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I think I had similar issues with AIJ and the spreadsheet in the past which is why I also use ASTAP now. Although AIJ is useful for graphing light curves it’s not so “friendly” as ASTAP for other tasks. The easy AAVSO/BAAVSS report output from ASTAP wins it for me.
Sorry I can’t help on the AIJ/spreadsheet issue.
MarkOn the “Stack method” tab, I think for mono you just need to choose the stack method from the dropdown. You can ignore everything under the “RAW one shot colour images” section.
Thanks Mark,
What does Calibrate Photometry and MZero actually do?
KevinASTAP compares the flux levels of the stars in the image against a catalog of stars which allows you to measure the brightness of any objects (photometry) in the image easily. MZERO is the magnitude zeropoint of the image and this can be used by comphot to measure the brightness of a comet for example.
I believe the flat-darks calibrate the flats so you get master darks and calibrated-flats.
Platesolve your stacked image and you can do photometry on the stars and also any comets. If you do the Tools – Calibrate Photometry command it also creates MZero in the fits header (which I recently checked against Astrometrica’s version and it closely agrees).ASTAP is my favourite, free and can also write files in AAVSO and BAA format.
https://sourceforge.net/projects/astap-program/Nick – I’m beginning to see why Comphot is the best way of doing comet photometry and my lack of understanding. Finding the extent of the coma is too subjective in my technique but useful for a quick analysis.
The way I normally work with ASTAP is to use a small number of images in the stack so as not to trail too much for a magnitude measurement. Coma size is measured using just one frame. Not ideal for a good SNR though. Also basically using Han’s technique that he shows in the video, removing any stars from the measurement area.Any further forward on porting this to Windows and a GUI?
Thanks
MarkI use NINA which automatically writes all the FITS keywords to the file header. Definitely recommend NINA as the best I’ve used by far and it’s become very popular – for obvious reasons.
Ni Nick
I’ve tried to roughly write down the details of how I did the measurements on your files. Attached a PDF.
It was a bit of a fix but see what you think. I’m not an experienced comet observer so happy to be proved wrong with this technique. I just think there’s a lot of potential with ASTAP, for comets and many other objects. Han is very responsive to adding new features too.
Mark
PS Currently it is only the development version of ASTAP that contains some of this:
http://www.hnsky.org/astap_setup.exeWell that’s not true now. If I stretch the levels to extremes I can get a coma width of about 29/30′.
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Hi Nick
I’ve had a go using ASTAP. It should be said that the two files you provided are not in a form we would normally use for ASTAP so this can’t be accurate.
I get mag. 5.6 and coma of 20′. There’s no way I can see a coma diameter of 29′ in the data using ASTAP.Measuring the coma diameter is always tricky and I’m sure Comphot will be better at that with the techniques it uses.
It would be interesting to see if the files produced by ASTAP are suitable for use with Comphot though. It can stack on comet or stars, platesolve the star stack and also provide MZERO.
MarkThe Jerusalem Post (not my normal reading!) published this… https://www.jpost.com/science/article-729035
“2 asteroids the size of 22 penguins to pass Earth this weekend
Both asteroids 2023 AT and 2023 AE1 are as much as 22 meters wide, meaning 22 emperor penguins. They won’t hit us though – penguins are more likely to.“Emperor penguins have an average swimming speed between six to nine kilometres per hour. This means that, at best, asteroid 2023 AT is barrelling through space at a speed that’s around 2,892 times faster than the swim speed of an emperor penguin.”
I responded to it in my weekly newsletter to the Astronomical Society of Edinburgh:
“On 17 Feb 2023 asteroid 2020 DG4, the size of 4.5 ± 0.2 ASE Presidents laid end-to-end, will come within 1.4 ± 0.05 Lunar Diameters of the Earth at a speed of 6.9 km/s, 222 ± 5 times the speed of his car on a motorway.”
Suspect it won’t catch on.
MarkAttachments:
There’s a conversation on the ASTAP forum about adding a circle / ellipse and how to measure the sky background. Perhaps others who know more about comet photometry than me (most people!) could advise and join?
https://sourceforge.net/p/astap-program/discussion/suggestions/thread/b1c1be085c/
Han has added the option to measure inside a circle / ellipse now in the development version (right mouse drag while holding down the Ctrl key).
Thanks
MarkI hadn’t realised just how prolific the Geminids had become until I got a meteorcam. Last night was just amazing!
MarkAttachments:
I’ve been chatting to Han who wrote ASTAP and he’s created a modified version with an option to format the AAVSO export for BAA VSS use, extracting the extra header fields from the FITS header. I uploaded an entry for DO Dra and it seemed to go well. Could you check it out please and see if anything else is required?
The latest version of the installer is here:
https://sourceforge.net/projects/astap-program/files/windows_installer/
Thanks
MarkAttachments:
So far I’ve entered it manually. Next time I will try a modified AAVSO version to see how that looks. Doesn’t look very difficult to do.
ThanksThat’s great thanks. Well I definitely recommend it as a really nice tool that is easy to use.
Here’s a video showing how simple it is if anyone is interested:
https://www.youtube.com/watch?v=99XxzmJPPPQ
MarkWell 8 days is all I will get before they disappear from the Sun. Weather will no longer co-operate so this is the final set.
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Day 8. From the forecast for tomorrow I suspect this will be the last day.
250mm f4.8 Newtonian
Black polymer filter + R filter
2022-04-25 09:27:02 UT
120s .ser video
Best 25% frames
