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buzz

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Everything posted by buzz

  1. Managed to use the X-T1 to successfully record the supermoon eclipse. I used their tethering software to download a sequence of images of a bright star through a focus mask and then controlled it for the lunar exposures.Now the 'wow' part. I was able to read the RAW files directly into PixInsight. It worked out the complex Bayer pattern and correctly generated the image. How cool is that! It took Adobe the best part of a year to convert the RAW files from the Fuji sensor...
  2. I don't recall having any particular difficulty when I removed mine - just checked my original post: "- you don't pull the knobs off! - they are held on by grubs crews. On the WO, (I don't know about the TS) you have to remove a grub screw on the baseplate to reveal a hole. You turn the knob until you see a second grub screw in the shaft of the knob. You completely remove this and the knob will slide off. If you just loosen it, the screw fouls the housing and the knob will not slide off."
  3. Good to know. I still have some old fashioned solder. Maybe some Araldite too might help, in case I have a problem.
  4. I have had problems with both sensors! Both have had banding issues on the bias that would not calibrate out. Both were fixed with firmware updates. It is as much about the implementation, as the chip itself. I have had two different cameras with the Kodak chip, the SXVR H18 and the QSI683. The H18 is now discontinued; practically it had a design flaw that housed the shutter immediately above the sensor. The swiping action of the shutter deposited dust over the sensor and it needed regular cleaning. The QSI houses the shutter externally, and has shutter design that does not contact moving parts. My pair of images were put up to kinda show that the chip is only one step on the path to the final image and lots of things can occur to mess things up. The upper delicate one was with the QSI683 chip, using SGP, PHD2 and PixInsight on a FLT98 scope. I need to check but I think the lower one was with the Sony, the FLT132, but using Maxim for acquisition, guiding and processing. The good thing is that sensor performance is measurable with scientifc method, so subjective comparisons are just the final confirmation. When I get the opportunity, I'll pitch the Fuji vs the Kodak. I just need to remind myself of the process to calculate the parameters.
  5. It is an interesting comparison - but these are both CCD's, used on different equipment, with different exposure lengths etc. The colors pop on one but the data is on luminance, so I am a little confused, especially since the OP is on CCD vs CMOS. We are very used to analyzing the data for well depth, read noise, thermal noise for CCD's. Until one has a proper back to back test with the same imaging workflow, operating temperature etc, it is difficult to draw a conclusion. I had a Trius with the ICX694 Sony chip and replaced it with a QSI683. I admit the Sony was a quieter chip, evidenced by the calibration frames but do not notice it on the final result after calibration. I have a APS-C Fuji X-T1, which I know has good red sensitivity. I have a t-thread adaptor for it and will try and compare it to the similar sized 8300 chip, both on the bench, and in practice (no TEC applied). There are some variables here too, like RAW frame conversion but it should be possible to get a measure of dynamic range and noise. This comparison - by sheer chance of the same galaxy pair was taken with comparable WO refractors, at different times, different processing, one with the 6 Mpixel SX and the other with the 8 Mpixel QSI. It would be interesting to see what others make of this comparison. I know one has dust spots - I used old flat frames, but that is not the point.
  6. Ball bearings and sunlight work well in sunlight for visual adjustment but are too bright for normal CCD cameras, even with a fraction of a second exposure. For CCD use, I have a Maglight LED torch, which I diffuse with a tissue and place at a distance so that it subtends 0.5 degrees (as the sun does). Now here is the fun part - for RCT collimation, you need a central and peripheral stars for star testing the primary and secondary mirror alignments. I bought 9 balls and glued them to a 500-mm square black planter base (from a garden center). (One center ball and the others in a circle.) I place this at 25x the focal length of the RCT and it fills my 8300-based CCD just right for a good view of the balance of aberrations. If you can, take a look at Harold Suiter's book on star testing. It has a lot of useful information. regards Chris Woodhouse
  7. You can use a ball bearing in sunlight too. I have a 1-inch ball on the end of a stick. The effective size is about 1/350th of the ball diameter.
  8. Just an interesting development. Fuji announced a X T1 camera without filtering. It does UV through to IR. If they could improve their tethering software a little....I think I might write to their head office...
  9. I switched to SGP a year ago, at the same time I switched mounts. SGP is a breath of fresh air and although not perfect, it is very capable and fantastic value. The guys are responsive to user input. They implemented features that I suggested in 24 hours! They are closely coupled with the PHD2 guys and the two programs work very well together. The weakest part of the imaging chain is focusing, but there again, if Maxim's had been that good, Focusmax would not have had much following.
  10. Coco The X T1 can be tethered with the HS V5 software (about £80) through USB but the software does not mention it being compatible with the X10. I'm just about to use mine for a holiday with an Astrotrac. I'm going to use tethering software for framing and focus (using a focus mask) and then revert back to a simple Chinese intervalometer for the exposures. (The tethering software only goes up to 30" exposures.)
  11. I made the swap. The sensor is better and if you are using the guide port, it uses a standard RJ connector that is infinitely better. The sensor in my X2 also had considerably fewer hot pixels and lines. I cannot say if that was just luck or better quality control. I'm using mine on a QSI683WSG. I have not had any reliability issues with the X2. I changed over from Maxim to SGP at the same time I upgraded and I had a few hangs with the original working with Maxim.
  12. I just got the HS-V5 tethering software. It interfaces through the USB port and usefully allows either PC or Camera controls to prevail. I worked out that I can focus and frame using PC operation, since I only need relatively short exposures (no more than 30"). It can download frames to the PC rather than onto the card and they can be analysed by my GoldFocus software to confirm and set focus. (I could use the liveview and use the mask only) I then turn it over to Camera control. That is when I use the microphone socket, that doubles up as a standard release. I can set the Camera's dial setting to Bulb and use a standard trigger via serial port, or a fleabay intervalometer I bought for £20. I then save Raw files to the card, which saves on USB bandwidth. I already had the vertical grip, and I just bought a cheap battery adaptor and a DC-DC voltage converter. I now have a 9V DC feed from my 12V distribution panel running the camera . Just need a clear night to try it out. I'll post some pictures. When I compared it to my son's EOS 1100D, it was inherently less noisy on the RAW files, something that is borne out by the dpreview comparisons too. I don't think any RAW files are truly unprocessed but it was not swallowing faint stars, which is I believe a criticism of the early Nikon bodies.
  13. I'm going to (initially) try a different route. My normal camera is a Fuji X-T1, which as some may note from prior posts, has good Ha and some SII sensitivity. I already have a T-thread adaptor and an intervalometer but wanted to do things by USB. It has WiFi but that is a primitive app. I just discovered that Fuji has released tethered software for the X-T1, called HS-V5, for about £80. I can do my focusing and framing with that (using a GoldFocus mask for focusing) and then switch over to the intervalometer for the imaging exposures themselves. I was never particularly convinced with liveview focusing and I think I can get round it with the mask, since GoldFocus monitors a folder for image exposures and works on those. It might not work, but for £80 it is probably worth a go.
  14. I go through button cells with ease. Once they expire sufficiently to not operate a calculator or photo meter, I put them into the RDF. I then find the dot intensity is about right and they still last for hours.
  15. Ole, that 6d shot looks amazing - there is also a 60Da on Amazon right now that is winking at me.
  16. I normally use CCD's for imaging but need to do a project with a normal DSLR. At one time the old EOS 40D and the 1100D had liveview and good SNR performance and I seem to recall that the later models with higher pixel counts were not as good. I have been out of this camp for a while and wondered what the perceived wisdom is on the best choice for an EOS body? APS-C is fine, since I doubt my imaging field will cover a full frame.
  17. There are few bad cameras these days. Lots of folks get up tight on this spec or the other. It never ends. Over the last 30 years I have owned too many; you name it, I probably had it at one time, in all formats. You quickly learn that the body is only a part of the story. Leica, Mamiya and Schneider Glass (with the occassional CZ too) had more lasting impact. The X-T1 does a lot of things very well. Their lenses are very good indeed. The ergonomics appeal to those of us who remember what it was to make our own exposure and focus decisions. It has to have one of the best viewfinders around at the moment, (very very important to be able see the image to compose the shot) and the standard colours are fantastic. Those who shot transparencies on Leica will know what I mean. The images do not need sharpening or tweaking. Who wants to Photoshop hundreds of images? The recent firmware 4.0 release just made it better still. Things do get more technical for astrophotography. I did some testing of my Fuji against an EOS 1100D. Without modification, the Fuji was picking up Ha and SII very well and the noise level was very low indeed. I estimated the SII sensitivity was the same as the Canon's Ha sensitivity. There is tethering software now, and WiFi remote control but it has some way to go before it is integrated into a live-view over USB into the mainstream acquisition packages. You can also get a battery converter - that helps with long exposures (I found one on fleabay), that I rigged up, via a DC voltage converter to my 12V battery. I even found an adaptor and my Contax G Carl Zeiss lenses, which works very well with the 45 / 90 mm. I have read about the green mush but never seen it in practice. Mush or Moire - take your pick. Sharpness is overrated. Tonality creates mood.
  18. The 10" carbon fiber truss RC arrived last month. I found a way of an almost invisible secondary heater attachment using copper tape. (There is a picture of the completed assembly below and the method is on my website) The scope was not collimated and I spent the next weeks researching every possible collimation technique. It was very interesting. So far, I have managed to discard about half the proposals, since they rely upon mechanical characteristics that may or may not be good. I have done good bench alignment of both mirrors and the focuser with just a Howie Glatter laser and using a telephoto lens on a SLR, confirmed by star testing (outside of focus). I borrowed a Tak scope but discovered I did not need it. I could reproduce the Tak blot view using a laser with faint diffraction rings (like the Howie). I also discovered that my mirror separation was wrong, something that is not often mentioned and which caused excessive star elongation in the corners of the KAF8300 chip. I found a website that suggested the focal length increases by 9 mm for every 1 mm reduction in mirror separation. I unscrewed the secondary mirror baffle by about 2.5 mm (it has a fine thread ) and did up the knurled lock ring. My focal length is now exactly 2000 mm and the stars are much better in the corners. I still have to evaluate and compare the sensitivity of the Howe Glatter holographic attachment and I have just ordered the GoldAstro collimation tool too. You cannot write about this stuff unless you have carefully evaluated for yourself. It also gives me something to do over the summer. First Light: I couldn't resist capturing a few hours of M3 before it sets too early - the collimation is about 95% complete for this shot. Processing was done quickly in PixInsight but I think I should have used masked stretch to avoid blowing out the core. One other interesting thing, I need to take more care with Sequence Generator Pro autofocus with a RC. The autofocus algorithm does not like donuts. Thanks for all the help and advice. I think the truss scope is very good, no sign of pinched optics and it keeps the collimation after multiple handling on and off the mount. I probably could have gone for the 12" - I think the weight would just be OK for me.
  19. For portable use, I use two 24VA sealed lead acid gel batteries. These are the sort used in golf buggies. One runs the cooled camera and the other does the rest. Their nominal is about 13.5V at full charge and they run above 12 V for some time. They feed a home made electonics hub that provides switching and fusing. At home, I use a twin channel regulated DC bench supply with dual meters and run 13V out to the garden using good quality speaker cables. (I don't put mains equipment outside in the dew) I was looking at the Tracer LiPo batteries but from what I can see, they drop slightly below 12V quite quickly and some equipment is a bit touchy about that. For my laptop - I extend the battery with a PowerGorilla Lithum pack. Expensive but excellent.
  20. I completed the comparison between a direct diffuser over the dew shield and imaging a white wall at 3 m. The difference is very subtle. I ran both integrated flat frames with the PixelMath equation 0.5+(flat1/med(flat1))-(flat2/med(flat2). This normalizes the flat frames to the median value and subtracts them, adding 0.5 to make it mid grey. There was a faint narrow ring where the main vignetting edge was, which could account for the pale arc I saw on my backgrounds. This only affected the vignetting outline- the one dust spot on the filter disappeared when the two flat frames were subtracted in this way, proving this is not a registration or scaling issue. It is easy to see how most will be fine with a simple diffuser over the dew shield.
  21. A full set of flats takes 3 hours for me, 50x exposures for 8 filters and 2 binning levels. I cannot rely on consistent sky conditions over that time and for that reason, I do them indoors. Currently I'm using a bathroom light, (50W Tungsten Halogen Bulb with opal glass), illuminating a white emulsioned wall. Plenty of Ha and SII. Anyway it is Easter, it is cloudy and I'm bored and it is surprising what happens when you challenge the norm! In the back of my mind, a friend and I both have some flat calibration issues on our images - leaving a very slight halo affect - as if the vignetting on the image has a very slight different radius to the calibrated flats. He's using Maxim, I'm using SGP/PixInsight but the faint effect is very similar. It would be good to nail it down.
  22. I'm not so sure.... Something in the back of my mind says sticking a diffuser directly in front of the lens, floods the entire optical system and you get a lot of stray light. In terms of imaging, the light coming into the scope is almost collimated. In my mind, I would want the quality of light to be the same. Anyway - enough of the theory - I'm doing some tests to compare a diffuser directly over the lens hood or taking an image of a matt white wall from several meters away. I shall do calibrated flats using both systems and then do a PixelMath comparison 0.5+ (Experiment1 - Med(Experiment1))-(Experiment2-Med(Experiment2)) - that will give me a difference image to evaluate.
  23. Hi Derek - I did some experiments with daylight balanced LED's. I was using a QSI 683 with Baader filters: At a dim light setting: Filter Exposure ADU L 0.2s 34K R 0.5s 26K G 0.5s 37K B 0.5s 20K Ha 10s 30K OIII 10s 24K SII 10s 23K SII 0.2s 22K (light on full power) With the lamp on full - I had SII, at 0.2s at 22K - so, although the spectral output range varies across the wavelengths, the light level adjustment from the panel is such that I could achieve similar exposures through each filter and vary the power (my led array is attach to a dew-heater output ) Might be worth a go. I could also substitute some of the LEDs for deep red ones too if I chose to.
  24. I have decided on the 10" RC. I think the 12" is too heavy for me to lift safely each time I want to use it. I am not in an obsy, so the Edge HD is going to be a dew magnet, or with its dew shield, a sail. The actual central obstruction in f/stops is marginal between the designs. I have researched all the various ingenious RC alignment procudures - they make very interesting reading. Some challenge the premise that the optical surfaces's optical center is the physical center of the mirror, a 'fact' used by many procedures to align both mirrors, another one, from a University, looks very interesting indeed - creating a cross hair in the middle, between the mirrors, to act as an independent optical center for each mirror. Another uses aberrations and their symmetry to set each mirror (again, assuming they are centered). There is the Holtech multiple laser device and another, that uses platesolving to determine the focal length and hence the mirror separation. Sounds like enough material to write a chapter for the 2nd edition of the book! I'm going to have to dig out my MSc Optics notes from 25 years ago.
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