Astrophotography

Catching up on Images

It’s been something of a hectic week, so it was nice to have a chance this weekend to download some pictures from last week, when Andy and James were round, and do a bit of processing.

Firstly- the best of the moon photos. These were mostly captured with my Meade ETX105 Mak, which I’ve mounted on my HEQ5 mount, because the original mount is not reliable. The pictures were taken with an ASI224 camera through a 2x Barlow- which gives a focal length of 2.8m and a hard time focusing! Each image is a 30second avi that I  stacked using Autostakkert, and then the multiscale process in Pixinsight for the sharpening. This seems to work in the same way as wavelets in Registax.

This is one of Sam’s of the Mare on the Eastern Side:

This is one that James took centred on the Cuvier crater:

This is one of mine – I loved this view, because you can just see the summit of the central mountain in what I think is the Walther Crater, upper left. This view was stunning in the eyepiece. If I’ve identified it correctly then this little spec is 4.1k high- i.e. it’s a similar size to Mont Blanc sat on a crater floor that’s about the same size as the entire English Midlands.

Finally, on the moon, from a bit later in the week is Montes Jura, which is the prominent range towards the top of the picture. This feature is 3800m high and 422km long- it’d be a pretty substantial mountain range here on earth.

Next up were some globs, which are a great target when the sky’s not properly dark. I took these with the 130pd-s, and again used the ASI224, but taking 20 second .pngs rather than .avi’s. The mount was unguided (the ASI224 is usually my guide camera) and even over 20 seconds there were some wobbles so when I stacked it I set DSS to only take the best 50%. Each imaging run was 30 minutes, so these are effectively a 15 minute exposure and all use darks and bias frames. I took flats as well, but between M92 and M3 a big lump of something landed somewhere on the image train which meant they could only be used on the last 2 images.

First up was M13:

Next was M92. I’d normally crop and re-size this to present it better, but I wanted to make it comparable to the M13 pic above, so all the settings are exactly the same, although my processing has yielded a slightly different background colour. You can clearly see M92 is a bit smaller, but I think it’s also neater and more compact.

Next up was M3- again with the same parameters:

Finally, I had meant to go over to M5 and get another glob, but went for M64, the Black Eye galaxy. I took this with exactly the same parameters as the globs above (mainly because I was having fun doing visual and didn’t want to faf around with settings). I’m quite pleased with this; at the Practical Astronomy Show earlier in the year Dr Robin Glover (author of Sharpcap) gave a talk about how, for CMOS cameras, long exposures are not necessarily needed, or, indeed, optimal. This has enormous potential, because, by stacking loads of shorter sub exposures instead of a small number of long ones, it greatly reduces the precision (and therefore cost) needed for an AP setup. Well, that’s all well in theory, but I’ve had a go at M81 and NGC2903 using this method and the results were pretty pants! In this case, the exposures, at 20s were a bit longer, and the gain a bit lower and I’m really pleased with the outcome. I mean you can see what it is, which is more than can be said for the other 2 I’ve had a go with.

 

Schroters Valley and the Gruithuisen Domes.

Looking at the Moon from the “window-sill observatory” last night, the lunar phase looked suitable to observe Mons Rumker. Unfortunately the exact phase and unfavourable libration precluded this, but as compensation there was a nice view of Schroters valley and the Gruithuisen domes. Better images of the domes than the last time I tried! (https://roslistonastronomy.uk/more-domes)

Moon, Methane and Messiers

Splendid night of observing and (hopefully) imaging last night.

Sam had his mate James round, and then Andy T came over to join us as well. Due to the long evening twilight and the terminator being in a prime position on the moon, we started there. Once they’d got the hang of it the 2 lads were thoroughly enjoying scanning up and down the terminator taking videos of moonscapes, which when I get some time will hopefully become some nice images.

The areas we looked at were the craters around the South Pole (Scott and Amundsen!) then worked our way down (the image appeared upside down in the mark/planetary camera) past Cuvier, Stofler, Albertegnius and Hipparchus toward the smoother area that’s more dominated by mare. The highlight for me was Albertegnius which was just in the perfect position to be in complete darkness, but with the sun illuminating just the summit of the central peak.

By this time Andy had set up his spectroscopy rig and took a reading from the moon- and matched in to an internet reading of the sun- explaining to the lads that this was because all the light coming from the moon was reflected from the sun, and how the technique enables us to derive what the elements are in the star.

We also did some visual exploration of the terminator- and no matter how amazing the views of the moon through the planetary camera, there is nothing for comes close to the stunning HD quality through the eyepiece. Even at 465x through the zoom the view was sharp and full of contrast; a really stunning view.

It was, by this time, bed o’clock for the boys, but Andy and I carried on. First step was swapping the mak for the 130pd-s and setting some imaging runs going on globular clusters with the planetary camera as I felt that the glare from the moon made any other targets a bit unrealistic. I’ll post these when I get the chance to do some processing!

For the same reasons I decided to go for similar targets visually whilst Andy did his spectroscopy and we shared the results with each other. First up, though, was the double-double- it didn’t split as easily as normal which suggested the seeing wasn’t great (I already knew my scope was both cooled and collimated). Nonetheless I pressed onto some globs:

– M13 Obvs! Always a lovely sight. Whilst there Andy moved the scope onto NGC 6207- a new one on me, and just next to M13. It was a struggle to see and needed averted vision to spot, but at Mag 11 the skies cannot have been too bad to pick this up.
– M92 It’s a bit smaller, but somehow feels more compact and symmetrical than its big brother.
– M3 Again- like M92, more compact and symmetrical. It was nice going through these one after the other- on their own globs are all similar, but when looking at them one after the other you really start to see the differences.
– As we were in the neighbourhood popped over to see the Whale galaxy- several club members have been imaging this lately so it was good to have a proper look. With proximity to the moon it was quite an effort to find this and I had it in the eyepiece for quite a while before I was sure I had it. By relaxing and just looking around the target it became obvious how huge it was- nearly filling the ep at 210x. I couldn’t make out the distinctive shape, however, and neither could we spot NGC4656
– Next stop as M5, which was visibly smaller, but with a dense bright core and was pleasingly circular.
– The next Messier glob easily visible looked to be M9. Whilst aiming the scope Andy asked about the bright light in the same direction- which is over towards East Mids airport- and we both agreed was clearly a plane- although not moving too much. Realising that this meant it was heading towards away from us I tried to aim the scope at it, because sometimes it’s a great view in the eyepiece. This plane turned out to have horizontal banding and 4 moons. JUPITER IS BACK!! Albeit hugging the horizon in a boiling atmosphere. Because of this the views were not brilliant, but it was great to see after a long break. Andy quickly headed back to his spectroscopy gear and lined it up- the result was a mixture of the same elements we’d found from the moon, plus a couple of lines for methane. Very pleasing! I then moved onto M9 and caught a quick glimpse, but was kneeling uncomfortably over the telescope by this stage and was getting decidedly cold so we decided to head in for a cup of tea in the warm and to look at Andy’s spectroscopy results.

Suitably refreshed, and with the moon down near the horizon the sky was darker, but also more hazy. We decided to look at some summer targets and started off with the Ring nebula. I think the effects of time and cold were beginning to set in by this stage as I struggled to get it in the eyepiece- not helped by the fact that everything was dewing over. Andy quickly rectified this and we were rewarded with some lovely rich views and spent some time comparing the views in the Baader zoom with Andy’s Binoviewers. The conclusion was that the binoviewers offered a different experience- more natural and pleasing to look at, but also there was some loss of detail. Partly this is caused by the higher magnification available to the Baader, but we also thought it may be down to the greater number of optical surfaces involved on the binoviewers. We returned to M13 to see if we’d find the same outcome- and it was pretty much the same; although the binoviewers rendered the glob as a sphere- a wonderful view.

I’d have liked to try them out on Jupiter, but by this point it was behind the neighbours house, so we returned to deep sky targets instead- trying for M51. Unfortunately, by this point, the sky was pretty hazy and despite being certain I had the dob in the right place, I could not see the galaxies. Spent a while trying to remove dew from EPs, finders etc, but it was pretty clear that the sky was lightening and it was time to pack up. Big thanks to Andy for coming over- observing in company and sharing ideas adds so much to an evening and the output from the spectroscopy was really interesting!