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physicus

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Everything posted by physicus

  1. Despite the murk, 46P was actually naked eye (with a hint of averted vision) tonight. Here it is headed into Taurus: brightest close star is t Tau. I'll be out on 16th for the close pass to the Pleiades.
  2. I periodically have a go at imaging this bright spot in the broader Merope reflection nebula in the Pleiades. This is 13 x 30s C9.25 w reducer / Atik460/ AZEQ6. Accidentally binned 2x2 - although that's probably all the seeing was worth. Laplacian sharpening in Nebulosity (software). Sure NASA/HST are grateful I've verified the main structural features their effort picked out. Tim
  3. From the Malvern Ridge near Black Hill this morning. These are with 100-400L on Canon 7D. Had no luck closer in with the camera attached to an ETX90 tube. Too low / distorted for any Jupiter detail, but can just make out a couple of satellites here.
  4. Quite pleased with this for only 40 mins luminance and given it's so tiny (5' x 3' or so). A bit of structure in dust lane. Structure-wise I've seen worse from C14 and 16" instruments; must have had a spot of seeing. C9.25 w. reducer / Atik 460 / AZEQ6 8 x 300s. Incidentally, almost exactly two years the AZEQ6 has been outside continuously in all weathers with only a John Lewis bag (and later a Green Witch cover) to protect it; bit of rust on the chrome screws, otherwise no probs ! Tim
  5. Thanks. Bit nerve-wracking setting up for it. You don't get a second go!
  6. Just as a post-script to this, I did today decide to return the scope to the dealer, who after I'd shared the wisdom of this forum (and some photos from Etsy / Ebay showing the same item sometimes even available made new to order !!) returned my hard-earned. So another educated dealer. I don't think anyone was acting in bad faith here, and I've learnt a lot about the scientific instrument reproduction and/or fake business.
  7. Okay. With Philj's and Cosmic Geoff's help, and further research, I've convinced myself it's a repro. So thank you guys. Disappointing from the romantic historical associations point of view, but polished up (which I can now shamelessly do!) it will make a nice piece of interior decor in the garden room :-) Interesting though how many apparently reputable (and accredited in some cases) antique dealers are pushing these as original. There's one out there without a doubt exactly the same as this, but polished up with new leather at a ticket price over £1200. I found one auction house listing it's exact twin (no leather etc), but owning up to it being a reproduction. Problem now will be if I get the bug for the real thing!
  8. I also wondered if these were made with rolled and soldered tubes - for which I think B&C were famous; I certainly have a drawtube made that way from Fullerscopes using the old B&C kit. Or were they extruded from bored/cast/machined tube? No obvious solder seams on this example.
  9. Thanks for the comments guys. Yes, I guess it could well be a repro; for £75 though I'm happy to keep as a decorative piece. Anything substantive I'd normally research to the n'th degree before purchase. Of course I'll have to now research this one to double-death just for the sake of knowing !! One thing I'm pretty sure of, there are a few of these out there that look exactly the same. The weight of this one btw is 1.1 kg. I wonder how that compares with your similar example philj? Also, the fit of the tubes is very good - perhaps too good? I'll let you know what I come up with after a bit more Googling.
  10. Okay, so it's not an astronomical telescope as such, but it could be pointed at the sky, and it is the only telescope I have that actually...telescopes! I picked this up today in a local antique shop for less than the price of a NB filter, and it's just nice to hold such an iconic and well-made collection of brass tubing and glass. Made by the illustrious Broadhurst & Clarkson company (later bought up by Dudley Fuller in the 1970s) at Farringdon Road, some of these had stitched leather cladding - missing from this if ever present - and existed as a military variant as part of a WWII snipers spotting kit. This one lacks the MOD designation/over-stamping , so is likely free of grim associations. Optics seem pretty good just pointing it out the window at the birds; not had a chance on the stars yet. It's about 11 inch collapsed, 32 extended, about a 2" objective. B&C also made a range of astro telescopes, and I bought my first 6" reflector from the London store in 1976; soa bit of nostalgia too :-)
  11. It's difficult to get a sense of scale in this astronomy game; but we try. So here are 8 pics of the ISS passing between Vega and Epsilon Lyra last night - which is a second's worth of my Canon 7D firing off as fast as it can. The background is a single 30 second tracked exposure for a bit of context. Details: Esprit 100 prime focus/Canon 7D:1/1000s ISO1600 +30s background. The trick if you want to try this is to use planetarium software to find out exactly when the ISS will be near a bright object, then pre-align and focus on or near that object, then wait for the ISS to appear in the finder before letting the shutter go in rapid mode. I also optimised pre-focus on the computer using the focus feature on Nebulosity before switching the camera back to stand alone mode.
  12. Today is really the day for this comet, with Owl Nebula and M108 coming into view, but the forecast looked dicey last night, so I thought I'd bag it. An Atik 16200 would be nice about now, but this with the Canon 7D will have to do for now. (Esprit100/AZEQ6/Canon &D. 90s x 14). Suspect I may just get the three objects in frame tonight (if it clears) - may be close thing. Tim
  13. It's quite a special object at any focal length. I've tried with my Esprit 100, but the SCT is about right if the seeing plays nice. This image is very much seeing limited; those central stars would sharpen up in the right conditions.
  14. Not posted for a bit, but I did recently capture some half way respectable OIII data for the Crab, which I've here combined with some Ha/S/Lum data from last year - some of it reprocessed. This is with the C9.25 with reducer and Atik 460, which I think gives a nice image scale for this object if you want to see the pulsar properly and a bit of structure (but don't bother at this scale without an off-axis-guider). Colourful Ha(red)/S(green)/O(blue) palette :-). (About 12 hours all in) Tim
  15. Thanks Chris. Waiting for a bit of transparency to get the luminance. I have a couple of hours, but it's poor. Re the purple tinge - quite likely! I rushed this to press without agonizing over the processing for a few hours like I normally do. A long calm re-process may well balance things up and bring out more detail and colour differences. While the rig is set up like this I think I will try for more data, skies allowing. My green was noisy as hell (even more than usual), so that channel was well softened/noised. Surprisingly little processing otherwise - all Nebulosity + PS. Btw, apologies for not catching up. Will be in touch. Cheers Tim.
  16. As supernova remnants go, the Crab Nebula seems to get all the attention. So here for a change is Cassiopeia A. Unfortunately, while it may be the brightest radio source in the sky outside the solar system, there's precious little in the visible. And it's small too. This is about 3 to 4 hours worth of RGB in 300s subs, with the C9.25 at f10 / AZEQ6/ Celestron OAG w ZWO ASI120MM / Atik 460 binned 2x2. I hardly ever use the scope at f10, but it was set up and calibrated for a crack at Einstein's Cross (clearly feeling optimistic these days), but the seeing wasn't up to that. The Hubble version of Cas A looks like a Christmas ornament of course, and while I haven't got the same sparkle, there is a bit of structure visible. I got a couple of hours of Luminance on an earlier occasion, but it's low quality and only damages the image - so RGB it is. Tim
  17. Hi John, Thanks for your comments. I've looked at a few other folks' plots and it looks like angular size of the planet may well be the main factor re resolution. And yes, this is without a slit. I've been messing with pencil sharpener blades etc, but guiding is the issue. Commercial options, while relatively expensive, aren't completely out of the question, but I usually like to have a go myself first. Latest brainwave is to build an angled slit from polished blades and catch the reflection in suitably modifed Celestron OAG (reversed). Meantime, I think I will check out the moon as you suggest :-) Regards Tim
  18. I'm working my way through the 'classic' low-res spectroscopy targets with my newly acquired SA200. So nothing ground-breaking here to be sure, but here are my spectra for Uranus and Neptune. I switched to the Esprit 100 (from the C9.25 SCT, see earlier post). I'm still using a 25mm collimator eyepiece with a 50mm 1.4 Olympus Zuiko imaging lens, so 1100mm fl after magnification factor. The CH4 lines are obvious for both planets, but the higher resolution on the Neptune chart struck me. Wanton Googling of literature on outer planet spectra suggests I could be seeing several lines for Neptune not resolved for Uranus (if there). The spectra were captured one after the other (Uranus 11.45 to 12:00, Neptune 12:00 on). Neptune had more subs: 10x120s vs 7 x 120s, and Neptune was higher (30 degrees vs. 25 degrees). Neptune presents at 2.4", Uranus at 3.7" . Processing was Nebulosity (stacking), Gimp (minor straightening), and BASS Project. Just wondered why the Uranus curve is smoother? Is it the size of the source/altitude/other/act of god/who knows. In other news I'm generally playing around with various optical configurations and figuring out how/whether/why to move to higher res. slit spectroscopy - and all that entails.
  19. I had a crack at WR140 and P-Cygni last night, also Altair (below). Those carbon 'beads' in WR140 really jump off the screen! The fully collimated set-up to your design is working nicely now (w 25mm eyepiece+50mm zuiko camera lens, so some mag.) and I've reduced the scope to f6.3. I'll do the maths for this arrangement, but it's giving a good image scale with hardly any vignetting on the 460. As I'm now collimated, is it fair to say the first order star image should be at the same focus as the rest of the image plane? It certainly looks that way on my raw images, and I can anticipate with dimmer targets it would be useful to focus (minimise FWHM) on that rather than the dispersed region. Pleased with having what seems a quite capable collimated spectroscope for a hundred quid. Tim
  20. Thanks Robin; I'll check those next outing. Spooky you suggest WR140; I was just this afternoon reading about it in Richard Walker's 'Atlas'. Tim
  21. For good order, here's the above data with instrument responsivity corrected and continuum removed. Indeed, Balmer lines better defined, and a few other suspects appearing.
  22. Thanks Robin, I started out intending to use the SA200 in a collimated configuration with an eyepiece and spare Zuiko 50mm, per one of your own rigs; but on the night my junk box lacked the critical mass to quite make that happen with the right distances/geometry. Also tried barlow collimation and got severe coma at edge of field. I'll work it out though. Regards Tim
  23. I've been into deep-sky astrophotography for a couple of years now, but am only now putting my toe in the spectroscopy pond. And for a week's worth of learning I'm happy enough with this spectrum. The rig is a C9.25 at f10 with the SA200 mounted in the nose-piece of my Atik460. Processing was in Nebulosity (stacking), GIMP (for rotation) and the BASS Project software for charting/calibration. My workflow through that lot was a bit of a mess, but the fastest way to get a result without learning BASS inside out; which may be where things end up. I chose the SA200 over the SA100 as, looking through Robin Leadbetter's material, there seem to be more possibilities down the line re collimation/imaging configurations. The main thing that struck me at this stage was the ambiguity in focusing on the spectrum. After assisted FWHM on point sources, this was a bit of a challenge. Lots more to do, but I can feel the bug biting...
  24. Last night I added 2hrs OIII to 2hrs Ha from last November = bi-colour Pacman. My processing was a little different on this one (I have a slightly irrational aversion to any noise reduction). But this way both channels pre-processed separately with curve stretch + star reduction (morphological) + GREYCstoration (all in Nebulosity), then aligned and synthesised in usual R=Ha, G=OIII, B=OIII way. And I can almost live with the slightly mottled smoothness. Probably change my mind again by the time the Sulphur arrives :-). Esprit 100/Atik460/AZEQ6/Baader filters
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