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eshy76

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Everything posted by eshy76

  1. Wow Mark - I just saw this - fantastic shot! Congratulations!
  2. Hi Steve - yes that's exactly it - Tools/APT Settings. Once you plug in figures for gain per filter (and autofocus offsets if applicable) in the dialog in your screenshot, whenever you select the filter in an imaging plan, the same gain/focus offset will be brought into the plan...very convenient once you've settled on what you want to use.
  3. Hi there - I'm on a pretty recent Ascom version, maybe not the latest one....however, the answer is in the post above this one. When I set up my filter wheel, I use APT's settings, not the Ascom settings, so Tools/APT Settings as specified by Steve. That should work.
  4. Hi there - do you have the latest version of APT? I believe the gain per filter was only recently added. I have version 3.63. APT is not updated within the program - you have to download and install the new version over the old one. Settings survive that process! That would be my best guess.
  5. Thank you Alan - yes, I collected the data pretty much as a side project to the tadpole/flaming star mosaic I was working on. It wasn't one of my primary targets for the winter - I was also after M45 and the Horsehead - so the data just got forgotten. But processing the clean narrowband data was a pleasure and NGC 281 itself surprised me with its pillars of dust and the little star cluster at its heart. It's a beautiful object in its own right, which I realised when I zoomed in.
  6. And here's the original field of view
  7. Hi everyone, This has been on my hard drive for some months, so nice to have finally got round to processing it! Shot over several nights in January in my back garden. NGC 281, also known casually as the Pacman Nebula, is a bright emission nebula and part of an H II region in the northern constellation of Cassiopeia and is part of the Milky Way's Perseus Spiral Arm. It lies about 9,500 light years from us and is 48 light years across. As the final version, I've gone for a crop, which I think holds up well, though I'll include the wider fov version in the next post. I used a more natural colour blend for this image: R = 76%*Ha + 24%*SII G = 100%*OIII B = 85%*OIII + 15%*Ha For some reason, I was not expecting much from this image, but the result looks like it will be one of my favourites...the narrowband data was really good! Captured using APT, stacked using APP and processed in Pixinsight. 5.4 hours integration time. Link to full details and higher res version. Thanks for looking!
  8. Yep done that one too....one to add to the slapstick astro mess ups...though not as bad as taking 20 mins to realize that the cap was still on my polemaster once...the hot pixels looked like stars on the ipad screen...it took me time to figure out why they weren't moving when I rotated the RA axis....!
  9. The way it works is that if you put a gain number in the little box on the camera tab, that will override whatever was in the Ascom driver pop up, for a single shot and for an imaging plan - *if* you haven't assigned a gain to each filter in settings. In APT's settings when you set up your filter wheel, you can add a couple of things per filter which are useful as defaults for every time each filter is used - (1) the focus offset, if you are using autofocus and (2) the gain. So I tend have 139 assigned to LRGB filters and 200 for narrowband filters for example. I then leave the little box on the camera tab blank to make sure it doesn't override the filter wheel settings I put in when an imaging plan starts. It works perfectly for me....APT's scripting is pretty powerful...I also used it to platesolve to another target (Goto++) and restart PHD guiding in the same night...worked fine. Glad it's working for you now!
  10. Hi there - this seems very odd - I have the same camera and also use APT, and I'm pretty sure the gain can be set higher than 100. I tend to use 139.... My first reaction to your post is that you might not have the right driver selected in APT....to check, click on the "Settings" button next to the camera name at the bottom of the APT screen...then make sure the ASI-1600 is selected specifically from the driver drop down menu in the Ascom screen that pops up. Personally I tend to set the gain using the Ascom driver (in the same "Settings" pop up) and leave the gain setting blank in APT itself - this is because in my filter wheel setup, I have a different gain associated with each filter and I don't want that overridden by the manual gain setting on the camera screen. Let me know if you need me to explain the above more clearly...happy to help!
  11. Yep another vote for SkySafari...has been my invaluable companion on imaging/observing nights in both the Northern and Southern Hemispheres. I also prefer its forward and backward time controls compared to the swiping in Stellarium (which is also a very good app).
  12. I watched the vid and read those posts yesterday - superb! The new stuff versus what I had read before was actually getting a number for light pollution and incorporating that into the equations. It was an impressive presentation and makes me want to dig deeper into Sharpcap, if its creator is so knowledgeable. Thanks again for sharing!
  13. Thank you tomato! I went straight to CMOS, so short subs is all I know...looks like Sharpcap does a lot more than just polar alignment...I need to take a closer look.
  14. By the way, NGC 4440 was the pretty barred spiral galaxy I was referring to earlier....you will be mine one day!
  15. Thank you! I really wanted to bring out the blues more but the data was not cooperating...in any case it's a nice data set to come back and add to. The background is a mottled black too - I actually think that is the beginnings of IFN (integrated flux nebula), but the integration time was too low and the light pollution too high to get close to bringing that out as pretty dust.
  16. Thank you very much! Something to devour this weekend!
  17. I hear you! The basic theory is that each sub should be long enough to drown out the read noise and with the really low read noise of CMOS cameras, that level is reached quickly with light pollution. Of course you can shoot longer than that for practicality, but if subs are too long, stars and highlights could get saturated. That is it in words - there are mathematical formula that try to calculate the optimal sub lengths! Those cameras have really good reputations - I was looking at a 071, but ended up getting a 294, which I'm still learning. I think the 071 has an APS-C sensor? Thank you for the kind words!
  18. Thank you - that sounds interesting - I like the theory side of things as a guideline to what I do! And I did not know that about Sharpcap...I've got the pro version for the polar alignment routine, but have been using APT for capture.
  19. Thank you! That is the golden question which I intend to find the answer to - with my level of light pollution, 15 secs at unity gain on my camera is more than enough for my Lum subs to drown out the read noise...so I've always used that sub length... ...which was fine for 200-300 subs, but this project really brought home the impracticality of stacking 1000+ subs. I just was thinking in terms of total Lum integration time (250 mins) and set the number of subs that way. As far as I am aware, SNR benefits of stacking enter the realm of diminishing returns from about 200 subs onwards...so going forwards I'm going to lower the gain from unity (139 on the ASI1600) to 76 or 0 to try and get sub length up to between 30s and 60s and hopefully more like 200-400 subs to stack. I can then answer your question fully. The 15sec approach benefits in terms of guiding being less critical, and things like clouds or planes or satellites not meaning minutes of data being binned. The Lum integration WAS beautifully smooth at least!
  20. Thanks! Yes - an incredible part of space. There is a tiny barred spiral in the bottom middle of the image which is just beautiful and perfectly formed...I'll focus on that one one day when I have some more focal length!
  21. Thank you! Yes indeed...so while I got, erm, stacking benefits, the practical side was an issue in terms of the time it took to stack on a good PC. I also didn't dare drizzle the integration - that might have taken 2 days!
  22. Hi everyone, This is Markarian's Chain shot from my back garden over three nights in late March. Probably the deepest single image I've taken in terms of integration time...which leaves me feeling my processing is not quite doing the data justice...maybe I'll come back to it. In any case, this is an incredible part of space; looking away from our galaxy reveals countless others! The crazy number of Lum subs took a whole day for APP to chug through and so I've resolved to lower the gain from unity going forwards to get more manageable sub lengths than 15 seconds! L: 1050 (!) x 15s R: 92 x 60s G: 165 x 30s B 165 x 30s....total integration time 8.2 hours. Captured using APT, stacked in APP and processed in Pixinsight. Thanks for looking! Edit: Link to higher res version
  23. From left to right - 1. Minix mini-PC - this runs all my imaging and guiding. I remote into it using an iPad via the little white travel router on top 2. Bottom - yes a lithium ion battery for the dew heater 3. On top of the battery is a Lacerta dew heater controller which measures the ambient temperature to regulate my dew heater. I velcro all this to a dovetail which is bolted onto the scope rings...I've since moved to a lighter dovetail, as the one in the picture was unnecessarily heavy. Next stop is to shorten as many of the cables as I can....
  24. Thanks for the clarification - when I said I wasn't scientific in PHD2, I mean I still tweaked the more "obvious" settings...but I haven't spent an evening fine-tuning all the settings to perfection for example! Here is a picture of my rig:
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