michael.h.f.wilkinson

Cracking image! Is that at full aperture?

Finally the clouds that have been following me around all summer found someone else to harras, so I got out the big Helios LightQuest 16x80 mm bins and drove to a nearby dark location. I first checked out the sky quality in my usual way by having a peak at M101, which is generally hard from my suburban garden, but popped out neatly here. M81 and M82 were also easily spotted, but those are much easier targets. I then turned my attention to Cygnus, and had no difficulty seeing the North America Nebula, and some hints of Pelican to the side. I moved over in the direction of Pegasus, and found comet C/2023 E1 (ATLAS) quite easily, my second successful attempt at this object. I always feel you only really spot a comet if you can detect its motion, so two views is sort of a minimum. I then trailed along the Milky Way, spotting a host of summer objects I had missed all summer, due to clouds. M11 is always a favourite of mine, and onwards towards M24, the star cloud, picking up M26, M16, M17, M18, M25, and M23 on the way. Further down, M20 and M8 could be spotted, and M7 just a short way above the horizon. Swinging the bins back up, I managed to spot the Veil, which I always find hard in bins, had a quick peek at some globulars (M13, M92 and M3), before going for our galactic neighbours M31 with satellites and M33. A quick, farewell look at C/2023 E1 (ATLAS) closed the session. Really lovely to have a relaxing session with bins, with no technology that can all too easily go BING getting in the way.

After a dreadfully torrid time with a seemingly infinite supply of clouds, I finally got a good load of H-alpha data. I actually captured two sets of 15 panes, because I thought I might have missed focus the first time round, but actually, the first batch was fine, and the seeing was better in the earlier session. I used my APM 80mm F/6 with Beloptik Tri-Band ERF, a Baader TZ-4 4x tele-centric lens, a Solar Spectrum 0.3 Å H-alpha filters, and ASI174MM camera. I took 15 SER files of 1000 frames each, stacked 35% in AS!3, sharpened in ImPPG, stitched in MS-ICE, and did final tweaks and curves in GIMP. Grey scale: Pseudo-colour: Part-inverted: Part-inverted + pseudo-colour: Clicking for full resolution highly recommended.

Finally managed to grab a load of solar data, for the first time since June 25, all with the trusty APM 80mm F/6, and Beloptik Tri-Band ERF. First up white light with a Lunt Herschel wedge and Baader Solar Continuum, and ASI178MM Seeing was pretty decent allowing me to stack 40% of 2000 frames. I then switched to the Lunt Ca-K module, and grabbed another 2000 frames. Grey scale: Pseudo-colour: Part-Inverted: Part-Inverted + pseudo-colour: Clicking for full resolution is recommended. I also grabbed some H-alpha, but I will post these separately.

After a very torrid time with constant bad weather, I finally managed to bag this comet with my Helios LightQuest 16x80 mm bins. Dodging some passing clouds, I spotted it as a hazy ball fairly close to M39. I checked and double checked the sighting, and consulted the Sky Atlas 2000.0 to check for any stray DSO with a similar appearance, but none were show. Quite chuffed at bagging yet another comet. That makes 35.

The thing is, you are spreading out the photons over far too many pixels. For optimal results, you need to match the focal ratio to the pixel size. I remember using 3 s exposures at 1600 ISO and 19 m (that's right: 19,000 mm) focal length with my C8 using EP projection with the SLR I had, as planetary cameras and even webcams were a thing of the future at the time. You get far better results using either crop-mode video (uncompressed, 1:1 relation between physical pixels and actual pixels in the image, unlike the regular video modes) or a proper planetary camera. I typically use tele-centric Barlows, which give better results than EP projection. For my ASI183MC camera I either use native F/10, or perhaps F/13 with a 1.3x Siebert optics tele-centric Barlow. With the older cameras with larger pixels I went for either a Meade 2x TeleXtender or a 2.5x Tele-Vue PowerMate. You can get great results even with cheap planetary cameras. The result below was with an ASI224MC, which pop up second-hand for modest prices. The ASI120MC-S is also quite a performer for a low price

Just to give a dissenting opinion: I have a series of planetary eyepieces, quite closely spaced to adjust to the seeing In my C8 the Pentax XW 10mm gives me 203x, the Delos 8mm (made par-focal with the XWs) gives 254x, the XW 7mm gives 290x. I also have a Vixen SLV 9mm (226x) in my travel kit, which I am tempted to use to bridge the gap between 10 and 8 mm. In rare cases of superb seeing, and then only on Moon and Mars, I might even use the Delos 6mm 338x, or the XW 5mm 406x. I use the latter EPs in my 80mm F/6 triplet and 6" F/5 Schmidt-Newton a lot more.

I want to pick the galaxy up anyway

Thanks for the information. Will have to wait for the next REAL bright one to pop up

I have just used the AAVSO Variable Star Plotter to create these maps, with and without DSS data: There is this very bright star in the image close to the reported SN. This would suggest finding the SN should be easy

Forecast not good here either. I do hope to take my 8" scope for a spin next week, from a more southerly point on earth, with a better forecast. Fingers crossed it doesn't fade too fast

Just spotted an alert here, that a bright SN labelled AT2023mlt has been spotted in NGC5297. Would love to have a chance to spot that, as the SN is well within reach of my C8, and I haven't bagged that galaxy yet (mag 11.7 according to Wikipedia). Has anybody else spotted this? Update: as posted below, the observation turns out to be a false alarm.

Nothing to write home about, and focus was a bit off, but sunspots can be spotted. Just a single, unprocessed shot with the M6

Hada first try with the EOS M6 mk-ii on a simple photo tripod. Quite tricky to get focus right, but with a planetary camera and proper screen to view focus, things might be better. Will post the results later

Clouds block all wavelengths except the really long ones (i.e. radio waves)

Just got myself a Dörr Danubia 500 mm F/6.3 mirror lens, together with a Teleskop Service white-light objective solar filter. Hope to use this as travel solar scope, especially for eclipse hunting. The lens has a T2 mount, so I can also attach my planetary cameras. Will give a full report when I have had a chance to test it properly.

Near infrared is possible however, and the atmosphere is fairly transparent in a number of bands (e.g., the one around 10 micron)

Actually, an antenna can be shorter than the wavelength it detects, but it has to be the same order of magnitude. Focusing of radio waves can be done in the same way as light (look at all the parabolic dishes used), but they can be full of holes (which must be significantly smaller than the wavelength you want to detect). However, to get sufficient resolution, it would require HUGE dishes, so instead we use multiple smaller antennas, and combine the signals, and digitally recreating an image with a resolution equal to a dish as large as the widest separation between antennas. Examples are the Westerbork Radio Synthesis Telescope, in the Netherlands, the Very Large Array in the USA, and more recently LOFAR (all over Europe), and SKA in South Africa and Australia.

Radio waves require very different apertures and detectors compared to visible light. In the visible spectrum, individual photons have enough energy to general electron-hole pairs in semiconductors, which then can be accumulated and detected (this is how CCDs and the like work). In radio frequencies, each photon carries far too little energy for this process, so no "radio CCD"could be built. Furthermore, to resolve anything, the aperture of the telescope needs to be much larger, as the resolution depends on the ratio of wavelength to aperture

In the solar imaging session I had, I didn't have perfect Dec balance, but it worked fine. There is definitely some leeway there

As it is the little brother of the HEM27, and if all the iOptron mounts you mention use the same commands, I would guess it should work

The top of the mount is about 120 cm from the ground. The weight is just shy of 5kg (4,968 g according to my scales)

Had my first light with the HEM15 on some solar imaging. The set-up of the mount was quite straightforward, and slewing was quick and quiet. The whole rig felt really sturdy, and the only thing that stopped my from grabbing H-alpha data as well as white-light, and Ca-K was the sweltering heat. I think this mount will serve me very well indeed. Call me oldfashioned, but I really like the factthat the scope has a hand controller rather than forcing me to use some app.

Too bleedin' hot, but still captured the sun in two wavelengths, using my iOptron HEM15 mount for the first time. It worked smoothly. All taken with the APM 80 mm F/6 triplet, with Beloptik Tri-Band ERF, and ASI178MM camera, with Lunt Herschel wedge and Baader Solar Continuum filter for WL, and the Lunt B1800s Ca-K module WL, grey scale: Ca-K, grey scale: Ca-K, pseudo-colour: Ca-K, part inverted: Ca-K, part inverted + pseudo-colour:

If you really want to go to 82 degrees at this length, I can recommend the Nagler 31T5, which is probably my most-used wide-field EP in my Celestron C8. It is also astounding in my Meade SN-6 6" F/5 Schmidt Newton. Very bulky, very heavy, but really good.