Dithering issue . . . .

DLivesay · May 9, 2025

Hey, folks. I hope everyone is doing well.

I've been very much enjoying the BYE program for a short while now and am trying to get Dithering to work correctly.
- I'm using a Canon EOS 6D.
- I'm using the latest release of BYE (3.2.3 premium). I've set the dithering parameters in BYE to the ASCOM way.
- I'm using the latest ASCOM platform software (v7.0.2).
- I'm using a new SkyWatcher EQ6R pro mount with the appropriate EQASCOM driver (V200q).
- I'm using the EQMOD software to steer the mount in general (without the mount's corded controller connected so no hardware arguments there).
- I'm not using any supplemental Guiding at this point in time and am working with Stellarium exclusively in that regard.
When it comes to Dithering, when I start it in BYE, it appears to work as intended (I'm able to verify this by simply zooming in to a given star and seeing it move randomly a little with each dither).
- The issue I'm having is that after a seemingly random time of normal operation, the dithering will change to VERY aggressive jumps that if left in play, the subject of interest has moved off the screen within a few dithers. Changing the dither Aggressiveness in BYE changes nothing.

Where should I start to look? It's my understanding that BYE itself doesn't do the dithering control. Could there be a bug in the ASCOM stuff?
I've searched the BYE forums and can't find anything specific to this issue.

* Naturally, I've just completed upgrading the storage capacity of my dedicated PC (1000GB for the downloads and another 1000GB for the temporary folder should I drizzle) so, I don't have any logs from BYE to show at the moment (might be another week before clear skies around my house).

Would anyone have any suggestions as to where I might start in diagnosing this?

Thanks,
David

astroman133 · May 9, 2025

First, thanks for providing all the information about the software and setup that you are using.

Next, if you have a question about BYE and your Canon camera, please post to the BaciyardEOS Forum. This is where BYE users and Canon owners hang out.

BYE has 4 dither providers. They are PHD, ASCOM, Metaguide, and MGen.

I am unfamiliar with Metaguide and MGen. When PHD is selected as the dither provider, PHD does the dithering when requested by BYE and lets BYE know when the telescope has settled at its dithered location. The ASCOM selection is really Direct Dithering. In this case BYE is giving movement commands to the mount through its ASCOM driver, which is EQASCOM in your case.

If I have your setup correct, the most likely places for issues with this configuration it would be in EQASCOM or EQMOD, but it could also possibly be a bug in BYE. BYE always logs every run, so its dithering commands will be written to a log. You could also try the pre-release version of BYE 3.5.0.RC9. I do not recommend using the x64 version since it will not work if any of the ASCOM drivers that you are using are 32-bit only software. The ASCOM side also has logging, and most drivers also have logging. These may point out where the pointing is going askew.

In the How-To Forum on this web site is a useful post entitled "Debunking Dithering". This may provide some background on how to intelligently use dithering.

Another option is to use PHD2 for your dithering. It is a separate download, but is a very popular and proven approach.

I hope this helps.

DLivesay · May 10, 2025

Thank you for replying, astroman133. 😉

From what I can tell in my related research, PHD2 does not support dithering without a guide-camera.
Further, again from my research, perhaps many are successfully dithering with just BYE and the ASCOM/EQMOD. Dithering works for me using BYE and the ASCOM/EQMOD.

There's just the issue with the running off-track as it were. For the sake of simplicity, I prefer to continue with the current setup and just workout the bugs (that my very well be on my part).

It's not suppose to rain this evening so, I may just run out there and fire-up the upgraded PC, mount and camera. Set the mount to look/track "that away" and turn on dithering just so I can hopefully catch something in the log(s).

astroman133 · May 10, 2025

If you are not guiding then there may be enough declination drift due to polar misalignment that ditnering is not necessary. It probably depends on the amount of drift and the length of your exposures.

In any case, good luck with your efforts.

DLivesay · May 10, 2025

OK.
- My re-configuring the storage of the telescope's computer the other day included a complete reformatting and new installation of the Windows 10 64bit operating system, BYE, Stellarium and the ASCOM stuff.
- Setting it all up for tonight's tests included the initial setting of all the various parameters of BYE, Stellarium and the ASCOM so as to allow them to communicate with one another.
- My location's Latitude, Longitude and elevation are the same in both Stellarium and EQMOD.
- Tracking control is by Stellarium (rather than the EQ6 mount) as set in EQMOD.
- Everything appears to operate correctly.
- Set up the telescope OTA and camera.
- Dialed-in my night's sky in Stellarium via eight (8) stars. Tonight's target is M51. Having centered M51 in the BYE display, I also made M51 a location alignment point in Stellarium (that way, I can simply have Stellarium command the mount directly to and centered in the screen should the need arise).
- Set the Dithering to an aggression of 1, the Calm-Down period to one second at a dithering rate of once every four frames.
- Proceeded with a standard capture of 100 ten second frames with an ISO of 1600 (including a two second pause for vibration to settle).

Everything seemed to work correctly including the dithering every fourth frame. I was able to see the result of the mild dithering by zooming in on a neighboring star and seeing it move.

At 50 frames (+/-) things went south. From that point forward, the individual dithers had M51 move notably down in the images. By the 75th frame, M51 was at the very bottom of the image. I had Stellarium recenter M51 on the screen. Still, with each following dither, M51 continued march straight down the screen such the by the 100th frame M51 was again at the very bottom of the image.

- If it's worth anything, M51 stayed dead-center of the screen (left to right) as it aggressively dithered down and out of view.

Here's the log:

Quote

22:01:44 Licensed to DLivesay
22:01:44 BackyardEOS 3.2.3 Premium Edition
22:01:59 Attempting to connect camera...
22:01:59 Canon drivers 'Canon\' initialized.
22:02:01 6D CONNECTED!
22:24:33 Imaging session started.
22:24:58 M51 May 10-11_LIGHT_10s_1600iso_+32c_ra(13.50211)_dec(47.22078)_20250509-22h24m37s835ms.CR2
22:25:11 M51 May 10-11_LIGHT_10s_1600iso_+32c_ra(13.50216)_dec(47.22168)_20250509-22h24m53s194ms.CR2
22:25:27 M51 May 10-11_LIGHT_10s_1600iso_+32c_ra(13.50221)_dec(47.22258)_20250509-22h25m08s679ms.CR2
22:25:41 M51 May 10-11_LIGHT_10s_1600iso_+32c_ra(13.50226)_dec(47.22340)_20250509-22h25m24s101ms.CR2
22:25:57 M51 May 10-11_LIGHT_10s_1600iso_+31c_ra(13.50230)_dec(47.22430)_20250509-22h25m38s648ms.CR2
22:26:12 M51 May 10-11_LIGHT_10s_1600iso_+31c_ra(13.50235)_dec(47.22516)_20250509-22h25m54s022ms.CR2
22:26:28 M51 May 10-11_LIGHT_10s_1600iso_+31c_ra(13.50240)_dec(47.22606)_20250509-22h26m09s413ms.CR2
22:26:38 ASCOM dithering...
22:26:39 PRE-DITHER Telescope RA(13.50244662) DEC(47.22695313)
22:26:43 M51 May 10-11_LIGHT_10s_1600iso_+31c_ra(13.50245)_dec(47.22691)_20250509-22h26m24s804ms.CR2
22:26:43 Dither settled to RA(13.50243356) DEC(47.22715313)
22:26:43 Difference of RA(-0.00001306) DEC(0.00020000)
22:26:45 POST-DITHER Telescope RA(13.50669868) DEC(47.25613281)
22:27:06 M51 May 10-11_LIGHT_10s_1600iso_+30c_ra(13.50675)_dec(47.25711)_20250509-22h26m47s663ms.CR2
22:27:21 M51 May 10-11_LIGHT_10s_1600iso_+29c_ra(13.50680)_dec(47.25801)_20250509-22h27m03s131ms.CR2
22:27:37 M51 May 10-11_LIGHT_10s_1600iso_+29c_ra(13.50684)_dec(47.25887)_20250509-22h27m19s538ms.CR2
22:27:47 ASCOM dithering...
22:27:47 PRE-DITHER Telescope RA(13.50689137) DEC(47.25976563)
22:27:52 M51 May 10-11_LIGHT_10s_1600iso_+29c_ra(13.50689)_dec(47.25973)_20250509-22h27m34s803ms.CR2
22:27:53 Dither settled to RA(13.50696693) DEC(47.26042396)
22:27:53 Difference of RA(0.00007556) DEC(0.00065833)
22:27:54 POST-DITHER Telescope RA(13.51145253) DEC(47.29171875)
22:28:15 M51 May 10-11_LIGHT_10s_1600iso_+29c_ra(13.50688)_dec(47.26051)_20250509-22h27m57s101ms.CR2
22:28:30 M51 May 10-11_LIGHT_10s_1600iso_+29c_ra(13.50685)_dec(47.26059)_20250509-22h28m13s381ms.CR2
22:28:45 M51 May 10-11_LIGHT_10s_1600iso_+28c_ra(13.50681)_dec(47.26063)_20250509-22h28m27s085ms.CR2
22:28:57 ASCOM dithering...
22:28:57 PRE-DITHER Telescope RA(13.50677775) DEC(47.26070313)
22:29:01 Dither settled to RA(13.50685474) DEC(47.26086146)
22:29:01 Difference of RA(0.00007694) DEC(0.00015833)
22:29:02 M51 May 10-11_LIGHT_10s_1600iso_+28c_ra(13.50678)_dec(47.26070)_20250509-22h28m43s319ms.CR2
22:29:02 POST-DITHER Telescope RA(13.50683191) DEC(47.26085938)
22:29:24 M51 May 10-11_LIGHT_10s_1600iso_+28c_ra(13.50679)_dec(47.26094)_20250509-22h29m05s350ms.CR2
22:29:40 M51 May 10-11_LIGHT_10s_1600iso_+28c_ra(13.50676)_dec(47.26098)_20250509-22h29m21s663ms.CR2
22:29:56 M51 May 10-11_LIGHT_10s_1600iso_+28c_ra(13.50672)_dec(47.26106)_20250509-22h29m37s866ms.CR2
22:30:07 ASCOM dithering...
22:30:07 PRE-DITHER Telescope RA(13.50668534) DEC(47.26109375)
22:30:11 Dither settled to RA(13.50674895) DEC(47.26165208)
22:30:11 Difference of RA(0.00006361) DEC(0.00055833)
22:30:11 M51 May 10-11_LIGHT_10s_1600iso_+28c_ra(13.50669)_dec(47.26109)_20250509-22h29m54s101ms.CR2
22:30:12 POST-DITHER Telescope RA(13.50674893) DEC(47.26167969)
22:30:33 M51 May 10-11_LIGHT_10s_1600iso_+27c_ra(13.50671)_dec(47.26172)_20250509-22h30m15s272ms.CR2
22:30:49 M51 May 10-11_LIGHT_10s_1600iso_+27c_ra(13.50668)_dec(47.26180)_20250509-22h30m30s647ms.CR2
22:31:04 M51 May 10-11_LIGHT_10s_1600iso_+27c_ra(13.50664)_dec(47.26184)_20250509-22h30m46s819ms.CR2
22:31:15 ASCOM dithering...
22:31:15 PRE-DITHER Telescope RA(13.50660797) DEC(47.26187500)
22:31:19 Dither settled to RA(13.50665463) DEC(47.26117500)
22:31:19 Difference of RA(0.00004667) DEC(-0.00070000)
22:31:20 M51 May 10-11_LIGHT_10s_1600iso_+27c_ra(13.50661)_dec(47.26188)_20250509-22h31m01s303ms.CR2
22:31:20 POST-DITHER Telescope RA(13.50666562) DEC(47.26121094)
22:31:41 M51 May 10-11_LIGHT_10s_1600iso_+26c_ra(13.50663)_dec(47.26125)_20250509-22h31m23s351ms.CR2
22:31:56 M51 May 10-11_LIGHT_10s_1600iso_+26c_ra(13.50659)_dec(47.26129)_20250509-22h31m38s522ms.CR2
22:32:12 M51 May 10-11_LIGHT_10s_1600iso_+26c_ra(13.50656)_dec(47.26137)_20250509-22h31m53s960ms.CR2
22:32:23 ASCOM dithering...
22:32:23 PRE-DITHER Telescope RA(13.50652143) DEC(47.26140625)
22:32:27 Dither settled to RA(13.50654865) DEC(47.26061458)
22:32:27 Difference of RA(0.00002722) DEC(-0.00079167)
22:32:28 M51 May 10-11_LIGHT_10s_1600iso_+26c_ra(13.50652)_dec(47.26141)_20250509-22h32m10s178ms.CR2
22:32:28 POST-DITHER Telescope RA(13.50658205) DEC(47.26062500)
22:32:50 M51 May 10-11_LIGHT_10s_1600iso_+26c_ra(13.50654)_dec(47.26070)_20250509-22h32m31s319ms.CR2
22:33:05 M51 May 10-11_LIGHT_10s_1600iso_+26c_ra(13.50651)_dec(47.26074)_20250509-22h32m46s694ms.CR2
22:33:21 M51 May 10-11_LIGHT_10s_1600iso_+26c_ra(13.50647)_dec(47.26082)_20250509-22h33m03s007ms.CR2
22:33:32 ASCOM dithering...
22:33:32 PRE-DITHER Telescope RA(13.50643991) DEC(47.26085938)
22:33:36 Dither settled to RA(13.50648630) DEC(47.26123438)
22:33:36 Difference of RA(0.00004639) DEC(0.00037500)
22:33:37 M51 May 10-11_LIGHT_10s_1600iso_+26c_ra(13.50644)_dec(47.26086)_20250509-22h33m18s366ms.CR2
22:33:37 POST-DITHER Telescope RA(13.50649714) DEC(47.26125000)
22:33:58 M51 May 10-11_LIGHT_10s_1600iso_+26c_ra(13.50646)_dec(47.26133)_20250509-22h33m40s413ms.CR2
22:34:13 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50643)_dec(47.26137)_20250509-22h33m55s929ms.CR2
22:34:30 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50639)_dec(47.26141)_20250509-22h34m11s585ms.CR2
22:34:40 ASCOM dithering...
22:34:41 PRE-DITHER Telescope RA(13.50635250) DEC(47.26144531)
22:34:44 Dither settled to RA(13.50639861) DEC(47.26169531)
22:34:44 Difference of RA(0.00004611) DEC(0.00025000)
22:34:45 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50635)_dec(47.26145)_20250509-22h34m27s850ms.CR2
22:34:45 POST-DITHER Telescope RA(13.50641074) DEC(47.26171875)
22:35:07 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50637)_dec(47.26176)_20250509-22h34m48s866ms.CR2
22:35:22 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50634)_dec(47.26180)_20250509-22h35m05s038ms.CR2
22:35:39 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50630)_dec(47.26188)_20250509-22h35m20s476ms.CR2
22:35:51 ASCOM dithering...
22:35:51 PRE-DITHER Telescope RA(13.50626331) DEC(47.26191406)
22:35:54 Dither settled to RA(13.50624359) DEC(47.26143073)
22:35:54 Difference of RA(-0.00001972) DEC(-0.00048333)
22:35:55 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50626)_dec(47.26191)_20250509-22h35m36s850ms.CR2
22:35:55 POST-DITHER Telescope RA(13.50619427) DEC(47.26144531)
22:36:17 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50616)_dec(47.26152)_20250509-22h35m58s976ms.CR2
22:36:32 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50612)_dec(47.26156)_20250509-22h36m14s554ms.CR2
22:36:47 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50609)_dec(47.26160)_20250509-22h36m28s897ms.CR2
22:36:59 ASCOM dithering...
22:36:59 PRE-DITHER Telescope RA(13.50605317) DEC(47.26164063)
22:37:03 Dither settled to RA(13.50603095) DEC(47.26234063)
22:37:03 Difference of RA(-0.00002222) DEC(0.00070000)
22:37:04 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50605)_dec(47.26164)_20250509-22h36m45s382ms.CR2
22:37:04 POST-DITHER Telescope RA(13.50598610) DEC(47.26234375)
22:37:25 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50595)_dec(47.26242)_20250509-22h37m07s334ms.CR2
22:37:41 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50591)_dec(47.26246)_20250509-22h37m22s773ms.CR2
22:37:57 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50588)_dec(47.26250)_20250509-22h37m38s960ms.CR2
22:38:08 ASCOM dithering...
22:38:08 PRE-DITHER Telescope RA(13.50584014) DEC(47.26253906)
22:38:12 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.50584)_dec(47.26254)_20250509-22h37m55s178ms.CR2
22:38:13 Dither settled to RA(13.50585347) DEC(47.26190573)
22:38:13 Difference of RA(0.00001333) DEC(-0.00063333)
22:38:14 POST-DITHER Telescope RA(13.51317041) DEC(47.32929688)
22:38:36 M51 May 10-11_LIGHT_10s_1600iso_+25c_ra(13.51313)_dec(47.32934)_20250509-22h38m17s428ms.CR2
22:38:51 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.51310)_dec(47.32938)_20250509-22h38m33s022ms.CR2
22:39:07 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.51306)_dec(47.32941)_20250509-22h38m49s272ms.CR2
22:39:17 ASCOM dithering...
22:39:18 PRE-DITHER Telescope RA(13.51303032) DEC(47.32945313)
22:39:22 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.51303)_dec(47.32945)_20250509-22h39m03s882ms.CR2
22:39:22 Dither settled to RA(13.51308393) DEC(47.32951146)
22:39:23 Difference of RA(0.00005361) DEC(0.00005833)
22:39:24 POST-DITHER Telescope RA(13.52031096) DEC(47.39742188)
22:39:45 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.52028)_dec(47.39746)_20250509-22h39m26s710ms.CR2
22:40:01 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.52024)_dec(47.39750)_20250509-22h39m43s100ms.CR2
22:40:17 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.52020)_dec(47.39754)_20250509-22h39m59s256ms.CR2
22:40:28 ASCOM dithering...
22:40:28 PRE-DITHER Telescope RA(13.52016484) DEC(47.39757813)
22:40:33 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.52017)_dec(47.39758)_20250509-22h40m15s538ms.CR2
22:40:33 Dither settled to RA(13.52021928) DEC(47.39683646)
22:40:33 Difference of RA(0.00005444) DEC(-0.00074167)
22:40:34 POST-DITHER Telescope RA(13.52735400) DEC(47.46531250)
22:40:56 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.52732)_dec(47.46535)_20250509-22h40m37s382ms.CR2
22:41:11 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.52728)_dec(47.46539)_20250509-22h40m52s631ms.CR2
22:41:26 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.52725)_dec(47.46543)_20250509-22h41m08s866ms.CR2
22:41:37 ASCOM dithering...
22:41:37 PRE-DITHER Telescope RA(13.52721182) DEC(47.46546875)
22:41:42 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.52721)_dec(47.46547)_20250509-22h41m23s506ms.CR2
22:41:42 Dither settled to RA(13.52723598) DEC(47.46579375)
22:41:42 Difference of RA(0.00002417) DEC(0.00032500)
22:41:43 POST-DITHER Telescope RA(13.53427602) DEC(47.53484375)
22:42:05 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.53424)_dec(47.53488)_20250509-22h41m46s476ms.CR2
22:42:19 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.53421)_dec(47.53488)_20250509-22h42m01s851ms.CR2
22:42:35 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.53417)_dec(47.53492)_20250509-22h42m16s241ms.CR2
22:42:46 ASCOM dithering...
22:42:46 PRE-DITHER Telescope RA(13.53413376) DEC(47.53496094)
22:42:51 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.53413)_dec(47.53496)_20250509-22h42m32s585ms.CR2
22:42:51 Dither settled to RA(13.53412987) DEC(47.53533594)
22:42:51 Difference of RA(-0.00000389) DEC(0.00037500)
22:42:52 POST-DITHER Telescope RA(13.54106918) DEC(47.60496094)
22:43:14 M51 May 10-11_LIGHT_10s_1600iso_+24c_ra(13.54103)_dec(47.60500)_20250509-22h42m55s506ms.CR2
22:43:29 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54100)_dec(47.60504)_20250509-22h43m11s757ms.CR2
22:43:43 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54096)_dec(47.60504)_20250509-22h43m26s116ms.CR2
22:43:53 ASCOM dithering...
22:43:53 PRE-DITHER Telescope RA(13.54092826) DEC(47.60507813)
22:43:58 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54093)_dec(47.60508)_20250509-22h43m40s429ms.CR2
22:43:58 Dither settled to RA(13.54092493) DEC(47.60477813)
22:43:58 Difference of RA(-0.00000333) DEC(-0.00030000)
22:43:59 POST-DITHER Telescope RA(13.53261047) DEC(47.53128906)
22:44:21 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53257)_dec(47.53133)_20250509-22h44m02s491ms.CR2
22:44:36 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53254)_dec(47.53137)_20250509-22h44m18s085ms.CR2
22:44:53 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53250)_dec(47.53141)_20250509-22h44m34s429ms.CR2
22:45:03 ASCOM dithering...
22:45:04 PRE-DITHER Telescope RA(13.53246160) DEC(47.53140625)
22:45:08 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53246)_dec(47.53141)_20250509-22h44m49s881ms.CR2
22:45:08 Dither settled to RA(13.53252521) DEC(47.53107292)
22:45:08 Difference of RA(0.00006361) DEC(-0.00033333)
22:45:09 POST-DITHER Telescope RA(13.53693026) DEC(47.57546875)
22:45:31 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53689)_dec(47.57551)_20250509-22h45m12s569ms.CR2
22:45:45 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53686)_dec(47.57555)_20250509-22h45m28s054ms.CR2
22:46:01 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53682)_dec(47.57555)_20250509-22h45m43s381ms.CR2
22:46:12 ASCOM dithering...
22:46:12 PRE-DITHER Telescope RA(13.53678642) DEC(47.57558594)
22:46:17 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53679)_dec(47.57559)_20250509-22h45m58s679ms.CR2
22:46:17 Dither settled to RA(13.53676476) DEC(47.57604427)
22:46:17 Difference of RA(-0.00002167) DEC(0.00045833)
22:46:18 POST-DITHER Telescope RA(13.54114319) DEC(47.62011719)
22:46:39 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54110)_dec(47.62016)_20250509-22h46m21s507ms.CR2
22:46:54 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54107)_dec(47.62016)_20250509-22h46m36s022ms.CR2
22:47:09 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54104)_dec(47.62020)_20250509-22h46m52s194ms.CR2
22:47:21 ASCOM dithering...
22:47:21 PRE-DITHER Telescope RA(13.54099764) DEC(47.62023438)
22:47:26 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54100)_dec(47.62023)_20250509-22h47m07s538ms.CR2
22:47:26 Dither settled to RA(13.54106792) DEC(47.61982604)
22:47:26 Difference of RA(0.00007028) DEC(-0.00040833)
22:47:27 POST-DITHER Telescope RA(13.54542455) DEC(47.66355469)
22:47:49 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54538)_dec(47.66359)_20250509-22h47m30s319ms.CR2
22:48:04 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54535)_dec(47.66363)_20250509-22h47m45s850ms.CR2
22:48:20 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.50832)_dec(47.29469)_20250509-22h48m01s475ms.CR2
22:48:31 ASCOM dithering...
22:48:31 PRE-DITHER Telescope RA(13.50818956) DEC(47.29414063)
22:48:35 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.50819)_dec(47.29418)_20250509-22h48m16s788ms.CR2
22:48:35 Dither settled to RA(13.50819262) DEC(47.29407396)
22:48:36 Difference of RA(0.00000306) DEC(-0.00006667)
22:48:37 POST-DITHER Telescope RA(13.51832311) DEC(47.39425781)
22:48:57 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.51820)_dec(47.39371)_20250509-22h48m39s694ms.CR2
22:49:12 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.51807)_dec(47.39316)_20250509-22h48m54s116ms.CR2
22:49:28 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.51795)_dec(47.39262)_20250509-22h49m10s225ms.CR2
22:49:39 ASCOM dithering...
22:49:39 PRE-DITHER Telescope RA(13.51782366) DEC(47.39207031)
22:49:43 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.51782)_dec(47.39207)_20250509-22h49m25s147ms.CR2
22:49:44 Dither settled to RA(13.51781255) DEC(47.39163698)
22:49:44 Difference of RA(-0.00001111) DEC(-0.00043333)
22:49:45 POST-DITHER Telescope RA(13.52788409) DEC(47.49132813)
22:50:06 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.52775)_dec(47.49074)_20250509-22h49m48s022ms.CR2
22:50:22 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.52763)_dec(47.49020)_20250509-22h50m03s600ms.CR2
22:50:38 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.52749)_dec(47.48961)_20250509-22h50m20s023ms.CR2
22:50:49 ASCOM dithering...
22:50:49 PRE-DITHER Telescope RA(13.52736763) DEC(47.48906250)
22:50:54 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.52737)_dec(47.48906)_20250509-22h50m36s116ms.CR2
22:50:54 Dither settled to RA(13.52744291) DEC(47.48882917)
22:50:54 Difference of RA(0.00007528) DEC(-0.00023333)
22:50:55 POST-DITHER Telescope RA(13.53744288) DEC(47.58789063)
22:51:16 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53731)_dec(47.58734)_20250509-22h50m58s210ms.CR2
22:51:31 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53719)_dec(47.58680)_20250509-22h51m12s819ms.CR2
22:51:47 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53706)_dec(47.58625)_20250509-22h51m28s335ms.CR2
22:51:58 ASCOM dithering...
22:51:59 PRE-DITHER Telescope RA(13.53693111) DEC(47.58566406)
22:52:03 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.53693)_dec(47.58566)_20250509-22h51m44s803ms.CR2
22:52:03 Dither settled to RA(13.53699972) DEC(47.58551406)
22:52:03 Difference of RA(0.00006861) DEC(-0.00015000)
22:52:05 POST-DITHER Telescope RA(13.54692864) DEC(47.68402344)
22:52:26 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54680)_dec(47.68340)_20250509-22h52m07s678ms.CR2
22:52:41 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54667)_dec(47.68289)_20250509-22h52m23s069ms.CR2
22:52:57 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54654)_dec(47.68231)_20250509-22h52m39s273ms.CR2
22:53:12 Imaging session completed successfully
22:53:13 M51 May 10-11_LIGHT_10s_1600iso_+23c_ra(13.54642)_dec(47.68176)_20250509-22h52m54s023ms.CR2
22:59:29 Camera SHUTDOWN!

DLivesay · May 10, 2025

If I'm reading the log right (and I'm not sure), the "Difference Of" line for each dither seems sorta similar (+/-) for all of the dithers.
- IF I'm reading that right, it perhaps contradicts what's actually happening at the mount .. . ?

astroman133 · May 10, 2025

Have you considered that the drift could be due to a less than perfect polar alignment which would cause M51 to drift in DEC because you are not constantly correcting the position with autoguiding?

DLivesay · May 10, 2025

The polar alignment is spot-on. There is NO drift (of this sudden, out of the blue magnitude).

Besides, how would an ill polar alignment cause correct, in small increment random dithering for 50 frames then turn around and cause gross dithering in one specific direction (straight dead-center) down the screen for the next 50?

My without a camera guiding is very good for what I'm doing.

DLivesay · May 10, 2025

I need to submit the BYE system log-files to ADMIN. From what I'm seeing in there, there's a LOT of conflicts going on.

admin · May 10, 2025

Send me the log file.

DLivesay · May 10, 2025

1 hour ago, admin said:

Send me the log file.

Done.

admin · May 11, 2025

The amount of dithering in the log file sent are not showing erratic behaviour.

However, I wonder if the issue is perhaps related to epoch. In the log file, it looks like eqmod is returning equOther as the set epoch, and BYN requires JNOW (preferred) or J2000. Can this be changed in eqmod (or the mount handpad?)

2025-05-10 13:31:58,239 [24] ERROR - Telescope Epoch equOther not supported.  Defaulting to JNOW
2025-05-10 13:31:58,280 [24] INFO  - Telescope EQMOD HEQ5/6 connected.
2025-05-10 13:31:58,280 [24] INFO  - +--- Epoch                 : JNOW
2025-05-10 13:31:58,281 [24] INFO  - +--- RightAscension        : 12.539172373072 : 12h32m21s
2025-05-10 13:31:58,281 [24] INFO  - +--- Declination           : 90.000000000000 : 90°00'00"
2025-05-10 13:31:58,281 [24] INFO  - +--- Altitude              : 35.418888840330 : 35°25'08"
2025-05-10 13:31:58,281 [24] INFO  - +--- Azimuth               : 0.000000208392 : 00°00'00"

DLivesay · May 11, 2025

13 minutes ago, admin said:
The amount of dithering in the log file sent are not showing erratic behaviour.

However, I wonder if the issue is perhaps related to epoch. In the log file, it looks like eqmod is returning equOther as the set epoch, and BYN requires JNOW (preferred) or J2000. Can this be changed in eqmod (or the mount handpad?)
2025-05-10 13:31:58,239 [24] ERROR - Telescope Epoch equOther not supported.  Defaulting to JNOW
2025-05-10 13:31:58,280 [24] INFO  - Telescope EQMOD HEQ5/6 connected.
2025-05-10 13:31:58,280 [24] INFO  - +--- Epoch                 : JNOW
2025-05-10 13:31:58,281 [24] INFO  - +--- RightAscension        : 12.539172373072 : 12h32m21s
2025-05-10 13:31:58,281 [24] INFO  - +--- Declination           : 90.000000000000 : 90°00'00"
2025-05-10 13:31:58,281 [24] INFO  - +--- Altitude              : 35.418888840330 : 35°25'08"
2025-05-10 13:31:58,281 [24] INFO  - +--- Azimuth               : 0.000000208392 : 00°00'00"

With regard to the dithering error not presenting in the log vs what I'm seeing, my response is "Naturally" (sarcastic stab at humor).

As to the Epoch setting in EQMOD, YES. That user adjustable setting is there. I need to fire up that system to see what the current setting is.
I do recall that user adjustable setting in Stellarium. IIRC, it is set to J2000 (I think by default there).

Again, I need to fire up that system to confirm that all are set to the BYE preferred JNOW (with J2000 being the alternate should JNOW not being available in one of them).

My telescope setup is based around my actually being there and enjoying the quiet of night along with the critters roaming. I sit at a small table with the PC and monitor under a tent-type shelter. The telescope sits just to my right. No WIFI and running in and out to mess with stuff. It's just what my heap has evolved to.
Currently, the OTA is in the house and everything else is under rainproof covers
RADAR shows big rain just over there . . . The forecast calls for notable rain till Wednesday.
I'll try to do something to test things as the weather allows.

@ADMIN and astroman133: Thank you. Your efforts to help me resolve this are greatly appreciated. 🔭🙂

astroman133 · May 11, 2025

The EquatorialSystem (what the log is calling Epoch) is usually only used to convert between the Altitude/Azimuth coordinates and Declination/RightAscension coordinates. The ASCOM library methods for performing those transformations only support J2000 and Topocentric (what you are calling JNOW). Virtually all amateur telescopes use Topocentric as their EquatorialSystem.

It may be worth asking the EQMOD experts or the folks at SkyWatcher why they are not following the norm and using the Topocentric coordinate system.

But also, if BYE can get and set both RA/Dec and Alt/Az directly from the telescope, how exactly why they need to use the ASCOM.Astrometry.Transform to convert between them. If BYE is not using the Transform logic, then the EquatorialSystem used by the mount may not be the cause of your issue.

astroman133 · May 11, 2025

I am not familiar with EQMOD, but I did a bit of googling and saw that the Epoch can apparently be set in EQMOD in the ASCOM Setup dialog. This should probably be JNOW or Topocentric. They are the same.

Here is a link to the article that I found.

https://astrocookbook.com/2018/07/20/setting-up-a-skywatcher-mount-with-ascom-platform-and-eqmod/

DLivesay · May 12, 2025

18 hours ago, astroman133 said:

I am not familiar with EQMOD, but I did a bit of googling and saw that the Epoch can apparently be set in EQMOD in the ASCOM Setup dialog. This should probably be JNOW or Topocentric. They are the same.

Here is a link to the article that I found.

https://astrocookbook.com/2018/07/20/setting-up-a-skywatcher-mount-with-ascom-platform-and-eqmod/

Yes. That appears to be the standard procedure for setting it up.

- Word to the wise, while one wants the com port variables set a given way in EQMOD (timeout, retry, baud, etc), be sure those same figures are set in the actual PC's com port.
- Sometimes, things may still not work right, if at all. Some, myself included, have found relief by completely uninstalling the .NET Framework as found in your PC's system apps. Restart and, reinstall the .NET Framework just as you initially found it. Restart again and have a go. Good times!!

Currently under a flood-watch till Tuesday. 🌨️

DLivesay · May 16, 2025

Well, insuring that Stellarium, EQMOD and BYE are all referencing the same Epoch (JNOW) appears to have resolved my issue of Dithering going off on wild tangents.
- NICE!!

Gentlemen, your time and efforts in helping me address this are greatly appreciated.

astroman133 · May 16, 2025

Thanks for letting us know.

DLivesay · May 17, 2025

It's those pesky details that perhaps make or break many, IMO. While many see the woods, one would do well to also see the trees.

As I'm using an F8 Newtonian, it has a bit more magnification as compared to say, an F4. Yeah, well, that magnification isn't necessarily just a visual thing, it effects the apparent magnitude of dithering as well. For my application, an aggression setting of one (1) initially appears to achieve the goal of moving things to an adjacent pixel or so. A setting of two (2) has things jump an 1/8"(+) on a 18" (diag) screen (and I may best use that setting with the 6D). A setting of three (3) is even larger jumps.

I'm the type that enjoys the voyage more than the final image.
Next is to figure out why my calibration-frames aren't fully/correctly addressing a notable color-gradient in my lights. I have no light-leaks . . . now. The attached image is a grossly exaggerated example but, such is a conversation best suited for elsewhere.

Anyhoo, thanks all for the help.

astroman133 · May 18, 2025

If I remember correctly, the 6D is a full frame camera, rather than a model with an APS-C size sensor. The larger sensor can require the optical system to also be larger to ensure that the entire sensor is uniformly illuminated. I wonder if the secondary mirror is undersized and you are seeing anomalies from the edge of the mirror in your images...just a guess. If you have access to a camera with a C-sized sensor it could be useful to see of the problem still exists. Also, I don't know what ISO you are typically shooting with, but if it is a high value you could try to lower it to 400 or 800. Just some random thoughts that occurred to me after looking at your image.

DLivesay · May 22, 2025

On 5/18/2025 at 10:51 AM, astroman133 said:

If I remember correctly, the 6D is a full frame camera, rather than a model with an APS-C size sensor. The larger sensor can require the optical system to also be larger to ensure that the entire sensor is uniformly illuminated. I wonder if the secondary mirror is undersized and you are seeing anomalies from the edge of the mirror in your images...just a guess. If you have access to a camera with a C-sized sensor it could be useful to see of the problem still exists. Also, I don't know what ISO you are typically shooting with, but if it is a high value you could try to lower it to 400 or 800. Just some random thoughts that occurred to me after looking at your image.

The 6D is a full frame camera.
- The secondary is fine (has been again confirmed during a recent, extensive focuser alignment).

As far as the ISO, It depends on whether you're doing planetary/lunar work or DSOs.
Regarding planetary/lunar work with the 6D, it's common practice to capture the images via the camera's Live-View feature. As the live-view process uses a Simulation of the image(s) presented, the shutter-speed apparently doesn't really matter. The general hive-mind contention is that a shutter speed of 1/30th of a second "fits" best in the simulation process. With that, one changes the ISO setting to make the final images look/work correct.
On the other hand, when doing DSO work, it has been shown/proven that the ideal ISO is 1600 [with some exceptions (800 or 3200) pending the image sensor's working environment temperature]. With that, the shutter-speed is varied for best image presentation.

** I've been successful in rectifying the vignetting/color-gradient issue. It turns out that the customary fashion of capturing the Flats using the camera in the AV-Mode just plain doesn't work in my application (gross over-correction). I've found relief by capturing the Flats in the Manual-Mode and setting the exposure such that the resulting histogram presents with a much more compacted plot that is situated WELL into the the 1st third of the histogram. At the end of the day, the Flats I need are perhaps a lot darker than the average I've seen others use.

This works VERY well:

DLivesay · May 22, 2025

Compared to the customary AV-Mode Flat:

astroman133 · May 22, 2025

I am glad that you figured out your issue.

FYI, in LiveView/Planetary mode, both the ISO and the shutter speed affect the brightness of the captured frames, without slowing down the frame rate.

Shutter speeds of 2 seconds down to the minimum supported speed, like 1/4000 can affect the brightness of the frames. For Planetary imaging of Mars Jupiter. and Saturn, I would set the ISO to 800 and adjust the shutter so that the image appears under exposed. For example, you should just be able to see the bands on Jupiter. You can stretch it in post processing.

Dithering issue . . . .

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