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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?
I well remember C/1983 H1. On the night of closest approach it was very obviously crawling across the field of view in the eyepiece at quite lo powers.
A further characteristic of the Trim-Phone is that the frequency of their tone was exactly in the middle of the ranges where human hearing distinguishes location between sound intensity in each ear and the phase difference of sound waves across the head. Consequently, it was very difficult to work out where the ringing sound (in actuality a warbling) was coming from.
Not only that, blackbirds and starlings loved to imitate the noise which did not help the humans.
Thank ${DEITY} they are no longer common. May they Rust In Pieces.
<p class=”wp-dark-mode-bg-image”>I think I may have captured fragments A & C with my humble Seestar. Here’s a comparison with Nick’s image taken about 35 hours earlier. Image scale is the same. The orientation of the tail is consistent with its motion. Thoughts or an artifact?
Well, I am impressed!
Though I may be an impressionable person.
I have been very happy with the Starlight Xpress CCD cameras I have used. Whether they meet your requirements may perhaps be answered by perusing https://www.sxccd.com/ and links therein.
Paul
I shouldn’t boast but will do anyway. 😉
I am also a co-author of a paper in MNRAS, https://academic.oup.com/mnras/article/479/1/1401/5035837 to be precise.
Beware: unless you know at least a little about quantum chemistry and molecular spectroscopy it will not make very much sense to you. That is why it is quite unsuitable material for me to boast about in JBAA. Doubtless there are numerous members who can say the same thing.
Paul
An excellent meeting, in my opinion. I learned a lot from the presentations and it was good to meet people in person with whom I had previously only communicated over the interweb thingy.
My thanks to all those who put in such hard work in organizing the event.
Paul, I know you are after various editions of Norton’s which I look out for, but none so far. I’ll see what else I’ve got.
James
Back when I was an undergraduate another member of OUAS had a copy of “Webbs Atlas of the Stars”. It disappeared and the erstwhile owner regretted it greatly.
I have always wanted a copy of my own but they are almost unobtainable now. When they do appear on the market the prices are ridiculous — several hundred USD/EUR/GBP — and I refuse to pay that much. I own a good number of atlases, old and new, for which I have paid much less than that.
If anyone has a copy of Bečvář’s Australis at a reasonable price I am also interested. His atlases are already in my possession and I have a spare copy of Eclipticalis if anyone is interested.
I’ll be there with a load of secondhand books for sale, so bring your money.
I am often in the market for old atlases, especially editions of Norton’s not yet in my collection. Don’t know if this will influence your choice of books to bring.
Paul
Measuring stellar proper motions has been possible for amateurs for a long time now, though we will not reach Gaia levels of accuracy.
In particular, I really must update my track of Barnard’s Star with images from this year. Ok, that’s an extreme case but proper motions greater than, say, 100mas per annum should be fairly easy to measure over the course of a year or few.
The pipeline I use is MaximDL for taking images; local astrometry.net using the Gaia catalogue to put a WCS on each sub; SWarp for stacking if required; and then APT for photometry (my primary interest) and initial astrometry (if desired). The source list fed into APT contains Gaia positions and its output includes substantially sub-pixel precision on the stars’ centroids, in both pixel and sky co-ordinates. That’s good enough for me (and I repeat that my primary interest is in photometry rather than astrometry). Perhaps I could, and should, try harder to achieve ultimate accuracy in astrometrical positions.
Paul
<p class=”wp-dark-mode-bg-image”>A test would be to take images with the telescope rotated to different angles (but with the camera orientated the same relative to the horizon). If it is atmospheric refraction the red and blue areas will always be top and bottom relative to the horizon. If it is the telescope, they will move to different angles relative to the horizon
<p class=”wp-dark-mode-bg-image”>Cheers<br class=”wp-dark-mode-bg-image”>
RobinGood point. I wish I had thought of that.
At what altitude was the moon at the time?
The atmosphere acts as a prism and deviates red and blue light differently at different altitudes. The effect is most apparent where the air is thickest — at low altitude.
https://en.wikipedia.org/wiki/Atmospheric_refraction covers the phenomenon but only slightly and could be greatly improved in my opinion. Searching on “atmospheric dispersion corrector” will produce more information and a fair description appears at https://astronomytechnologytoday.com/2017/07/06/atmospheric-dispersion-corrector/ but the available information is far from satisfactory in my opinion.
Paul
