wimvb

When I create a new profile and use the simulators as the devices, I can change pixel size, focal length, filters, etc. But I can also change seeing conditions in the simulator configuration tab of CCD Simulator, and in the Focuser Simulator. In the focuser module, I can then autofocus and get different fwhm values, depending on what I put in the seeing field of the focuser. In the align module, the stars get wider or narrower depending on focus position (and possibly seeing). Note that you can't change much in the default simulator profile of Ekos. This in order to make sure that for testing purposes all settings are equal. But you can change simulator settings in a profile you create. In fact, when I created a new simulator profile, the CCD settings were preset with the values of my ASI294MM.

Just a wild guess. In the simulator camera driver you can enter pixel size. And I believe that there is also a way to adjust seeing conditions. I can't check that atm, but can have a look tonight.

Here are the things that grab my attention. The moves in RA and DEC are always in the same direction at the same time. This makes me wonder, how good is your calibration? Whenever guiding missbehaves, I start with redoing the calibration. Something may have changed which I missed, and I want to rule out that calibration is no longer valid. Second, you have a MinMo of 0.11 and 0.13, and this is also what your guiding shows as RMS. With your guiding scale of 6.5"/pixel (!! not 5.1 "/pixel), and MinMo of 0.11 pixels, the best guiding you can hope for is with an RMS of about 0.7" in RA and 0.8" in DEC, or more than 1" RMS total. Any smaller star movements are simply never dealt with. If your mount has even a small amount of stiction, this is amplified by the settings. The guide graph is overall very noisy; how was your seeing? If you use a motorised autofocuser, you can tell from the reported fwhm/hfr values how good your seeing is. If seeing is bad, you should increase the MinMo values, so you won't chase the seeing. Also, with a guide exposure time of 1.5 seconds, you are definitely chasing the seeing. Try to increase this to 2.5 - 3 seconds and use multi star guiding. You use a large value for the aggression. Too much aggression can cause erratic behaviour. All these changes should help calm the graph down. Try this remedy: 1. redo the calibration. Calibrate near the Meridian and close to the celestial equator (but at least 40 degrees altitude to minimise atmospheric disturbances). 2. run the guiding assistant (for at least one full worm period, preferrably two). Let the GA measure backlash. 3. Accept the settings suggested by GA, then guide for at least half an hour, preferrably longer. After all this, examine the guide log.

Great. If you want to get the most out of phd, start with calibrating near the meridian, followed by at least 10 minutes (but preferrably 20 minutes) guiding assistant. This will give you a good baseline for your guiding setup. PHD will also determine your DEC backlash. Accept the settings suggested by the guiding assistant. To analyze the mount, let PHD guide for an hour or so with 1 s exposures. (You can image during that time, clear skies are all too precious.) Using a short exposure time will give you better values for the short time periods in the belt drive. Normally you wouldn't use such short exposures, but rather 2-3 s. If the 10 s peak is more pronounced for short exposure guiding, you will probably need to tighten the RA belt. This is a fairly simple procedure.

Yes, exactly so. I was referring to dithering 12 p in the imaging camera of course. For 2 pixels dithering @ 3.3”/p in the guide camera to be sufficient, the imaging scale would need to be 0.55”/p at most, which seems unlikely.

A bit late, but I had a look at your data. Calibration is ok, but your mount has some DEC backlash. I don't know if the ASIAIR compensates for this. If you have another computer to which you can connect your gear, you can measure this with PHD2. Although it doesn't seem too severe and guiding handles it. You dither only 2 pixels. you might want to increase that to 10 pixels or more. This will make it necessary to let the mount settle longer between exposures. The periodic error curve of your mount is very jagged. Normally this curve is much smoother. In your guiding algorithm, use PPEC for RA guiding (Predictive Periodic Error Correction). Your mount (AZ-EQ6) does have the capabality to use Permanent Periodic Error Correction, stored in the mount. But this feature is not compatible with guiding; it's either or, not both. A frequency analysis of RA guiding shows main peaks at 120 s and 240 s. 120 seconds coincides with the motor timing pulley doing one full revolution. The much smaller peak at 10 s is this pulley advancing exactly one section/tooth. Imo, you should do a test with guiding for one hour with 1 s guiding exposures. This will resolve the 10 s peak better. My guess is that it will increase. The 10 s peak (and to a lesser extent the 120 s peak) is related to belt tension. If you tighten the belt, this peak will decrease. If you use 2 s or longer guide exposures, the 10 s peak will cause what looks like noisy guiding.

Go for it. It's a great scope.

Thanks. It is actually often compared to that galaxy.

Thank you, Alan. There are a few images of this object posted on Astrobin recently. But imo, not many really do this gem justice.

A standard ASI120MM is a bit of a gamble. It is so wide that it may not fit between the imaging camera and the focuser. For some people it works, but for me it didn't. (With a dedicated astro camera on a Skywatcher 190MN). I invested in an ASI290 Mini. This camera is more light weight, more sensitive, and smaller.

Ngc 2403 is a liner galaxy in the constellation Camelopardalis. The galaxy has a diameter of about 70 000 light years, making it somewhat smaller than the Milky Way. It is about 10 Million Lightyears distant. The galaxy is a member of the M81 group of galaxies. Capture data: Telescope/camera: Skywatcher 190MN + ZWO ASI294MM-Pro with Optolong LRGB filters and Baader 7 nm Ha filter RGB: 220 x 4 minutes exposures L: 270 x 3 minutes exposures Ha: 80 x 4 minutes exposures Captured 26 January - 11 February. Total integration time, approximately 2010 minutes (33,5 hours). Processed in PixInsight. I just (20 feb just after midnight) put this version on Astrobin. I added Ha to luminance to get better definition in the Hydrogen clouds, and dialed the blue back a little. To get this image where I wanted it, I had to experiment with LRGB combination, using the channel weights to increase colour.

Which gadget is this?

+1 for RPi and INDI/Kstars (Astroberry). I run everything on an RPi4 on top of my scope, and use remote desktop from inside the house. I just set up a sequence and let it run through the night. In the morning I ftp all images to my laptop and close the observatory roof.

Camera information is taken from the camera firmware, and you should never need to edit that. Otoh, if you have two cameras of the same manufacturer, you always need to double check that the right camera is used for guiding and the right camera for imaging. The FL of the guide scope seems a bit short at 190 mm, but I guess you entered that ok. You can easily check the FL by taking an image and uploading that to a plate solver.

Probably because it’s random, so half the time it will push South and East

How accurate is this? If you want the best accuracy in your image framing, then the imaging camera should be used. The guide scope and camera can be used for polar alignment, but I would always use the imaging camera for framing.

I thought that that was how you transport your kit (”t” not ”d”). Ah well, a few years from now perhaps. 😉

You are fine with the guidescope you have (fov is in arc minutes, 86>60) but change the options profile in the stellarsolver settings. I believe that in my configuration I have the first option, but would need to check that to be sure.

One strand of ordinary copper wire can do the job. This also comes in different dimensions.

Platrsolving near the pole is not a problem, I do it every time that I need to polar align. Have you tried uploading one of the images to astrometry.net? Maybe that will give you some clues. The internal solver can be a bit sensitive to fov, which needs to be near or larger than 1 degree. Hope this helps.

This night's automated meridian flip in Ekos. Unfortunately a hickup in the video feed from the observatory camera. The video starts 10 seconds before the last pre-flip exposure is complete, and ends 10 seconds after the first post-flip exposure starts. The flip consists of: halt exposure sequence halt guiding meridian flip (of course) alignment (2 plate solves) continue guiding continue exposure sequence

From my observatory security camera just now. Targeting ngc 2403, 15 minutes before a scheduled automatic flip. At the very right edge of this image you can just see @Firas telescope aiming at the same galaxy.

If the focal length is wrong, then any result in arc seconds or arc minutes is also wrong. The op needs to correct this first.

In most cases, guiding failure after dithering or after a meridian flip is caused by improper balancing and backlash. Use the guide assistant on both sides of the meridian. If the results, especially backlash, are significantly different you need to improve both balance and backlash. Try to get backlash below 1000 ms. PHD can handle what’s left. Slight imbalance and a small polar alignment error can help getting more consistent guiding, but the keywords here are slight and small.

I get it, but it isn't obvious at first glance. Add a 'z' to it? Otoh, people didn't get this one either. 😉