What I miss most about the older cameras is we use to have FOVi for those cameras already configured. All we had to do is take an image that had enough stars to plate solve and we were golden. The system I'm trying to setup remotely is an ASA600 24" f/7 RC mounted on an AP3600GTO using a AC4040BSI camera and Star Chaser guider. I have the system fairly well setup so that focus is reliable, pointing is close but not dead on yet however using ACP it will take the initial image, plate solve, then center accordingly. The biggest issue now is seems to be finding a place in the sky that will have enough stars to plate solve both the main chip and the guider. The AC4040's image scale unbinned is 0.46 so my guess is I should bin both main chip and guider. The AO is not functional at this time but is installed. The huge crutch in this scenario is being remote and having a 3 hour time difference. The earliest time for me in Virginia to try anything under the stars at SRO in California is about 1:30 am my time (EST). Doesn't do much to help keep the mind clear at that hour and 70 years old. Any sage advice, ideas, or magic in getting over this hurdle would be extremely appreciated. The only other solution I see might just be very short exposures combined using Doug's High Gain Stack Pro. That said I see important advantages of using a guider and if for some reason an older camera was again used it would require guiding. The better choice may be Stack Pro but I'd like to have the choice if possible. From this morning's foggy attempt I could not find locations to slew to that gave me more than 3 stars in the Star Chaser which isn't going to plate solve. Is there a way to calculate the offset from the main camera as to where the star chaser should be? If I have some indication it would help immensely. Maybe I can find an open cluster that will populate bot chips and give me a fighting chance. Wide open to suggestions please.
From what I see in the manual the Star Chaser is installed in one position only so the only way I can see the calculation of the guide chip being any different is if any adjustment was made to the pick off mirror. Is this correct? That means the angle of the guide chip should be at a predictable offset/angle? Trust me this is like trying to do surgery blind folded and with no feeling in your hands, maybe deaf too. Getting this at least close is very important on this larger scope. Ideas and thoughts appreciated just keep it clean please
The old cameras had a fixed position for the guide sensor relative to the imaging sensor, which made it trivial to create a FOV indicator. It's not so easy when the guider is a separate and adjustable component, and there's no way to make a predefined one that will work. First step is to figure out what side of the main chip the guider is on. You can go through the machinations in your head and still end up with a good chance of getting it wrong (from experience)... or you can figure it out taking images. My usual technique for this is to use the moon. It's big and very obvious target - even when it's not in the image you can see the bright sky gradient from it. Then you need to know the distance from the guide chip to the main chip. If you know the offset range of your guider, and you have it at one end or the other, it should just be math. Or... you can center a target in the main camera and note the position, and then adjust the telescope position until it's centered in the guide chip, and note the position. Subtract the two and you know the arcsecond distance. (If you're moving in RA multiply by 15 to account for hours versus degrees.)
Thanks Doug. Not having installed the equipment I'm a bit clueless as to orientation but was under the impression that the SC could only be in one position with the 4 screws. Is that not correct? As far as the process to create, The Sky X has a procedure that minimizes the process by taking an image with the main chip, plate sole it, then take the guider image and do the same. Following their 4-3 step process will generate the accurate FOVi. Issue is having the needed stars to plate solve hence a highly populated open cluster or double cluster is ideal. I used this with my STX-16803 and OAG very successfully. My issue here appears to be image scale and star density. Aside from this can it be assumed that the guide chip would be parallel to the main chip at a multiple of 90d? Or is this way off? Trying to get a picture of this in my head. Do you have an example of a FOVi for this camera by chance?
Yes it can be hard to get enough stars to plate solve. That's why I suggested using the moon to get a rough idea of where things are, and then center the same star in each chip to get the precise offset. In terms of the mounting interface, you can attach the SC in any of four different positions. Of course some positions might not be convenient for cabling etc. I haven't got around to doing an FOVi for this combination.
Thanks Doug. Something like the double cluster, NGC869, would be great but it transits at 08:26 am...but always above horizon. Well at SRO it's that time. Might be worth a try or I get up much earlier and try.....
While my setup doesn't have nearly as much focal length as yours, I've always managed to get a plate solve on the guide chip by going to a large open cluster, solve with the main camera to make sure the pointing is dead on, then just bump the mount until I get a lot of stars on the guide chip. Are you using the online all sky plate solve? That is much more robust at getting a good solve when the area isn't known, at least in my experience.
The process I use for creating a new FOVi is using The Sky X to go through a 5-6 step process to create extremely accurate results. You take the primary camera image, plate solve, take the guider image , plate solve, then combine. This is down via the program. I use astrometry for images that TSX can't for some reason solve. But the process I find easiest is using Software Bisque's TSX. They updated the process a year or two ago and it takes all guesswork out of the process and makes it fairly simple. The key for all of the ways to do this is number of stars to solve with.
Interestingly enough with both guider and main image chip populated using NGC869 I can't get the guider image to plate solve regardless of method. The stars aren't perfectly round but enough I would think to plate solve. Tom on The Sky X forum is trying to see if he can get it to solve. I tried the online Astronomic site as well without any luck....I did all the exposures with High Gain.
Hi Steve. Attached are two solved images of NGC869 and the OAG from your DropBox link. Main camera at 3.051"/pix, horizontally flipped for solving and saved with embedded solution, and Guide camera at 0.234"/pix, saved with embedded solution. Guide camera was solved using only four matched stars in TheSky but eight matched on Astrometry.net using the advanced solver settings, image centre coordinates were the same for both and image overlay looks good, obviously can't say 100% that these are correct, you'll just have to try it and see.... You can use the images to create your FOVi's automatically in TheSky via Image Link, or just create your FOVi elements 1&2 using the data in the attached screenshots. You'll probably want to set up MaxIm to flip the main camera images on capture, at the moment you are capturing images from the main camera horizontally reversed, if you do flip the main camera image on capture the FOVi will still be valid, no changes needed. William. FYI... Solution to solving the guider image was the following. 1. Export the guider image from PixInsight as .fit after noise reduction and hot pixel removal, saved (exported) a duplicate as monochrome .tiff. 2. Open the duplicate .tiff image in Affinity Photo and create synthetic star layer by placing "star" shaped symbols over the existing weak and blurred stars in the native image layer. 3. Flatten the image and apply gaussian blur to convert the artificial stars back into more realistic stars. 4. Export the image as .jpg. 5. Upload the synthetic star field .jpg to Astrometry.net via the "Advanced" options page with "Scale" set to "Tiny (2 to 10 arcmin)" and under "Limits" the estimated RA and DEC of the guider image center entered in decimal format together with a search radius of 6 degrees. 6. After Astrometry solved the image (less than a minute) note the true image centre and scale for the solved image. 7. Upload the noise and hot-pixel reduced .fits guider image to Astrometry.net via the "Advanced" page using the true image center coordinates derived from the synthetic solution and a search radius of 6 degrees in the "Limits" field and under "Scale" the same "Tiny (2 to 10 arcmin)" selection. 8. After Astrometry solved the native (cleaned) image (less than a minute) export the "New-image.fits" copy of the solved image from Astrometry's results page, which contains the solved solution added to the original .fits image. 9. Start TheSky and temporarily switch off time tracking ("||" pause button) then import the "New-image.fits" into TheSky via the Image Link tool. 10. After Image Link places the "New-image.fits" on top of the TheSky's chart adjust the photo transparency to 50% and then switch on-off-on the photo several times and check that the blurry stars of the New-image.fits image align with the underlying star chart with a good degree of certainty. You may (will) need to adjust the star display options in TheSky to display the very faint chart stars that are in the guider image. 11. If happy, break the Image Link with the New-image.fits file and rename it as "Autoguider Image Solved.fits" 12 Upload the main camera image to Astrometry.net using the default upload options. 13. After the main camera image solves (less than a minute" download the "New-image.fits" file from the Astrometry results page, the "New-image.fits" file is now horizontally flipped (correct) so that you can use Image Link to import it and overlay it with the same orientation as the guider image in TheSky. 14. Rename the downloaded "New-image.fits" file "Main Camera Solved.fit". 15. In TheSky use Image Link to import the Main Camera Solved.fit image, TheSky should place the image directly into the sky chart, as before check by switching the image on-off-on to ensure that the photo-overlay stars match the sky chart stars. 16. If the match is good use the FOVi tab in TheSky’s Image Link to create a new FOVi from the main camera image. 17. Repeat the same steps with the "Autoguider Image Solved.fit" image and add as the second element to the Main Camera FOVi. 18. Add/Edit the name of the new combined FOVi. 19. Start time tracking again in the TheSky by clicking the "Computer time" icon on the top of screen tool bar. 20. If necessary, reset the star display options in TheSky to your preferred level of detail. 21. Take a stiff drink to recover....
So I've got the images downloaded and saved but as soon as I open one in TSX to try to plate solve it immediately plate solves by itself before i can tell it to do so. If I hit solve it takes forever and than no result. This happens in both 64 and 32 programs. Any idea why this is happening? This was the behavior before as well.
Steve. The images are already solved, you don’t need to solve them again, just use them to automatically create the FOVi’s but remember to switch the time control at the top of TheSky’s desktop to stop (pause) before you start, otherwise one FOVi element will be displaced to the second element in the RA direction by an amount equal to the time it takes you to import and create the two FOVi elements. The guider image does not have enough sky chart catalogue stars to solve in Image Link without help, you were unlucky to end up with the guide camera placed on a part of the sky that has so few charted stars. The main camera image should solve provided you give Image Link the pixel scale and adjust the detection thresholds to detect only genuine stars and not latch on to noise and hot pixels. In the past, for solving crowded star clusters in Image Link I found it useful to raise the detection threshold so that only a dozen or so of the brightest source stars are detected, the default detection settings are too sensitive and detect too many stars, and false stars due to noise, and Image link fails with too many false pattern matches. With the main camera being so sensitive you will need to reduce the detection settings in Image Link for a successful solve, the opposite is the case for the guide camera where its tiny FOV will require good focus and raised detection settings to capture as many real stars as possible. With the SC guide camera having a physical shutter it will be helpful if you set MaxIm guide camera options to “Auto Dark” to remove the dark current and as many hot pixels as possible. I’m going to be busy the next few days but if I get the chance I’ll run your original images through Image Link again and see if I can find the detection settings that worked for these particular images, I’ve already reset them for my own cameras. I suspect you will have to alter the detection settings in Image Link to suit the image more than in the past with older less-sensitive CCD cameras.
