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It is decimals of a minute. So e.g. 10:47.7 is 10:47 and 7/10 of a minute, which is 42 seconds.
Some software packages used in astronomy produce this output.
I observe Jupiter a lot and use the WinJupos package by Grischa Hahn, and that gives everything in decimals of a minute. So also every piece of software that feeds into this (e.g. the image capture software) has to use that time format as well. In this case I think the reason is just historical, that visual observations could not be accurate to better than this, and in early days of programming it was easier to do it this way, and it has carried on. I don’t really like it.
Occultations of course can be timed to at least a tenth of a second, but I suppose the prediction does not need to be so accurate, so I suspect this is really due to both trying to save space (in print) and software that is a bit long in the tooth.
But someone who works with occultation predictions might care to comment.
Sorry to hear about this.
I don’t know it there is a systemic problem here, but as there are three of you, it sounds as if we need to take this up with the printer, who sends them out directly from the print works.
In the short term I’ll let the BAA Office know that you are missing your October Journals, and they should be able to send you copies from their stock.
David
PresidentThe full financial statement is now available to members here:
https://britastro.org/wp-content/uploads/2023/10/BAA-2023-Financial-Statements.pdf
Sorry for the delay.The financial statement published in the Journal is an abbreviated version of the full financial statement which should be published on the website. I have just looked for it and found it has not yet been published. My apologies for this oversight, and thanks for bringing this to my attention. I will see that it is fixed shortly.
The full financial statement has this paragraph on page 21, which answers your question:
‘The British Astronomical Association has been notified of a will in which they are beneficiary. However this is currently being contested. The charity will be liable for the advice in arriving at a decision. The cost of the legal fees to settle this case may be deducted from the estate or may be awarded against the Association. To date, approximately £30,000 of costs have been incurred by the Association and further costs of up to £70,000 could be expected.’
As you will be aware, the Trustees are elected by the members to manage the assets of the Association. They keep this case, and expenditure on it, constantly under review. They believe it is highly likely that the BAA will win this case and these costs will be recovered, plus more. However, it is our duty to tell the members that there is a chance that the case could be lost and the costs could be awarded against the Association.
You would be, of course, quite at liberty to ask questions on this at the AGM. The case of the Roy Panther estate is in the public domain, and has been widely reported.
David Arditti, President
Indeed the question as posed is unanswerable.
Telescopes are used to take images in two basic ways (not counting spectroscopy):
1. To image faint objects
2. To image fine detail
(3. Some combination of these)Aperture allows you to resolve detail, but focal length allows you to image the resolved detail with a detector. Aperture also allows you to image faint stars, but the imaging of faint extended objects depends inversely on focal ratio. Width of field, with a given detector, depends inversely on focal length. If you wish to image the combination of faint stars, faint extended objects, and detail, you require a large aperture at a low focal ratio. If you wish to image wide fields you need a short focal length, but unless you have a large aperture and hence a low focal ratio as well, your detection of faint objects and your resolution will be limited. But there is a limit to how low focal ratio can go without optical problems, so for the widest fields, very small telescopes are needed, which are limited in both resolution and limiting magnitude.
This is all before one gets into considerations of mounts and drives.
So what is ‘a good telescope for astrophotography’ depends on what exactly you are trying to achieve.
If the main problem is backlash in dec. you could try only guiding in RA. It is one of the options. You may be able to get long enough out of it.
If the star is wandering in RA, and the communications are all working, the possibilities are that the star is not bright enough, so the SNR is too low, or that the errors in the drive are just too large and random to allow guiding to work. I have this issue with my ancient Fullerscopes Mk.IV mount.
You haven’t actually explained what your problem is Jack. What results have you been getting from your attempts to use PhD2 so far? What is the guiding instrument? Have you succeeded in calibrating the system? Have you found suitable guide stars? What happens when you try to guide on them?
In my experience PhD2 either works or it doesn’t work with a system, and if it doesn’t, there’s some fundamental hardware problem that no changes to the default settings will make any difference to.
The first step is to enter the guiding focal length and pixel size. PhD then calculates appropriate increments for the movements. It should then be possible to do a calibration using a star. If that is successful, then it should guide.
Problems are pretty much always problems with the hardware rather than with PhD’s settings.
I would not rule out the possibility that your 1.25″ Lunt solar wedge is sub-par. I don’t have experience with this unit, but I do have experience with the Lunt 1.25″ diagonal blocking filter units for H alpha telescopes. I tried two, the B600 6mm one and the B1200 12mm one. On the same telescope, the 12mm one was clearly better. However, and this is where I get to my point, I tried a home-brew experiment (that I do not recommend to anyone who does not know what they are doing) where I pulled the 12mm blocking filter out of the 1.25″ diagonal (it was glued in) and made (on a lathe) a straight tube unit of 2″ outer diameter to house it, and a 1.25″ eyepiece tube. I was then able to use my H alpha system with a 2″ diagonal. The result was clearly better. There was therefore definitely a quality difference between the 2″ diagonal I had substituted and both Lunt 1.25″ diagonals, that was perceptible even in typical poor daytime seeing conditions. The Lunt diagonals did not seem good when one pulled them apart – well-finished outside, weighty, but just crudely glued together inside, unlikely to be precise. One experience.
Here’s a picture taken afterwards, at the doors of the National Museum of Wales: from right, Hazel Collett, Graham Collett, Graham Winstanley, Mike ?
Attachments:
The easiest type of recording of talks to make is an HDMI interception of the projector display, coupled with a recording of the speaker. We have a ‘black box’ that does this, and I am thinking of using it at the forthcoming Cardiff meeting. This does not give a video showing the speakers, but it shows their talks content. The trouble is…it’s still not so simple. The achilles heel is the sound. The integrated sound recorder in the box does not give good quality if the speaker is somewhat away from it, or wandering around. The solution to this is to use a digital sound recorder with a lapel mic. We have this equipment as well. This, however, will not capture the speaking of the meeting chair, nor of questioners. And it gives someone a big job later to marry up the video with the sound. Since none of these small gadgets have a very clear display of what they are doing, it is easy to make mistakes and fail to record one or the other of the video or sound. It is not a job the chair of the meeting (i.e. me) should be doing, as the chair has multiple other things to think about. It needs a volunteer dedicated to the task. For last year’s meeting in Elgin, a member of the local society (or possibly they were university staff) succeeded in making such a recording of most of the talks, using university equipment, for which we are very grateful. Generally, however, it does not happen. I feel the only way we could ensure videos made of each meeting outside London would be to pay contractors. When you look at the numbers of people who watch our videos, they are, by YouTube global standards, very, very low. Therefore it is a decision we have to weigh up as to whether it is worth it. The arrangement we have with the Institute of Physics in London is fantastic, because their technician, at no cost to us, records the sound, the view in the hall, the faces of the speakers, and the slides. We still have to pay our staff to edit and upload the video, but in this case it seems justifiable.
If you wish to loose some weight after drinking that beer there’s a Moberley Sports Centre (one b) in Kensal Rise, NW London. I’m not sure if it should be pronounced Mobberley or Mowberley.
On Alex and Paul’s point, I think it is quite understandable that so many people get the terms astrology/astrologer and astronomy/astronomer confused. Other scientific disciplines have the ‘ology’ suffix – think of geology, meteorology, physiology, biology etc. ‘Astronomy’ is a peculiarity, linguistically. It means, literally, the naming of the stars. It would be more logical for the science of the stars to be called astrology.
I’ve been looking into this event, and, for the record, there seems to be an error in Bill Barton’s original post.
On 24 March the figures that were being given by news outlets for this close approach were that the asteroid would pass the Moon at 515,000km and Earth at 168,000km (not 68,000km). In fact this prediction was quite accurate, the miss distance being 175,000km. The object was measured at 70m diameter.
The BBC news article Bill linked to was revised on 25 March, but see, for example, the Guardian article:
https://www.theguardian.com/science/2023/mar/24/city-killer-asteroid-to-pass-harmlessly-between-earth-and-moonI wonder if what we need, in view of recent discoveries by the JWST of massive galaxies only 500 million years after the Big Bang, is a revival of the Steady State theory of cosmology, or some version of it. The detection of evolved galaxies further and further back in time through advancing telescope technology (that actually was going on for some time before JWST) does not fit with the standard model, and was not predicted.
The main discovery that caused the Steady State Theory to loose out against the Big Bang Theory in the 1960s was the discovery of the cosmic microwave background. But could there be some other explanation for that than the Big Bang, I wonder?
Allow me to formally welcome to the Association again 😀
I see this question exactly was asked on Cloudy nights forum in 2009. No-one seemed to have a good answer.
https://www.cloudynights.com/topic/231104-field-flattener-for-megrez-110/I’ve tried flatteners on telescopes they were not designed for, and they always improve the results over a non-flatted setup, though not necessarily as much as should be possible when using exactly the right thing for the job.
It might be best to find one or other of the lenses suggested in that thread second-hand and just try it out. It might not be fantastic but might be good enough to be getting on with without large expenditure.
Others may have other suggestions.
I think it would mainly cost an enormous amount of time to convert it into a telescope, but if the glass is suitable (and I really don’t know whether it is), it should be possible; after all, Andrew Common in the 19th century managed to build an even bigger telescope on an amateur basis, with little prior experience of mirror-making. The mechanics would perhaps be more challenging than the optics.
As for a remote BAA telescope, I have to say, without saying too much, that Council has not been very keen on going down that route, feeling it is a service well-covered by commercial suppliers, and not wanting to risk a ‘stranded asset’ that could be difficult to manage. But we may discuss it again.
