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NigeB

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About NigeB

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    Star Forming

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    http://www2.le.ac.uk/departments/physics/people/nigelbannister

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    Male
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    Rutland, UK
  1. NigeB

    M33

    Hello Everyone, Thanks for your positive comments! Kirkster, yes, I agree, I think there's more in there. I decided to back of a little bit - a lot of my images have suffered from processing noise, so I'm adopting a more cautious approach. But @wimvb provided some nice approaches to correcting this which I'm going to try. Olly, I agree, it's definitely green-heavy. I've tried a little SCNR noise reduction and some manual adjustments, but I've so far succeeded only in making the colours look even less natural... One of the reasons I've held off adding in the H-alpha is that I found it exacerbated the issue (I've read that taking OIII and adding that into the Green channel can help that). I'll have a go at re-processing to see if I can improve things. Thanks Nigel
  2. NigeB

    M33

    Evening All, I've been sitting on a set of M33 subs I took last October - finally got around to doing something with them. It's been a bit of a challenge, difficult to do a reasonable background subtraction when there's so much going on, and I've found colour calibration a bit of a problem. This is as close to "natural" as I've managed so far. I took some H-alpha frames, but haven't added them in yet. Exposure details: TOA-150 @ F/11 / Mesu 200 / Atix 460ex 10 minute sub-exposures L:R:G:B 47:15:15:14 Nigel
  3. Wow - that's a great image - your chuffedness is entirely deserved! Is that a cropped image or are you using the full frame? Those are really nice star shapes - that's a pretty large sensor and even so, the stars a nice and round across a really wide field. Nice!
  4. NOW SOLD - Thanks Graham These units were uninstalled from my Mesu 200 mount which has been reconfigured with a Sitech controller. Sale includes: - ServoCat Gen-3 unit - ServoCat hand controller - Argo Navis unit (Version 3.0.1 firmware) - Argo Navis cradle - Argo Navis Software Install + Instructions disk - Long (several metres) serial cable for PC control of ArgoNavis - ServoCat power lead (12V car cigar style plug on the supply side) No other wires, motors or encoders - you'll need to add these. ServoCat drives the encoders in both RA and DEC as well as receiving guiding information. Argo Navis acts as a stand alone controller (no PC needed). Both have been installed on a wide range of telescope mounts, large and small. For ServoCat see: http://www.stellarcat.com/Pages/servocat.html For Argo Navis see: https://www.wildcard-innovations.com.au This is a highly capable system costing upwards of £1200 new, and should be a good deal for someone who wants to add high precision, highly configurable go-to control to almost any kind of mount. The buyer will need some technical capability - it's not "plug and play", and you'll need to add motors, cabling etc - but there is information in the manuals (available online) to help. SOLD.
  5. Hi Tom, I have experience of only one autofocus solution - the Lakeside system which Ian King Imaging is the dealer for. I've fitted these on all my telescopes to date - C14, TOA150, C11 and Altair Wave 80. I find they work very well, including integration into SGP (there's an ASCOM driver). Lakeside provide the motor, mechanical connectors, control unit and mounting bracket - if there's not an off-the-shelf bracket already available for your chosen 'scope, they'll make one - all you do in this case is make a few simple measurements of your telescope focuser geometry, using a diagram which Ian King will provide. Other solutions available etc etc, but I've been very happy with my experience of Lakeside's offering. Regards Nigel
  6. Hi Feilimb I've had a quick look at your image, and you've definitely got some good data in there. I think a major issue is that you've not applied any flat field correction, which makes it much more difficult to process and extract the real signal. I had a quick go in PixInsight, just with a simple Automatic Background Extraction followed by some histogram stretch, and you can see the nebula clearly - but there's a lot of vignetting and other features which would be easily solved with flats. Others more skilled at gradient correction may get better results than I have (and I've not taken any care over balance - just a quick and dirty attempt to show the signal is in there - so it's a bit gaudy!) So my advice would be to keep doing what you're doing, but to make sure flats are part of your routine - they're really important. Regards Nigel
  7. Blinky, I use SGP with a Lakeside focuser and have encountered a range of issues leading to the HFR warning message, most of which I've managed to solve. Seeing variations might be a cause, depending on how long your integrations are and how long your overall autofocus routine is. I used to have SGP set so that the guide-star was re-centered and guiding stabilised in-between each frame; that extended the time taken for the autofocus process, and recently I've just turned off the auto guiding during autofocus, resulting in much quicker AF routines and no issues with resuming tracking. You might avoid issues due to longer timescale variations in seeing by using this approach. Have you checked for any slippage, rotation of the motor etc, that might introduce a slight shift between the position of the focus at the optimum point, and the position which the system returns to at the end of the focus routine? It would be worth comparing the optimum focus settings as a function of time and temperature across several nights. Slippage doesn't have to be large, or noticeable when you look at the hardware during a run. I detected slippage by seeing a systematic shift towards smaller autofocus position settings over the course of several nights, due to a small slip during each AF routine. In my case, each slip in itself wasn't enough to give the HFR error - just a few steps, but clearly there was a small difference between the optimum and achieved focus position at each run of autofocus. Another issue I've occasionally come up against is due to guiding not being settled during integration of the final AF frame (taken at the optimum location). This leads to a slight elongation of the stars, which skews the HFR. Once settled, the HFR agrees with the value at optimum focus, within the tolerance bounds. I don't see any sign of this in the image you posted, but it's worth keeping an eye. There are a few posts on the SGP forum relating to this issue. Just some things to investigate if your issues persist. Nigel
  8. Nice images Wouter. I'm going to spoil the consistency in responses... I agree that the middle one is probably the best in terms of clarity of detail; but aesthetically I prefer the first one; the lower overall brightness level and the contrast appeal to me - perhaps because it's reminiscent of some of the Apollo imagery. The bottom one seems overly processed. Nigel
  9. Update - I managed to get some clear skies and image the same target with the TOA-150 and a x1.5 extender (so it's running at f/11, matching the Edge's focal ratio). Exposure details below. I've spent more time processing than I did with the Edge image ( @wimvb - many thanks for your tip regarding the mottled background control - it worked really well.) I've also found the reason for the really bad flatfield results in the previous attempt - a loose filter wheel adapter ring. I find that in side-by-side comparison, when enlarging the refractor image to match the view given by the 14", the star sizes are similar - so seeing seems to be the limiting factor. Exposure details: Takahashi TOA-150 Refractor Takahashi 1.5 Extender Atik 460ex CCD +EFW2 Filter Wheel & Baader LRGB Filters L: 20 x 1200 sec + 2 x 600 sec R: 10 x 1200 sec G: 10 x 1200 sec B: 7 x 1200 sec (All 1x1 binning). A side-by-side comparison of the Edge 14 and TOA 150 versions, with the TOA image zoomed to match approximately the Edge 14 (full frame) version is also shown below. The point being... nothing in particular, but it reinforces my view that the "softness" often claimed for SCTs is due more to plate scale than intrinsic optics - the central obstruction will have an effect, but this is not what people are seeing when they remark on softness. N.
  10. I'm selling my C11 OTA with some accessories - it sits between the other OTAs I have and isn't getting used. C11 XLT OTA with Fastar-Ready secondary. Used but in nice overall condition. The only point of note is a small indentation on one side of the tube, which I think happened when mounting up a couple of years ago. I've tried to show on the photos but it's really hard to see (no paint damage). Also included are the standard accessories: - 1.25" Celestron Diagonal - Celestron Finder scope - 40mm Celestron Plossl - The original Celestron CG5 (Vixen)-size dovetail Additional items included: - Celestron F6.3 flattener/reducer (Made In Japan version) - Celestron Losmandy-style dovetail - Celestron flexible dew shield (as shown on the photo, some of the Celestron lettering has come off). Price reduced to £970. SOLD Inspection welcome. Sale by cash or bank transfer, buyer collection only.
  11. Well, it's definitely to be avoided of course, but accidents do happen, and there are two features which offer some protection. This is a friction drive mount and there are no clutches. Even when it's tracking, it's possible to move the telescope by hand without releasing anything if you really want to. So conversely, if there's a clash, the system will slip rather than crumple your camera, and that should save major issues. There are encoders on both the motor and the axis in RA and Dec; if the Sitech detects a mismatch between the motor vs axis encoder (I think it's around 10° difference), it stops tracking (there's a message which appears on the on-screen Sitech panel). I've had that happen a few times when I was pushing my luck with meridian flip adjustments, and absolutely no harm done to mount or camera. If the clash is during a slew, then of course, there's a fair amount of momentum in the telescope assembly, and even if the mount stops, the motion can't be halted instantly without something giving - but again the friction drive seems to me to be the one most likely to keep your hardware intact because of the ability to slip if required.
  12. Gorann - definitely worth doing, but I feel the pain! Note that I've tried mounting my TOA150 + C11 together on the Mesu, and it's fine; I found some of the currently available side-by-side mounting plates introduced a bit of flexibility and lengthened damping times noticeably, and there were some issues with cameras clashing with my pillar - the dual mounting plate pushes the OTAs out over the side, so you need to watch out. In the end I found a Casady tandem bar used which is a phenomenal lump makes for a stable setup. So in principle you don't need to have either/or, you can have both your Esprit 150 and C11 (and probably the ED80 as well) up and running together. Good luck!
  13. Thanks Gorann! I think my EdgeHD14 is a similar story - good price so an opportunistic buy, but ultimately I find it hard to convince myself to remove the frac from the mount. But I think it's definitely worth a try. Regarding the soft stars - I think Wim has captured the situation very well in his reply to you. Certainly my experience with side-by-side comparisons between the TOA150 and C11 co-aligned is that the performance of these two designs is much closer than often portrayed in some forums - once you take into account the very high plate scales of the SCT and try to match that with the refractor, things look a lot more equal between a good frac and a well collimated SCT. Not perfectly so - that central obstruction in the SCT does spread the power out around the central maximum more than in the case of a refractor - but as Wim has identified, it's only part of the story. Much is down to simple image scale. I don't regret for one moment the money I spent on the 'frac, but it shows just how good modern SCT's are; in terms of "bang for buck" they're really amazing - even if a little more maintenance intensive to get good results from. Regards Nigel
  14. Hi Wim, Many thanks! Yes, I think seeing is the key limiting factor. The 14" was an itch I had to scratch, and it doesn't disappoint, but previously I've noticed how similar deep sky images from the 'frac and my C11 are. Planetary imaging is a different matter and that may be a good reason for keeping the 14" on the mount, but I've not tried that yet (unlikely to either, unless the trees in the wood opposite suddenly fall down so I can see below about 30° altitude!) I think you probably made the right decision with the MN190 vs the Edge 8... The mechanical compromises with the Celestron do take the "edge" off slightly. Thank you very much for that processing advice - this is really helpful, and I'm going to try re-processing the image adding this technique - I'll re-post when done. Best Regards Nigel
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