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Alkaid

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Everything posted by Alkaid

  1. I like this one. It's got a real atmospheric feeling.
  2. What an astonishing, mesmerising image. The detail is incredible! I am also a 'craterlet' fan, in the 8" and with poor UK seeing I can locate craterlet A quite easily and sometimes craterlet B with a little more patience. C & D can be challenging from my location unless the seeing is very good. Many of us observe / image during waxing phase. I am thinking of changing tactics and observing during waning phase, this would mean an early morning from here but the seeing may be better at that time. Did you image this during waxing or waning phase? Thanks Steve
  3. Yes, a dew heater strip around the corrector will sort that. The same happened to me with my SCT.
  4. Wasn't a smart choice for start-out / intermediate imaging an ED80 + HEQ5? That's where I would be, something like ED72, ED80 or new ED82...on a HEQ5.
  5. Definitely dew spots. Found on most refractors, they will not impede the views. I have found that bringing a cold / dewy scope back into a warm habitable room will instantly result in severe moisture problems. I now bring my scope to a 'halfway house' - I previously used a cold cellar, and after moving home we have an unheated porch which is just as good. Then when scope has acclimatised to that, I will eventually bring it back into a warm room, caps off. I once brought a new refractor straight in to a warm family room (after about 3hrs of sub-zero use) and left the caps on. Next day I found a HORRRENDOUS amount of dried dew spots, in the end I had to gently clean them off using baader wonder fluid. (Not a decision taken lightly either, I refuse to touch lenses unless absolutely necessary).
  6. This image is fantastic. I notice from your image (1st one in particular) that the north and south polar caps seem to 'extend' almost right around the planets limb. I also saw this visually in my scope and didn't understand what I was seeing, I put it down to some glare / dew / frost on the scopes corrector plate. But your image shows that it wasn't the scope or conditions, that the 'cold spots' of Mars do seem to extend right around the limb. I have no idea why this is! if anyone knows, be glad to hear. Thanks for the great image - Steve
  7. Great image! I could visually see both dark areas on the disk last night, but without the clarity.
  8. It’s so cold I’ve had to come in for a cup of tea. Back out in 20 min...
  9. Ganymede is visible against the disk right now. A dark, husky point slowly crossing the globe. GRS also nicely visible and will be central around 9pm UK. Steve
  10. I'll try and be a bit nicer 😀 As a general thing, I've had mine for 5 years and still like it. It's a great little scope.
  11. I have an ST102. At low power x20, it's a very nice image visually on starfields, with minimal CA. Anything above that power and it's very colourful! On the moon, even at low power the CA is present. You can use it as a spotter by removing the central cap, this turns it into a 50mm F10 scope, the CA disappears even at higher powers and the 50mm aperture doesn't matter as it's daylight, the view is still bright. It's a nice skysweeper however, as long as the limitations are understood.
  12. Same here. Seeing in Leeds was actually good(!) and my C8 was giving me some pretty darn good views. Detail seen in North Eq Belts, plus strong detail of cloud structures of the 2 or 3 faint belts between the NEB and SEB. GRS vividly on show. Just great.
  13. I think I got lucky with my C8, it was a bargain price 2nd hand (bought about 5 years back) and the seller who seemed to know his stuff said that the optics were in his opinion rather good for an SCT. I took that with a pinch of salt, but when using the scope for the first time and many times after that, I agreed with him. Some good hard views, although I do wish for more contrast on Jupiter. GRS and some other reasonably good detail is not a problem however. Contrast and sharpness on Lunar is good. It's my main telescope. I want to re-iterate that I was lucky with mine...most SCT's do deliver softer views / less contrast than the other designs. If I was in the market and didn't want to play the lottery, it would be an APO Frac or Mak on the cards as I do a lot of Lunar observing. It just so happens that my SCT hasn't really done anything wrong, so I won't be getting rid of it...
  14. GOTO mounts can be appealing at first, but my experience is that they take time and care to set up and often the targets are not centred after a slew. Sometimes they are outside of the view, but close. I don't think they are worth the hassle. The 8" scope will deliver far better views (brighter and more detailed resolution), is quick and easy to use, does not need power, will not cause annoyance due to not pointing correctly, plus it will be easy to sell on when you're done with it. You can even get a tracking platform (although these can add a bit of cost) for tracking at high power, or if you decide to get a beefy enough mount like an HEQ5 or EQ6 (not cheap, but future proof) you could even mount the tube on that and have the tracking and GOTO functions. Encoders as previously mentioned are also good for push-to. Get the 8", trust me.
  15. For planets, the image scale of the 10" F5 dob vs a 4" F11 refractor is about the same. 1270mm focal length as opposed to 1100mm focal length. Not much in it, so comparing the same eyepiece between the two scopes would result in a planetary image of about the same size. You should however get more detail with the dob due to it's distinct aperture difference. The refractor will show less detail overall, but it shows what it can with more contrast, so it appears sharper in many cases, even if it's not actually delivering as much visual information. Due to living in a city, my targets are only the Moon & Planets. From my experience, you need 4 main things for planets: Large aperture for detail. Long focal length for image scale. A very stable atmosphere (rare in the UK). A cooled telescope - make sure that the scope is cooled to outside ambient temp. Any one of these four not conforming can cause the view to be 'off'. Add to that the quality of the optics (mirror quality and collimation of mirrors, lenses, eyepieces, diagonals with fracs) and you soon learn that planetary observation has quite a lot of elements to it, whereby if any one of these is poor, so will be your viewing. But don't be put off. Once in a while it all comes together and the views can be very good.
  16. I have an st102. Does low power star fields extremely well. It’s a sky-surfer this one, the larger objects such as M31 and M45 are good at x20, especially from a dark site. Moon is awash with CA, don’t let anyone fool you into believing it’s a general purpose scope...cos it’s just not geared for solar system use and I daresay that the figure of the lens, while acceptable at low power, does not cut the mustard at higher powers. (Being F5 doesn’t help either). I find about x50 to be the max with mine. If you fancied something general purpose then the Apo’s are the way to go.
  17. I can answer your question having owned both. Moon: The 90mm achromat I found to be sharper on the Moon than a 150mm F5. Although the 150 F5 would naturally reveal more, this was offset by the view being slightly softer. (Yes, it was collimated). However, I have also owned a 150mm F8. This was a different league and was equally as sharp to the frac, plus much more detail. It wins hands down and I regret selling it. Planets: The 90mm is not wonderful, it just lacks the brightness at higher powers. The 150 F5 is much brighter, and more detail can be teased out. The 150 F8 is same brightness as F5, but sharper and reveals much more. Deep Sky: The 90mm is not wonderful, although I have attained many of the Messier objects form a dark site when camping. The 150 F5 is much better due to light grasp. The 150 F8 is roughly the same as the F5, with slightly tighter stars.
  18. Just slightly out of focus. A good way to ensure focus is to have camera in manual mode, focus by hand on the lens. But to achieve crisp focus, use the zoom in button for the screen. This magnifies the focus error, then you adjust till crisp. Then zoom back out and take the shot. Cheers Steve
  19. Interesting! Most shots of the moon through an ED80 reveal no false colour. The ED doublets only 'work' if they are in focus. It looks like your pic is slightly out of focus, that's probably where the CA is coming from. Also...eyepieces can induce their own CA. Next time, (if you can), try attaching a bodied camera to the scope (no eyepiece). You should see a difference in the images then. Cheers Steve
  20. Really nice Paul. That 102ED seems to be pulling it's weight. Is it one of you goto scopes for Luna?
  21. That’s brilliant John. Great capture!
  22. Looking at your shed pic, the tube is separate to the base for ease of lugging out? If you got the 12” couldn’t you store the tube on the base to make a smaller footprint? Just needs a think about the sequence of “lugging”.....tube off, gently put to one side on the slabs...base out.....tube back on... Could that work?
  23. Both my scopes dewed up by 8.30pm. Same for me too.
  24. Very good, I can see them in your image. Thanks Paul.
  25. Very nice report Nik, good reading. I must have a go at these domes.
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