Nik271

The distance is currently 9AU so 830 million miles. And Saturn is just barely reaching 20 degrees elevation in the UK, which makes this image even more impressive!

I'm pleased to say that I managed to resolve Dubhe last night with the 180 Skymax and 6mm EP, at x450 magnification. The seeing was superb around 11pm, and Dubhe presented very steady view. The diffraction rings were elongated and more dense towards NW and in short periods I could spot a blob forming on the first diffraction ring I wouldn't call this a clean split because it was never there for long periods of time and did not separate from the Airy disc of the primary but I'm pretty happy with this result! Dubhe was getting low at 40 degrees elevation and dispersion was starting to show up, so it's position is not ideal right now. I think in winter this will be even better when it is high overhead. This high pressure system has brought us very good seeing, at least in the south east!

Indeed, that is over twice the 50x per inch rule but I believe there are real benefits of going that high. I think the old rule of 50x per inch of maximal usable resolution is based on the fact that around this magnification the radius of the Airy disc (up to the first minimum) looks about 2' in the EP. And various sources claim that in practice the resolving limit of the average human eye is about 3'. However not everybody can spot fine details at separation of 3'. I know that I can't with dim objects. The Double Double's two pairs are 3.5' apart and I haven't split them with naked eye. So on nights of excellent seeing there are benefits of going above 50 per inch, unless you have the eye of an eagle. I think for me even 100 per inch could still deliver some visual benefit over 50 per inch. Nik

That's a great result, Chris! I had a look with my 180 Mak last night but it was close after sunset and the seeing was not stable in that part of the sky where Dubhe was. The diffraction ring was wobbly and I couldn't spot the secondary at my maximal available power which is also x450. Later in the night I moved to Hercules and Cygnus and managed to split Zeta Herc with ease and with some effort even Lambda Cygni, both at x450. The fact that they are higher in the sky than Dubhe must have helped. Tonight seems to be another good night, I will try for Dubhe a bit later, maybe around 11pm when the ground air has cooled. With these good conditions I haven't even bothered removing the 6mm EP from the diagonal

Well done John! With 130mm the secondary should be touching the primary within the first diff ring, just as you report. I made a simulation with Aberrator Ignore the PA in the picture, primary is mag 2, secondary is mag5 at 0.8' This corresponds well with your observation. I was not ready last night and forgot my small 'solar' Mak on the mount until late evening by which stage it was to late to cool its big brother. With only the the small Mak I focused on some 'easy' stuff. Izar, Mizar, Polaris and finally 65 U Ma, which was a first for me. 65 UMa is a nice triple visual system, which actually has 7 components. Tonight I'm not making changes, the storage bag with the big Mak is already out of the shed and in the shade

Thats awsome! Looks like you are very close. Good luck! I did give it a try with my 180mm Skymax in May but did not even get a hint of elongation. Since then the weather has been poor. I will give it a try this weekend. It will need excellent seeing of course. 🤞

Last night I got out at 3am to view Saturn and Jupiter. There was a light haze which dimmed the gas giants a bit but the seeing was good and I could see quite a bit of detail, the Cassini division on Saturn and several belts on Jupiter. All four of the Galileans moons were grouped very close to Jupiter which was an unusual sight for me. The other notable observation was Iapetus, the two faced moon of Saturn. It is now directly 6.5' west of Saturn and Titan is right in the middle between Saturn and Iapetus. In addition this is the time when Iapetus is at its brightest, I believe it is at mag 10 now, easily visible in my Skymax 127 even in astronomical twilight. This will persist for several weeks, after which Iapetus swings east of Saturn and dims considerably to magnitude 12. So now is the best time to observe it. Here is a screenshot from Stellarium for the coming night, at 1am on 15 July: Iapetus was discovered by D Cassini in 1671, and he noticed that the moon disappears when east of Saturn. His telescope was not powerful enough to spot it when at its dimmest. Nowadays we know that Iapetus has a dark side which is turned toward us at this part of its orbit. There are some interesting theories about its formation: https://en.wikipedia.org/wiki/Iapetus_(moon)#Two-tone_coloration Iapetus is the moon where the second monolith was located in Clarke's book '2001: A Space Odyssey'. (In the film and subsequent books the monolith was around Jupiter.)

Let's hope so! 🤞 With my neighbours lights being on all night I've pretty much given up on the dim fuzzies, but I'm looking forward to some planets and double stars.

Speaking as a SW 127 owner I think it punches well above its price bracket. Sure it is not as good as a 5 inch refractor, as these comparison images show. Perhaps a more competitive shootout will be with a 4 inch APO. I think it's considerably more portable and lighter that the Evostar 120 ED Pro (based on specs).

That's a lovely image of Jupiter from such a budget scope! (I have one myself, so admit to being biased here ) It just shows how good the little 127 Skywatcher Mak is, taking into account its price bracket. Sure it cannot compare to a 5 inch APO refractor but it is quite close

This is a very impressive sequence, 11 days of evolution of these sunspots. Thanks for sharing these! I'm particularly intrigued by day 4, when 2835 has developed a dark bar, which then disappears on the next day.

Thanks, it's simpler than I expected but a very effective method!

Thank you! I will check the continuum filter at @FLO next time I indulge in accessories shopping . I will only need the 1.25inch version in my scope so should keep the cost down

It was mediocre seeing this morning but I was determined to get a good image of the bridge over the umbra of AR 2835. Around 9:30am there was a spell of clear sky and I think I managed to get the focus just right. Skymax 127 with WL solar filter. Canon 250D, video of 7000 frames with 10% stacked in AS!2 and sharpened.

The proms are spectacular! Do you use some occultation device to cover the disc or can it be done in post processing?

Very clear shot, Paul, thank you! Do you use an extra green filter or is it the solar film that gives them the green colour? My single images with 127mm SW Mak are usually of much lower quality and I have to resort to lucky imaging and stacking to get sharp results. I had a quick session around 9am and the seeing was mediocre but I'm glad to catch the departing 2835.

Yes, it was much more clear even in mediocre seeing. Definitely worth checking it if you can! I just managed to stack my video, it's in the imaging section, here is the link: Nik

I just managed a quick session in between clouds. 2835 has indeed developed a light bridge across the dark umbra. The new group 2839 is now 6 tiny spots, a bit hard to see. I manged to take some pictures, here is a single frame: I took a 4 minute video centered on 2835 which I will process, stack and post in the imaging section. The seeing was dodgy but there were some moments of clarity, so hopefully a lot more detail can be extracted. I think 2835 is going to rotate out in a day or two. A pity - it just keeps evolving.

It's interesting to see the sun change from day to day, isn't it! I had a good sunny spell around lunchtime and also managed to see the group of three spots (2839), diametrically opposite to the big one - just as in your photo. As for the big one (2835) its umbral region had a bright center and on closer inspection with 130x it appeared bisected by a very thin white line visible only in short moments of good seeing. My safety check it to look at the filter behind the sun to check for small holes every time before I start observing. Never had any issues after 2+ years of use (Baader solar film on a Skymax 127).

Good work! AR 2835 keeps evolving I think it has become even larger. I managed to have a quick look at about 5pm yesterday (3 July) and it seem,s that the umbral region has split into two. It will be interesting to follow it today and tomorrow before it rotates away.

AR 2835 continues to evolve. The umbra has developed a 'notch'. (Skymax 127 with Baader WL solar filter, stacked 10% of 6000 frames this morning at 9am. Quite hazy but good seeing) It appears to be of complex magnetic polarity, classified as beta-gamma-delta. Afterwards I held the filter in front of my eyes and I could see the sunspot region on the disc even without a scope I also did a whole disc image with only 4 frames which has less detail. My focus was a bit off I think.

BBC has a story this morning with the shortlisted images https://www.bbc.co.uk/news/in-pictures-57653901

I don't think either RC or CC have chromatic abberations because they are reflectors. For DSO astrophotography the RC is better because it's better corrected and has faster focal ratio. For planets you only need the central parts of the field so CC has an advantage with longer focal length.

The sky brightness may play a role too. A lot of the light pollution these days is in all the spectrum because of the LED lights. Perhaps you are comparing with images taken from darker skies or in better conditions?

I regularly image the moon with the same scope and a DSLR with a crop sensor, the whole moon disc fits perfectly. So one solution can be to purchase a dirt cheap second hand crop sensor DSLR camera 😀