August Meeting

Information and updates on monthly meetings
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Ian-Raymant
Posts: 80
Joined: Tue Jun 30, 2015 1:18 pm

August Meeting

Post by Ian-Raymant » Fri Aug 14, 2020 1:16 pm

Hi Everyone,

I hope you are all keeping well and have made the most of the recent heat wave.

As you may have seen, Our August meeting is scheduled to be a talk on astro photography by Nik Szymanek and I'm really pleased to say this will be going ahead as planned.

As with our previous 2 meetings, we will get together via MS Teams and Nik will share his Powerpoint presentation from that platform.
He and I ran a test last weekend and all went well.
From the brief glimpse I had of the presentation it looks as though we're in for an interesting evening.
For those interested in carrying out some pre-meeting research, Nik's website is well worth a visit - www.ccdland.net

Later today or during the weekend I will email out MS Teams invitations to everyone as before.
This invitation will be from my business account so please don't be put off.

Hope you can all join the meeting on Wednesday 19th.

Best wishes

Ian

Trevor
Posts: 389
Joined: Sun Aug 30, 2009 7:39 pm

Re: August Meeting

Post by Trevor » Fri Aug 14, 2020 1:53 pm

Thanks Ian, that’s great thanks for the info will take a look this website.

PhilBrew
Posts: 294
Joined: Fri Sep 04, 2009 9:37 pm

Re: August Meeting

Post by PhilBrew » Fri Aug 14, 2020 2:46 pm

Nik Szymanek's web site is absolutely gob-smacking. I had no idea! I thought astrophotography was about stars! Can't wait to hear from him and see his presentation. Phil

Trevor
Posts: 389
Joined: Sun Aug 30, 2009 7:39 pm

Re: August Meeting

Post by Trevor » Thu Aug 20, 2020 8:58 am

Good morning everyone and apologies for not being online last night.

I reminded myself twice through the day, but got distracted with something else and completely forgot 🤦🏼‍♂️ I was absolutely gutted when I realised. Hope you all had a good evening and found it useful and informative.

Trevor

Ian-Raymant
Posts: 80
Joined: Tue Jun 30, 2015 1:18 pm

Re: August Meeting

Post by Ian-Raymant » Thu Aug 20, 2020 10:17 am

Hi Trevor,

Sorry you missed out.
It was an interesting evening for sure; Lisa summed it up perfectly - mind blowing.
An aspect of photography I simply had not appreciated and was clearly unaware of the complexity.
Lisa was right, let's just start with the moon and see how it goes !!!

Ed, conscious you did'nt join us and am concerned you didn't receive my invitation. Huge apologies if so. I did send one to you last Friday 14th, separate from the main group admittedly but sent nonetheless. The vagaries of email and spam filters maybe, just hope I have your email address noted correctly.

Best wishes to all

Ian

Ed Jeffries
Posts: 107
Joined: Sat Mar 14, 2020 11:20 am

Re: August Meeting

Post by Ed Jeffries » Thu Aug 20, 2020 11:55 am

Hi Ian and everybody,

Very sorry I haven't been active for a while and really sorry I missed the astrophotography session. There have been situations that unfortunately have taken most if not all of my time - I'm hoping for easier times in the future. I hope everybody and your respective families are keeping well.

Thank you for the concern, Ian. Much appreciated.

Take care, stay safe and keep photographing!

Jim Spurgeon
Posts: 91
Joined: Sat Aug 19, 2017 1:30 pm

Re: August Meeting

Post by Jim Spurgeon » Thu Aug 20, 2020 1:14 pm

Hi all. Following Nik's highly impressive talk last night I thought I'd look at something he mentioned....remote access to observatories. I found a website that has micro observatories across the U.S that you can access for free. I've put my request in for a 60 second exposure of the milky way (there's loads of targets to select on their site). Fingers crossed and clear skies permitting I should get an email from them with a RAW image for me in the next couple of days. Link to the website below.

https://mo-www.cfa.harvard.edu/OWN/index.html

robertofbaycot
Posts: 51
Joined: Mon Jan 30, 2017 7:25 pm

Re: August Meeting

Post by robertofbaycot » Thu Aug 20, 2020 1:58 pm

I thought it was worth making some notes on Nik's talk, so here they are fresh from memory.

Notes on Nik Szymanek’s astrophotography talk

For pictures, see Nik’s site www.ccdland.net

Can take good pictures of moon using DSLR & telephoto lens. Can use around 250 mm but 500 mm small telescope better. Good to photo half moon as angle of sun throws craters into sharp relief so see structure. Particularly clear near day/night terminator. Full moon OK but craters flat; however, can see ejecta trails from asteroids' impact.

Can take pictures of prominent planets, especially Venus, with DLSR. Few seconds, on a tripod. These are of, e.g. Venus, as part of night sky, not close-ups.

Can take picture of sun using DLSR & special filters available cheaply. Will see sun-spots but not much other structure. Showed pictures of transits of Mercury & Venus. Can use filter for hydrogen-alpha lines which show a lot of the structure of the sun but filter are expensive. Must be careful filters don’t slip off lens otherwise may damage eyes and camera!

Problem with using a DLSR on a fixed mount is that Earth’s rotation smears everything out. Duration before appreciable smearing given by 500 rule. Depends on focal length of lens. May only be a few seconds for a telephoto lens. Can get tracking mounts for few hundred pound that can effectively remove rotation. Also comes with software for setup etc. Can get decent pictures of our galaxy (Milky Way) with this kind of setup. Needs long exposure time. Need very clear seeing in UK for this kind of pic.

Next step up is mini-observatory. Need three things camera, telescope & tracking mount. The mount is key to cancel out the rotation of the Earth so that long-exposure pictures of stars etc. may be taken. Also allows repeat exposures to build up pics - see below. Long exposure is key since this enables signal to noise ratio to be increased so that much more can be seen. Nik showed his own system consisting of equatorial and tracking mounts, a large & a small telescope plus cameras. The cameras were monochrome CCD devices which were cooled to get better signal-to-noise ratio. They are used with colour filters to build up colour images. The simplest case was using three filters, red, green, blue. Consecutive exposures are taken with each filter (this is possible because the tracking mount keeps everything in the same place throughout), then the three photos are combined in the same way as RGB channels in a DLSR. Also showed pictures using a narrow-band red/green/blue triplet which gives artificial but rather spectacular colouring as used by the Hubble space telescope. Also showed graph of dimming of light as exoplanet passed in front of a star. Wow - you can discover planets using hobbyist kit!

Talk also included at some point discussion of use of image stacks. Take multiple images of sky then combine using cheap software to increase signal-to-noise. Earth rotation needs to be removed by tracking mount.

Final litem was possibility of hiring time on research grade telescopes set in places with good viewing, e.g., Chile. Just request where to look & specify exposure times etc., pay hire fees & away you go.

Trevor
Posts: 389
Joined: Sun Aug 30, 2009 7:39 pm

Re: August Meeting

Post by Trevor » Thu Aug 20, 2020 4:18 pm

Hi guys thanks for the info and Robert for the detailed notes. Sounds very interesting. I think I’ll start with the moon photos first and then try for a star trail. As the nights are pulling in I will sort a date in which to try this. I’ve done a little research on this and you need dark skies with a Bortle rating of 5 or below. You can check the Bortle scale on various web sites. This is the one I’ve been using https://darksitefinder.com/maps/world.h ... .00/-98.00
I was thinking of just taking the plunge and going out to Thetford Forest and just following the instructions I’ve got from various websites.

Jim Spurgeon
Posts: 91
Joined: Sat Aug 19, 2017 1:30 pm

Re: August Meeting

Post by Jim Spurgeon » Thu Aug 20, 2020 4:59 pm

Here's another remote control telescope site. Only looked briefly but it looks as though you have a lot more control over exposure times, number of exposures etc. It's not free and as yet I'm unsure of what the cost of credits is, might be worth investigating though.

https://telescope.live/

Trevor
Posts: 389
Joined: Sun Aug 30, 2009 7:39 pm

Re: August Meeting

Post by Trevor » Thu Aug 20, 2020 5:28 pm

Thanks for the info Jim, worth a peep 👍🏻👍🏻

PhilBrew
Posts: 294
Joined: Fri Sep 04, 2009 9:37 pm

Re: August Meeting

Post by PhilBrew » Thu Aug 20, 2020 8:39 pm

Well done Robert - very useful set of notes - good to have them. Phil

MarkJones
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Joined: Sun Jul 28, 2019 4:48 pm

Re: August Meeting

Post by MarkJones » Thu Aug 20, 2020 9:17 pm

Ian, thanks for setting up the meeting on Astro photography - interesting session. Thanks also to Robert for the detailed notes and Jim for the info on the US sites.
Think will start with moon shots and see how things progress from there.
Mark

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Lisa
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Joined: Mon Aug 24, 2009 3:40 pm
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Re: August Meeting

Post by Lisa » Fri Aug 21, 2020 6:19 pm

Thank you for the notes Robert and for the links Jim. I'd love to explore this further - perhaps in the winter when there are no gardens to photograph!

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