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parallaxerr

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Everything posted by parallaxerr

  1. Is this one Alan? http://ensoptical.co.uk/celestron-12.5mm-ultima-plossl?sort=p.price&order=DESC
  2. Don't you just love it when the forecast promises clear skies, only to change at the last minute...

    1. Alan White

      Alan White

      Yep, a regular feature in my life. Plan all day for an Astro night and find you have a spare evening on your hands.

  3. Hi Mark, the AZ4 is absolutely fine for low to medium power stuff, it makes a nice combo with the 120 for DSO work. It's only above about X150 where the damping time takes a bit too long, so I'm considering an EQ5 head or equivalent to go on my pier extension for planetary work, but there's no rush given that they're all hiding at the moment!
  4. I had a rather pleasant observing session this evening. My mount has been setup and strapped down in the garden for a good week or so now, but the presence of the full Moon, high winds and some cloudier nights prevented me from going out. Tonight though I was presented with clear, steady skies and the Moon is late to rise, so I put the new Omni XLT 120 out to cool after dinner. Went out to observe about 9.45pm with poorly adjusted eyes so started off just focusing in on a few bright stars at low power. I used the opportunity to try out some of my filters to see what effect they had on controlling the (minimal) CA in the achro. After a bit of to and fro, I decided to stack the Baader semi-apo and a #8 light yellow and to my surprise found they nearly completely eliminated CA, even at X200 mag on Vega with only a very slight yellow cast. So slight I believe because the un-filtered views through this scope are particularly cool. After 10 minutes or so visiting Arcturus & Vega I could start to feel my eyes adapting and seeing fainter stars and by about 10.30pm I was surprised at just how much I could see with the naked eye. I was expecting a bit of a wash out given Stellariums estimation of my atmosphere & LP. As I cruised around the Eastern extremity of my observable skies at X50 using a humble 20mm plossl, I stumbled in to the glob M92. I was not expecting to pick out anything faint this evening but it really popped into view. I decided to try the Great Cluster in Hercules just next door and was rewarded with a very nice view indeed. Changing to the 9mm LER yielding X110, I could resolve individual stars albeit very faint, seemingly quite deep into the core. This is the resolution I missed in the 4" scope and tonights view very much reminded me of the view through my C8 a few years ago. Seeing as I was in the neighbourhood, I panned across to Lyra to pick out the double double. Very clean split at X200. To finish off I located the Ring Nebula with the 20mm, then with a UHC filter pushed the mag up to X110 again. I was rewarded with a very nice contrasty view with subtle hints of what looked like a twist in the ring. Given that I was in two minds tonight, that was most enjoyable!
  5. TADA.. they say a picture paints a thousand words! It's a mobile phone holder so I can use stellarium to pull up alt-az cords and find the fuzzies using the az ring and a wixey angle finder
  6. Yes, that's right. It's a ground anchor, cant remember what the original use for it was but it's about 12" long. It's been there for about 18 months now, never budges.
  7. Agreed. I found if I tap the pillar there was next to no vibration, but tapping the scope there was. This suggests the flex is in the mount head itself and the pillar and tripod are sturdy enough.
  8. I should have mentioned the weight. The Omni with Crayford and finder weighs in at 6kg. Do you know what your ED120 weighs John?
  9. I have, for a long time, restricted myself to the use of a Sky-Watcher AZ4 mount and for good reason. There’s no two ways about it, I like refractors. I’ve had quite a few over the last few years and the pick of the bunch was a lovely Sky-watcher Equinox 120ED. I picked the Equinox up at a bargain price and very much regret letting go of it, but it wasn’t getting the use it deserved. The mounting requirements were significant and to enable the scope to perform at its best I mounted it on a Giro Ercole atop a 16” steel pier extension and a CG5 2” stainless steel tripod. Having spent a lot of money arriving at this setup, I stopped using it. Why? Size & weight. The whole mount assembly was very heavy. Combined with the required journey through the house to get to the garden (resulting in many door frame dings), followed by the many steps to set it up on the top level of our tiered garden, it just became too cumbersome and I stopped bothering. Shortly after selling that setup I discovered the AZ4 and it was a bit of a revelation for me. With a bit of tuning I found I have a great Alt-Az mount with smooth motion that handled a 4” scope with ease. One of the features I particularly like is the fact that the scope rotates around the Az axis, whereas with Giro style mounts the scope is mounted out on an arm and the throw and motion of the scope at the eyepiece end felt a little un-natural to me. For a while I used a 102mm ED with the AZ4 which was a perfect match, but that scope didn’t really float my boat. Then I picked up an 80mm F11 Vixen achro which is a great performer, but of course all the while I’ve been suffering aperture fever knowing what a 120mm scope can pull in from my location. So, I started researching how the AZ4 would handle a 120mm refractor, I read many posts and spoke directly via PM with several other owners. There were mixed opinions that ranged from “unusable” to “rock-solid” but of course there are variables such as the tripod used, the weight and focal length of the scope etc. I am confident that my AZ4, again mounted on top of a steel pier but this time on a 1.75” steel legged tripod is as sturdy as an AZ4 can get. This mount weighs considerably less than the Giro and 2” legged version and is far easier to handle. When I found a batch of new Celestron Omni XLT120 F8.3 achros for sale, I pulled the trigger. First impressions of the scope on the mount were that it looked perfectly acceptable and everything balanced up nicely. The Axes remained smooth in operation giving me some confidence that it would all be OK. First light came at the end of last week. The forecast was not great with gusty winds and scattered cloud, but I setup anyway. The moon presented itself in the perfect pre-dusk position, nice and high just past the meridian and at approximately 50% phase. The lighting was near perfect for observing one of my favourite lunar features – the Apennine Mountains and the Apollo 15 landing site at Mons Hadley. I decided I’d have a bash at Hadley Rille and set about testing the scopes performance at a range of magnifications right down to my shortest 5mm EP, yielding a mag of X200. The scope held up VERY well, far better than I had imagined it would. I noted that the view was particularly cool, compared to me previous ED scopes. CA was present of course, but only really became distracting at the higher mags. I tried the Baader semi-apo filter but didn’t really get on with it this time, instead opting for a #8 light yellow filter which suppressed the CA more than satisfactorily and only gave a very light cast to the image. The shadows of the Apennine Mountains were a deep dark black with fantastic resolution. The 5mm LER eyepiece presented a very sharp image which I was pleased about considering the image starting breaking down in my 80mm scope with this EP, obviously a function of the scopes aperture. In fact, so sharp was the image I pushed further using the 9mm LER barlowed to approximately 4.5mm yielding X222 and Hadley Rille was there in all its glory. Clearly defined at its Southern end with the Northern end a little harder to define, but it came and went with the seeing. The resolution of the image with this 120mm glass was notably superior to the 80mm. When reasonable darkness set in I slewed the scope around to the East, away from bright moon and inserted the 32mm plossl, this time un-filtered. I scanned around waiting for my eye to adjust after the bright moon, taking in the very sharp pinpoint stars displaying no discernible CA at this low mag. I decided to carry out a star test and with my limited horizons, Arcturus presented itself well. The star test was all that I had hoped for. Very nice concentric rings inside of focus and slightly softer outside of focus suggesting slight under-correction. I am aware though that the spread of colour due to being an achro can cause the softness so would need a green filter to test properly. Most importantly though, the lens cell is collimated well so I know at least it’s performing at its best and I am more than happy with the result. So far so good then. Very happy with the scope but how did the AZ4 perform? I would say that the 120mm F8 frac has the AZ4 at its limit for high mag work. There was some wobble when the wind picked up, however I would not normally observe in such winds. Pre-empting vibration during focusing, I had already fitted the scope with a Sky-Watcher dual speed Crayford focuser which worked very well. The light touch required to focus with the fine knob did not impart excessive vibration, it was a level I can certainly live with. The limitation comes when manually tracking while observing. The 55° FoV of my short FL EP’s results in lots of manual correction at high mag with the associated vibration. A wider apparent FoV EP would be better suited here, or a tracking mount. Placing the target in the upper right of the FoV and allowing it to drift was the best option, allowing enough dwell time to make out fine detail, though at X222 the target moves fast! My desire for more aperture though comes from improving DSO observations, and for this, at lower magnifications this setup will be AOK. With a 25mm EP giving me close to my known preferred exit pupil, vibration is not an issue and I’m really looking forward to seeing what can be pulled in come the Autumn when the skies darken and more interesting objects come in to my view. I am particularly looking forward to viewing the Veil Nebula considering the success I had with the 4” ED using an Astronomk OIII filter. All in all, a positive first test of the scope and how the mount handles it. Hopefully I’ve put a bit more meat on the bones on the subject of how the AZ4 handles a 120mm refractor and this will help someone considering a similar setup to make an informed decision. If you give the AZ4 a solid foundation it can work well, depending on the type of observation you want to do. My setup is very sturdy and any residual vibration comes from the mount head itself as opposed to the tripod, I think I’d be inclined to agree that this wouldn’t work on the aluminium legged version! Cheers, Jon
  10. I've laid this idea to rest now, t's an unknown scope and too expensive to take a risk on. I think it would have been a good fit for the AZ4, but as you say Mike, given it's short focal length it may not have been the best all-rounder anyway.
  11. See, I knew the "Tak pack" were friendly really
  12. Bringing the thread back down to earth with a bump, sorry, here's my latest frac. I always liked the look of the Omni XLT120 but it was never available as an OTA alone in the UK (at least that I could find). It's out of production now so I was surprised to find a batch of them for sale by Altair Astro recently, apparently they had the last "old new" stock from Celestron UK who finally broke out the mounts and OTAs to sell separately. Not a bad deal really at £199 versus the £269 of the equivalent Skywatcher Evostar and the Celestron has a collimatable cell to boot. I immediately adorned it with a Skywatcher Crayford focuser (which is a far better, more snug fit than the standard R&P), Altair finder shoe which went straight on with the supplied screws and red dot finder. It comes in just over twice the weight of my 80mm Vixen @ 6kg, so time will tell if the AZ4 will cope. There are so many mixed opinions on this, I decided I just had to try myself.
  13. BOO, DHL fail 🙁

  14. Here's hoping DHL are on form tomorrow, new glass and goodies inbound. Just in time for the rain!

  15. Hi, actually no it didn't sell, so still available
  16. Looking for a 6mm LER EP from Altair Astro to complete my set. Currently unavailable new, cash waiting.
  17. I'm considering a wedge at the moment to use with my Vixen A80MF. I use that scope on an AZ4 and it's perfect weight and length wise. Being F11.4 it also has a very well corrected objective, SA is very well controlled. There's one of these for sale at ENS optical, but even better there's a skywatcher version for sale on ABS for £50 listed as Skywatcher 80/910 (wish I'd seen it before buying mine, new). May be worth a punt for a comparison. Of course, it wont offer any more resolution than your current scope but does offer a very well corrected lens and CA is a non issue with a continuum filter. It copes with X200 on the moon very well.
  18. Despite currently trying not to make any more astro purchases, I always enjoy a little window shopping. My "theoretical" search for the biggest, all purpose refractor to mount on my AZ4 (considering what I know works with respect to physical size, weight and focal length) has bought me to this ED doublet from Omegon... https://www.omegon.eu/telescopes/omegon-apochromatic-refractor-pro-apo-ap-110-660-ed-carbon-ota/p,55229 I can find nothing in the way of reviews though, apart from one Amazon review that says it's good, but no further detail. There has been talk of it on CN and it was apparently incorrectly identified as an Orion EON110 clone which received mixed reviews due to varying amounts of CA. This scope however is listed as having FPL53 glass over the FPL51 of the Orion and that's where the conversation ends. So, what's the chances that anyone here has one, or has looked through one? I find it very appealing knowing how well I liked my ST120, but this of course has the ED glass and is a bit slower. It's also fairly light thanks to the Carbon OTA but it's a lot of money to take a chance on! I'm not overly concerned with small amounts of colour, but I'd be interested to know how it performs in other areas such as SA considering it's still reasonably fast at F6. Is it the full 110mm clear aperture etc? This would be strictly for visual use, I must add.
  19. Imaging certainly will be, but it will badly affect visual observation too. I don't know if it's the coronavirus pollution dip, but I've never seen so many satellites as tonight, notwithstanding the Starlinks. I felt giddy looking up at one point, trying to find a reference star and everything was in motion
  20. Re: the "criticism" section of this article. At least the IAU have objected the plans, but clearly it has fallen of deaf ears and lip service is being payed to reducing the impact on astronomers.
  21. It's only going to get worse. Makes me sad....
  22. For a moment, when I first noticed them, I was considering PM'ing you John to confirm I wasn't going mad as you're the closest astronomer I know of observing similar horizons to my own!
  23. This lot is showing up in Stellarium EDIT: I don't think these are the Starlink satellites. They are still showing in the same place in Stellarium, so must be geo-stationary but co-incidentally aligned with the Starlink trains trajectory. Goes to show how many are up there.
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