The image below was captured on my iPhone whilst sat in my armchair, pointing the phone at a wall at 15:00. I think the app is iPhone only?
There might be similar planetarium software available for other types of phones.
Thanks for that suggestion! I'm a Windows/Android user, but fortunately, there is a version for Android and I purchased it and installed it on my phone. It is impressive how it works. It was difficult to pinpoint whether it showed its image of the Sun directly on the actual Sun because the Sun is so bright and Luna is currently only two days from New Moon and is not visible here at the moment.
Because its title is “Ephemeris: Sun and Moon Seeker”, I had presumed it only pinpoints those two celestial objects. But upon re-reading your message, it implies that it also will provide a marker for others, such as Polaris, and hopefully more? But I was not able to find a way to display anything other than Sun and Moon even thought any object nears the Celestial Pole (a la Polaris) is always in the same spot.
Is there a way to display celestial targets? Does this work only when the Sun goes down and we enter night mode?
Regardless, this is a cool app and I thank you for recommending it.
Thanks for your suggestion! Unfortunately, you may be correct that this is an iPhone only app and I am and Android only user because I could not find it for Android.
However, I do use Stellarium often and also the ASI Mount software which controls the AM5 mount. For whatever reason, neither SharpCap nor ASI Mount move the AM5 to exactly where the selected target actually is – this is the problem I’ve been having since converting to the AM5 and why I contacted Robin in the first place. And try as I might, and trying all of Robin’s many and insightful suggestions has not fully resolved the problem. Initially, SharpCap pointed the scope in entirely wrong directions for where the target actually was. Robin suggested installing and using ASI Mount to somehow sync SharpCap with the ASI Mount settings and that made a huge difference, but the scope still doesn’t point exactly where it should.
What I’m going to try this afternoon is determine whether or not the dovetail on the scope is directly in line with the C8 axis or something similar. And I also want to test if I can determine that the error or difference between where the scope ultimately points and where the target actually is always has the same error, such as 1.7 degrees in the same direction. If it’s always the same, then I may be able to find a way to mechanically align the scope properly and it should work on all other targets. If it varies, this would be a bankrupt approach that won’t work.
Alternatively, and easier, is if I can set a permanent offset to the mount programmatically through a setting in SharpCap or ASI Mount. That would certainly be easier and more accurate than a mechanical offset.
Of course, there could be a problem with the AM5 mount itself, but I doubt it. I’m going to contact High Point Scientific where I purchased the mount this afternoon. They’ve got great tech support, and hopefully, they’ve seen and resolved this issue for other customers. If such a solution exists, I will share it on this forum for other users.
I'll only point it at the Sun when the Sun is below the horizon and I want to photograph it rising being a lighthouse, for example. I'll do the same for the Moon.
It just shows the Sun and Moon, but I figured in your case you needed to verify that Polaris is where you hope it is. Do that by clicking the button for Equatorial Grid. At approximately 90 degrees declination on the grid will be Polaris.
I should have turned on the grid and what you just mentioned would have been obvious - Brain lapse. I know Polaris is not exactly at the pole, but at 0.67 degrees off, that isn't much, nor can I see with that resolution, so it's definitely close enough.
determine whether or not the dovetail on the scope is directly in line with the C8 axis
You state you switched to the AM5 mount. On your previous mount, did it work correctly with the C8? If yes, that implies that the scope/dovetail alignment is 'good enough'.
Previously, the C8 was a CPC-800 I bought from a friend, so it was an Alt/Az mount. The images I was getting from it were very good and it passed the Star Test handily, so I decided to keep the scope, de-fork it, and get a harmonic EQ mount.
The dovetail can only mount one way of the OTA and in checking the alignment it appears to be spot on. I called HighPoint Scientific and they said there are known problems using the AM5 mount for aiming, but several of the staff use it with the ASIAir and are very happy with itl. Is that just a way to sell another accessory? Possibly, but as I mentioned earlier, HighPoint has been great about standing behind their products and I've never had them trying to push any product. Because I'm experiencing that the mount aiming is poor, I bit the bullet and ordered an ASIAir. If that doesn't work properly, I'll definitely complain and return it, but HighPoint has never steered me wrong yet, so I trust them.
I'll let you know what happens. The Air should be here in a few days and I'll install soon after. The bigger issue lately is all the cloudy nights we're experiencing - that can delay my testing. Because of the weather, I'm feeling like it's time to move to a drier clime or mountaintop, somewhere that we can experience much more clear sky weather.
Thanks for the link to alternative apps for GoSkyWatch! I'll check them out,
If a camera's back focus is not correct, can that cause an inaccurate polar alignment?
I ask this because I've just realized that, compared to my prior use of Celestron StarSense, which is a completely self-contained system that includes it's own scope and purpose-match camera) to aim my prior alt/az scope. Conversely, my current polar alignment with my AM5 is with my C8 (which is now doing double duty for astro photography AND polar alignment. With the alt/az scope, I never worried about back focus distance accuracy because I was stacking and had to cropped most photos anyway, so was not concerned about round stars in the corners. But now I'm using SharpCap or the ASIAir to polar align as well as to shoot photos, and the AM5 doesn't quite aim accurately enough no matter how I polar align, yet it tracks superbly and I've had what seems like perfect tracking for over 30 minutes with no guiding. Therefore, I'm finding it hard to believe the mount is the problem, and yet know that it also can't be SharpCap or the ASIAir because thousands of astronomers are using both very successfully.
So, I'm asking whether a back focus that isn't accurate enough can affect polar alignment, and as a result, make it somewhat in accurate. I'm about to order some narrower tube sections and shims and wondering if this is a bogus path to explore.
shouldn't be an issue - the way that SharpCap detects the current pointing of the RA axis is equivalent to the way star trails arc round the pole in a long exposure, but there is no movement *at* the pole. It doesn't matter which way you point your camera, what position on the earth you are or how your lenses are set - the stationary point is always the pole.
If you are tracking well then that indicates good polar alignment (at least in the direction at right angles to the current position of the mount). Poor slewing with good alignment could be caused by cone error - if your errors are largest when the mount has performed a flip from one side to the other then that is definitely something to investigate.
I wanted to follow up with the progress I’ve made over the months since we last corresponded in the hopes this proves helpful to others and to you who has spent significant time helping me. Ultimately, plate solving resolved my issue, but two things conspired to undercut me. First, plate solving was set to “Sync mount” and not to “Sync mount and re-center target”, which it now is. It’s certainly possible that I did not set it correctly, or if that is the default, that I inadvertently changed it. There were also other such settings that needed to be corrected. I was trying a lot of things initially to get SharpCap working with the AM5.
Second, I was doing all this with my C8 and sometimes using it with a Barlow in an attempt to give me a larger image of small galaxies. This obviously let in even less light and that caused me to mistakenly think I had a problem with a new DSO camera.
I’ve been a part-time professional nature and landscape photographer for much of my life and an amateur astronomer for decades, but am new to astro photography. My assumptions of the similarities were not all correct, especially at longer focal lengths with extremely dim targets. The “Ah Ha!” moment came when I purchased a good-quality 4 inch refractor (Esprit 100ED) at the suggestion of a fellow astronomer and everything started to fall into place.
My camera (2600MC Duo) was now able to see the stars easily and the images were bright, contrasty, and sharp. And then I found that plate solving was not set properly and changed it; all of a sudden targets were nicely centered when plate solving completed.
So, what does this tell us? It tells me that my engineering and photography background were far less helpful in getting me started in astro-photography than I could have ever imagined. It also tells us that the AM5 works well with SharpCap. Though I don’t understand why I had to perform certain steps to somehow get the AM5 to sync with SharpCap, for instance, by using N.I.N.A. to set Lat and Long the first time. How you divined that would help is beyond me, but it handily solved that problem. I also don’t know why using the AM5 app to select targets from its own database also started pointing the scope very close to the target’s position so plate solving could finish the process; and then it started working properly by using SharpCap or ASIAIR alone. ASIAIR works well, but doesn’t provide anywhere near the nuance of control of SharpCap. No matter, without plate solving, not even a small vestige of the target was in view.
Regardless, I’m finally having fun with everything working. In time, I will go back to doing some testing with the C8. I need it for planets and for small DSO objects. I’ll start with including the reducer in the image train and transition to its longer, native focal length of f/10 as I learn more. And for what it’s worth, I can now polar align in 3 -5 minutes and quickly slew to a target, so that incessantly long and frustrating practice over the winter months when nothing appeared to work turned out to be time well spent in retrospect (whether I liked it or not).
On a slightly different front, I found a video of a presentation you made entitled “Deep Sky Astrophotography with CMOS Cameras“ and it was very helpful indeed — thank you for that! I have a question related to it and will post it shortly in the Deep Sky Imaging topic.
Thanks again for all your help! I really appreciate it!
