Jim Smith

Thank you. Yes, it was f/4.0. I had previously done a comparison of f/2.8 and f/4.0 with this lens. Pictures below...everything the same except for focal ratio. I didn't like the asymmetric, blobby stars I get at f/2.8. f/4.0 has diffraction spikes but I don't mind those so much! I raised the exposure of the f/4.0 photo in post to make the comparison easier so it's a bit noisier. No filters...just the D5500 directly on the back of the lens. Clear Outside says I'm Bortle 4. Yes, it was cropped. Third image below shows full field of view captured.

I know that zoom lenses are considered a compromise compared to telescopes. However, I closed the aperture down a bit and got better results than I usually do. Interesting diffraction spikes on the brightest stars. Nikon D5500, Sigma 120-300mm f/2.8 @ 300mm f/4.0, 60x30s, ISO 400 SkyWatcher AZ-EQ5, Affinity Photo, Astroflat Pro, Topaz De-noise

I like... Nightwatch: A Practical Guide to Viewing the Universe by Terence Dickinson

A couple of Messier Object observations from last night. I used an 18mm eyepiece in my 80mm f/6 refractor, giving about 27x magnification. These two clips show pretty much the same views as through the telescope. M1, the Crab Nebula, is only just visible to me eventhough I have quite dark skies. It is very tricky to see in the video clip as well! It is barely visible as a faint smudge in the centre of the video. You may have more luck with the original videos available here...https://www.ishoo.co.uk/messier/ Messier001.mp4 Messier037.mp4

Well spotted! I blame that extra glass of port.

FiveTelescopeTargets.mp4 Five targets from Thursday night with, I think, a view similar to a small telescope. Tweaked in Premiere Pro to get as close as possible to the live view in my 6" field monitor. Sony A7s, Celestron C6, 2 x focal reducers so ~750mm, ~f/5.0, 1/4 second, ISO 51200.

For some time now I have been experimenting with making videos that show various astronomical targets as they appear to the naked eye or through binoculars or small telescopes. I have finally got round to making a home for them and it is here... www.stargazing.camera I hope that it might be useful for anyone just starting out. I have tried to get the videos looking as similar as I can to the live, real-time experience. I will try to add something new every week or two...weather permitting! Any constructive suggestions for improving the site are welcome. 🙂

The Seven Sisters is another name for The Pleiades.

Thanks Neil. I haven't done any more quite like that one, but did you see... ...and... Cheers, Jim

Some more video from Tuesday night. Here are three views of Orion... First 15 seconds: Naked eye view over neighbour's house. Next 15 seconds: Binocular view of Orion's belt and sword. Last 15 seconds: Telescope view of sword with nebula. WARNING! The videos show colour in the nebula which you won't see in a small telescope. 300orionNebula_1.mp4

In my experience, the most reliable method to find them is by getting their exact, current position from an app like Sky Safari. The app will show which of the "stars" in the field of view is the planet you're looking for. They are both visible in binoculars. They do look a bit different to the stars, (slightly different colour or perhaps a bit less twinkly) but at lower magnifications the difference isn't obvious to my eyes. I wouldn't be able to readily identify them without the app.

If you're using binoculars or a small telescope at low magnification, asteroids and outer Solar System planets can be rather unspectacular. It's still interesting though to observe their changing positions from night to night. I was lucky enough to get two clear nights in close proximity to try this out. I have made a short video of Vesta and Uranus shot two nights apart. I haven't shown which of the objects are Vesta and Uranus but you should be able to detect them by their movement. (Hint: Vesta is in the bottom-right of the field, Uranus is roughly in the middle.) The view is somewhat like what you would see through a small telescope at about 25x magnification. VestaUranus.mp4

Thanks for the advice and links. It seems that my polar alignment does not need to be super accurate.

I'm sure I once came across a formula (or perhaps it was some tables) that allowed you to work out how accurate your polar alignment needs to be based on lens/telescope focal length, sensor pixel size and exposure time. I've searched but not managed to find it. Can anybody point me in the right direction? I'm planning to take 30 second exposures using a 500mm lens on a Nikon D750 ( 5.95 µm pixels). I'm just wondering if being, say, 10 arcminutes off true polar alignment will be noticeable. Thanks, Jim

I made a video showing a few objects that can be seen with binoculars or a small telescope. I captured the video at around 22:00 on the 22nd of October. You should get the same view at about 20:00 this week. (The moon may be a bit bright though!) I've tried to get the views as close as I can to what can be seen with the naked eye, 8x40 binoculars and an 80mm spotting scope or similar. All comments and criticism welcome!

Thanks for the thoughts Ruud. I think the difference in fogging may be mostly due to the ventilation factor. I've just checked and the eyecups on the Olympus binoculars are significantly wider than the Canon ones. I can see more daylight when using them. I would think more ouside air can circulate over the lenses as you suspected. It's interesting that this makes such a big difference in usability. I prefer the Canons in many ways, but if I can't see through them...

About two seconds after I raise my Canon 10x30 IS binoculars to my eyes, the eyepiece lenses fog over, blurring the view. This does not happen with my Olympus DPS I 8x40s. They stay clear. I view without glasses. Does anybody have any ideas as to why this might be? Different lens coatings? Thanks in advance, Jim

I made this video to show approximately what you can see with binoculars or a small telescope on a moonless night away from city lights. Viewing full screen helps.

Thanks to Paul for the software and Don for the manual.

Very accurate for me last night...the moon rose exactly when it said it would. (OK the cloud cleared when it said it would too.)

This looks very useful. Thank you!

10x30 works for me. Compact and light.