[Dawson]

Thanks Chris. I think an article or the like about this would be very good.

[Dawson]

Mike, it is a massive undertaking to record one meeting, let alone three days’ worth of meetings. And that is just the recording of audio and video, putting microphones on speakers, along with capturing the slides, let alone the subsequent editing, matching of sound and video, labeling, electronically adjusting lighting and sound, and then uploading, plus checking nothing infringes copyright and seeking speaker permissions. It really is a massive job, and not an enjoyable one for a volunteer.

[Dawson]

What a great weekend it was Pauline.

[Dawson]

I’ve resolved the streaking comet. Now I have streaking stars when they are not meant to be. An overly stretched image shows the subtle streaking. I’ve posted this question on SGL too, but I do wonder if this is somehow related to my flats or darks, or maybe because I had the ISO too high (3200 for Canon 6D). More work in progress. It is just a case of finding the time to sit down and change the myriad of variables, stack and see if things have improved. I am SLOWLY getting there.

https://stargazerslounge.com/topic/407703-streaky-stars-in-dss-comet-stack/

James

Attachments:

1. 

   streaky-scaled.jpg
   

[Dawson]

Thanks Peter. I think I may have discovered the issue. I hadn’t appreciated it was possible to use roller ball on my mouse to zoom right into the comet to get a better placement of the purple ring, and also I hadn’t been pressing the save icon on the right, under the comet icon. I’m still not sure if I am meant to press the save icon on EVERY sub, or just at the end of marking the comet on all the subs. Anyway, the first stack I’ve done since implementing these changes seems to be OK, now I’m trying to keep the stars and comet static so it taking my poor laptop even longer!

I will report back with results.

Thanks for replying.

James

[Dawson]

I agree that there should be very clear comments on what has been done to manipulate ANY image. For planetary this will usually be along the lines of “best 50% of 10,000 frames stacked, sharpened with wavelets and brightness, contrast and RGB adjusted”. The difficulty arises when dealing with images like this lunar occultation of Mars. I have seen several images of this occultation online where the processing comments should read along these lines:

1. Best 50% of 10,000 frames of Mars stacked (taken 60 minutes prior to lunar occultation). Derotated in Winjupos. Wavelets and RGB adjustments.
2. Best 50% of 10,000 frames of the lunar limb stacked (taken 60 minutes prior to the occultation of Mars). Wavelets and RGB adjustments.
3. Capture of lunar occultation taken during the event to show apparent spatial interaction between the Moon and Mars and to collect timing points.
4. Photoshop editing of two separate images (Mars and lunar limb) to merge into spatially correct apparent lunar occultation of Mars.

Using a bit of lunar limb and a full-face Mars from Richard’s original data (https://britastro.org/observations/observation.php?id=20221211_181703_df51689fca6965b0) as shown below, it is possible to construct the attached animated gif, which is totally made up, but just a rough representation of what was observed in time-lapse. But this face of Mars wasn’t the one that got occulted by the Moon, it is just the same full face of Mars slipping behind a layer in Photoshop. The issue then is neither the actual lunar limb, nor the actual face of Mars are correct; if the Mars image was taken 60 minutes before the Martian features will be in the wrong place, and the illumination of the lunar limb will be subtly wrong too.

But this all boils down to what is the purpose of the image? If it is for scientific scrutiny then this made-up composite has little value. If it is for maximal visual impact of a lay audience then this method is likely the one to follow.

James

Attachments:

1. 

   FRAGMENTS.png
   

2. 

   ezgif.com-gif-maker.gif
   

[Dawson]

Thanks all for the comments.

I’ve made contact with Robert Mackenzie and he is happy for me to scan the publication.

Another job to add to the list… 🙂

I will share once scanned.

James

[Dawson]

Ok, I think we have a plan for people who want a copy.

Either post a cheque for £20 to Alan and he’ll post the book out. Or if you want to send me £20 electronically along with your address and whether you want him to write anything in the front of the book, and I’ll write Alan out a cheque for the money and print out the address and give it him a print out once a week or so.

I spoke to him on the telephone just, and he thinks we may need more copies…

I’ve also listed the book on Amazon, but they take £6 per item, so to cover costs of the book and postage and the Amazon fees, it is listed at £25.

I’ll message everyone who has shown interest in the book this same message. Contact me for Alan’s address if you don’t already have it.

James

[Dawson]

Yes an excellent edition. Well done David and team. It is great to see the work we are doing on our observatory in Nottingham mentioned. It is still very much work in progress but we are getting there. I will write up a report for the Section in due course about the final version and the issues we faced. The current intermittent issue relates to the surface of the capstan; too “dry” and the rope doesn’t slip well, but too “shiny” and there is insufficient friction. It’s all good fun.

[Dawson]

It would be interesting to see if there were similar postings in the forum the last time the website had a major overhaul. I suspect there was.

I think resolving the issue about having to log in every visit would be good, and if you could get rid of the page immediately after logging on which tells you that you are logging in would be good too.

I do think summer is a quiet time for the website traditionally, but like others have said, I am conscious my visits have reduced in recent times. I think some of this is down to the fact I mostly visit from my phone, and I’m yet to bond with the way the new website appears on my phone. There seem to be lots of graphics that presumably indicate different parts of the website, but as I’ve not linked the pictures to the graphics yet it all just looks foreign still. I suspect the graphics wouldn’t be missed on my iphone, and just having text links would be sufficient.

If it was possible, I’d also reinstate the option to be able to start a new forum thread from within the different fora, rather than having to somehow go back, go back, go back to the start of all fora and then click start new.

I also miss being able to click a members name or picture and being able to send them an email directly. That was a really useful feature.

I’ve not explored or done much else to comment, but overall I think I’ve not used it enough to learn my way around, and none of us like change.

We also have to remember most of this is probably undertaken by volunteers.

James Dawson

[Dawson]

Please have them. Where is your brother, if relatively close I could drop them off with him. They just need to go ASAP.

James

[Dawson]

I think it is worth £300 or more.

[Dawson]

If it had the maps, I suspect £1000.

[Dawson]

I’ve found a copy. The cover is just the same as the 1st edition. There is a short new preface to the second edition which reads:

“A few changes have been made – particularly in the Occultation section. Since 1972 Mr. Ringsdore has, unhappily, been compelled to retire as Section Secretary because of ill-health. In his place, we welcome Mr. Geoffrey Buss.”

The only change I can see in the 1974 edition is there is an additional page on occultations, see attachment.

James

Attachments:

1. 

   1974-rotated.jpg
   

[Dawson]

David, is it possible to see some more images of the device to see all sides of it and get any idea how it might have been used. The turning know suggests a focus or a means to act as some kind of comparator.

James

[Dawson]

Stewart, thank you, that is interesting and helpful. I’ve got a spare copy of number 1 which you can have for free if you want, I can bring it to Winchester.

James

[Dawson]

I’ve had a look on line and looked through a few books both for the telescope and for the event (Lord Morison handing over the telescope) and I can’t find anything. As you say, several of similar design, but none VERY close. The altitude bar, the fixings to the mount, the location of the focus knobs, the combination of exposed and covered brass…

It would probably be worth contacting the antique Telescope Society. Also try the Society for the History of Astronomy as they will likely put a picture of it in a coming publication to broaden exposure. 

James [Librarian for the Society for the History of Astronomy]

[Dawson]

If anyone has the early copies of the handbook, I am looking for these to fill gaps in the Society for the History of Astronomy Library. The earliest I’ve got is 1936 so looking for the 15 or so before this.

Thanks

James Dawson

Librarian, Society for the History of Astronomy

[Dawson]

And the crazy flashing thing bottom left quadrant from 1:36 to 1:57?

[Dawson]

What is the object which appears about 49 seconds in an d vanishes about 52 seconds just to the west of HIP 45336, 22 Hya (top left qudrant of the image)?

[Author]

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