wimvb

Nice setup, but as @MarkAR noted, the ball head may be a potential cause of flexure. There's only one way to find out: test it. If your imaging scale is high/coarse enough, this may not be an issue.

One more parameter to calculate in: number of subs. At high gain, you lose dynamic range. In order to increase this, you need more subs. Can your computer handle this? With my ASI174MM-Cool, I use low gain (20), low offset (10) and still take more than 100 x 2 mins L-exposures. I also keep gain and temperature constant for all filters (except Ha, which I rarely use). This makes maintaining a dark library much easier.

The polar alignment method used by SharpCap (and Astrotortilla?) needs about 1 degree fov to work reliably. Depending on your guide scope/camera combo, that may be an issue. But you can also use your imaging scope/camera to polar align. PHD also has various polar alignment routines that may be of use.

The simulator profile can not be deleted in Ekos, because it is used for development purposes. "It's a feature, not a bug."

I have only used INDI and Ekos/Kstars. I started with INDI on a raspberry pi, installed from scratch, this was pre-StellarMate. Ran Ekos on my windows laptop. But I found that my wifi wasn't up to the task as I kept losing connections. I upgraded to a Rock64 which had usb3 before the Pi, and ran Ekos/Kstars off that. I believe I was the first person to use a Linux/Rock64 as data capture computer, because I had to ask Patrick Chevalley to fork the Linux version of phd to arm64, and there was no mention of one on any astronomy forums. There were also a lot of bugs in the Rock version of ubuntu. Eventually I ironed out most of the wrinkles with the help of members from the INDI forum. Now I have gone from Ubuntu/mate to Armbian, and replaced the sd card with an emmc module. This has resulted in a substantial increase in speed and stability. I still use windows remote desktop to connect to the sbc, but once I have everything up and running, I can disconnect and use my laptop for other stuff. This winter/spring I have experimented with the scheduler module in Ekos, in order to increase the level of automation. Atm only focusing is not automated, because the mechanical connection between the Pegasus focuscube and the sw focuser keeps slipping. This will be an easy fix during summer recess.

Probably good as a guide cam, but because of the Bayer matrix, not ideal.

Where do you set up your mount? If it's on a lawn or other soft surface, put a brick or something underneath each leg of your tripod. I used three fence post anchors in the soil, and left them there. https://www.ebay.co.uk/itm/Zinc-Plated-U-Type-Post-Fence-Foot-Anchors-Packs-/262736097733 Mine were L-type, with the vertical part removed.

When you start up phd for the first time, you're asked which mount/telescope and which camera you use. I believe it's called the profile wizard or hardware wizard. You can add as many profiles as you like. You should have a profile for each configuration you use.

I don't think you can differentiate between them in phd. I get that forked icon when I connect through indi. It shows my guide cam (ASI120) and my imaging camera (ASI174). How about making two profiles?

Do you plan to have both cameras physically connected to the computer at all times? I know that in Linux you can create a rule for this situation, but am not sure how it works in MS windows. If an option, only connect one camera at a time.

Adam Block is very good at explaining what processes in PI do. He is clearly targeting his videos to the more advanced users who want to understand how processes work. With exponential transformation you always have to be very careful not to stretch noise. The process can easily result in a noisy and mottled background.

That changes the outcome of the image, but not the capability of the hardware.

Do you mean like this: https://skyandtelescope.org/astronomy-blogs/astrophotography-benefits-dark-skies/

https://arxiv.org/pdf/1401.5473.pdf (eqs. 3 and 4, mainly) A crude approximation: the light gathering ability of an imaging system is proportional to the square of pixel size divided by focal ratio, (p/F)^2 This is equivalent to: the light gathering ability of an imaging system is proportional to the square of the pixel scale multiplied by the aperture (diameter), (rD)^2 This is under the assumption that the system isn't undersampled, and any light smearing effects, such as poor seeing, poor focus, or poor guiding, are not accounted for. Oh, and nothing about signal to noise ratio.

I'm sorry, I don't follow.

Isn't that the Rayleigh criterion? Rayleigh: angular resolution =1.22 L/D, where L is wavelength, D is aperture.

The first chapter of "Lessons from the Masters" written by Stan Moore, gives a good overview. The book itself is edited by Robert Gendler.

The 150pds is slightly heavier than the 130pds. It's also longer, and more sensitive to wind. This makes the 130pds easier to handle. Quality wise, these scopes are very similar. Both need a coma corrector, so you need to calculate that into the cost. All in all, I'd say that it depends very much on your personal circumstances as to which will suit you better.

Nice image. I think that with some carefull processing, you should be able to separate those dark clouds from the background. Which processing software do you use?

You have a very nice image already. As for the use of an Ha filter; this is ONLY of use if you image emission nebulae. With an unmodified dslr it's utterly useless. Some unmodified cameras are sensitive to Ha, but most need to be modified to allow Ha imaging. As suggested by others, capture more data. I think you need at least 4-6 hours more for the really faint stuff. If your 3 minutes exposures lift the histogram on the lcd screen of your camera, from the left side, then don't change the exposure time. But if you see read noise in your subs, then increase the exposure time to, say, 5 minutes.

From the phd site Orthogonality error - the camera axes are normally computed independently even though they should be perpendicular. The angle calculations do not require great precision, but if they are signfiicantly non-orthogonal, you should repeat the calibration. If you see repetitive alerts of this type and the axes are significantly non-orthogonal, you'll need to identify the problem and fix it. Common causes are bad polar alignment, large declination backlash, or large periodic error in RA. Any of these problems can cause the guide star to move significantly on one axis while PHD2 is trying to measure its motion on the other axis. If you suspect these problems, go ahead and accept the calibration, then run the Guiding Assistant to measure your polar alignment error, declination backlash, and RA tracking error. In other cases, the mount may not be moving at all, and the measured displacements of the star are just caused by seeing effects. This sort of problem should be obvious in the calibration graph at the left of the dialog. If the axis error is relatively small and you are convinced the hardware is working properly, you can avoid further alerts of this type by setting the option to 'Assume Dec orthogonal to RA' in the 'Guiding' tab of the Advanced Setup dialog. But you should do this only if the error is fairly small - otherwise, you are simply ignoring a serious problem. https://openphdguiding.org/man-dev/Trouble_shooting.htm

Filters are plane with parallell surfaces, which won't result in much aberration. But the light travels at an angle, so the effect isn't completely absent. Otoh, if it was much of an effect, we wouldn't be able too look out a window without seeing a rainbow. For fast scopes, it is more of a problem, of course. And it depends on how accurate you want to be. I don't know if ca is affected by atmospheric conditions, in the sense that it may be more visible when seeing is excellent than when seeing is poor. Colour aberration itself does not depend on atmospheric conditions, of course.

Does it have to be Meade? Capacity wuse an eq8 or maybe even an eq6R could do the job for substantially less money.

Depends on the corrector glass and how fast the optics are. Faster optics have a steeper light cone, and are more susceptible to aberration, afaIk. So far, I haven't found my reflectors at f/5 sensitive to chromatic aberration. The 150pds has a Baader coma corrector, and the 190 mak-newt has a corrector cell.

Not in a reflector. Difference in focal point is a result of dispersion, ie difference in refractive index for different wavelengths. But refractive index isn't relevant for mirrors, because the light never goes through glass. If you have a corrector, there may be minimal chromatic abberation. Most ca is generated in the objective of a refractor.