michael8554
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Everything posted by michael8554
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Strange behavior of Sigma 40mm F/1.4 Art lens.
michael8554 replied to Vroobel's topic in Imaging - Discussion
Hi Vroobel Backfocus is only of concern if you have a FF or FR. All a lens needs is to be the correct Flange Distance from the sensor, in order to reach infinity focus. The Canon Flange Distance is 44mm. So you raise an interesting thought that reducing the lens to sensor distance has similar effects to altering the Backfocus from a FF or FR. Have you started at 44mm Spacing ? Michael -
first go at auto guiding
michael8554 replied to TiffsAndAstro's topic in Getting Started With Imaging
PHD2 likes to Cal where the stars are "moving ' the fastest ie near Dec = 0 Michael -
Depends how you are Polar Aligning. With a polarscope, most have a year scale for compensating for Polaris's shift. If you run out of years then you can guesstimate. After all the polarscope is only really good enough for visual. If you have a PC based tool, I don't know if they even use Polaris. Michael
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What is the worm end-float like when loaded ? Michael
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first go at auto guiding
michael8554 replied to TiffsAndAstro's topic in Getting Started With Imaging
Time to say what your equipment is - mount, focal lengths, pixel sizes. Lets say you have one of those tiny guidescopes that give 6arcsec/pixel. And you're imaging at 2arcsecs/pixel. A 12 pixel dither on the imaging camera is 2 x 12 = 24arcsecs. How many pixels does the guidecam have to Dither to make the imaging camera Dither 24arcsecs ? 24/6 = 4 pixels. If the NINA setting is for the guidecam, your 7 pixel Dithers are too much, and probably increasing Settling times. If the NINA setting is for the imaging camera, then you should try 12. Michael -
first go at auto guiding
michael8554 replied to TiffsAndAstro's topic in Getting Started With Imaging
Was that 7 pixels of the imaging camera, or the guide camera ? 12 pixels of the imaging camera on every image is common. Michael -
first go at auto guiding
michael8554 replied to TiffsAndAstro's topic in Getting Started With Imaging
"Stars didn't look tight in test shots," 2 arcsec/pixel may be Under Sampling, leading to enlarged stars. Or poor focus ? "cuiv the lg" ? Beats me. Closest I could find was Cuiv, The Lazy Geek Michael -
Am I right that this indicates I needed to take Darks?
michael8554 replied to Gfamily's topic in Getting Started With Imaging
You haven't said which camera ? Dithering, Darks, and Flats. Michael -
first go at auto guiding
michael8554 replied to TiffsAndAstro's topic in Getting Started With Imaging
1. Can't see the settings as the screen grab is overexposed. If you hit the print screen or Prnt Scrn button at the right of the top row of your keyboard you get a copy of the screen in the Clip Board that you can paste. 2. Everything is green on the status bar. RA = 0.29, Dec = 0.20, Tot = 0.35 look good. As long as your Imaging scale is larger than about 0.4arcsec/pixel you should have round tight stars. 3. "i can't change the scale from pixels in phd2 its greyed out" I can only suggest you reload PHD2. Don't erase it, you will loose your settings. Just reinstall, it will overwrite. Michael -
At 1626mm FL you'll need a guidecam with big pixels, to get a sensible pixel scale. The Costar is 5.2um, the ASI 220MM only 4um, a LodeStar has 8.2umx8.4um pixels. Perhaps the ASI 220MM Binned 2X or 3X would do. But the guidecam sensor needs to be a good size-match for the 10mm x 10mm prism, the ASI 220MM is only 7.68mm x 4.42mm. Probably there are better matches out there. Michael
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Yep, you just stepped down your 360mm lens to f/115. The "camera obscura" concept is very old. A rich Victorian might have a special darkroom in his mansion for his camera. The novelty was the production of an (inverted) image with no lens. Why ? lead to the discovery of the wave/particle duality of light. Michael
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Skywatcher AZ GTi mount in Australia.
michael8554 replied to octebra's topic in Getting Started Equipment Help and Advice
Generally speaking a mount in the northern hemisphere starts off pointing north, and points south in the southern hemisphere. Towards the celestial pole for that hemisphere. An Alt/Az mount should be levelled. I have seen that the left or right attachment is important, but I don't know whether the hemisphere affects that choice. Michael -
I won't say my imaging expectations are up to Olly's standards. But many do DSO's with wedge-mounted SCT's, including myself. The older Meade and Celestron wedges are flimsy, which is why I went for the AE MegaWedge. The main problem is the time taken to setup if you don't have a permanent rig. I would expect that the challenges are similar on a EQ mount at 1500mm FL. Michael
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Vixen centre negative question
michael8554 replied to woldsman's topic in Getting Started Equipment Help and Advice
My Bad, I misread that you were testing the round plug on the battery pack. Michael -
Vixen centre negative question
michael8554 replied to woldsman's topic in Getting Started Equipment Help and Advice
If that is the correct D-cell pack for the mount, you have proved that a centre positive supply is needed. Michael -
I have a print of "Portrait of the Moon. Pastel drawing by John Russell 1795", hanging in our house. Amazing detail. Gift from our daughter, who was a curator at The History of Science Museum in Oxford. Michael
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Yes it would help to know which mount you have. My AE MegaWedge is made from 15mm steel. "Could this be accurate enough to allow tracking?" If you only want to track, you don't need a wedge, the Alt/Az mount will do that already. If you want to guide, then Polar Mode on a wedge is best. You will need a method of adjusting the Alt and Az of the wedge, even if it's made to sub-millimeter tolerances. To get a PA error of no worse than 5 arcmins. Michael
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Guidescope: Where should I point it?
michael8554 replied to stillneon's topic in Getting Started Equipment Help and Advice
If you're using PHD2 to guide, the PHD2 Calibration Assistant will slew the mount to near south and Dec = 0 before Calibration starts. PHD2 will then automatically adjust the RA guiding to match the higher Dec of the target you eventually GoTo. So if the guidescope is pointing considerably far off Dec = 0 when the mount is at Dec = 0, that might affect how well PHD2 guides RA on the target. Pointing the guidecam at Dec = 0 will still confuse, as PHD2 will still calculate based on the Dec of the mount. Michael -
Lodestar Pro binning question/problem
michael8554 replied to Skipper Billy's topic in Discussions - Cameras
Thanks kobu, I'll try that newer driver on my LodeStar X2, weather permitting :-< Michael -
Castor thinks it's a load of Pollux........... Michael
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Decathlon do rubber coated weights. Make "cotton reel" adapters from wood dowel. Michael
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Lodestar Pro binning question/problem
michael8554 replied to Skipper Billy's topic in Discussions - Cameras
High Skip I have a LodeStar X2 and have never seen the interlace problem associated with this camera's sensor. I use the "Starlight Xpress SXV" driver, not the "Starlight Xpress LodeStar (ASCOM), with an OAG, and no Binning. Michael -
LX90 REMOTE CONTROL
michael8554 replied to BRUCE J's topic in Getting Started Equipment Help and Advice
Hi Bruce I hope you get some answers here, but the Meade section of the US "Cloudy Nights" forum has Meade experts lurking. To control the LX90 remotely you don't need a camera, just the right cables and software. Michael -
Celestron C8 XLT with Meade 4000 F6.3 reducer
michael8554 replied to IDM's topic in Discussions - Scopes / Whole setups
I'd be interested to know: If it is the short FL version, how bad was it at 105mm ? Michael