[Dawson]

Yes, the Mayor emailed me to see if she could come to the observatory tonight for the spectacle.

[Dawson]

Denis, thank you. I’ll email you my address.

If anyone else has copies, I’ll still need:

Winter 1994
Spring 1997
Summer 1997
Fall 1997

James

[Dawson]

Given the site the tank ended up is known, is all this information used to refine the models for predicting where actual metoerites land?

[Dawson]

Pick up by our two meteor cameras in Nottignham, and if it is the same lump which landed in poland, this is a rough ground track (no scientific data used for this, just me and Microsoft Paint).

Attachments:

1. 

   Poland.png
   

[Dawson]

Thanks Robin. Indeed with a dedicated planetary camera, one minute of video is typically in excess of 3GB. I am just writing a talk for my local society and showing them how Registax and AS!4 both handle a 10GB video file… AS!4 does all the processing in 2 minutes, whilst RegiStax has only aligned 7% of the frames at 25 minutes, and has yet to limit them, and stack them…

I will have to look what the file size is for the lowest compression DSLR video at 60fps.

James

[Dawson]

Alex, yes, a number of stills in RAW with the added dynamic range is also a good option. Thanks.

[Dawson]

I learnt that Canon has a live chat function. I asked them. This is the answer I got:

“In general when changing resolutions the camera uses the data from the sensor to interpolate the resolution, this is done by merging and binning pixels to record lower resolutions on the camera so it will still show the same aspect ratio at different resolutions”

If it is binning, with the sensor 5184×3456 (18MP) to get 1920×1280 (Full HD), there would be roughly 3×3 binning (effective pixel size 12.9um), for 1280×720 (HD) there would be roughly 4×4 binning (effective pixel size 17.2um), and to get 640×480 (SD) would be roughly 7×7 binning (effective pixel size 30um).

Maximum fps for video is 30fps for Full HD and SD, and 60fps for HD.

Therefore, using a 2x Powermate on his C11 with his 700D camera in 1280×720 mode with least compression, that gives him 0.63″ per [effective] pixel amd 60 fps. Sounds reasonable. Given the compression, he’s likely better off with a dedicated planetary camera, but interesting exercise to figure out what the DSLR does.

James

[Dawson]

An interesting film. Thank you.

[Dawson]

I’ve had a useful email conversation with a technical person at Lunt. This is a summary of their suggestions which I have yet to try asI’ve not had time nor a clear day! It has a new blue filter in which I replcaed before the April 2024 total solar eclipse.

Now, may I ask with the double stack removed, do you also experience such views? It is certainly true that a double stack can really make your image extra special but if not tuned correctly, can also consistently be at odds with the primary etalon.

What I might recommend here, might seem like a step backwards. When I test double stack units, for the LS50THa or otherwise, I of course start with my scope in single stack mode. I tune and adjust until I am at the best point, and then I introduce the double stack. From there, I make sure my double stack is at rest (that is, no tilt introduced through the tuning wheel) and begin to tune from there. There are times when double stacks need a little something else. If I was testing your LS50THa, with this LS50c, the first thing I might do is go through the entire range on the LS50c that is attached and find my absolute best view while tuning that (after having tuned the primary without the double stack attached). If my field is much like your picture, my next thing I do, is to attempt to retune the primary etalon. At times, a little adjustment on the primary can really go a long way to making the double stack image what I would like it to be. From there, I would lastly try rotation of the double stack unit itself. This may seem the most precarious, but of course you have multiple threads securing it, and you wont need to during any more rotation than the initial 360 degrees, as anything past the first complete turn will put you at the same physical position in terms of lens tilt, but with just less thread to hold the filter onto the telescope.

Very often, customers who are experiencing a lack in quality views with their double stacks will find some relief between these suggestions.

Lastly, I am uncertain how old your telescope may be- but have you checked the BG (Blue glass) optic in your blocking filter as of late? This would be the blue glass element found under the nose tube that is introduced into your focuser. It should be perfectly clear, and without occlusion. Some of our older scopes have an uncoated version of the BG, while the new ones have a coated version. In either case, it should be 100% clear.

[Dawson]

Thanks both.

The Lunt website talks about the issue, but gives conflicting advice on a solution. At one point says the B600 is fine for imaging with the 50mm Lunt, but then in the next paragraph suggests one should go to the next blocking filter up for imaging. I’ll email them, as they have been helpful in the past. It also sounds like tilt may be an issue, so something else to explore and MUCH cheaper to rectify!

Thanks.

James

[Dawson]

Yes, another one of that era gone. Sad indeed.

I never met Storm but we had emailed, mostly me picking his brains about things from the past, and he was always helpful, even when the topic related to Patrick Moore! I don’t know the full story of the bust up in the BAA with Storm and Patrick and others apart from what I’ve read in Martin Mobberley’s books.

Storm’s knowledge of weather phenonomena was amazing and I’ve got several of hie weather books. We most recently corresponded about Cecilia Botley who like Storm was also interested in the weather. I had emailed him last week about a book he had translated (Atlas of Great Comets by Ronald Stoyan) saying what a great book it is and would he pass my thanks onto the author. I never recieved a reply.

I look forward to reading more about his life as and when someone writes a biographical article about him.

James Dawson

[Dawson]

Thanks for all the comments.

I will download Astro surface and have a play with that but in the meantime I’ll stick with AS!4 and Wavesharp which both appear to process very quickly and seem to use all available processing power.

James

[Dawson]

Looking at this again on my desktop PC (rather than my laptop), I think the bottleneck is the software. Registax only seems to use one or two cores of the CPU and then the utilisation of these appears to be about 50%, whereas if I use Autostakkert it uses all cores and utilisation for each goes up to near 100%. This is despite altering Registax to use “8 CPUs” in its settings (this PC has 12 cores). I just need to now teach myself how to properly use Autostakkert and just use Registax for wavelets though their Wavesharp software seems much better at this.

James

[Dawson]

Thanks Grant.

Windows 11, 32 GB RAM, nothing else major running. Task manager doesn’t suggest the bottleneck is CPU, RAM, GPU, disk, WiFi… so I wonder what is the limiting factor which causes software to not run quicker?

[Dawson]

In fact, I’ve got several on Amazon too if anyone is interested; most have been given to the Society for the History of Astronomy and they just need to go to good homes.

Attachments:

1. Amazon-books.pdf

[Dawson]

Jack there is a video of a chap making adjustmetns to one of these mounts, and also a thread on cloudy nights describing adjustment of the slop in the system, these may help you:

https://www.youtube.com/watch?v=zvf8SJiXZOg

https://www.cloudynights.com/topic/382939-vixen-porta-mount-repair/

James

[Dawson]

Bill if this meets your requirements in terms of capacity and connections, then it looks good; it seems to be £20 cheaper on Amazon. The others out there seem to be significantly bigger and heavier.

[Dawson]

Bill there are countless options out there. As Jeremy says, you need to work out how much power you need between recharges and go from there. Much more expensive than lead acid though, and still needs to be looked after and recharged appropraitely and regularly. There is nothing wrong with lead acid batteries, though twice the weight of lithium, as long as you take care of them.

[Dawson]

Thanks Paul. If the solar panel is on the dome, that makes sense. I’ll discuss the idea with the others. Thank you.

[Dawson]

Mel, thanks. We want something which will hold it whenever someone takes their hand off the crank handle; if they let go it runs away as described above. The U bolt idea is good though for holding it; we use a rope at present which does something similar. But thank you.

Paul, that is a good idea. Our shutter is pretty heavy so it may need to be a chunky battery. How do you go about charging up that battery? We’d need someone to remember to connect it to the charging circuit unless we always parked the dome in azimuth in the same position and set up a positive and negative contacts at specific locations on the dome and the on the rim of the supporting wall. But an interesting idea.

James

[Author]

Posts