Xio1996

I agree with Peter and Martin. Flats and Darks go together, or much weirdness will happen in SharpCap. I believe there is a post in the forum on the subject by Robin. Talking of Robin 😀 Here is an interesting quote, about people such as myself, that use background subtraction as a flat replacement. Robin, then goes on to discuss synthetic flats New Feature : Background Subtraction - Page 6 - SharpCap Forums I hope he implements the solution. Then I won't feel so yucky using background subtraction 😁 If I ever get a clear sky without it blowing a gale I want to try out a dark/flat on the 533mm. However, I would much prefer to use Hot and Cold pixel removal and a synthetic flat. Have fun. Pete

Hi Peter, I'm far too lazy to unscrew the f6.3 focal reducer from my scope! A CPC-800 at f6.3 is always the ideal solution for all observing sessions 😄 Have fun dithering. Pete

Hi Peter, That's interesting, I find dithering gives a smoother, less noisy background. Usually, I dither every 4 frames with a movement of 15px. Though, I think the 294 used 30px. I would be interested what you think when using it with one scope. Pete

Thanks Peter, for the information. On my Altair Astro 294 colour camera I use a flat as the vignetting was too noticeable when I stretched the image, or as in your case, I had dust somewhere in the system. I do zoom the histogram in SharpCap for the colour camera but not for my mono 533 camera. It has a broader peak than the colour. For the ZWO ASI 533mm sensor I don't use darks or flats. Like you, I find SharpCap's 'Hot and Cold Pixel' removal works very well. I also use 'Low Frequency Wave' background subtraction. Where the 533mm's field of view is much smaller than the 294 colour, I found that I could get away without using a flat. The background subtraction method, to my eyes, improves on the 'flat-less' view in most conditions. I will have to make a flat for the 533 and compare the view. I was so happy with the 533's image that I didn't bother to make a flat in the past. The only other thing I do, is dither every 4-5 frames using SharpCap's non-guiding dithering functionality. That really cleans up the image when combined with sigma-clipping. SharpCap is a wonderful tool 😃 I'm looking forward to seeing your next observing session. Pete

Hi Peter, Great images. It looks like you had a very enjoyable observing session. Do you have any thoughts on why your flats improved the detail in your images? Have fun. Pete

Hi Richard, I use AstroPlanner. It is still being developed and you can get the latest beta updates here AstroPlanner Beta Testing and there is a user group here astroplanner@groups.io | Home Having seen Deep Sky Planner in use by other astronomers (on Youtube) it looks like a great product. One of the great features of AstroPlanner is its built-in scripting environment and its ability to be controlled externally via its web services interface. This allows custom features to be added by the user. It also allows AstroPlanner to be integrated with other applications. For planning, (though most of the time I see where the evening takes me 😄) I use a mixture of Stellarium and AstroPlanner. AstroPlanner gives me similar features as Deep Sky Planner, such as to search for targets with different criteria. While Stellarium is great to look around an area of sky and pick what looks interesting to view, especially with its DSS and HIPS functionality. There is even an AstroPlanner script that allows any object selected in Stellarium to be added into an AstroPlanner plan. Logging an observation, is great for EAA, as I can link in my final 'snapshot' of the image. Hats off to the dedicated people who produce these great applications that make our hobby even more enjoyable. Pete

Hi Peter, Those images are impressive. Your Orion belt image is stunning. Pete

Hi Richard, That is a novel solution and much better than my original solution. When I was starting out in EAA, I would adjust the focus and then run back inside and check focus on the screen, repeat until bored. 😀 I'm afraid, very quickly after that I got extremely boring (and less fit 😄) and purchased a Celestron Electronic Focuser. Though, that does allow me to use SharpCap's automatic focussing routines. Cool solution and you get to stream live to the world. Have fun. Pete

Hi Phyllis, Thank you for the information on the central star. Magnitude 19.12 wow! I believe Celestron specify 14.2 as the limiting visual magnitude of the CPC-800. I guess that is the power of EAA! Have fun. Pete

Hi Everyone, I had a great night (morning 😄?) of EAA fun and wanted to share some snapshots of the session. Each of the snapshots below is the final image of the observation, cropped and maybe resized in GIMP. As usual my trusty Celestron CPC-800 and Altair Astro 294C camera did not let me down. All images were shot at 1000 gain, dark, flat and blended background removal. The session started at 21:13 (BST), after the clouds rolled over, with a look at the impressive globular cluster M2 in Aquarius. While in the area I travelled north to view M15. Both clusters are of a similar size but with M2 being more condensed. 22 September 2023 20:13:44 (UTC) - Subs: 54, Exp (s): 8.0, Total Exp (s): 432.0, Alt: 35.8°, Az: 155.3°, Airmass: 1.7, App Mag: 8.0 Globular cluster M73, low-down in Aquarius (Alt 26 deg). I believe this is the faintest globular cluster in the Messier catalogue. 22 September 2023 21:33:44 (UTC) - Subs: 29, Exp (s): 4.0, Total Exp (s): 116.0, Alt: 26.2°, Az: 189.7°, Airmass: 2.3, App Mag: 9.7 Next up was a favourite target. Big, bright and structured the impressive planetary nebula M27. I have been trying to measure the light curve of the variable star V0571 Vul. This star lies many light years behind M27 and is a Mira type. It has dimmed quite a lot now and try as I might, I did not manage to get ASTAP to measure this very faint star through M27's nebulosity. 22 September 2023 22:00:54 (UTC) - Subs: 73, Exp (s): 12.0, Total Exp (s): 876.0, Alt: 53.3°, Az: 231.6°, Airmass: 1.2, App Mag: 7.9 This is my light curve so far of V0571 Vul, but I was really hoping to measure the star down to minimum in November 🙁 It is still visible as a faint red smudge in the image. Moving on from globular clusters, my next target was the planetary nebula NGC7048 in Cygnus. A lovely red-ringed sphere in a rich starfield. I'm not sure which is the central star of this planetary? 22 September 2023 23:27:08 (UTC) - Subs: 83, Exp (s): 8.0, Total Exp (s): 664.0, Alt: 67.6°, Az: 271.6°, Airmass: 1.1, App Mag: 11.3 Another planetary, NGC 7008 (Cygnus) appears to be wrapping itself around a pair of adjacent stars 😄. There is some nice structure in this object, a really enjoyable view. 23 September 2023 00:24:37 (UTC) - Subs: 75, Exp (s): 8.0, Total Exp (s): 600.0, Alt: 59.3°, Az: 297.4°, Airmass: 1.2, App Mag: 12.4 I finished the EAA session in the early hours of today by viewing IC5146, the Cocoon Nebula. A Triffid 'like' nebula, with lines of dark gas and clouds criss-crossing the object. IC5146 sits at the end of the dark nebula Barnard 168 and there is a hint of this nebula dimming the stars from the nebula diagonally down to the bottom right corner. 23 September 2023 01:08:20 (UTC) - Subs: 100, Exp (s): 12.0, Total Exp (s): 1200.0, Alt: 58.2°, Az: 283.2°, Airmass: 1.2, App Mag: 10.4 I immensely enjoyed my EAA session, filled with colour and structure that was impossible to see in my visual astronomy days (with the same telescope)! Please finds the full list of objects observed, in the AstroPlanner screenshot below . Clear skies and have fun! Pete

I'm not sure what the recommended gain/sub settings are for an object. Its just that some objects like globular clusters/open clusters/PN etc are bright, hence I shorten the sub length. I don't alter the gain settings that much. For a long time now I was using a gain of 900 (Altair Astro scale, HCG start point). However, I have moved up a little to 1000 recently as my 294 chip has problems at that LCG/HCG crossover point. Maybe, I should just pick a single sub length and go with it? One thing I found on flats is that the black level (offset?) has to be the same as the light frames. Using darks and flats together is most probably the best solution but SharpCap can use hot pixel removal and flats together as long as the lights black level is the same as the flats. As always, give it a go and see what you prefer. 🙂

That was a great observing session. I agree with @PeterC65 that darks have the edge on SharpCap's Hot Pixel Removal. However, I found Hot (Cold) Pixel Removal with SharpCap's unguided ASCOM dithering function covered up a multitude of evils 😄 I do find myself using 4, 8 and 15s subs during an evening, depending upon the object being observed. If I stuck to one (sub-exposure) then maybe I wouldn't find darks quite the chore! As has been pointed out, creating darks is a straightforward activity even with an uncooled camera. Give them a go. I don't know if it is down to the chip size of my camera (AA294C) or just my individual preference but I do like a flat calibration frame. A flat does improve my observing experience but I have done plenty of observing sessions without flats. To create flats I use a cheap A3 light panel off Amazon to provide the illumination. Using SharpCap's Flat Capture seems straightforward - Monochrome flat with dark, 25'ish frames, short 200-600ms subs, lowest gain. Flats allow a more aggressive image stretch before dust and the vignetting become objectionable (to me 😄) without them. Have fun. Pete

Hi Curtis, I really enjoyed your video, very informative. Looking forward to your next video instalment. Have fun Pete

Hi Jonathan, I find I use between 4s and 15s subs. I have an Altair Astro camera so my gain setting is 900. Which sounds huge to ZWO camera owners but this is just where the Altair Astro camera enters HCG mode on their gain scale. The enhancement features are good in SharpCap as are the background gradient removal settings. Have fun Pete