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jefrs

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Everything posted by jefrs

  1. Ah but which "Photoshop"? The are several flavours. So far, even with tracking, I am finding that using an actual camera is producing far less noise and a sharper image than stacking. Perhaps I am doing something wrong with the stacking but I do find a modern camera's dark frame and noise reduction to be significantly better than Photoshop Elements or Lightroom, or for that matter processing the raw with Adobe Camera Raw 8.5 - Photoshop can "do more" but it seems to be designed for family holiday snaps. Focus is important, it has to be spot on and a modern camera will/should have focus confirmation or highlighting to assist, which is more reliable than my old Mk.1 eyeball Fyi dumping a good long lens on the GH4 on EQ tracking allows me to pinpoint autofocus nicely on Jupiter, which is just plain silly. The Lumix 100-300 gives me 300mm at f/5.6 (gets stopped down to sharpen image, f/6.3-f/8) which on M43 is a "600mm" field of view i.e. not far short of the 130SLT's 650mm f/5 I seriously need to learn more about stacking and processing astro shots.
  2. I/we have the 130SLT which I think is almost the same tube, there may be differences in the focuser: the 130SLT has both 1.1/4 and 2-in focuser parts; this may mean this model has deeper travel focus range, there are differences between models/years. It also comes with the 1.1/4 T2 adaptor. I use micro four thirds cameras (aka CSC or DSLM). The ones I have with remote cable release are the G5 and the GH4. These are mirrorless which places the sensor some 15mm closer to the lens mount than a DSLR. The drawback is that with the lens off the sensor is open to the sky; I have had to clean the sensor after using it on the scope. With a DLSR there is a mirror/shutter concealing the sensor and protecting it from the elements. Consequently I like to use a Barlow to enclose the sensor access. A plain or clear UV filter would function just as well . I can achieve prime focus using the short nose and lens mount adaptor but not with the longer Celestron 1.1/4 T2 adaptor (as shown above). The lens mount adaptors can be obtained in various lengths to adjust the back focus e.g. ask Zoltan at 365astronomy. The normal long adaptor is for fitting "legacy" lenses onto the camera at the position they should be if the camera had a mirror box, approx 35mm from sensor. Some adaptors have a 2cm tube which can be taken out; a short M43/T2 adaptor. Different length lens mount adaptor should be available for DSLR but you have less wiggle room than does a mirrorless system camera.. Getting the camera to prime focus is something of a matter of guesswork. I have before now resorted to screwing the lens adaptor straight on to the focuser as it also has a T2 thread with its eyepiece collar unscrewed. The magnification should vary with the distances between secondary to Barlow lens and Barlow to sensor; these can be fiddled with. I can almost image the entire disc of the moon on the x2 Barlow alone. If I fit an eyepiece as well then I have to juggle extension tubes as the back focus has altered again; only the short 9mm will fit inside the adaptors without screwing tubes together Heath-Robinson fashion, and then finding I cannot get a focus point But like I said, I do not like having the delicate sensor exposed. A digital camera with its state of the art sensor is much more sophisticated than a CCTV or webcam and far more expensive.
  3. My laser alignment tool arrived yesterday and it shocked me as to how far the collimation was out on our 130SLT. Fiddly little job done but images are so much sharper now. I only got to test it in daylight because last night we got big heavy clouds blotting out everything. Daylight however was tack sharp whereas it had been washed out with halos.
  4. I've seen more drums bags than I care for. Most of them are oversize hat boxes. Pretty sure those won't work. The long one for the stands looks something like a cricket kit holdall, it's not all that big because stands break down small, likewise mic stands: they all have to fit in the back of a family car these days.
  5. 29/01/2015 - 30/01/2015 New toy day - laser alignment tool. I thought the 130SLT was working pretty well until I checked the collimation: way out. There should be a warning that your new scope will be off focus until a laser alignment tool is used and the collimation corrected. So that done I got the scope outside only to have the batteries die. Then I found that my 12V PSU is the wrong polarity. So I got the NiMH fast-charged, and of course the skies clouded over 8/8 with some heavy stuff from the west for the rest of the foreseeable.
  6. jefrs

    Hi from new bloke

    Welcome Steve. We have not had many fine nights since Christmas but if the clouds break there is the moon and Jupiter is nice and bright and easy to find left of Orion up from Sirius Have fun, Jeff.
  7. The T5i is perhaps better known as the 700D which may help when looking for accessories. Once hooked up it should offer better pics than a CCD but may lack functionality e.g. stacking. It should connect to 2-in or 1.1/4-in by a screw-on adaptor tube or by a nose but you may want to use a Barlow in front which probably means 1.1/4-in fittings. The adaptor may screw straight on to the focuser tube. I prefer to have a Barlow on there since it keeps the sensor sealed up and kept clean. The Amazon T-ring shown is EOS to T2 (T-thread) which is a 42mm metric thread (not the Praktica M42 lens mount) This adaptor should screw straight on to a Barlow T-adaptor but you may need an extension tube depending on back focus and whether you can or want to fit an eyepiece inside.
  8. I cured the rust problem by putting an oil-filled electric radiator in my workshop (not the dilapidated shed). It doesn't do much heating but enough to keep dampness at bay and rust off my good tools. If you're getting rust on the screws then your mirrors might be getting foxed.
  9. Yes. Pretty much all stock condition cameras have Bayer. A few models have unusual configuration but amount to the same. Quite a few camera models are getting rid of their anti-aliasing filter (for Moire) to increase sensitivity.
  10. I have myself seen cheap Li-ION batteries (and others) explode in the lab under test, and I do mean sparks, flames, shrapnel, flying debris and loud scary bang; instrument under test catastrophically destroyed too. Cheap batteries or worse knock-offs can and do get very hot in use. Hence I try to only use the hideously expensive OEM batteries which last a lot longer charge and barely get warm. The AC adaptors I've got have rather dodgy looking wall-wart PSUs and no earth lead. Now if you can touch any exposed metal part of mains operated equipment then it should be earthed. This is not only for safety but can also reduce electrical noise on the system. I know one can argue that the PSU are low voltage but they are so cheaply made that I can envisage a fault dumping live mains onto your scope's ironmongery: your RCD should cut off; always use an RCD breaker on this kind of stuff. A simple mains spike filter and conditioner may also be beneficial in reducing noise too; mains is noisy so if it gets near sensitive instruments it can and will introduce noise (Murphy's Law): batteries are electrically the quietest.
  11. The Plough's pointers (Ursa Major) are the olde skool method of finding Polaris but Cassiopeia's lopsided "W" is usually brighter, it is further away than The Plough. Being lopsided it should be easy to check it it is right way up or base over apex in the scope. Charts and planispheres usually "what you see" with naked eye, we invert them on the fly. Patrick Moore and Pete Lawrence "The 21st Century Astronomer" ISBN978-1-78177-125-9 is well worth a read anyway and has a nice set of charts in the back and a big pull-out sky map
  12. Possibly worth having a trawl through Flickr's Infrared Photography Group's forum because they regularly perform major open-sensor surgery on cameras. Pretty much the same tech as here. https://www.flickr.com/groups/infraredphotography/
  13. Could be. I find I have to wipe dry the camera lens fairly often My biggest concern is the exposed sensor when mounted on "prime", hence I like to screw a Barlow onto the adaptor to keep things sealed tight. Red mist could unlikely be hot pixelation which can happen with long-long exposures but you can easily tell from the picture, it's increased noise. Depends on camera some go reddish and some get a mauve tinge and some don't do it at all. Not at all likely unless all-over even faint tinge showing. What camera are you using and how are you mounting it to the scope? I too suffer gas and have irrational urges to rush out and buy stuff on-line and then find it don't work as expected or I've got two things that do the exact same job different ways. Best to slow down and research from the armchair with a cat.
  14. Seems like a good idea but you do know you can buy cable tidy clips like that for pennies? That does not mean stop making them. Us humans make labour saving tools not because we're clever but because we're bone idle. We used hundreds of cable-tidies, cable-clips, P-clips and even string in the laboratories to keep the plumber's nightmare under control. One of the best was a peel-off sticky-backed plastic square with a zip-tie attached.
  15. Yeah! :- more like 3 tads and Richter 5 and a supernova Btw native ISO on wunderkind Canon 7Dii is 100-12,800 and it has two processors giving it a dynamic range of 12EV, on GH4 it's 200-25,600 and it's got four processors, oh yeah and 13EV plus an effective heat sink on the LMOS (lower noise then CMOS) sensor, noise is low at ISO3200, noise is acceptable as ISO16,000 and still "publishable" at ISO25,600 (if you like grainy). Shooting at ISO10,000 or ISO12,000 is normal for dim indoor shots, no worries. The 16MP is same pixel density as 7Dii and equivalent to a full frame 62Mp. The GH4 is unbelievable, I've yet to find anything it can't do except maybe make coffee. The other M43 we have ain't too shabby neither: we do have access to a FF Nikki D600 which is awesome but cannot shoot in the dark at all. An exposure of 1 second on static tripod with 500mm means slight star trail should'a been less then 1/2 second like you said 500/(500x2) incl drop factor and highlights blown way out at only ISO3200 and the Star Adventurer arrived the next day (birthday pressie to me from her) I think that was the 500/F6.3 but could have been the 800/F8.0 which was on back order (I'm still waiting for the Sky Watcher counter-weight) I'd have to check delivery dates, everything seemed to arrive at once over Christmas. These lenses are tricky to focus due to sensitive focus ring (see earlier post re removing the tube), focus is off by a hair and a brace of rabbits. The 100-300 does an AF to infinity better than the reflex lenses on manual. Seeing was good or exceptional. I have seen the moons before through a scope. I do not know why the one on the right is bright blue? I think it was blue through the 130SLT as well. Shot on 07/01/2015 at 3 o'clock ...
  16. A thought - long exposures are done on the tripod with a remote shutter release. Some remote shutter switches do have a timer built into them. My Panny GH4 goes to 60 second plus B-bulb only in manual mode but there is a Panny remote/timer release (DMW-RSL1), and there are several cheaper similar non-OEM releases. And so there are for Canon too
  17. I had to check acronym RDF in the sticky since the commonest meaning is "Radio Direction Finder" not "Red Dot Finder" but the olde marine and aircraft radio beacon systems are obsolete having been replaced by GPS. - not many people want to know that On wedge scales - The Star Adventurer scale for example is marked in 3° increments (there are 5 marks between 45° and 60°) but it is possible to set it within 0.5° by interpolation, you estimate where the third divisions are and then halfway between that. However the scale is probably not be particularly accurate in the first place; having worked a calibration laboratory for years, I consider it to be "For Indication Only" as labelled on anything not calibrated. We are about 51.5°N here but Polaris got aligned at 54° on the scale. So don't set the scale and expect to find Polaris spot-on. It can be a pain finding Polaris. The southern sky can be crystal clear but the north veiled in cloud. If you have sufficient patience the north may clear and the south will then cloud over.
  18. Thank you for recommending Stellarium. Oooo!!! - Billy$ Windoze 8.1 hates it and protects me from installing it. Fortunately I have Windows 8.1 Pro and can override but I had to "install anyway" and run it as Administrator. Hope that helps anyone arguing with it. Very nice
  19. You just said "all-weather cover", that is so not plastic sheeting, if it is really all-weather; it's not just rain, it's the damp that gets inside. I have a weather-proofed camera. It cost me £1300 quid. I am so not leaving it in the garden shed.
  20. Rule of thumb for maximum exposure time for static tripod is 500 / focal.length (thanks to RichM43 for reminding me) But if I try 1 second with a 500mm on my micro four thirds on a static tripod I get little trails and have to drop to 1/2 second so I think it has to be converted to 35mm film field of view i.e. multiply lens by your crop factor (Canon = x1.6, Nikon, Sony, Fujifilm = x1.5, M43 = x2, etc) hence 500 / 500 = 1 second (500mm lens) but 500 / 1000 = 0.5 second (500mm lens x2 M43 crop factor = 1000mm FoV)
  21. jefrs

    Hello from Newbury

    diolch yn fawr Our dog is from Abergavenny
  22. By Jupiter!This what I'm seeing with the GH4 1 second ISO3200 f/6.3 sooc jpeg
  23. jefrs

    jefrs' album

    astro photos
  24. jefrs

    P1130754

    From the album: jefrs' album

    By Jupiter I think I've got it! with moons too. Panasonic GH4 1 second at ISO3200 sooc jpeg with Samyang reflex 500mm f/6.3 from Newbury England on 07/01/2015 about 03:00 UTC

    © Copyright 2015 Jeff Slade

  25. Thanks. The 130SLT is a steel tube. I mounts to tripod with a long dovetail. I have not noticed any flex but then we have not had it long. However I am part mech/elec engineer and tend to notice stuff and fix it. I am considering options for best engineering solution, I always do that; simple is best. Our M43 camera system(s) are lighter that any DSLR, say 2kg tops. I am concerned that the alt/az motors can cope with the weight on the nose of the tube but it already copes with the 560g GH4 back on the eyepiece. We also have the Sky-Watcher Star Adventurer EQ (I remember these things with a wind-up clockwork mechanism) which I'm using for AP. I can get it thrown together and aligned on Polaris in a just few minutes now despite the sodium street lamp. I needed to fabricate (bodge) a little hood for the finder from a 35mm film can. And tie it to a white find-me string. And find a plastic washer to insulate the battery so I can actually turn it off. One of our cats is a Siamese, I'm pretty sure he can read ... I have a Celestron camera piggyback mount intended for their larger scopes. It is supposed to fit under the finder but would foul the focuser on the 130SLT. It's screw holes are further apart too. I can drill and fit it opposite the eyepiece but the rings can be re-positioned. The rings are a good idea need a camera mounting bar, and all are additional expense: I shall probably drill the tube. Doing that I need to ensure the finder does not foul any lenses not the lenses protrude too far past the tube. I cannot fit my hand down past the mirror and do not want to dismantle that.
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