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Whirlwind

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About Whirlwind

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    Star Forming

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    Leicester
  1. Oculus Dewing Up Inside - Help!

    You'd just get dew on the outside then though, so you've swapped one problem for another. The plastic will radiate heat to the sky faster than conduction from the atmosphere transfers heat to it. The plastic then cools quicker than the surrounding air, resulting in 'warmer' moist air impacting on the surface cooling and the moisture will drop out. It won't work unless you live in a dry environment which the UK definitely is not!
  2. Oculus Dewing Up Inside - Help!

    It's more that the air inside is still warmer than the dome. Dew will form when the warm moist air impacts on the cold plastic. Is the unit is not sealed are you sure that the dew isn't forming on the camera lens as well? The dew heater then has to heat the plastic until it exceeds that of the internal air (at the same time whilst cooling to the outside) so it is likely to take some time. You could perhaps speed things along by taking off the dome, give it five minutes and then replace it. That should let all the hot air be replaced with ambient air which should then not form dew quite so easily once the dew heater is on. Really you'd want the dome to release the warm air, but I guess there is no fan on the unit? Alternatively some dessicant inside the unit might help dry out the interior.
  3. Really the only two that are significantly larger but then don't necessarily require larger filters (though for some 383 setups is preferable) are the 383 and the Kodak KAI04022 chip (like the Atik 4000) which by area is 95% of the size of the 383 but because it is square generally can use 1.25" filters (assuming the filter wheel isn't miles away). The disadvantage is that it is more blue sensitive and less red (so worse for Halpha) compared to the 383 IIRC but which is partly made up for by larger pixels. It is also generally deemed a noisier camera (though I have never directly compared) and generally a bit more expensive than the 383. However not having to pay for new filters would offset that (especially if you can find one second hand).
  4. Please Help Me Upgrade My Mount...

    There's also Astrophysics mounts to consider. I have the Mach1GTO and has never given me any issues. Though the exchange rate isn't as polite these days compared to when I got mine. They also have the absolute encoder and without versions for the 1100 (but is definitely £'s) but should keep you going for a fair while. More middle range mounts to consider might be the Vixen's; they are also a lot more portable (apart from the Atlux) but weight capacity is less.
  5. Which APO refractor

    Congratulations (and ever so slightly jealous...) Keeping to the original post how about the new FSQ130? Not quite as good light grasp as the TOA150 but ideal for imaging. Depends on where the priorities are. However if it is sooooo much money it really is ridiculous you could widen your plans a bit. For example you could get a large Dobsonian (such an Obsession for visual observing, with suitable observatory) and then look at a remote link location for imaging (for example IC Astronomy and pay them to deal with all the set up issues) and really mount up a decent imaging set up - For example I'd go for something like an ASA DDM with a modified equatorial pier (no pier flip) and whatever imaging platform you prefer (I'd probably eye up a small RIFAST with a large CCD). That's all assuming you are going to stay in this country and deal with more cloudy nights than clear ones!
  6. Whilst on holiday chasing an eclipse I also got chance to stay near to Crater Lake and took the opportunity to take a milky way image in the early night of 19th August. At the Cloudcap overlook you are at 2400m above sea level and with hardly any light pollution the visual vista of the milky way was stunning. There was a bit of drifting smoke from state forest fires but at this height we were mostly above it. This is an image using a Canon 650D and 18-200mm lens (at 18mm) using ISO 800 and F4.5. It was all mounted on a Star Adventurer Mini (that was roughly polar aligned). The image is a stack of 20 x 60s, 1 x 120s, 1 x 90s. Aligned and combined in pixinsight with a histogram adjustment slightly tweed using the HDRmultiscaletransform tool. However otherwise processing was a breeze (I can only wish for an observatory at some point with similar conditions!). Astrobin location below:- http://www.astrobin.com/309623/?nc=all
  7. Total Eclipse Images

    Here are my humble attempts at my first total solar eclipse on 21st August 2017. Images were taken using a Canon 650D using a sigma 135-400mm lens (at 300mm) on a Star Adventurer Mini (SAM) tracking mount. Stupidly after taking night sky images at crater lake I left the camera using ISO800 so any inner corona detail has been lost (but the outer details have been captured). This probably wasn't helped by the high cloud that moved in about an hour before the eclipse. The mounting was a bit light for the lens (particularly the tripod and the ball head, rather than the SAM). The observing location was the John Day Fossil Beds in Oregon. It was busy but not the madness that was seen at Madras. Still it was an amazing spectacle and well worth the effort. The first image is a combined image of the corona from 3 separate images of different exposures and the second is a more artistic shot of the diamond ring. Thanks
  8. Adaptive (active) Optics

    Yeah that's what I was thinking. The advantage of the RASA is that it is 11" and the brightness of stars is simply based on aperture (as they are point sources). I was also trying to limit myself to the equipment you already have. Yes a large longer focal instrument would be better to allow more accurate monitoring of seeing but it doesn't appear you have one of those. Hence I was thinking of the ATIK4120EX on the RASA and TRIUS SX-36 (with AO) on the TEC. The only issue I can see with the RASA is if there is mirror movement as that would mess up the AO. If there is movement really you'd want a large fixed mirror system (such as a large aperture Newtonian or RC).
  9. Adaptive (active) Optics

    Yeah that's fine. As you have DDM you shouldn't really be correcting for guiding anyway. Hence you are just trying to correct for seeing. The difference is that you are using a separate telescope to measure the seeing rather than the OAG which has a limited field (and hence reduces the chance of finding a bright star to monitor at 5 to 10Hz. The only issue with the RASA might be if it doesn't have a fixed primary as that might move when the imaging scope does not. As such the RASA gives a wide deep field of stars to choose from. The seeing adjustments arise from the RASA camera (that would have otherwise been on the OAG). If pointed in the same general direction should be about the same but you get a better S/N from a brighter star/larger telescope. Hence the you can determine the seeing issues from the RASA and that feeds into making adjustments to the AO on the imaging telescope. In some ways it is similar to the professional AO except they use laser guide stars in the upper atmosphere as they then have an ideal comparison 'star'.
  10. Adaptive (active) Optics

    I thought only the SBIG version mentioned seeing? Perhaps in the most idealised scenario where you have a large telescope with small pixels it may make a difference assuming you can find a bright enough star that allows you to monitor a star every 1/5 - 1/10 sec or so. These circumstances are rare at best. It also depends on the pixel scale you use as at larger scales you are unlikely to see much difference anyway. I still see it is a 'light' way of managing guiding rather than solving seeing. It probably doesn't help with using an oag as that limits your field of view. In hindsight and thinking about it again if you used the RASA as the 'guide scope' pointing at the same region; a fast downloading sensitive ccd could feed the information from that to the AO system attached to adjust the main imaging scope view might work but would need some experimentation. Really you just want to minimise the seeing issues so La Palma sounds like a good idea (up the mountain anyway) - at sea level you will still have the same issues.
  11. Adaptive (active) Optics

    I think you have the incorrect understanding of what these AO systems are for. They are not there to correct for atmospheric turbulence! They are there to correct for short term, 'jumpy' guiding errors. If you are using an ASA DDM then I'm fairly certain you aren't going to see any benefit at all (and might just make things worse). It might be effective for controlling any jumpy tracking in the ioptron (I used one successfully on with Vixen SXD, although I also had some software issues, but they were limited to MaximDL, it worked fine using Astroart). If you want to beat atmospheric turbulence the best thing you can do is build you observatory at a high altitude as possible because the true AO systems are currently outside of the realms of the amateur
  12. I think the issue with the C8 Edge is whether you use the reducer or not. With the reducer the in place you may not have enough back focus (105mm in total) depending on the imaging train - I see you are using a QSI wsg and they are about as compact as you can get (IIRC correctly about 50mm from chip to flange). I have only found one focuser that attempts to resolve this partially which is moonlite CHL (http://focuser.com/products.php) as the reducer fits into the focuser partially.
  13. Cure my hankering for a 4022

    You can still get decent NB images with the 4022 CCD. For example http://www.astrobin.com/141614/ (4.25hours integration) They are effectively the same CCD as KAI11002 (with smaller pixels) or KAI16070 (with the same size pixels) but just a smaller CCD. With the larger pixels over the 8300 you compensate for lower sensitivity, but I don't think you can go wrong with either one.
  14. OAG how difficult to setup?

    I had one that came with a AO unit SX sells about 10 years ago, so my experience might no longer be relevant. However I did not like the design at all. With a relatively fast system it was a bit of a pain to get it to focus because there simply was no fine control. You had to slide it up and down relatively roughly and then try and hold it in position whilst you tightened the set screws. I could never get it to be focused brilliantly when I pointed at stars. It nearly put me off OAGs altogether. However I then went the OAG route with the QSI camera and that was a completely different ball game. You could focus the guider with a rotation mechanism and then the only part with a set screw was the part that allowed you to rotate the guide camera back into position. Compared to the SX version it worked exceedingly well with the fast system and then after that it held focus completely.
  15. why cant I do flats?

    If it is damage to the CCD then it may be responding differently at different flux levels. Hence you could be overcorrecting/undercorrecting any structure.
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