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Everything posted by Nik271

  1. Very unusual view of Vallis Schroteri right now on the terminator. The mountains cast long shadows over the rille and it looks very different from when the sun is higher. Take a look if you can. This is the simulated view from NASA but imho the real time view from a scope is even better!
  2. Caph (Beta Cas) is the westernmost star of the 'W 'of Cassiopeia and rises high in the sky in autumn and winter. As the full moon approaches I was looking for some double star challenges and with the help of some excellent books I made this list. All of them except the last should be doable in theory with a good scope of 4 inches of aperture or above. I have seen some of them with a 5 inch Mak, of course larger aperture will make it easier. Here is a star chart: 1: Caph itself. It's an optical double with very wide separation, more than 1' (minute!) west, however the primary is 2.3 and the secondary is 12.4. You need good transparency if you have small aperture. Southwest of Caph are two 6-th magnitide stars, and they are both challenging doubles: STF 3057 and STF 3062 2: STF 3057 (mag 6.7 and 9.3 separattion 3.9'') has a dim secondary which makes it a challenge. 3: STF 3062 (mag 6.4 and 7.3 separation 1.5'') is a close double, on the limits of a 4inch aperture. This is a physical double with a period of 106 years. the pair is sarting to close again and by 2050 will be only .5'' apart 4: Sigma Cas (mag 5 and 7.2, separation 3''). Again the challenge for this one is the dim secondary. 5: 6 Cas (mag 5.6 and 8, separation 1.5'') This one is the most challenging I've seen myself from this list. It's both close and with magnitude difference, reminds me of Zeta Herc. I used a 7 inch Mak for the split. 6: 9 Cas (mag 5.9 and 12.6, separation 82'') This one is very similar to Caph. Optical double of course. Every list has to have one impossible/improbable challenge so here it is. Not for the 4 inch aperture, more likley for a 20 incher on top of a mountain and the observer with the eyes of an eagle. 7: Bu 1224 (mag 6.7 and 13.7 separation 3.5''). One of Burnham's discoveries. Never seen it myself. I had a look last night, no chance. Clear skies! Nik
  3. Yes, it's pretty close to the maximal elongation, which is at the end of October I think. Because it's far away from the Sun you can also find and look at it in the afternoon even before sunset. Binoculars show it easily.
  4. The planets are low in the sky this year and the atmosphere rarely allows magnification much higher than x100. I assume you have the 102mm Startravel. If it came with the erect image diagonal my advice is to get an ordinary mirror diagonal as the errcting prism does not work very well with small bright objects like Jupiter. You could get a 6mm eyepiece which you can then barlow for x166 magnification but the scope will be at its limits.
  5. I just came back from a good session with my Skymax 180. The seeing was decent and managed to push the magnification to x220 on Jupiter. Ganymede is obvious as a sharp dark disc slowly moving along the equator. Many bands on Jupter are visible. Now fog is rising again and I decided to pack up. My best seeing in autumn and winter seems to be just before the fog arrives
  6. Well done on M33 an M110! I'm always thrilled to see them myself, becuase it happens very rarely in perfect conditions. M1 is much easier compared to M33, especially a bit later in the year.
  7. Sadly the mist has now covered all of the sky, Jupiter is surrounded by a glowing halo. First I lost sight ot Io, then Ganymede and Callisto vanished. Well, it was a good view while it lasted. Tomorrow's forecast seems a bit more promising.
  8. I'm enjoying excellent seeing on the gas giants at the moment. I only have the small Mak set up but it gives plenty of detail, can use x200 on Jupiter and x250 on Saturn. Waiting for the emergence of Europa from Jupiter's shadow around 9:30pm, just a bit worried the fog from the river may close in. Fingers crossed.
  9. Skymax 127 with WL solar filter, Canon 250D. Best 20% of 5000 frames stacked and sharpened.
  10. 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.
  11. 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.
  12. 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.
  13. 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.
  14. 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!
  15. 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.
  16. 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!
  17. 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.
  18. 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...
  19. 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
  20. 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.
  21. That will be fun to watch! Now if only those white fluffy things in the sky stay away....
  22. 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.
  23. 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.
  24. 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.
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