Alien 13

1 minute ago, Stu said:

We get a bit spoiled don’t we! All these old school SRBs which just fall into the sea! It’s so ‘noughties’ 🤣

The landing is often the best bit..

Alan

Have I missed something, still waiting for the first stage landing 😋

Alan

I think even a 90mm Mak would give a long 80mm Frac a close call and the Mak is much easier to mount, the other big benefit is no wobbly focusser, you can hang several kilos off the back of a Mak with no ill effects..

Alan 

Some lovely bits of kit there..

Alan

My problem is that there is no realy decent 40-60mm scopes on the market with short focal lengths with field flatteners that can handle a correct image 2 in diagonal.

Alan

I do like small scopes but there is a case for both, a large scope is never going to give low magnification or wide field views which is what I prefer... give me a 40-50mm objective any day.

Alan 

I have enjoyed them all, have missed the last few because Leicester City have been playing a lot of matches on a Sunday recently 🙂

Would love to see more tutorials using Afinity Photo especially now that it has dedicated Astro stacking tools etc.

Alan

14 minutes ago, JeremyS said:

Really? You’ll be telling us you don’t lick lenses next

🤣

I do and my dog used to do the same,..

Alan

8 minutes ago, twobleak said:

I did initially think that, but surely you would expect the shutter to close after the first shot still? I could understand subsequent shots then being missed but for the shutter to not close after the first shot seems odd to me. I am using a Sandisk Extreme Pro SD card and you can see the camera has finished writing to the card after about a second. 

Not sure why this is unless you have the in camera long exposure noise reduction turned on or are using mirror lock up in combination with the intervalometer and adding in the self timer function.

Alan

Nothing wrong, you have to allow time between shots for the camera to write to the SD card..I normally leave a 10 second gap. An ultra fast SD card might reduce this though.

Alan

1 hour ago, Virtus said:

I'll second the Artcise. I've got the AS90C version.

Very nice, had the Artcise and Sirui tripods in my basket for a week, eventually chose the Sirui because it would get more use and Amazon were offering free 4 months credit too. I did buy an Artcise MB 36 ball head to go with it though..

Alan

I have the 254 version of the SIRUI (same design and construction) and its superb for my needs, weight around 1 Kg and can hold 12Kg with ease..

Have a look at the Artcise tripod, probably the best on the planet for the money here.

Alan

Great stuff, when I was a teenager the thought of a electric helicopter/drone being able to lift off while being self powered was the stuff of Science Fiction.

As to space exploration in general each generation hits a brick wall with the limits of the current technology and has to wait for another breakthrough before planning new types of missions. We are a bit stuck with rocket propulsion at the moment but the payloads can be incredibly small in the future.

Alan

Ooh, just noticed the range includes microscope bags, nice..

Alan

Hi Steve, Its a difficult choice with so many lenses out there but for starters the 50mm f/1.8 STM is good for the price, after that you get into serous money with the likes of the Samyang 14mm/28mm/135mm which are very good for AP.

You can also get good results with the standard kit lenses or push the boat out a bit for the 70-200mm f/4 L lens which is reasonably priced second hand from WEX or MPB photographic.

Alan

7 hours ago, michael8554 said:

Hi Alan

Can you expand on that?

To me it seems counter-intuitive to say focusing is easier on a 3inch screen than on a 12inch or more Laptop screen ?

Michael

I think tethering uses the basic video out rather than the processed image you see on the camera screen that has other options too like exposure simulation. I know I can easily see mag 6 stars and below on the live view screen.

Alan

In my experience the on camera screen will give far better results than any tethering software for focus using x10 zoom etc.

Alan

As far as mirrors go the Questar 90mm scopes leave Tak in the dust for price per sguare mm.

Alan

Its odd but looking at the realy dim stars some looked to have focus nailed and some off...

Alan

13 minutes ago, JeremyS said:

They are both losers. They should have used a small refractor. Preferably a Tak.

(My assumption is that Noah, like most people, couldn’t afford an 8 inch OG)

 

😊

Didn't think small Taks were any good for imaging without replacing the focusser and using a tiny sensor 😀

Alan

It depends somewhat on the type of scope too, if its a frac then changing the f/ratio by increasing aperture would be disastrous without also increasing focal length too and by more than double, you might be able to do this with a mirror based scope though.

Alan

4 minutes ago, Astro Noodles said:

They have a robotic dog called Zeus whose job it is to go in first to make sure the area is safe.

It even has its own kennel.

Zeus looks like one of these not that expensive either in the grand scheme of things..

Alan

9 hours ago, Stu said:

Betelgeuse is one of the best I think, bulging like crazy like a ball of jelly!

https://www.google.co.uk/amp/s/www.inverse.com/article/33408-supergiant-star-betelgeuse-is-bulging/amp

Makes you wonder when it goes Supernova if the energy released will be directional or offset.

Alan

6 minutes ago, ollypenrice said:

Noooo!!! Shock horror. 😁 Crop factor is the most misleading term ever introduced into photography. It's not entirely meaningless because it allows subject framing (AKA field of view) to be compared across two focal lengths and chip sizes. However, it implies a relationship between resolution and chip size when no such relationship exists. It also, I've discovered since exploring daytime photography, adds confusion regarding depth of field.  I've read numerous claims to the effect that full frame sensors give a greater depth of field. They may do, but not because they are larger sensors but because they have larger pixels.

Olly

I quite like "crop factor" provided the calculations are done correctly, works for depth of field too.

Lets say you have a full frame Canon camera with a f/4 50mm lens, you can get the equivalent image from a Canon crop body including identical depth of field and noise by applying the calculations as follows.

50mm/1.6 = 31.25mm but you also have to apply to the f/ratio so (f/4)/1.6 = f/2.5

So a 32 mm f/2.5 lens would give near identical results on a crop body to the 50mm f/4 on a full frame.

Alan 

Assuming you are using the same sensor with these scopes then aperture will win for light collection but will not necessarily give the best results if one of the combinations is a mismatch regarding the pixel size etc.

In the Camera world f/ratio is useful for obtaining correct exposures but there is no way a Camera phone lens at f/4 is the same as a full frame f/4. Perhaps astro kit should use the "crop factor" calculations in there specs 😋

Alan