michael8554

Why ? Your guiding appears to have been good. Michael

If Blue is the direction of drift with RA tracking off, then the Yellow-Blue direction is RA. So your PA is good enough to show acceptable drift in individual subs, but enough to cause image framing drift over multiple exposures. Michael

It would be easier if you image pointing south, with the 6D parallel to the horizon. Then up/down drift would be PAE. Your image scale is 0.34 arcsec/pixel. You could measure the Dec drift in pixels in a 1 minute exposure. And then applying the image scale, work out the drift in arcmins in 1 minute But I don't have the maths to convert that to the polar positional error of X arcmins. Michael

What is preventing you adding more adapters ? Here's a set of 3mm to 40mm M42 adapters that you can add to or replace your 16.5mm and 21mm adapters, to get a wide range of different lengths: https://www.rothervalleyoptics.co.uk/VSA19-10.html Michael

Looks like the OTA has been designed with AP in mind, as the focus point is well outside of the eyepiece, to allow a camera to focus. So you need either the screw-on extension, that is likely to be impossible to source. Or a long 1.25" extension, something like this, they stock various lengths: https://www.rothervalleyoptics.co.uk/farpoint-125-extension-tube-3-long.html Michael

Yes, 105mm is the accepted figure, but based on your star shapes in the corners, you could add a couple of mm and see if the star shape improves. Michael

From your lastest GuideLog. All your Calibrations had about 15 to 20 steps of Dec Backlash clearing before the Dec part of Cal commenced. Here's one of your Dec Cals: Resulting in very different RA and Dec guiderates, as reported after each Cal: Cal Dec = 43.2, Last Cal Issue = Rates Norm rates RA = 11.5"/s @ dec 0, Dec = 3.6"/s; Your mount was set to 7.5arcsecs/sec on RA and Dec. For your very last of many Cals you moved down to close to Dec =0 and then guided for about 5 minutes with okay results: RA = 0.62 Dec = 0.72 arcsec. You had Dec guiding switched to DEC guide mode = South. Which was true at midnight when you did your only Guide Assistant run, but by 02;00 that was no longer true, as by then Dec was drifting south, so needed guiding north !! So for most of the night Dec was unguided, resulting in huge uncorrected Dec excursions at times. Luckily your PA was good enough that no corrections were required on that last run, hence the good Dec figure. The procedure is to move to your target, switch off guiding and see what way Dec is drifting over several minutes, set Dec guiding to correct that drift. So bottom line, you need to pulse north a lot more before Cal, until you see equal star movements for several pulses. An even better solution, adjust your Dec worm and bearings ! And guidescope focus is still poor.

The star shapes in the corners suggest you could increase the 105mm spacing. But does the Focal Reduce act as a Coma Corrector too ? Michael

I get tired of seeing the same old problems with so many OPs PHD2 guiding. Because they are ignoring, or hadn't bothered to read, the PHD2 Instructions. Instead of fine-tuning OPs PHD2 guiding we're sorting out their basic settings for them. So yes I'm getting harsh. Michael

Really ! Seems fine ? Sounds like you haven't read the PHD2 instructions if you don't understand that. Use the handset buttons at lowest slew speed, or the PHD2 Manual Guide with 5000mS Pulse setting, to move the mount north until the guide star actually moves on the screen. Then the Dec Backlash has been taken up. Then you can get a realistic Calibration. Again, it's all in the PHD2 instructiions, you just need to read them. Michael

From your GuideLog: As already mentioned, you have the FL entered as 240mm. The bunched-up steps in the Calibration indicate some Stiction on RA and Dec. PA is very good, so Dec chugs along with almost no correction. Until you Dither :-< Then at times Dec never recovers between Dithers, because of the Stiction. Guidecam focus isn't good, HFD = 5.23 px Ideally you should Calibrate near Dec =0, and close to south. Pulse the mount north until you see the star move, to clear Dec Backlash, THEN Calibrate. And run the Guiding Assistant to get settings. So get your new bearings in and the worms adjusted, and post the new logs. Michael

Steve, your diagram is more conclusive than mine is (though 20 + 27.5 + 6.5 only makes 54mm) Andywilliams, this 55mm Back Spacing is not difficult to measure. Use Steve's diagram and post the result.

50 x 4 = 200mm Focal Length. So if it's actually 180mm then AE are misinforming. Entering 240mm in the Equipment Profile would make a difference if it's really 180mm, but Calibration would compensate to a degree. But PHD2 wouldn't compensate for those who enter 50mm Aperture as the Focal Length.......... :-< Post a PHD2 GuideLog that includes a Calibration. Michael

To me it looks like it could be correct. Certainly not 11mm out. Michael

32GB SSD, 4GB RAM, and Win 10 Pro for only £60 is a real surprise to me. Seller Refurbished is what ? Michael

You're right, been so long since I used that I was struggling to even remember the name. Michael

From your GuideLog: The 5.8 degree orthogonality error in the Cal with the new Profile was tolerable and due to the poor PAE of 21arcmins. Get that PAE down to no worse than 5arcmins. As others have said, it's worth spending a few minutes Calibrating each night, as your setup isn't permanent. Immediately followed by a Guide Assistant run, which would have alerted you to the poor PA, you ran for about 30 minutes before doing the GA run. The Seeing during the only significant run after that was poor, causing low camera signal, Star Lost messages, and large RA spikes. In the short periods when the Seeing was good your guiding looked okay, but should be better with good PA. Michael

Do you need USB3 ? A Lindy 10m powered USB3 hub will cost about £75. A 10m USB2 powered hub is less than £20, and worth a punt before you shell out £500 for a Pegasus box. But USB is always a gamble. Then there's USB over Ethernet cable, the cheap adapters seem to be suspect, Startech adapters are £200 to £400. Michael

Your finderscope problems are probably due to the soft-tipped screws that hold it in the rings. Remove the tips and live with screw marks on the tube. Are you using this same finder on both scopes ? Bound to be a difference in the centre of the FOV. Plenty of people successfully guiding a NEQ6 Pro, it isn't the scope that's being guided, it's the mount. Post a PHD2 GuideLog that includes a Calibration. You'll find them in the PHD2 folder, make sure the date in the filename is relevant. Michael

Hi Razz There's an old-school solution involving an adapter that screws into the filter thread on the end of the camera lens. And an adapter that clamps into the groove of the rubber eyepiece shield of a telescope eyepiece. This gives you "Eyepiece Projection". The camera focuses on the image projected by the eyepiece. Or there are brackets and clamps available to hold the camera lens close to an eyepiece, usually for phones with cameras. Michael

Maybe I'm missing something in the above posts. Andy says he already has the ASI 1600 55mm back from the MPCC (let's ignore the tweak for the filter thickness for the moment). So adding a further 11mm spacer between the MPCC and the ASI 1600 is going to make the spacing 66mm. The 11mm spacer would be better placed between the MPCC and the focuser, so that the focuser can be moved inwards to get focus. And just for clarity. The diagrams that ZWO show on their website keep recommending 56mm Backspacing WITH NO CC. Only CCs and FFs have Backspacing. Cameras only have a Flange Distance, 6.5mm in the case of the ASI 1600. So a Camera and EFW and no CC/FF can be placed anywhere in the range of the OTA's focuser. The 56mm in this case is irrelevant and causes confusion. Michael

The grabs don't show much. Please post the PHD2 GuideLog. You'll find them in the PHD2 folder. Check that the date in the file name is relevant. Michael

Might be frost forming on the sensor. Quite a distinct edge to the cutoff, so might be the filters are not locating centrally. Post a jpeg of a Flat and a Light. Your image is showing coma in the corners, FF too close to the sensor ? Michael

I don't use Darks with my modded 6D, but I do Dither. Load Bias as Darks in DSS. Michael

Since we're wondering if the connections are intermittent: Your cables may work, but there are many connections that could be to blame. If you do find the lights flicker: There's probably a fuse in the black item in the croc clip cable, and another in the "Cigarette Lighter" plug, which could be loose. Ideally dispense with the croc clip cable, cut off the "Cigarette Lighter" plug on the other cable, and attach that end by bolts through the lugholes on the battery, crocodile clips aren't the best connection. Michael