Light Pollution BLUES !

Discuss the greatest threat to amateur astronomy today

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Cliff
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Joined: Sat Dec 11, 2004 8:18 pm
Location: Manchester
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Light Pollution BLUES !

Post by Cliff »

Dear al and anybody else
About a year ago I attended two meetings in the North West Region of England related to Light Pollution. The first was fronted by Dr Brian Iddon MP when he presented the House of Commons, Science and Technology Committes- Astronomy and Light Pollution Report.
The second meeting was organised by the Institution of Lighting Engineers (NW region) there was a discussion about light pollution. At the latter meeting amongst other things I asked that since I understood the human eye is most sensitive somewhere about the orange-greenish part of the spectrum, would there be more merit in using Full Cut Off Low Pressure Sodium street-lights, rather than the High Pressure Sodium lighting currently favoured by the lighting fraternity.
One of my reasons for my comments being that in my experience it seems where HPS lighting is used to replace LPS the lighting fraternity seem to employ HPS of twice the wattage of the old LPS street-lights. The response to my question\ suggestion made by the representative of a major UK lighting manufacturing company was very interesting. He said that although what I said was broadly correct at ordinary lighting levels (ie day-light), but at the lighting levels provided at night by street-lighting the human eye tends to be more sensitive towards the blue. So he suggested that High Pressure Sodium Lighting was preferable to LPS.
I have not since then found anything either positive or negative indicating the lighting fraternaty's representative was right or wrong.
However, whilst I already understood that the human eye has both rods (low light sensitive) and cones (colour sensitive) just recently I read that roughly two thirds of our cones are sensitive to Red, one third to Green but only about 2 PERCENT to Blue.
That being the case it has made me wonder if what I had been told by the Lighting Manufacturer was really correct.
If anyone has any ideas or suggestions about this matter I would be very pleased to hear them.
Best wishes from a curious grumpy old codger Cliff
Kaustav
Posts: 214
Joined: Fri Dec 03, 2004 3:24 pm
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Dark skies

Post by Kaustav »

Hey Cliff, I hope this doesn't make you cry, but don't you just WISH we had light polution controls like this?
Kaustav Bhattacharya
>> http://kaustav.uk.com/unisphere/ - An online magazine about Astronomy, Science, Social Media and Society.
>> Follow me on Twitter @jupiterorbit
jeremyll33
Posts: 184
Joined: Wed Feb 02, 2005 11:40 am
Location: Holzkirchen, Bavaria, Germany
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Jupiter

Post by jeremyll33 »

Hi Kaustav,

I was impressed by sour Jupiter image on the popastro website splash page.

I own a ETX125 and cannot get this quality. Please can you advise how to gain similar quality to yours.

I have as yet no camera setup and am considering a Video camera link to my ETX.
Equipment: ETX 125, 10x50 Binoculars, Canon EOS 350D DSLR
Kaustav
Posts: 214
Joined: Fri Dec 03, 2004 3:24 pm
Location: London, UK
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Quality images

Post by Kaustav »

Hey Jez :-)
I'm not sure my image is of that high quality, especially considering it was my first or second attempt ever. If I'm getting any praise from others, I'll put it down to pure fluke on my part. Anyway, here's how I took my image. Maybe you can emulate what I did?

1. Seeing was fair on the day I took the Jupiter image. This means that there wasn't too much air turbulence which helps to make the image sharper.
2. I cooled down my 'scope for at least one hour to allow it to reach thermal equilibrium with the outdoor temperature.
3. My ETX 105 has the UHTC coating, does yours?
4. I used a x2 Meade Barlow, in to which I plugged in my Meade LPI (Lunar Planetary Imager).
5. I used Autostar Suite to capture the image. I had track and combine enabled. Before I started capturing the image, I drew a square box around the image of Jupiter which told Autostar what I was tracking. It then tracked the image of jupiter even when it jumped about on screen due to wing/vibrations/etc. The "combine" feature seems to tell Autostar to stack the images and "work it's magic" and form a sharper image than the raw captures.
6. I then save the image out to my hard disk and load it in to Photoshop and apply an unsharpen filter to it which considerably enhances the image. Note that the image on the homepage of the SPA web site has not been enhanced in photoshop. If you read the actual posting where I posted the image, you'll see further down that I have reposted an enhanced image which has the photoshop unsharpen filter applied.

I think the key to image coming out as well as it did is the use of a x2 Barlow and the track/combine in Autostar Suite.

Hope this helps!

Kaustav
Kaustav Bhattacharya
>> http://kaustav.uk.com/unisphere/ - An online magazine about Astronomy, Science, Social Media and Society.
>> Follow me on Twitter @jupiterorbit
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