lukebl

After a night not seeing many Perseids, I scooted up to North Norfolk and captured this transit of the ISS with my PST Coronado. The path of visibility for this transit was only 6.5km wide.

The weather wasn't promising and at the precise moment of the transit, clouds rolled across and the image went virtually black, so I assumed that I'd missed it. However, on stretching the image, I realised that I did manage to capture the transit.
Coronado PST, ASI290MM cam, Exposure 0.88ms, 23 frames per second.

On this transit, which took just 0.66 seconds, the ISS had an angular size of about 50 Arc Seconds and was 513km distant. Other upcoming transits near me have the ISS at 1416km distant and only 20 Arc secs across

Sounds like some of you were luckier than me. I guess my eyes aren't what they were.

Here's an hour's worth of my north-facing camera. One Perseid and a brighter sporadic (or maybe a satellite flare). Canon 6D. 30 sec exposures ISO 1600.

I don’t know about you, but I was pretty underwhelmed by this year’s Perseids.

I had two clear nights and stayed up for a few hours both nights, and also had two cameras running in different directions, but saw and captured very few compared to previous years.

What are other’s thoughts?

8 minutes ago, randomic said:

During midday to midnight, the same number of meteors are hitting Earth, it's just that most of them are hitting the other side of the planet from you.

Fair enough! I think I get now. Many thanks!

1 hour ago, randomic said:

sn't it just that from midnight-midday you're on the side of the earth which is going "forward" into the meteors?

But, like I said, if the meteors are travelling at 30,000mph and the earth is rotating at 1000 mph, it wouldn’t make much difference whether the earth was rotating into the storm or away from it. i.e. the speed of the meteor entering the atmosphere would be c. 29,000mph in the evening and 31,000mph in the morning. Not much difference. 

1 minute ago, russ said:

Will you be doing another video tonight if you get the chance?

Thanks! I sure will. The forecast here is fairly promising for tonight, and there should be a lot more activity.

Here's a video of about 6½ hours of 30 second exposures from my garden, from about 22:00 BST to 04:30 BST) compressed into just over a minute. Canon 700d, 8mm Samyang fisheye lens, f/3.5, ISO 800. Night of 11th August 2021.

The aim was to capture some Perseids. There were a few relatively minor ones, plus a few planes, satellite trails and flares. Nice cloud movement, though!

8 hours ago, Tiny Clanger said:

A previous thread has some good explanations (and some confusing ones too)

Thanks. I missed that earlier thread. 

I found this quote from National Geographic: “Think of it like an automobile that has a windshield on the side facing forward,” Murphy says. “You get more bugs on the front windshield than you do on the back window.”

Like I said. I don’t buy it! The difference in relative speed of the meteor before and after midnight would be insignificant. The bugs are still flying into the back window nearly as fast as on the front windshield.

17 minutes ago, globular said:

Isn’t it just that there are more hours of darkness after midnight than before… 

Well, that what I think too. But as I said, various guides (books, internet, magazines, etc) perpetuate the claim that there are more meteors in the hours before dawn because the earth is rotating into them.

I’ve never bought that unfounded claim for the reasons I said in my post.

As I sit here waiting for some Perseids I’ve been giving some thought regarding the frequency of meteors before midnight and after midnight. i.e. the fact that meteors are apparently more frequent after midnight than before. 

The perceived wisdom is that in the morning the earth is rotating INTO the meteoroid, and thus the relative speed is greater, air friction is greater, and the meteors are brighter and otherwise faint ones are more visible. In the evening the earth is rotating AWAY from the meteoroid, so the relative speed is slower, ipso facto less air resistance, less friction and the meteors are fewer and less bright.

HOWEVER, my understanding is that meteors are travelling at, say, 30,000 mph or more, while at the equator the earth is rotating at around 1000 mph (and effectively zero at the poles). So the speed of the Earth’s rotation is pretty negligible compared to the meteor’s speed, and can’t really have a significant effect on the meteor’s entry speed? A meteor hitting the earth’s atmosphere at 31,000 mph surely can’t be significantly brighter than one hitting it at 29,000 mph?

Or am I just being stupid? 
 

Hi folks.

This is a painstaking animation from 20 videos captured every 10 minutes (about 3½ hours) with a PST Coronado this afternoon, 2x TAL Barlow, ASI290MM Mini cam. Each video was consisted of 500 frames. The prominences were 2.25ms exposures at 64 fps. The sun's surface was a single capture of 500 frames at an exposure of 0.22ms. Stacked in Registax 5, and processed in Photoshop.

Obviously, in reality the sun's surface should have been animated too, but I sadly didn't have the patience to do an additional 20 videos of the surface on top of the prominence ones. That's for another day when there's a completely clear sky, uninterrupted by passing clouds. However, I'm reasonably pleased with the result.

I'm really looking forward to a biggie, like this legendary one in 1946!

Now that the sun's livening up a bit, I did a quick capture today with the PST Coronado, 2x TAL Barlow and ASI290MM cam.

I've probably overcooked the processing a bit, but I'm always amazed at what this tiny wee scope with a mere 40mm objective can do. Obviously not a patch on bigger specialised scopes but worth every penny as a grab-and-go IMHO.

1200 frames, 0.3ms exposure, 30 fps. Stacked in Registax 5 (I'm very old-fashioned):

Prominences 620 frames, 1.8ms, 30 fps

Inverted:

Prominences combined

Here's a not-so-sharp capture of the ISS transiting the moon at sunset last night. It was hot and above the heat haze of my garage roof.

I captured it using an RC8, 2x Tal Barlow (3200mm FL), ASI290MM cam. About 29 fps. The big, middle and small craters in a line from top to bottom are Ptolemaeus, Alphonsus and Arzachel.

It's the first time I've captured a transit with the ISS illuminated. Not at its best though. Apparently, the station was 1018.95 km distant. At other times it can be half that distance

I also captured a video on my Canon 700d, with a 70-300mm Zoom. The ISS moves from bottom right to upper left, with a couple of swifts buzzing by the moment it crosses the moon. It was around mag -2.9 at the time.

I love it too. I want one!

Belgium’s finest export. As a complete Tintin nerd since infancy, I’ve always said that Hergé’s Adventures of Tintin would be my specialist subject if I ever applied to go on Mastermind. I’ve always thought it strange that in almost every language the captain is called Haddock, but in Afrikaans he’s Sardine!

Weird. In despair, I restored my iPad from a backup 6 months ago to see if that might work. Still no luck. Didn’t dare deleting the app in case I had to buy it all over again. I left it overnight and miraculously SkySafari Pro has suddenly started working again. 

I guess I’ll never know what that was all about. 

Anyway, thanks for all the helpful replies. 

Just now, globular said:

My ipad is on 14.6 (18F72) and Skysafari 6 Pro seems fine.... I've just launched it and used a few functions and all seem well..... does any function in particular cause the message to pop up?

Just clicking on the icon make the message come up, and the app doesn’t run. All very frustrating.

Just now, Knighty2112 said:

Skysafari 6 on my ipad working Ok after update on my ipad. 

Weird. Which version of iOS has it updated to?

My wretched iPad just updated itself to iPadOS 14.6, and now says 'SkySafari Pro Needs to be updated. The developer of this app needs to update it to work with this version of iOS'.

Has anyone else had this problem, and can I re-install an earlier iOS?

How dare Apple do this to my most expensive app and leave me in the lurch! 🤬🤬🤬

That looks identical to the one I had in the 1970s. That was all we could afford, but it got me an O-Level in astronomy! Very fond memories.

(I a got Grade A, by the way!)

The view of mid-eclipse from Banham, Norfolk. The clouds add a sense of drama, I think.

Some quick captures of the full supermoon rising over my local church in Banham, Norfolk, last night.

Canon 700d, Canon 75-300mm zoom @ 300mm, cropped.

13 minutes ago, david_taurus83 said:

Did you calibrate the darks with bias?

No I didn't take any bias frames. They've never seemed to make any difference before, but perhaps I'll give it a go.

As I've mentioned on another thread, I'm struggling a bit with my Atik383L+ which is a bit of a disappointment after my old 428ex and even my vintage SVHF-H9.

Can anyone exlpain what these black lines are on this stacked image? This is about 50 frames with darks and flats stacked in DeepSkyStacker. I can't see anything untoward on any of the individual flats, darks or lights.

19 minutes ago, Knight of Clear Skies said:

Good demonstration that there are many ways making astronomical observations, it's certainly not just about the showpiece images.

Thanks! I’ve long realised that I’m not capable of showpiece images, so I concentrate more on nerdy stuff that I find interesting!

Had a very interesting session doing some photometry on asteroids last night.

You can usually observe their rotation by a dip in the magnitude over a period of time. The more irregular ones show the greatest fluctuation. I noticed that asteroid 1727 Mette is well-placed in Serpens and has a fast rotation of about 3 hours, and I managed to capture 5 hours-worth of images. It's just a small object about 5-8 km in diameter and is a Mars-crosser asteroid, orbiting every 2.52 years.

Here is a light curve I prepared using data from the photometry program Muniwin. It's derived from 100 x 3 minute exposures, binned 2x captured with an Atik383L+, Omegon RC cam.

Once Muniwin had processed the data it came up with this strikingly obvious rotation curve, with its magnitude ranging by about 0.35 magnitudes over a period of 3 hours, matching the official rotational data with a peak at around 23:37 and another at 2:32. As usual with asteroid magnitude curves, there are two peaks and troughs per rotation. There are a few binary asteroids, like Antiope, which behave like eclipsing binaries when lined up correctly, so I hope to capture that some time.

Here's a capture of the whole field, with the position of Mette at 22:24 and 2:57 highlighted. Based on two 5 x 3 minute exposures. The brightest star here is magnitude 7.8 and the field of view is 38.5 x 29 arc minutes.

And here's an animation of 9 clipped frames over the session, 15 minutes apart