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Apologies to Nick, I accidentally deleted his light curve of SN 2023ixf. Now added back after Nick sent me a copy.
As an admin I have delete and detach links, next to the link to view attachments. I must have hit one of those when trying to view his light curve.
It is great seeing all the photometry and spectroscopy of this supernova.
Andy
Hi,
How do you calculate its magnitude please ?Hi Kwong,
A variety of software packages can do photometry, including some image processing packages such as MaxIm DL. If the software you are already using doesn’t have the ability to calculate magnitudes, then I would opt for a free package that is easy to use, unless you are sure you will get into photometry of variable stars, exoplanets or asteroids.
There is a list of some software packages at the top of this page on submitting to the BAA Photometry database.
https://britastro.org/vssdb/notes_submissions.php
I’ve not tried them all, but MuniPack might be the easiest to get started with.
The trick is you have to measure the magnitude of the target star (the supernova) as well as several comparison stars. The comparison stars need to be carefully chosen, to avoid variable stars and to ensure they themselves have a robust magnitude. The AAVSO chart plotter is the perfect place for this.
The other key point. The supernova and none of the comparison stars must be over exposed as that would cause the calculation to go wrong. A good rule of thumb is for the peak counts in any pixel of those stars should be at most 2/3rds the full well capacity of your camera.
Good luck with your observations.
Andy (BAA Variable Star Section Database Secretary)
Here is a link to the AAVSO chart. For those who haven’t used them before you can adjust the size and orientation by clicking plot other chart, and access the magnitudes of the labelled comparison stars by clicking photometry table for this chart.
https://app.aavso.org/vsp/chart/?star=SN%202023ixf&fov=60&maglimit=14.5&resolution=150&north=up&east=left
AndyI saw it visually through a 10-inch last night and it was very obvious. I estimated it at magnitude 11.8. I don’t consider myself a seasoned visual observer so being close to a V magnitude of 12 sounds about right.
AndyHi Paul,
I have sent you an email where I have included the BAA Office who manage the donations.
At present we use Square to take donations. The same service we use for the BAA shop and telephone payments. I have tested the donation page just now and it was working on Chrome, Firefox, MS Edge and Safari, running on Windows 11 and macOS Ventura. I wonder if it was a temporary glitch or whether something in your browser might be blocking the Square site, link below.
https://checkout.square.site/merchant/MLW65481JK36P/checkout/SL5VCCR2YENEZGEKFZPD6AGH
Best wishes,
AndyI have received confirmation from the venue that they successfully made the recordings, apart from a problem with the slides not being recorded at the start. They are hoping to be able to fix this. They need to get everything together and make some edits, with an expected timeframe of a week or two before they are with us to add to the BAA YouTube channel.
AndyHi Paul,
Yes, you are missing something.
If we loaded the AAVSO data at a point in time, it would slowly become out of date. This would then generate errors rather than warnings for those charts during observation uploads. When you provide a chart recognised by the BAA database, it then checks the comparison stars match, their magnitudes, and checks the photometry calculation. So adding data that becomes out of date would cause bigger problems than just accepting a warning message.
The whole point of the charts in the BAA database is to allow checks and recalculations. As the AAVSO use numbered comparison stars based on the magnitude, this means star 102 in a chart at one point in time, can be replaced by a different star later. That would corrupt the calculations giving incorrect results. I would not implement a system that I know would give incorrect results under realistic scenarios.
It is much simpler to accept the explanation that you can ignore the chart warning if you don’t expect the chart to be present, as per the user guide for the database.
https://britastro.org/photdb/help/WarningAndErrorInvestigation_UserGuide.htm
Best wishes,
AndyHi Paul,
Sorry this is causing you hassle. The point is these ‘warning’ messages are very useful to a large number of our observers. A ‘warning’ simply means ‘can you take a quick look at this to make sure it is expected’. It allows you to proceed with adding the data as only the observer has the knowledge of whether to expect a recognised chart or the other warning messages that are generated. When the upload generates an ‘error’ message then that means something is wrong and it won’t let the upload proceed.
We do have some AAVSO charts in the database. These tend to be older charts before they implemented their latest chart system, or charts created at a specific point in time. When I created the database I had discussions with the AAVSO about getting a copy of their chart data to add to our database. The problem is their charts are not static. A chart ID is not guaranteed to generate the same chart when entered at a later date, as any changes to the AAVSO chart database will result in the same ID giving a slightly different chart.
The chart is particularly important to the visual observers as the BAA database can recalculate magnitudes to the latest sequence. It can actually do that for digital as well as visual observations where sufficient information is provided, though we currently only have it turned on for visual observations.
As a final note, I would point out the AAVSO charts are fantastic and used by many BAA observers. It is just the BAA database cannot use them for more detailed processing as their chart IDs do not uniquely identify the comparison stars and their magnitudes.
Best wishes,
AndyHi Paul,
I successfully use a Quark Chromosphere with a Williams Optics 66 and 81mm refractors for visual observing. I use a UV/IR filter.
While this works, it isn’t quite a quick grab and go setup as I have to wait for the Quark to reach the right temperature and sometimes tweak it to get the view at its best.
Best wishes,
AndyHi Paul,
I believe these charts are designed for use by visual observers. There the simplicity of a single decimal place is beneficial to the visual observer.
Cheers,
AndyFor those who are going, I have added some information about car parking sent to me by Hazel Collett.
https://britastro.org/event/baa-spring-meeting
Best wishes,
AndyHi Alex,
We are in discussions with the venue to try to get the talks recorded. I think this is likely but not completely guaranteed.
They are definitely not going to be on Zoom or livestreamed to YouTube. What we are working on is the venue making the recording, then sending this to us afterwards for editing and adding to the BAA YouTube channel.
Best wishes,
AndyThis has somewhat hi-jacked the Winchester thread, but it is good to discuss these matters.
I suspect there may now be easier ways we can record meetings. For example, since Windows 10 an inbuilt screen recorder comes as standard. I also expect that more venues will gain the ability to record meetings for us. At Elgin the university staff kindly recorded the meeting for us without charging us extra. However, they had to work this out on the fly and we did not know if the meeting would be successfully recorded until the actual day.
There are also occasions where the organisers as well as the presenters do not want the meeting recorded, to encourage in-person attendance.
Whatever we do, I think finding more volunteers would help to increase the number of meetings we record.
Hi Mike,
James has hit the proverbial nail on the head.
The BAA is lacking volunteers. With some venues we are fortunate enough that they already have the IT equipment and staff available to make the recordings, but this is not the case at Winchester. Even then it requires a BAA volunteer or paid staff to edit the videos and put them online. It could be argued that the BAA should pay contractors to record meetings around the country. That would need to be paid out of the reserves as our annual outgoings are about twice the subscription income.
This is a good opportunity to point out that we don’t yet have a volunteer to become the Meetings Secretary after Hazel Collett stands down a the end of this year. Noting Ann Davies rather than Hazel Collett organises the Winchester Weekend, with help from other BAA volunteers.
The 1972 recording is 3 minutes of people walking around the venue without sound. Interesting to see that for 50 years ago but the expectations for current meeting recordings are much higher.
Best wishes,
AndySorry but there are no videos of the Winchester talks as it is not straightforward to get them recorded. The year we had videos was when we held a webinar instead due to the lockdown.
AndyTo my understanding there is nothing to indicate a return to the Steady State theory. There is a lot of evidence for a “big bang” style to the beginning of the observable universe, or at least changes to the universe with time that are very difficult for the Steady State theory to explain, such as the increase in the abundance of heavy elements with time. Even though the JWST results don’t quite match expectations, the evolution of galaxies with time can be seen by JWST and other observations. For example, star formation rates observed in galaxies peaked a few billion years ago. Also, quasar activity is observed to decrease with age, i.e. more common in more distance galaxies.
I believe they are still at the stage of analysing and gathering data. So it is too early to tell whether this can be resolved by adjusting model parameters rather than requiring a whole new model.This is on a list of changes that will be going to the BAA website developer. Unfortunately I do not have a time frame but I shall ask for this to be done sooner rather than later.
I’ve not delved sufficiently deeply into this aspect of spectroscopy to properly comment. However, I can see it is a detailed and interesting model.
Best wishes,
Andy
