Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

stargazine_ep15_banner.thumb.jpg.34f8495864951c81ec35e285b4d7b2e0.jpg

Astrofriend

DIY, High efficient narrow band camera system

Recommended Posts

Hi,

What can you do during a rainy and boring day?

Yes, write something about about old project ideas that newer have been realized.

For many years I have been wondering how to construct a beam splitter system to make more efficient use of exposure time when doing color or narrow band imaging.

I have today written down my ideas here:

http://astrofriend.eu/astronomy/projects/project-high-efficiency-narrow-band-imaging/project-high-efficiency-narrow-band-imaging.html


There are a lot of interesting links there too to read.

/Lars

  • Like 1

Share this post


Link to post
Share on other sites

I'm not an expert but wouldn't the split beams be dimmer than the input beam thus you'd have to increase the exposure time?

Share this post


Link to post
Share on other sites

That's a very interesting idea. So a beamsplitter doesn't spread the different wavelengths out like a normal prism? Of course, if it did then the idea wouldn't work as the different blue wavelengths, for example, would hit different parts of the sensor.

59 minutes ago, kbrown said:

I'm not an expert but wouldn't the split beams be dimmer than the input beam thus you'd have to increase the exposure time?

I believe the idea is that the "blue" sensor would receive all the blue wavelengths, just like using a filter.

Share this post


Link to post
Share on other sites

Here's the theory of it:

https://en.wikipedia.org/wiki/Dichroic_prism

If anybody feels particularly brave, then how about a wrecked 3ccd broadcast camera as a source of a tricroic prism bloc:

https://www.ebay.co.uk/itm/Sony-DVCAM-DSP-WS-Studio-Broadcast-Camera-USED-DAMAGED-835/222731637408?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3Dd56ec756752b488ca2ce9b8cbcb2b792%26pid%3D100033%26rk%3D6%26rkt%3D8%26sd%3D272800656087&_trksid=p2045573.c100033.m2042

https://www.ebay.co.uk/itm/Sony-Power-HAD-EX-Professional-Video-Camera-USED-DAMAGED-832/222731627942?hash=item33dbd6eda6:g:1xIAAOSwvD5aGEW3

(DISCLAIMER: the guy selling these has not mentioned model numbers, they both LOOK like pro 3CCD models, but I'm not putting my neck on the line)

CCD targets are probably bonded to the prism, so not easy to remove, but would be worth a punt for anybody interested in playing with the idea.

Me, I'm finding controlling one camera difficult enough:icon_biggrin:

 

Huw

 

  • Like 1

Share this post


Link to post
Share on other sites

Hi,

It will catch three wavelength in parallel, one telescope, three cameras. Normally you only have one camera and one filter, then to get a rgb color from a mono chrome camera you have to take three exposures. Of course you can have three telescopes and three cameras als, then no need for a beam splitter.

Normally when doing rgb photos with mono cameras you block 2/3 of the incomming photons.

With other beamsplitters you can divide the incomming light in one visual and one IR beam. Then you need a mirror telescope. Some use the IR beam to autoguide on.

Lars

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By pblackwell
      Hi all,
      is there a best filter to use to view comet Neowise? 
       
      Many thanks!
      Paul
    • By AstroRuz
      SkyTech L-Pro Max Light Pollution Suppression Filter
      Used for about a year now and still in very good condition. really helped me out in my garden but now I've moved to tougher skies and need a slightly stronger filter. So it's time to pass this on to someone else.
      Filter is in very good condition with no scratches on it. Used extensively to great effect. Cardboard box slightly tatty but to be expected.
      Creates very nice pictures with good star colour retention and no halos. Horsehead is a HaRGB composite photo where the RGB was shot with this filter.
      2" fitting (M48). Will come with outside box, interior box and of course the filter.
      £100 + £8 P&P (Royal Mail Special Delivery)








    • By Astrofriend
      A friend ask me about filter size, I already had a Excel sheet with that calculation. But I did a new web calculator.
      It's the first version but it looks to calculate it correct, have a look:
      http://www.astrofriend.eu/astronomy/astronomy-calculations/minimize-vignetting/minimize-vignetting.html
      It's not any high precision calculation, but gives knowledge enough I think.
      Too small filter gives vignetting, too big filter empty the wallet.
      /Lars
    • By UKAstroBill
      The weather has been so bad I have had the time to finish a video on using astro filters with the Nikon Z bodies and Nikon camera lenses. There is a manual alternative to the FTZ allowing 1.25 inch filters to be fitted between camera and F-mount lenses, and for some lenses and end of lens solution make sense. FAstroTZ is described here:
       
       
       
    • By knobby
      Slowly dabbling with narrow band and the processing that is becoming more like art than science 🙂
      I really am enjoying it though, Imaged this in my red zone back garden last night, it's 10 x  300 secs each of Ha Oiii and Sii ( no darks as they looked weird )
      Thanks for looking / feedback.
      DSS - Photoshop levels / curves - gradient xterminator - photoshop channel combine as per @swag72 tutorial - photoshop levels to balance colours to my taste - slight noise and star size reduction  (Noels tools)

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.