Nik271

Skymax 127 with WL solar filter, Canon 250D. Best 20% of 5000 frames stacked and sharpened.

Indeed, Uranus looks a bit like that to me too, and in fact this is where the name 'planetary nebula' comes from. One of the most confusing names in astronomy imo. For a long time Herschel himself believed he had found a comet. I think it took 2 years before he publicly acknowledged that it was a planet, by which stage all his colleagues were in agreement that it was a new planet. Then he wanted to call it George Uranus should get even better to view later in winter when it's higher in early evening.

I observed Pallas last night (6 October). It's 9-th magnitide at the moment so tricky to find manually. It is currently close to Lambda Aqr and from there it's an easy star hop in the finder to the 7-th magnitude HD 216503. Pallas was 10' west of it last night and is moving south for the next few weeks. Pallas is the largest asteroid that we haven't observed close up. Unlike Ceres and Vesta future missions to Pallas will be difficult because it has very large orbital inclination. I guess we'll have to live with blurry views of it from terrestrial telescopes for the near future. In my telescope (127 Mak at x120 magnification) it looked like a star. I was happy just to be able to track it down.

Just came back from a quick viewing session of Venus. Seeing is the usual poor form, the best I can do was magnification of x120. Venus is nearly at 'last quarter' and getting larger, almost 20''. I used a circular polarising filter to darken the sky a little and it reduced the atmospheric dispersion a bit, at least to my eyes. I highly recommend to try viewing Venus in the day, for one thing its higher in the sky than in the evening right now: it's about 15 degrees in altitude at transit about 4pm this week and it's going to get higher and better in the winter. It's easily visible in the finderscope.

My answer is that even though the light receptors in our eyes receive the same number of photon per unit for both scopes, there are 4 times more of them getting this stimulation with the bigger scope and our brain can easier register the object. It probably needs to hit a certain threshold at each light intensity, and once this is reached increasing the size of the image does not matter. PS. Just another thought: this is defintitely connected with how the brain processes the image. If it was detecting the galaxies on a sensor, I believe that both scopes will do equally well in the same given time (except the larger scope will show smaller detail of course). The brain is probably not so efficient as a computer and just needs the bigger image to recognize it from noise and the background.

Agains all odds I managed to get a good view of both shadows at around 9pm. The seeing was ok-ish half of the time, I could only push the magnification to x120 but still very happy with the opportunity. The sky in the south was all looking good at 7pm but then, just as I went out, clouds arrived and started raining. I had packed up and given up, but at 9pm I looked outside and it had cleared again! Thankfully I have a fast 'grab and go' set up (SW Mak 127 on EQ5) and was up and running in 5 minutes. Ganymede's shadow was right in the centre and looking obvious. Callisto's was creeping towards the edge and harder to see in the turbulent air, still 50% of the time was detectable. Then at 9:30 more cloud arrived and eventually it started pouring again. Very glad to see part of the double transit at all!

I like A a little bit more.

I'm pleased to report that I managed to see the Helix nebula yesterday It was a battle of perseverence though and the view was a subtle gray smudge, no detail at all. But still I'm very pleased, my southern horizon is polluted with the city centre lights and the Helix rises just a couple fo degrees over the house roofs when near the meridian. So the view actually beat my low expectations! The UHC filter was essential. Without it I had no chance. I used a 6 inch newtonian and a 27mm EP giving 5.4mm exit pupil and magnification of x28. It may be easier with a slightly more magnification as Kon suggests, just because the large exit pupil also makes the light pollution of the sky worse: without the UHC filter the star background in the EP view was grey instead of black. I had difficulty finding stars in the 6x30 finder in the haze so my star hop started with Jupiter towards Deneb Algedi and continuing all the way beyond until I hit the bright pair 47 and 41 Aqr. After that Upsilon (59) Aqr was spotted eastwards in the finder and I knew that the Helix is one third of the distance between Upsilon and 47. Nothing was visible initially but when I put the UHC filter and tapped the scope I spotted a subtle grey smudge with a 8-th magnitide star north west of it. Sadly there was no sign of the ring hole, but considering the conditions I'm glad I was able to spot it. Thanks, Kon, for suggesting this target! This is one of the most challenging objects I've managed from my backyard.

The Orion nebula is one of the brightest nebulae in the sky, so filters are generally not needed unless you live in a particularly light polluted area. 12 inch Dob in Bortle 3 will give a magnificent view of it, congratulations!

For a Dob or any open tube scope I would take the cap off to let the warm air escape, and in general this will take very little time, while the mirror is well protected inside the tube. For a catadioptics I tend to leave my caps on because the front corrector plate will dew up pretty quickly just sitting outside. The colling of a closed tube scope is largely by radiation and not so much from convection, caps do not affect the speed so much.

Tonight seems to be promising, it will be windy but that's not a problem for large DSO and low magnification, at least it will blow the fog away. I havent used my Newtonian in an year now, I'd better make sure its collimated. To be continued...

Great job! I've never seen the Helix and your account prompts me to try again this season before it goes away for another year. The Helix is at 17 degrees of altinute for me at 11pm, not too hopeless. Luckily I have a UHC filter. The proper tool for this job seem to be a fast widefield Newtonian, I have a Celestron 6 inch F5 Newt sitting somewhat neglected in a cupboard, time to take it out! Nik

In this cooler weather, I expect roof tiles will be near ambient temperature within 1 hour of sunset. Chimneys and flutes venting heat plumes from gas heating in the cold season are also responsible for poor seeing. A C8 should produce better images than these, but only in good seeing. Yesterday (Friday) was ok in Oxford, but nothing special there was quite a lot of wind. At F25 the images look oversampled, try a faster focal ratio for better sampling rate, I recommend something like F15 (x1.5 barlow) or even the native F10 rather than F25. It will give a smaller image but it will be cleaner and easier to focus. Also exposure time of 29ms seems too long to be able to freeze the seeing, aim for under 10ms, this is where the faster focal ratio will come useful, with more light you can get faster shutter speeds and take more images to stack.

That will be fun to watch! Now if only those white fluffy things in the sky stay away....

This was also my experience in Oxford, every now and then there will be a good steady spell with a view of the shadow, and then back to a mushy orange ball. The egress of Io was thankfully clear and fun to watch, it took 5-10 munutes. Just before it was the only time I could spot Io against Jupiter, I guess because of the better contrast against the darkened limb. Shame about the seeing, I think it's the jet wind bringing the new spell of wet and windy weather.

Just came in for a break and a warm drink. Seeing started terrible but slowly improved a bit, can see the NEB and SEB and the tropical zones in moments of stability. Io's shadow is right on the equator, about 1/3 across the disc already. Using modest magnification x150 with Skymax 127 and even that is a struggle, can see Io's shadow only 50% of the time. No sign of Io itself. Will keep looking.

To find it use your lowest magnification ( I guess that would be 650/25= 26). I think it looks best at about x50 mag, that's just my personal opinion.

The Met Office weather forecast for this evening is good for large parts of UK :-). Even better for planetary observers - there is a shadow transit of Io, beginning around 8pm and ending about 10pm, perfect timing when Jupiter is high and there is no need to stay up till late. Io itself will be transiting across Jupiter and emerging around 9:15pm. Also there will be no Moon until 11pm. What could be better

In your Heritage both north and south and east west are reversed. What type of finder are you using? If you have an optical finder you can actually see the bright star of the ET cluster, Phi Cass which is magnitude 5: Find the 5-th and 4-th stars of Cassiopeia, Segin and Ruchbach and move 1/3 step of their distance further beyond Ruchbach. The ET cluster should be within view with your lowest power EP. PS, here is my sketch from Stellarium:

Very nice! Cassiopeia is wonderful area with a widefield scope or binoculars. 'Turn left at Orion' has 2 chapters dedicated to it. The ET (Owl) cluster is my favourite there. M33 would have been too close to the haze/light pollution on the horizon before 9pm and after that the rising Moon will have rendered it invisible. M33 is harder than M110 because it is a lot larger and with low surface brightness. I've seen them both with difficulty from SQM 20 sky but it takes a night of good transparency and no moon.

The front lenses are indeed 80mm in diameter but the light path is clipped somewhere inside probably because of undersized prisms. You can measure your binoculars, (just need a strong flashlight and measuring tape), as follows Focus the binoculars to infinity and set them up on a table or a tripod facing a wall in a dark room. Now flash the light directly into one eyepiece from about 10-15cm away and as close to the optical axis as you can align it and measure the circle of light projected on the wall opposite. You may need a friend to help you while you hold the flashlight, othewise try to fix it on a table or on another tripod and measure the projected circle yourself. Ideally you should get the full diameter of the objective lens, i.e. 80mm. In reality in budget binoculars you will get less, sometimes you may even see a square instead of a circle (due to smaller prisms inside, for example in the popular Olympus 10x50). In Skymaster 20x80 you get a circle of diameter about 72-73mm. The 20x80 Skymasters weigh 2.2 kgs so an average photo tripod can definitely cope with them.

The separation is 11.2'' now (2021) and the maximal separation is in 2023 at 11.33''. Try to have a look in the mornings in October, around 6am when Sirius is at highest elevation.

I regularly use my 20x80 Skymasters with glasses. The eyecups can be foded back and then there is sufficient eye relief to use them with glasses. Just bear in mind that the actual aperture of the Skymasters (the non-pro 20x80 version) is something like 72-73mm, I have measured this myself and the same results have been obtained by many others. So if your Levenhuks have true aperture of 70mm you won't get much improvement in terms of light grasp. Celestron binoculars sometimes arrive out of collimation, again this is well documented. I bought mine from Amazon and they arrived well collimated. In any case be sure to have the option to return them if they are not in perfect order. This may sound off putting but actually I'm very happy with my Skymasters and use them regularly. They show quite a lot of deep sky objects, wonderful for the large nebulas like the Veil and have a good field of view. They are sharp across 80% of the field which is also normal for budget binoculars. The chromatic aberration is well controlled, in the centre of the field even the Moon shows very little purple fringing. Good luck with your search! Nik PS. I recommend to avoid the 25x100 unless you have a permanent mounting set up, they will be much more expensive and very heavy.

Hardware binning helps dramatically with signal to noise ratio but any binning severely reduces the resolution of your sensor. So for example if the image was 500x200 pixels wide to start with on the sensor then after 2x2 binning you will end with an image which is only 250x100 pixels wide. So you will decrease the fine detail visible, but on the plus side the image will be much cleaner, as the new super pixels will collect 4 times more light. The only way to get finer detail in the image is either get a longer focal lenth scope or a barlow, or a sensor with smaller pixels. But there is a price to pay, usually you end up with less light per pixel and need to expose for longer. Actually there is another very popular method: drizzle. This works when your images are moved a little bit by a few pixels (dithering). But others can advise on that as I'm not an expert.

I'm glad that it helped! In the coming days with less moonlight and Neptune getting higher early in the evening I'm convinced that Triton will become more visible with smaller aperture as John has demonstrated.