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Were it not for an Avast antivirus software update knackering – in a very subtle manner – the ability of the observatory PC to talk to the house, I would have been imaging at the same time as you – before the mist started rolling in about 12:30. Looking at my post meridian flip image sequence, the stars are gradually fading as the transparency went to pot.
Will measure some brightness values later…
Currently looking at the location suggested by JPL Horizons and am really surprised by how bright this thing is for something man made half a million miles away.
And thats under murky conditions. Image at https://britastro.org/observations/observation.php?id=20230418_002705_da18d9fe717fc9b0
Nice one!
here it was cloudy one night, then I had an equipment failure the next… Might have another clear night in time for the first flyby. 🙂
Separation of the Juice spacecraft from its launch vehicle was confirmed a few minutes ago. Its on the way!
Something to look forward to imaging – if it clears tonight.
Yes, I could make the code look for the TheSkyX COM process running and try to interrogate it for what the current pointing is, catching an error if need be. I have never bothered as I usually take many dozens of images of the same target and use a platesolving script that feeds the RA/Dec coordinates of the previous frame solved into an astrometry.NET instance. Upshot is that solving the first frame is slow, but the later frames solve in a second or two (depending on how many cores I use).
Worth thinking about – after I make the code rattle through the filters….
I just had a quick look at the ASTAP manual.
If I am reading it right, then ASTAP needs two FITS keywords* populated with the approximate field centre coordinates in RA/Dec and also guidance from the user (field diameter/search size) to run. So, its not doing blind solving, but the much simpler user assisted solving. Which probably explains the speed.
I’m not sure though how most of us would get the RA/Dec values into the header. Is there a command line tool or something available? I imagine you could supply a target name and the software then use Simbad or JPL Horizons online to supply the current position from your lat/long.
Does anyone know of such a tool? That would be extremely useful – and not too hard to write in Python.
Certainly, I control my telescope via TheSkyX, but I don’t like its imaging interface and so use my own CCD control software (or sometimes AstroArt) – which just takes images and does not talk to the mount. I imagine others may also be in the position of generating FITS from their camera without RA/Dec coordinates in.
*Or possibly 4, as I have seen two different definitions of keywords for RA/Dec.
Thats interesting. Glad to hear its still being developed.
Not sure a large circular aperture is always what you want for a comet, but its certainly a start.
Interesting.
As you say it brings out some nice detail in the dark bands and centre of the galaxy. Was surprised to see that in the top left part of the image some of the detail seemed to be blurred out. Would be interested to see what it did with something like the Rosette.
Ah, but is that Chlamyphoridae or Dasypodidae? These are important details.
You could also express it as the time an unladen swallow might take to fly it and then you would have to ask, european or african?
Thats inspired. Someone at the Jerusalem Post is very bored and having fun.
I’m looking forward to mass being expressed in terms of Tesla batteries or volume in terms of St Paul’s Cathedral.
The night of closest approach was largely cloudy here, besides which, I was stuck in Tesco’s car park for most the evening with a broken own car.
Did manage to get something on the 2nd though. https://britastro.org/observations/observation.php?id=20230303_232508_33211f79b6b09cc1
Ideal conditions but the 1C air temp combined with wind made my hands pretty cold by the end. I think the moonlight greatly improved on what I would have achieved with flash units.
In the spirit of full disclosure…. 🙂
Was -7.2C here last night (still -3.2C by 9:15) with a very heavy hoarfrost/fog in the early hours.
Looked in dome at 11:00 – by which time the air was registering as +5C – and found some condensation on the mirror.
Well , there goes my theory….
So, henceforth will also use a dew heater band near the secondary plus the fan. Can’t help matters having frost on the inside of the tube some nights. Don’t want to use too much power though.
The recommendations I was sent for people willing to service DSLRs, SLRs and lenses are:
This is an active list of good repairers – my friend has used a couple of them:
https://www.35mmc.com/17/07/2016/specialist-film-camera-repair-modification-companies/The two links below also get good reviews, but he has no personal experience of their work.
https://www.cameraworks-uk.com/camera-repairs-and-servicing
https://pppcameras.co.uk/aboutHowever, it must be remembered a 60mm lens may be out of their comfort zone of expertise.
He also warns that there are people out there who will do a poor job and charge you a lot, so you may prefer to watch a lot of youtube videos and then do it yourself.
Martin: Damn, had assumed the corrector lens in the Edge was up at the secondary. Sorry, bad advice on my part!
Martina: Have emailed friend. Will post here when he responds. The “forced ventilation” referred to keeping the small fan in my 300mm f/4 Newt going 24/7 – I am tempted to run it at 9V rather than 12 to spare the bearing a bit. Closing the tube or leaving open seemed to make little difference.
I did that in response to repeatedly finding condensation (water droplets and a fine dew plus a sheet of ice one night) on the mirror. Does the Edge have fans like the RASAs do?
Full dew conversation here….
https://britastro.org/forums/topic/suck-or-blow#post-615389There are camera specialist photographic companies that will attempt to dismantle lenses and clean mould off them. Given the number of elements in a DSLR lens, a telescope lens is a stroll in the park by comparison. I will ask camera enthusiast friend for a recommendation.
I noticed the inside of my 300mm F/4 starting to smell slightly of damp so went over to forced ventilation – have not had condensation on the mirror since.
One thought, I recall hearing of an SCT user inserting a tube containing packets of silica gel into the focuser (the tube had a wire mesh end so the air from the telescope got to the gel). You could also buy a couple of large packs silica gel from Amazon and put velcro tape on to them and place a fresh one on the inside of the lens cap at the end of every observing night. You then warm the spare up and store in an air tight jar so its ready for use on the next clear night.
So, is it the case that you manually select an unsaturated star on the first image, which is then automatically followed, or is it that you click on the same reference star in all images?
As I recall, you use a Paramount, so your periodic error is much smaller than with my NEQ6 – the former approach would not work well with the NEQ6 as a star can shift quite a lot at one point of the gear cycle (I lose about 15-20% of 30sec exposures – yeah, getting the OAG going sometime is on the “TO DO” list).
If you were interested I could dig out the code for automatically working out interframe offsets, so you don’t need to do a manual selection at all. The C version I lost years ago but, I still have the Fortran, VB6 and Python code knocking about. Translating to C would not be a long job. I was sort of surprised that there’s nothing obvious to use for image alignment in AstroPy.
Hi Nick,
Thanks for making the code available. Always interesting to hear how other people do things.
As you mention Ubuntu, I assume fcombine does not run under Windows.
For us heathens still using Windows, do you know if that archive can be used in a Windows WSL2 instance? Under W10 WSL2 there is a simple Linux command line environment*, but I believe W11 WSL2 instances have a full graphical interface. Have you used fcombine under that?
Finally, what language is the code in? The mention of libcfitsio kinda suggests C. Just curious as to how you work out interframe offsets and rotations – my own code for that works but isn’t elegant or especially fast.
*I run my astrometry.NET installation under it using Ubuntu installed on a Windows laptop via WSL2 – though Windows gave me a choice of which Linux.
I think I prefer a short duration dewing as that gives less time for the water droplets to absorb gases from the atmosphere and become acidic. Though, with the reduction in heavy industry over the last 50 years and diminished use of coal powered fire stations, perhaps I am being over cautious. But, realuminising mirrors ain’t cheap.
I was also disappointed that parking the telescope horizontally didn’t encourage the droplets to run off better – most of them seem to stay attached to the mirror. I assume its a surface tension effect.
Yes, I take your point regarding air temperature, but think the combination of glass being a poor thermal conductor and a fan means the surface of the mirror (not the bulk) can follow the air temperature quite closely. Thats very handwavium, but I don’t have time to make a mathematical simulation. Anyone?
I can remember many still nights with dew, but not that many windy ones – though it may be a selection effect as, before the dome, I didn’t observe on windy nights for fear of tube vibration.
I also considered a dehumidifier, but need to check the energy consumption first – a dome isn’t exactly a sealed system. A small computer fan is very low power, hence my enthusiasm.
I think the main change I need to apply now is a very fine mesh net over the secondary end of the tube to try to catch the bigger debris and discourage spiders.
Just checked. Third morning in a row without any condensation, ice or droplets on the mirror and none present when I used the telescope on the 27th. Will keep checking every morning.
