Forum Replies Created
-
Posts
-
A supernova at that distance is going to be pretty bright. Are any wavelengths reaching us likely to cause problems?
Happy Christmas/Hannukah/Saturnalia/Yule/Solstice
Thats really worth knowing. I have previously steered clear of trying to solve images with severely trailed stars assuming it would say “Sorry guv, no stars in here”.
Stop Press: seems to depend on the aspect ratio of the trails. The longer a trail is compared to its width the less likely it is to solve. Still worth knowing that Astrometry.net can be quite tolerant.
I was wondering how you did that. In the earlier pictures the stars were starlike but images 9-11 contained significantly trailed stars. Is astrometry.net really that forgiving/tolerant or did you extract some positions manually as a text list?
Even if they push the albedo from (say) 70% to 10% thats only going to be 2 and a bit magnitudes, so you go from a 3rd mag satellite mucking up your images to a 5th mag. Great.
Given that even geosats mess up deep sky images (and they are normally 8th mag or fainter) I’m not seeing much benefit.
The problem is he has a business plan to make money. What is his incentive to stop?
If we said anything, I wonder what he would call us?
Ah, I see. A 20 min running average certainly helps.
Impressive. Noise level at the 8-10mmags level perhaps.
This seemed appropriately timed: https://www.xkcd.com/2202/
Was it cellulose acetate or cellulose nitrate (nitrocellulose) that was the problem? Nitrocellulose was quite widely used in the early years of the 1900s.
I imagine cellulose acetate can burn but, nitrocellulose is also known as gun cotton and burns with vigour!
Without the addition of carbamite or another stabiliser, the decomposition products of nitrocellulose accumulate quite quickly making film go brownish – so colour film would really suffer.
Didnt some types of billiard ball made from nitrocellulose during the 20’s have a similar issue? I have a vague memory nitrocellulose was used as a coating for playing cards as well at some point.
Brilliant. Really hadnt realised you just had to look 60 degrees in front or following the sun. That makes it pretty easy, get the sun’s position on ecliptic in RA/Dec, convert to ecliptic cooords, add 60 degrees and convert back to RA/Dec again. Sure I can find something in AstroPy to do most of that. I imagine that drops it nicely into the edge of the Zodiacal light.
Thanks again.
