Forum Replies Created
-
Posts
-
ffmpeg doesn’t handle FITS directly but convert (one of the command line utilities in the Imagemagick suite) will convert from FITS to any common graphic format and can stretch, crop, etc. in the process. Being command line programs they are easy to script in bash or whatever and mean that you can make timelapses very easily from raws or FITS.
Hi Andy, Welcome to the forum. That looks like a fantastic image. Could you post a higher resolution version please with technical details (when, where, exposure, equipment, field of view etc.). You can submit it to the Comet Section via cometobs@britastro.org. Details of how to submit are here. Thanks.
The real detail in the comet is spectacular. I really don’t understand why anyone would want to make stuff up like that.
I use dcraw, Imagemagick and ffmpeg under Linux for batch manipulation of images including camera raws and generation of videos. Not sure if they are available in the Windows world.
David. The shot with the low-level NLC is wonderful. Get it printed and framed and hang it on the wall!
No secret, just lots of frames, careful focusing, very good flat fields and being in the right place at the right time. There should be lots of opportunities over the next week or so if the weather cooperates.
Robin, this is a very active and probably quite large nucleus that has been strongly heated through perihelion so it would be worth searching for a possible sodium tail. I don’t have a suitable filter (all mine are designed to block Na D!) but a good challenge for others.
Fantastic pics and observations everyone. Here is a colour pic of mine from this morning showing the two tails. The FoV is 6.4×4.3 deg.
Just got back from one of the great observing experiences of my life. A stunning comet and wonderful NLCs in a clear, deep blue sky. The images of 2020 F3 here are single frame JPEGS straight from the camera. I need some sleep now and will calibrate and stack the raw images later.
' xlink:href='%23b'/%3e%3cuse fill='black' filter='url(%23c)' xlink:href='%23b'/%3e%3cpath fill='white' d='M12.162 7.338c.176.123.338.245.338.674 0 .43-.229.604-.474.725a.73.73 0 01.089.546c-.077.344-.392.611-.672.69.121.194.159.385.015.62-.185.295-.346.407-1.058.407H7.5c-.988 0-1.5-.546-1.5-1V7.665c0-1.23 1.467-2.275 1.467-3.13L7.361 3.47c-.005-.065.008-.224.058-.27.08-.079.301-.2.635-.2.218 0 .363.041.534.123.581.277.732.978.732 1.542 0 .271-.414 1.083-.47 1.364 0 0 .867-.192 1.879-.199 1.061-.006 1.749.19 1.749.842 0 .261-.219.523-.316.666zM3.6 7h.8a.6.6 0 01.6.6v3.8a.6.6 0 01-.6.6h-.8a.6.6 0 01-.6-.6V7.6a.6.6 0 01.6-.6z'/%3e%3c/g%3e%3c/svg%3e)
11Lovely wide-angle shot David. So glad you have been able to see it. Here is my timelapse of it rising this morning. A really special thing to see.
Good luck to everyone with the weather. Set the alarm even if there is only a small chance of clear skies. It will be worth it!
I was incredibly lucky with the weather this morning in Chelmsford UK with a narrow slot of clear sky low down in the direction of the comet. C/2020 F3 was easy naked eye this morning. It is higher and in a darker sky than yesterday. The binocular view was fabulous. This is a single 5s frame taken at 0128UT using a 200mm, f/2.8 lens and a Canon EOS550D.
Great pictures from everybody. You just had to be lucky with the weather last night.
It is not quite up to Michael Jager’s standard and it shows the comet rising over TV aerials and trees rather than mountains but here is a short timelapse of C/2020 F3 rising from Chelmsford last night. It first appears at 0131 when the comet is 1.7 deg above the horizon.
Clear in Chelmsford this morning. Here is a single raw 3.2s frame of C/2020 F3 from this morning (for some reason my images are really dark when uploaded to the BAA site, the original is here. I have lots of frames which I’ll process properly after work today but need some sleep now. Great view in binoculars. Didn’t see it naked eye but theta Aur was very hard NE that low in a bright sky.
It is an impressive sequence. At the risk of unpopularity here is the link! The comet is probably mag 1 or so at the moment but seen against a very bright sky. As you say, Monday looks like our best chance weather-wise over the next few days. I’ll certainly be making the effort to get up early.
I had similar conditions but I think I got it (see attached). I have images taken 10 mins earlier that show stars so I can get a good reference position for the expected azimuth and elevation and it is in the right place. It is also moving at sidereal rate from images before and after this one.
Robin,
M85 is getting low in a bright sky but this is an image from a few minutes ago showing the SN. It doesn’t seem much brighter (Astrometrica gives 17.5 unfiltered using Gaia DR2 G and an unfiltered KAF-6303 CCD).
David, so you follow in illustrious footsteps! Chelmsford has Calver of course. A more recent connection but not an orbital dynamicist.
The cost of these photometric filters is pretty eye-watering compared to the bog-standard LRGB filters that people use for imaging. As Robin says it is necessary to calibrate the transformation coefficients for any particular sensor in any case and you then need to image in multiple bands so you can apply those coefficients. It may not be perfect but could you use imaging RGB filters and transform them to something close to the standard photometric bands? I know that people use DSLRs for variable work and do something similar with the Bayer RGB pixels. I’ve certainly found that the green pixels of my ASI294 match Gaia G quite nicely and I use a neat tool called rawtran which transforms the RGB into other photometric bands. It seems to work pretty well with reference to APASS photometry.
