn’t do in my image above!) is Deep Space Stacker, but off the top of my head I don’t think it can process video files. If I’ve remembered right you’ll either need to a converter programme to convert the AVI to a set of still images so that DSS can process them or use a different programme - AutoStakkert is worth a go because it’s also free, pretty straight forward to use, and can read AVI video files without conversion. Right, I’ll leave you to it, good luck!

Hiya Mitch Been along a similar learning curve myself. I’ll try not to repeat what others have said but briefly, magnification is equal to the “focal length” of the telescope divided by focal length of your eyepiece. So 500mm FL telescope with 10mm eyepiece = x50 magnification/zoom The SV105 is roughly equivalent to a 4mm eyepiece, so for a telescope of 500mm FL, and 4mm eyepiece, that’s a magnification of x125. If you have 1000mm FL telescope, then that’s x250! Great for planets, not great for wide-field shots of open star cluster etc The SV105 is also limited on exposure length by the looks of it, just half a second… when if you look at most pictures people share they’ll be using exposure lengths of 20s at least, sometime 2 minutes or more. OK. So, yes as has been said, good set up for planets, but a little deep sky might be possible with effort and managed expectations 😁 - and I’m thinking globular clusters. They’re fairly small targets and some are pretty bright. You’ll want to start with the brightest and you’re lucky enough to live in the Southern hemisphere you have a big advantage in what you can see- 47 Tucanae and Omega Centauri - both big for globulars, but also very bright. Have a go and see you can get anything! Getting on for ten years ago my first deep sky image was of a globular cluster using a second-hand cctv camera stuck in the back of my 1300mm telescope🤪. It had the same size sensor as you’re using (~4mm), and while it was able to do up to 4s exposures, I was imaging a much dimmer globular at longer FL… it’s errr… not staggering quality… but I’m still super proud of it and I got better and practiced more and in the end bought (slightly) better kit. So yeah, manage expectation, but do have a go your lovey bright Southern globulars and show us how you did 👍

This thread on CN might be worth a read, you may just need a little tightening on the correct nut. I needed to slightly tighten the altitude on my Nexstar 4 after piggybacking heavy loads for some time, and this worked for me: https://www.cloudynights.com/topic/258333-altitude-nut-adjustment-nexstar-se-series/

So, I was lucky enough to go the Royal Observatory in Greenwich today. Very enjoyable and interesting place to go, but I was very confused about a vertically mounted telescope (literally straight up) which sadly I didn't take a picture of, but I did take a snap of the label which I've attached, key bit as follows: "Located almost directly above, the star Gamma Draconis can be observed clearly with minimal distortion (refraction) caused by the Earth's atmosphere. Astronomers used observations of this star to correct for other stars lower in the sky whose positions appeared to change in the distorted light." And, looking further, Wikipedia says that: "It is by far the brightest star having a zenith above a point near London which led to its vaunting in these places as the "zenith star"." Now, I am very much the amateur, so I'm sure it's me, but... : Gamma Draconis is sometimes near "almost directly above" as stated at Greenwich, but it moves around the sky - it's not polaris afterall?? Presumably there is a critical time this is true, which is very useful for some reason?? What would a refraction correction even look like? That sounds like a vanishingly small impact to any measured position, so why was it necessary? The Wikipedia statement is bizarre and again seems to be missing out a key bit of information - surely every star has a zenith, whether you're observing from London or anywhere else? Is anyone able to explain this all to me in ever-so-simple language? Thanks!

I have been working on an observing list of irregular galaxies. It’s short. And then I brought out my trusty rule of thumb for visibility of objects and the list became very short! (May well post about this topic elsewhere) It made me wonder if it might be interesting to share our astro rules-of-thumb… Ok, so my “visibility rule” is as follows: Messier= I can see it NGC= I can probably see it IC= it should be called ICantC PGC/UGC= 😂 Comments and contributions gratefully received, if only for comedy purposes!

A bit bodged together in my case, but the garden storage box makes a handy place to rest the laptop.... And if you don’t have to skip around kids toys in the dark then you don’t know what you’re missing out on! (Scope only so low because I’m having a late crack at M33... and for once I seem to be winning?)

Thanks Rotatux. Sounds like I need to be braver at stopping down the 135mm. The Samyang looks fantastic, but out of my price range sadly. Regards star bloat I’ve not satisfied myself how much it’s due to poor focus, aberration, stacking technique, or bloom from a pixel well overflowing on the cmos (is that the right terminology?!). Not really thought about it like this before, but I suppose I need to work out how much each of those is contributing to star bloat to push my imaging on a level... that’s given me some homework for the next month!

What aperture do you tend to use with the 200mm? Do you run full open, or shut it down a bit? I’ve also got a f/2.8 135mm cosinon lens, but I’ve not had a chance to try it out much- and when I have I wasn’t particularly impressed- it appeared very soft at f2.8

Sooo... I have an M42 to C mount adapter - cost around £18 on eBay. I also have the Altair GPCAM bracket that holds the camera and provides various screw mount points. That I attach to the Nexstar 4 using the Nexstar 5/6/7 piggyback camera adapter. And because it’s designed for a SCT, it doesn’t quite fit.. however mounting the piggyback holder reverse does seem to fit ok (and not block the eyepiece holder), but it means the holder (and thus the camera) stick out to the side of the Nexstar, rather than being on top. All a little Heath Robinson... but.. kinda starting to get some results!

Good question! For M31 it was around f/4.5, but I tried stopping it down a little more on NGC2244, around f/5.6. Not sure it made a lot of difference to sharpness. While I nothing about camera lenses it seems pretty sharp, even wide open at f/4. And my thanks to @Bobby1970 who sold it to me a while back! Viewing this page now on my iPhone the colours are all a bit mangled (or absent) compared to on my laptop last night... so... if you’re looking at my pictures and wondering what’s going on then close your eyes and imagine Hubble took it ?

Last year I started experimenting with using a 200mm M42 lens piggybacked (well actually side-backed) on to my Nexstar 4SE to give a larger field of view through the GPCAM IMX224. I'm still early on the curve, but finally feel confident enough to share, especially as last night was suddenly a clear sky, and very welcome it was too. So please see M31 (59x16s subs, 14x8s darks) and NGC2244 Rosette Nebula (166x15s subs, 14x8s darks) taken last night. Oh yes, and just to confirm the Nexstar was running Alt-Az! All processed using DSS followed by GIMP for some stretching. Frankly I think my GIMP work could use some more practice! It's only when you give it a go that you realise just how much hard work goes in to even getting a half-decent image... The pictures you all take are amazing! Well, clear skies to all.

+1 to both of you! Thank you for spending the time thrashing this one out - I too have often wondered about the theory and practice of using an EP for focal reduction. Eyepiece projection has often appeared to me to be a dark art that is only discussed in hushed corners, and you get funny looks for talking about it out loud... I think you’ve handsomely demonstrated why this is the case; it’s fiddly and the results don’t merit the effort compared to the alternatives. Ah well, good job I spent the twenty quid years ago on a simple x0.5 reducer......