lukebl

9 hours ago, andrew s said:

Yes that's true per pixel but for the same total effective area of sensor, the one with the higher QE will detect more photons. 

Which will give the cleaner image will depend on read noise,  telegraph noise and other sensor parameters.

Regards Andrew 

I think I’m even more confused now!
The science of it baffles me. All I want to know is which camera is more sensitive, assuming the same optical setup, the 533MC-Pro or the 585MC-Pro?

Many thanks Vlaiv. I suspected that it would be your name providing a highly informed explanation!

So, the basic message is that the ASI 533MC-Pro, although it has a lower QE than the ASI 585MC-Pro, is more sensitive due to the larger pixels relative to the QE, and will capture objects of lower magnitude?

Hi folks, I’m after an OSC CMOS camera and don’t really understand Quantum Efficiency.

Basically, does a higher QE mean greater sensitivity and, therefore, fainter stars?

It’s just that I’m after the most sensitive OSC which I can afford (i.e. less than £1k). I’m not too bothered about the actual size of the sensor, just the sensitivity. I just can’t be doing with mono imaging any more with the UK climate.

The blurb about the ZWO ASI 533MC-Pro says how sensitive it is, but only has a QE of 80%. Whereas the cheaper ZWO ASI 585MC-Pro has a QE of 91%.

Does that mean the ZWO ASI 585MC-Pro will capture objects of a lower magnitude and/or require shorter exposures? And is there an alternative camera which would suit my needs?

Many thanks!

Hi all,

I haven't done any DSO imaging for a year or two and, as I mentioned in another thread, I realise that CCD cameras have now gone the way of Box Brownies, Betamax videos and CDs and have had their day.

So this is probably the last image to be captured with my old Atik383L+, before I take delivery of a new CMOS camera (not sure which one yet). My favourite, M104 the Sombrero galaxy, captured in a narrow time window as it passed low between two buildings from my garden obs.

250mm f/4.8 Newtonian, Atik 383L+, Baader Coma Corrector, 60 x 60s exposures + RGB 30s x 10 exposures each, binned 2x. Not perfect, but I'm a bit rusty!

Back in the day, a very long time ago when GCSEs were called O-Levels, I asked to take O-Level astronomy at my school in Ipswich.

My teachers initially refused, saying it wasn’t on the curriculum or something and they didn’t have anyone to teach it. I said I didn’t need a teacher, I can do it myself! Eventually, after further persuasion from my parents, they agreed. I recall sitting the written exam in the big exam hall, empty apart from one other guy also taking the astronomy exam after my actions. I sometimes wonder what happened to him.

I got an A. Actually, the only A I have ever received, although I haven’t done too badly in life.

I'm not sure if this qualifies as it was technically taken during the day, but it IS an astronomical image of a landscape captured when the day had turned to night!

It's a simple grab of a single frame from a video I captured with my iPhone 11 Pro of the total eclipse, seen from Magog, Quebec Province, Canada on 8th April 2024. The lens was set at 'wide', 26mm @ f/1.8. Venus can be seen to the lower right. The lake in the foreground is the delightfully-named Lake Memphremagog which is partly in the US state of Vermont. I think the small triangular peak left of centre is Mont Nixon, and the high land near the left hand edge is Mont Éléphant. It was a beautiful setting to view the eclipse.

This frame was shortly before 3rd Contact when the diamond ring was just about to appear, and the rapidly-approaching daylight can be seen beyond the receding lunar shadow. I had set up the phone on a tripod to record the whole eclipse from a minute or so before 2nd contact to about a minute after 3rd, and set it to a fixed exposure so that it didn't automatically increase the exposure time during totality. No manipulation of the image at all.

Here's a capture of the Jupiter and Uranus conjunction from my garden in Norfolk this evening. Very low in the WNW in twilight, about 10 degrees above the horizon and half a degree apart.

Canon 700d, ISO800, 4 seconds, Canon 150-500mm zoom, f/8, AZ SynScan mount.

So the general consensus seems to be that CMOS sensors are more sensitive than CCDs and involve less faffing about. And, at my age, I could certainly do with less faffing about. The faffing has been what’s put me off imaging recently.

So, I think it’s time to move on to CMOS! But which one? Hopefully I can get a couple of quid for my current CCD cameras.

I’ve been out of DSO imaging for a couple of years, and have noticed that most folk nowadays seem to be imaging with OSC CMOS cameras. I assume that’s because CMOS sensors (even OSC ones) are now as good as the old mono CCDs.

Does this mean that mono CCD is now obsolete and that my current vintage mono cameras (Atik 383L+ and Atik428ex) should be consigned to a museum?

Here's my attempt at an HDR image to capture the solar corona, comprised of 13 images at different exposures from 4 seconds to 1/1000 sec. Magog, Canada, 8th April 2024.

Canon 700d, Sigma 150-500mm zoom @ 400mm, f/11. ISO 200 Processed in Photoshop (Howto guide here)

Here's a video of last week's total solar eclipse from Magog, Canada, speeded up 8 times. Captured on my iPhone. The speeded up human voices sound like a flock of chickens!

...or if you're more patient, here it is at normal speed. Listen for the hollerin' at commencement and end of totality (at about 1:42 and 5:23 minutes) and see how the edge of the receding shadow appears on the horizon from around 3:55.

A further refinement of the animation.

I've only just got back from my trip to Magog, Canada, to observe the eclipse and have started to process my images.

It was an amazing event with perfect weather. We were located on the shore of Lake Memphremagog. Shortly before totality some strange waves started washing over the shore. In the eery twilight it was very spooky.

These captures were with a Canon 700d and Sigma 150-500mm zoom (a lens which really impresses me) set at 400mm, f/11, ISO 200 and various exposures.

My third total eclipse and definitely the most memorable.

One of the most noticeable features was a really bright prominence which began to appear as totality progressed. It was almost like a red searchlight shining on the lower left edge of the disk, very visible to the naked eye and something on which many casual observers commented. This is an animation showing it emerging.

The Baily's Beads at commencement and end of totality were beautiful.

Commencement:

End of totality:

Totality:

Diamond Ring:

And finally a sequence from beginning to end. Images captured every 5 minutes.

I’ll be going to Spain myself.
I think totality near the horizon could be visually much more impressive within the landscape rather than isolated high in the sky.

5 minutes ago, Louis D said:

For the 2017 eclipse, it was just the wife and I in Nebraska with a bunch of strangers…

That was the same for me in 2017. I was in an empty field in Wyoming with just my two sons and a few rattlesnakes! It was eerily quiet, unlike yesterday in Magog.

Many thanks for the nice comments.

I’ve made this animation of the diamond ring at the end of totality.

Here's a quick capture of Pons-Brooks last night from here in Norfolk. Alpha Arietis to its left.

Canon 700d, ISO1600, Sigma 150-500mm zoom @ 229mm, f/5.6. 12 frames @ 20 seconds. Stacked in DSS.

Guided on an old AZ Synscan, which guides remarkably well for an AZ mount.

26 minutes ago, johnturley said:

The best chance of clear skies (but not guaranteed) along the track of totality, is from the Torreon area in Northern Mexico, ,which is one of the observation sites that Astro Trails (UK Tour Operator) are organising, and with whom we are travelling.

John 

Thanks for rubbing it in. I'll be 4000km away under the clouds.

At least I saw the 2017 eclipse in Wyoming under clear skies. And the 1999 one from near Dieppe.

I'm off to (hopefully) see the total eclipse from the town of Magog, in Quebec Province, Canada in a couple of weeks. Statistically the cloudiest part of the whole eclipse path!

I know long-term weather forecasts are wildly inaccurate, but just for fun I thought I'd look at the alternative forceasts available. Here a selection of some of them. It makes you wonder why they bother attempting long-range forecasts.

They range from 3 degrees C and snow, through to 12 degrees and rain, mist, sleet and even SUN! The BBC predicts Sleet showers with sunny intevals.

The best one is the Weather Network which predicts sun and 10 degrees. I'll have that one please!

Thanks folks. I’m sure the sensor is dusty, so I’ve ordered a cleaning kit.

This is a single frame from my Canon 700d, captured with a 75-300mm zoom set at 75mm. 15 seconds, f/5.6, ISO1600.

There's a dark fuzzy blob in all of the images which I assume is some sort of dust mote, although it's quite large and diffuse. Any suggestions as to where it is in the image train and how to get rid of it?

I’m planning to go to Canada in April to view and capture the total eclipse. Normally I like to travel light, with just a cabin bag to avoid the hassle of hold luggage. However, this time I’ll be taking my AZ GOTO mount as well as a normal hefty camera tripod, so I’m going to have to take it as checked-in hold luggage. 

I’d like to simply just use the 12v power cable connected to the hired car cigarette lighter, but on a recent trip where I hired a brand new car (a VW, I think) it didn’t even have a lighter socket.

My question is, can I take my 12v 7Ah Skywatcher power tank on the plane or is it forbidden? Alternatively I could take a little power pack comprising 8 x AA batteries. Any idea how long that would power the mount?

Despite it blowing a hoolie, I had a go at capturing the shadow transit of Ganymede this evening.

Almost impossible to focus with the scope bouncing around in the wind, but at least I managed a short capture although not the sharpest view. It was very nice visually. The shadow was nice and crisp in the eyepiece.

Wide view, 250mm f/4.8 Newtonian, ZWO ASI120mc cam. c 5000 frames @ 2ms,  c.110 fps, Left to right: Callisto, Io, Ganymede, Europa.

Closer view. 250mm f/4.8 Newtonian, 5x Televue Powermate, ZWO ASI120mc cam. c 5000 frames 7ms @ c.45 fps,

3 hours ago, Kon said:

Did you try with the older as!3?  It seems to be something with the box size at the neb, you have a square artefact. You also seem to have a lot of noise from wavelets too.

Thanks for the input.

I had a go at capturing Jupiter last night using Sharpcap instead of Firecapture. Conditions were pretty poor with bad seeing and the results weren’t good. However, I seemed to be able to get shorter exposures and a higher frame rate with Sharpcap, and the initial results don’t seem to show those artefacts. 

So it might just be the capture software that’s a problem. I’ll try again when conditions are good.