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catburglar

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Everything posted by catburglar

  1. The 432 does look interesting for long focal lengths. When I look at the 294 or 183 based cameras binned to 9mm pixels they seem to have much higher read noise than the 432, so would need much longer exposures to reach any given ‘shot noise swamp factor’. This may be one area where a 3 or 4x binned CCD is a better option than a similarly binned CMOS camera because the CCD maintains the same read noise when binned but the CMOS scales read noise with bin factor.
  2. This is true- up to a point but, things in the corners of the FoV won’t appear in all of the images captured over a long period of time. It’s more apparent the longer the acquisition period. Conversely I guess it’s a little less apparent on a 3:2 aspect ratio sensor like the 178 than a 16:9 format that most of the small planetary camera cmos options seem to be adopting.
  3. @Vinnyvent84 If I were you I’d stick with your C6 for a while until you know whether you’re hooked or not…and if you do get hooked which direction you want to go…there are numerous ‘sub hobbies’ within this hobby - visual observing of planets and double stars vs deep sky, imaging of planets or deep sky and observation of variable stars to name a few. They will each have different optimum equipment configurations, so I think it makes sense to learn the ropes, find out what interests you and take it from there. The 6SE with starsense is a great combination-I had the same a couple of years back. I changed it t for a bigger scope which shows fainter things and has a bit more sharpness on the best of nights, but most nights the views are not massively different. The limiting factor right now will almost certainly be your own ability to critically observe things that your telescope shows you and to be able to tease out details that with experience will come to be obvious. In my view whatever scope you have you’ll spend a lot of time looking for things ‘at the limit’- close double stars, finest planetary details or faintest galaxy or nebula. There are thousands of things in the sky to see and challenge you- so get ready for the challenge, clear skies will come (sometime).
  4. Another vote for the TG365 covers. My entire setup (Meade LX200GPS) apart from the hand controller has been outside for two years…I wipe it down after an observing sessions to get rid of the worst of the condensation before putting the cover on. In winter I’ll uncover it a couple of times to ‘let it breathe’ but it’s almost always completely dry. A spray of WD40 on the electrical contacts every now and then plus a bit of a buff with some turtle wax on the OTA keeps it fairly sparkly.
  5. I downloaded HOPS from the Exoclock project and processed my images again. There are some helpful features in this application compared to AIJ- identifying a FoV that's in all of the images, alignment of frames that accounts for both rotation and translation, showing trends for PSF and background sky brightness prior so as to remove poor quality frames from the stack and also suggestion of suitable comparison stars based on flux compared to target. There are also some bits that I don't quite understand, so I'll need to do some more research. At this point- I'm not sure how to assess the quality of my data. The HOPS manual state lower values for stdev and autocorrelation are better, but I don't know if there's a threshold that's simply not good enough to be useful, but at least it feels like I'm in the ballpark...
  6. Thanks for that link- I missed it completely. I didn't think to look for a specific exoplanet section, I went straight to variable stars. First rule of observation- keep your eyes open!
  7. @lunator I did look at the BAA/VSS web pages - but the AAVSO pages seemed a bit more coherent with links / guides that went from start to finish. I’d hope to go back to the BAA (I like to keep it local 🙂 ) and contribute something meaningful when I’ve got a bit better. At this point I’m just seeing if I can get to a useful level of precision without needing major upgrades to my equipment. I started with exoplanets because they sound exotic…However, it seems like similar techniques apply to study of CV’s of which there there are also lots of fairly bright targets that can show clear results from a single session…whenever the weather cooperates. To me this seems like an almost ‘instantly rewarding’ observational activity, much more so than monitoring many other variable star types- I might get hooked.
  8. Last night (Friday 1st December) I decided to try and repurpose my EAA set up for a spot of exoplanet transit photometry. In many ways my set up is not really optimised for this sort of work- it's an alt-az mounted SCT with F3.3 reducer (reduced to approx 1000mm FL) with a whopping 0.32x0.18 degree FoV provided by an uncooled ASI290mm camera. Searching here (https://astro.swarthmore.edu/transits/transits.cgi) for potential targets gave lots of candidates for me to go at...I probably didn't make the best choice in retrospect. The target star was fairly dim (mag 13.7V) and it's track took it to approx 80 deg elevation at meridian crossing exacerbating the problems of field rotation with my alt-az mount...But the skies were forecast to be clear all evening and the target should at least be visible and not blocked by local obstructions for the entirety of the circa 4 hour observation session. So what's to lose? I did my usual set up- one star align from a parked position and then platesolve/sync the mount position, check focus etc and found the field easily- cross referencing with the AAVSO chart plotted for the same region hoping to find some suitable comparison stars. Given the limited FoV and the problems of field rotation, making sure the comp stars would remain in the images throughout the session was a bit too difficult for me to work out, so in the end I just took a punt on final framing. In the end it didn't matter so much because the tracking was a bit flakey and the images moved all over the place- I had to do a few platesolve / recenter cycles throughout the session. Before getting going with the "science images" I did a couple of trial exposures- I'd need to keep them short because of the rotation, but still needed to get a decent SNR- I was hoping to discern variation of approx 1.5%. Since there were no stars with similar magnitude labelled on the AAVSO chart I decided to hedge my bets and use low gain to maximise my dynamic range and avoid saturating any pixels if I did need to use some stars much brighter than HAT-P-53. I ended up using 5 seconds at 110 (unity) gain. I set up sharpcap to capture the images- made sure things were working ok at the scope end, and then came in from the cold...hoping it would do it's stuff for about 4 hours...I kept an eye on things remotely- recentreing periodically as required. I lost a lot of data in the second half of the transit due to the arrival of clouds, but luckily they cleared before the start of egress, so I was still able to get something useful. I processed the resulting images (bias, darks and flats) using astroimagej based on the guide from the AAVSO website and here's the result... The data is noisy, I binned to 3min "frames" in AIJ as a compromise- trying to maintain good temporal resolution. The fit to my data gives a transit duration of 2h46m36s- virtually identical to the values I find in the catalogues and the radius of the transiting planet is 1.27 Rjup, versus 1.318 from the pros. So...in short...I'm chuffed 🙂 ... I'll definitely try this again- I might put my scope on a wedge and apply some PEC training so that I have fewer problems keeping the target and comps on the CMOS chip... And I might find something a bit brighter to go at too...maybe mag13.7 was a bit too much of a stretch first time out... The good news is that there are loads of targets many which aren't too faint and because the periods are short transits happen every couple of days so it fits in with the vagaries of British weather...This could become addictive.
  9. My first night of EEVA for some time. Took a bit of fettling to get the reducer/camera/collimation sorted after my recent round of planetary observing with the SCT... By the time 'd got everything working again, the skies were becoming hazy in the west and south, so I had to pick a target towards North- Arp 25 (aka NGC 2276) in Cepheus is an almost face on spiral that looks to have been distorted by an interaction with a near neighbour. The prominent star forming regions in the spiral arms also point to an interaction with a neighbouring galaxy. Wikipedia suggests that the interacting galaxy is the prominent elliptical galaxy NGC 2300 (aka Arp 114) at the 8 o'clock position in the screen capture. This seems unlikely to me given the different redshifts found in SIMBAD. Using a Ho value of 70.8 km/s/Mpc gives distance of 110Mly for Arp 25 and circa 88Mly for Arp 114. Arp 25 is also home to 8 ultraluminous x-ray sources- one of them being an intermediate mass (50,000 solar mass) black hole according to a study with the Chandra observatory. Apparently this is thought to be captured from a previous collision with a dwarf galaxy.
  10. The hand controller for my 10inch LX200 has developed a fault - the direction buttons don't move the scope (although the motors still work when I start the alignment process). It may still work with a computer control to move it, but I was considering switching it to an EQ mount anyway, so this might be as good a time as any. I'm mostly visual/EEVA and liked the convenience of AltAz mounting, but I had a disappointing experience with an AZ-EQ 5GT (with a smaller scope)- there was too much play in the AZ motion so I was never really happy with it, so don't really want to try my luck with the AZEQ6... What's the sensible option- EQ6R? It's rated by the manufacturer to 20kg...I haven't weighed the OTA, but I read that they're about 14-15kg. I like the look (stiffness more than tracking accuracy) of the harmonic mounts, but I guess I don't really need the portability and the smaller ones are rated to 13-15kg so I think the scope may be pushing it a bit. Ioptron also have CEM and GEM mounts in the 40-45lb weight class, but they seem a lot more expensive and I'm not sure they add much over the EQ6-R.
  11. You’ll need usb cables for your cameras as well as the mount - but if you can manage with 4 or fewer then something like @teoria_del_big_bang suggested could work.
  12. I’m not a dedicated imager, although I dabbled a few years ago. I think I’m with @ollypenrice on this. If you already own a DSLR, or want to use it for daytime photography or want a light/mobile/star tracker type platform then DSLR may be the best option. But, in your earlier post you suggested that you didn’t want to fall into the “buy cheap/buy twice” trap- and I suspect buying a DSLR would be that trap. There’s lots of technical stuff in astrophotography irrespective of which camera you use. Finding your way around a dedicated astrocamera is unlikely to be the most difficult bit😜.
  13. Good spot… I’ll edit my original post to correct it.
  14. The Stellalyra looks like the better package to me- dual speed focuser and 9x50 right angled/correct image finder add more value to the package than the tube rings/bearings and solar filter add to the Bresser offering. Also the Stellalyra is a little cheaper (than the Bresser (£449 vs £470 on the FLO website at least)…Optically as others have said I’d expect them to perform similarly - so the SL would definitely get my vote.
  15. I think in your position I’d be sorely tempted to cut my losses and change the scope….But…. I suspect after taking a deep breath to think objectively that would probably be the wrong thing to do… It sounds like you’ve fixed the focuser…and an hour or two with Ed Reid is probably going to fix the lens…the bit between these two components doesn’t have a lot that can go wrong- so future troubles down the line seem unlikely. As it stands now, your scope probably has relatively little resale value to many potential purchasers (although someone may fancy the challenge) so you’d sell at a loss. If Ed does fix it and you’re still disenchanted with the scope then you’d at least be able to sell it in in good shape and likely recoup a bit more if your investment. In the unlikely event that the lens can’t be fettled into good shape then the money spent on Ed would have been wasted…but that seems a pretty unlikely outcome to me.
  16. Just come in from a great session. Mediocre seeing when I started at about 18:30 with clouds coming and going. Things improved a lot after a couple of hours with wall to wall clear skies and some of the best seeing this year😁. Spent most of the time on Mars with my 10inch SCT - the best views at 357x with a 7mm ortho and #21 orange filter to reduce the brightness and increase contrast. Watched for a couple of hours as Syrtis Major rotated into prime view. Took a detour to Uranus which showed an obvious disk and blue/gray colouring at the same magnification (without the orange filter). And finally- a scan over Luna- picked up 4 prominent craterlets in Plato, and 3 more in the moments of best seeing- A, B, C, D, e, g & h according to this annotated image…https://www.cloudynights.com/topic/34841-guide-to-plato-craterlets/
  17. I’m not sure about the reducer your proposing or the means of attaching it in your imaging train. The reducer is designed for refractors around F6 natively- your mak is F12. The 585 chip is a pretty small in comparison to APS-C so you may be OK with it. But- the reducer has got a 2inch nosepiece (and it looks like an internal M48/filer thread on the scope side). The mak typically has a 1 1/4 inch visual back…So you may need to get something to convert your mak thread to SCT thread like this: https://www.firstlightoptics.com/adapters/astro-essentials-mak-to-sct-adapter.html and then something to convert the SCT thread to M48 like this: https://www.firstlightoptics.com/adapters/astro-essentials-low-profile-sct-2-to-m48-adapter.html But I’d agree with @bomberbaz- best to check all of this with FLO…
  18. Like @Peter Drew said- I'd expect the moonlight to unscrew leaving a standard SCT thread. You could mount a normal SCT visual back or a 2 inch diagonal with an SCT fitting on the scope side. The LX200's often shipped with the Meade #1209 Zero Image Shift microfocuser that can be controlled through the autostar handset. I'm not sure if this is the "original" setup you're looking for. You need an adapter ring that converts the SCT thread to a circular groove- the microfocuser has three small allen screws that lock into the groove to secure the focuser to the OTA. It's part of the microfocuser package usually I think. I don't know if the same model of focuser fits all LX200's or if the older "LX200 classic" had a different model. I've seen the Meade #1209 microfocuser come up for sale used on UKABS occasionally and there's one listed on the ENS website now...I haven't looked at that one in detail, and I have no connection with the seller so you'd need to check that the adapter is included because I expect they'll be difficult to source if not.
  19. Had a great night last night with my 90mm ETX (deforked) on a Neewer fluid head. Setup at about 5pm for the scope to cool and then at about 5:45 homed in on Jupiter ready for the Ganymede transit. All 4 moons were visible as tiny discs surrounded by a faint first diffraction ring with a 7mm ortho for approx 180x. Jupiter was clear and detailed for most of the time rather than fleeting glimpses of clarity that come and go with the seeing. I was nipping in and out whilst cooking and caught the first contact- it was a memorable sight with Ganymede just touching the limb. I was able to follow the moon over the limb and across the disk of Jupiter as a slightly darker but pin sharp spot- which is something I’d not managed to see before this. I followed the transit almost to third contact but Jupiter dipped behind some trees so I missed egress. Whilst the seeing was so steady, I took a few detours during the transit - to pi Aquila which split with two slightly uneven airy disks just touching and a shared diffraction ring, Rigel - split fairly easily but not a ‘nice view’ because it was still pretty low down in the murk, Saturn - as for Rigel- not a great view, couldn’t see Casini division or any banding on the planet, and finally Mars- with definite dark but indiatinct surface markings in both the north and south hemispheres, a small north polar cap and some brightening towards the limb- not sure if these were Martian clouds or an effect of local seeing - because although it was at a decent altitude, the line of sight was over some adjacent houses - so the seeing was not quite as good as to my south. I’m always impressed by the quality of the view in the little mak- I’d been observing Jupiter and Mars the previous night with my 10inch SCT and the views hadn’t been as pleasing… I don’t know if the seeing was so much better than the previous night or if the bigger scope was having problems tracking the falling temps (scope handset said -10 Celsius at the end of the session), but I’m planning a side by side session tonight to see how the views compare. I’m hoping to get some really sharp views of Mars with the big scope at some point during this opposition…but not been lucky enough yet.
  20. I don’t think it’s going to be possible to track without doing some sort of alignment if you’re using the scope in alt-az configuration because the motor speed will vary depending on which direction the scope is pointing. Once you’ve aligned it then it can calculate the speed at which to drive the motors. How do you know it’s not tracking? You might not be able to see or hear the scope moving whilst it’s tracking unless you’re actually looking through the eyepiece to see the star is movin (or not) in the FoV. On my LX200 (and on several Autostar equipped ETX’s that I’ve used) tracking begins automatically as soon as the alignment is completed. Check the tracking rate is set correctly on the handset- go to the Setup menu, scroll down to tracking and select sidereal.
  21. 2 years on and still nobody’s had a go at it, so I hope I’m OK. From a distance it probably looks like a chiminea or patio heater under a cover- so not too exciting for a prospective thief. If they did want to steal it they’d need to bring a selection of allen keys and spanners to unbolt it from the pier, and a trolly to ease transport ‘cos it weighs about 60lb, so not too easy to make a dash with… In short, it’s probably easier to nick the car off my drive than to remove the telescope…🤞
  22. My LX200GPS has been outside under a Telegizmos 365 cover for a couple of years with no ill effects and minimal ‘maintenance’…I wipe it down after a dew laden session before putting the cover back on, I take the cover off on sunny winter days to give it a bit of an airing every now and then, and I spray the sockets on the control panel with WD40 a couple of times a year…
  23. I had my first session in ages last night- finally got to see Mars at decent altitude and in decent seeing. Weather forecasts have been next to useless recently- forecasting full on clouds and then finding out when it’s too late to bother setting up that it’s clear or forecasting clear and then seeing wall to wall cloud… I hear the skies are usually clear in Arizona?
  24. You’ll definitely need to move the scope using the handset…if you loosen the clutches and move it by hand the scope won’t know where it’s pointing and therefore tracking is likely to be poor (I guess depending on how far you’ve moved it from the position it thinks it’s in). If you’re not going to bother to centre the alignment stars (and if all you want is the tracking feature there may not be much value in getting a precise alignment) you may as well do a one star align. If your initial home positioning is reasonably accurate that might be good enough- you can always nudge the scope with the handset controls whilst it’s tracking to re-centre if the target drifts…
  25. I’m with @scotty38- keep it somewhere nice and warm for a couple of days and see how it is then. If there’s no improvement I’d take it to a professional rather than have a go myself…
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