michael8554

Hi Jim The PA routine in SharpCap is popular and fast, but has some requirements: "The camera must be supported by SharpCap. The cameras field of view should be 1-2.5 degrees. You need to see at least 15 stars in the FOV. You need to be aligned within 5 degrees of the pole (rough polar alignment)

Look at the star shapes in the corners of a sub. If they're round then change nothing. If they're elongated, pointing towards the centre of frame, try a few more mm of spacing. If the elongation is circular about the centre of frame then try a few mm less spacing. Michael

The usual Meade 0.63 reducer requires 105mm of back focus. The Altair 183C has a 12.5mm flange distance. So there's a 105 - 12.5 = 92.5mm gap that needs filling with spacers and the derotater. The derotater looks heavy, so place that close to the OTA. Michael

Hi John Post the PHD2 GuideLog from the PHD folder. Check the date in the file name is relevant Michael

Going to 3.76um pixels from 8.5um pixels means the poor star shapes are now being fully displayed, instead of being inside one 8.5um pixel. So an undersampled image scale of 3.9arcsec/pixel is hiding the problem, not fixing it. Michael

I can believe a new CC/FR might have cured the problem, but pixel size affecting coma/pinched optics/astigmatism ? Michael

Large DSLR FOV isn't a problem, just crop, ends up as a similar size in pixels that a Planetary camera would produce. Similarly LiveView 5X Movie will give about 1200 x 800, depending on camera. Michael

PHD2 responds to Dither commands from external software. The external dither setting may already be in imaging camera pixels. Or it may be the amount the guidecam is being dithered, requiring an adjustment to the PHD2 multiplication settings to translate into image camera pixels. Believing the Algorithm settings have anything to do with Dithering suggests you need to step back and read the PHD2 Instructions. Michael

Hi Olli Here a description on how to do non-compressed non-interpolated video with Canon DSLRs: https://www.astropix.com/html/equipment/canon_one_to_one_pixel_resolution.html Michael

No dip in the guidecam output. PHD2 is reacting to an external input to Dec and to RA. I notice your Minimum Move settings are a tiny 0.05, was that recommended by the PHD2 Guide Assistant ? And setting the Y-Axis to arcsecs give a more accurate account of the guiding than pixels. You could post the PHD2 GuideLog for more information on your setup. Michael

How many pixels are you dithering the ASI1600MM ? 12 pixels is a common figure. The dither needs to be in imaging cam pixels. With some imaging software it might be in guidecam pixels, requiring a calculation to give the correct dither for the imaging cam. Michael

Hi Ade OAG's require more sensitive cameras than will work with a guidescope. So I'd avoid a colour camera, and I found the non-mini ASI 120MM not sensitive enough for OAG use. Both cameras have 4.9mm x 3.7mm sensors, so will be a poor size-match to a 12mm x 12mm prism. But many people successfully use sensitive cameras with that size sensor on 8x8 and 12x12 prisms, they're just not a good match to the prism size. Michael

Flip or Limits settings ? Michael

Hello Peter. I found an ASI 120MM not sensitive enough for my SCT and OAG. Michael

The secret to loosening tight screws is to tighten them first ! A tiny clockwise turn results in a "click" as the galling is broken. Also the loosening side of the socket edges isn't being damaged. Failing that the next techniques have been well described. Michael

Going back to the start, I notice exposures are only 1 second. The RA problem might be as simple as "Chasing the Seeing" Michael

Hi William As no-one has answered here or on CN, I'll have a stab, but will need some detail. Are you using Canon lenses, or attaching to an OTA ? What focal length ? Michael

Here's my FOV with a Canon APS-C DSLR and a 8" SCT at f/6.3: Any of the Celestron, Meade, Antares etc f/6.3 SCT Reducers will do. Michael

Hi Noodles Gather those cables into a loose loop and attach to the mount. You'd be surprised how tracking can be affected by cables dragging on the ground. Michael

Hi Stuart, A good description, but we need a jpeg of the whole of a short exposure sub, stretched if necessary, to best judge the issue. And/or crops of all four corners. Michael

Hi Danan Your shots look blurred, probably due to atmospheric turbulence - like looking at a coin on the bottom of a swimming pool. Take lots of shots at the fastest shutter speed that gives a fairly good exposure. Some of those shots may be "lucky", taken at an instance when the air was still. For this reason Planetary Imagers usually use dedicated video Planetary cameras, taking long duration video files at fast frame rates. Stacking software then picks out the frames that aren't blurred. Michael

Fitswork. Infomode window in righthand side toolbar shows the value at the cursor. Michael

Results look good. I would only point out the guide rates RA guide speed = 1.5a-s/s , Dec guide rate = 1.5a-s/s. Theses are very low, should be at least 7.5a-s/s, and points to using the default ASCOM PulseGuide Setting in EQMOD: The fact that you tried to Calibrate at Dec=90 suggests you haven't read the PHD2 instructions ? Michael

You've lost me there I'm afraid. Michael

From your earlier post it seems this camera is for Planetary imaging. Long sequences of high frame rate video. Is SIRIL the right software for this purpose ? Screengrab is to poor to comment on, post a JPEG of the Siril result. Michael