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According to units(1), 1HP = 745.7W and 340kW = 456HP. The discrepancy is a factor of 4.7.
I am prepared to believe that bus engines have become markedly more powerful since the last published measurement made quite a few decades ago. Car and motorbike engines certainly have.
Already mailed Paul. Albondon is relatively close to La Palma (close by UK standards anyway, though still a 2-day journey in each direction) and although shipping would not be cheap, it should not to be too expensive — especially if I rent a van and drive/ferry over there and back myself.
A vacant concrete pad at Tacande Observatory already has power and ethernet laid on. It is big enough to hold a 4m diameter dome.
Arrangements have been made. In the fullness of time a ~4m dome will be planted on that pad ready to host a 0.4m RC telescope.
Sorry to hear about this. I hope the kit finds new worthy homes.
Likewise.
Already mailed Paul. Albondon is relatively close to La Palma (close by UK standards anyway, though still a 2-day journey in each direction) and although shipping would not be cheap, it should not to be too expensive — especially if I rent a van and drive/ferry over there and back myself.
A vacant concrete pad at Tacande Observatory already has power and ethernet laid on. It is big enough to hold a 4m diameter dome.
Paul (another one).
Interesting that no-one has yet picked up my albedo error. The albedo is the fraction reflected, not the fraction absorbed. Multiplying by the WAG of 0.9 is OK, but the albedo is likely about 0.1.
It will be 1360 * 1 / (0.0057*0.0057) = 41.8 MWm/2 assuming the Earth is at 1AU.
Strictly speaking (and one should always speak strictly, especially to animals and young children) the figure must be multiplied by the albedo as some of that power density will be reflected. I have little idea of the true albedo integrated over all wavelengths but a figure of 0.9 may be in the right ballpark. Still a fearsome figure.
Hi Nick,
The fcombine you provided no longer works on my Ubuntu system because the libcfitsio.so.9 library has been updated to version 10. Attempting to re-download your program gave an error.
Any chance of the source code being made available (to me only if you do not want a public release) so that it can be rebuilt as required in the future?
Thanks,
Paul
The only way I could get it to work iss to manually copy/paste the data parameters for each satellite.
Yes, that is exactly what I do. Takes an extra 30 seconds or so, but that is negligible compared with the exposure time needed to reach 20th magnitude or below.
Yes.
Both the MPC and JPL provide ephemerides, though MPC only for the outer satellites. The URLs are https://minorplanetcenter.net/iau/NatSats/NaturalSatellites.html and https://ssd.jpl.nasa.gov/horizons/app.html#/ respectively.
If you wander over to http://www.astropalma.com/Projects/planetary_satellites.html you will see (most of) the images I have taken using these resources. One day, assuming I get a round tuit from somewhere, I will update that page with some more images. A fair number appear in my image gallery here on britastro.org
Have fun!
Paul
I think this has been covered, but unfiltered is definitely preferable to a UVIR blocking filter.
For my part I tend to use unfiltered for time-series work (exoplanets previously, asteroids these days) to achieve the greatest SNR and the fastest cadence. As only the minute to minute variation is of interest there is no great need to have the observed magnitudes be comparable with measurements made by other observers.
When making precision measurements I almost always use a V filter but have been known to submit CV measurements — unfiltered with comparison magnitudes given in Johnson V.
No great need for a filter, in other words, except for red stars as noted above. A filter is nice to have, undoubtedly, but no-one should let expense put them off making scientifically valuable measurements.
One day I really must see if I can find a round tuit down the back of the sofa because there are literally thousands of images on disk which were taken with the Seestar’s OSC camera. Trouble is that all of them need de-Bayering and the green channel measurements transformed to standard V. Another example of where external filters are no needed — the Bayer mask consists of filters which are internal to the detector.
Strange: my post of a couple of hours ago has disappeared.
To re-iterate: I would like to have these magazines and will be attending the Winchester Weekend to collect them.
Thanks,
Paul
(Let’s see if this one survives for longer than a Ratner’s prawn sandwich.)
Thanks, Paul. I had a tooth pulled. I struggle to believe all the possibilities attributed to it, but if you confirm it, I’ll begin to dispel my doubts.
I’m referring here to the cheapest telescope AP 50/250 Seestar S50.
I’ll tell you, it’s a little hard to imagine having Pluto within reach. It seems that on M13, M31, M42, the Pleiades, etc., it’s truly miraculous. For “beautiful” photography, I think it’s a good instrument, even if the resolution leaves something to be desired. I wonder: what does it provide on Epsilon Lyrae?
Given its light weight, I’d take it to high mountains, to the Gran Sasso, even at altitudes above 2,800 meters, to photograph lunar eclipses, which I study seriously. At F=250mm, the lunar and solar disks have a diameter of about 2.5 mm. So I wonder what the quality of lunar photography is, taken for photometric purposes? No description provides information about the actual resolution on the Moon and Sun.
I would like to see some photographs of the Moon and the photosphere, taken without any post-production or retouching with various soft-focus techniques.My image of the Sun, one in the list given by Andy, is exactly as it came off the S50. No post-processing at all. Another image in the list shows Pluto. I can’t help with epsilon Lyrae, sorry. An image of Polarissima Borealis, aka NGC 3172, appears at https://britastro.org/observations/observation.php?id=20241121_180849_58cdbd49c5f6525c — that image took only 11 minutes to take. The galaxy is not very impressive in appearance, true, but it is magnitude 14.9 and the exposure was quite short. What really surprised me was LEDA36268 appearing — that one is 17th magnitude!
Re: Andy’s comment about access to the raw data. On the Seestar the lights frames, in FITS format, are easily available for subsequent post-processing. The calibration frames are not, as far as I know, but perhaps they may become available in subsequent versions of the firmware if enough people ask ZWO for them. The telescope firmware automatically applies dark frames. Flats can, presumably, be taken in the usual manner but I have not yet ventured there.
Paul
Which “Smart Telescope AP 50/250”? A web search on that term shows the Vespera II (https://www.apm-telescopes.net/en/86732-smart-telescope-ap-50250-vespera-ii-x-edition) and the ZWO Seestar S50 (https://www.astroshop.eu/telescopes/zwo-smart-telescope-ap-50-250-seestar-s50-with-universe2go-/p,84933). The latter is much cheaper and I own one myself.
The S50 most certainly can be used for scientific research as well as the canonical “pretty picture” field which is where most of the marketing is targeted. Precision photometry down to around 15th magnitude is possible with reasonable exposure times. Transformation coefficients to convert from its G channel to Johnson V are available. A 15 minute exposure seems to show a detection limit (SNR ~4, so useless for photometry) of around 17th magnitude.
https://astrobackyard.com/seestar-s50-review/ gives some detail but I don’t know how much more than that you want.
Very much not a piece of junk, IMAO.
Paul
I can’t recommend any particular company but my father, who was in the insurance business for many years until he retired, told me you can insure anything against any risk — as long as you are prepared to pay the premiums.
You may find it cost-effective to be self-insured in other words. Once the accumulated premiums exceed the repair or replacement costs you are ahead. An obvious exception is where insurance is a legal requirement, to drive a motor vehicle on public roads for example.
Insurance is essentially book-making on a larger scale (another of my father’s aphorisms). The company is gambling on you paying more in stakes than they will lose on payouts. Like bookies, on average insurance companies always make more than they lose.
Good luck.
Paul
This may sound like a silly question, but why not use the one on the Wikipedia page as viewed by Lunar Orbiter 4?
