RASC Hamilton Getting a DSLR modified...

[Gary Bennett]

You'll be glad to know that narrow band filters work rather well with a
modified camera. I shot this with a Ha filter on Saturday under a nearly
full moon:
https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/488078_1015125020813990
8_1470366923_n.jpg

  Gary Bennett

-----Original Message-----
From: astronomers-bounces at hamiltonrasc.ca
[mailto:astronomers-bounces at hamiltonrasc.ca] On Behalf Of Roger Hill
Sent: July-05-12 9:35 PM
To: astronomers at hamiltonrasc.ca
Subject: Re: RASC Hamilton Getting a DSLR modified...

The camera arrived  back home today.  Canada Customs have tried to charge me
the HST on the insured value of the camera.  I guess they didn't know that
the camera was mine in the first place!  I have to send them a letter with
all the details to try to get re-imbursed.

Oh joy...dealing with a bureaucracy to try to get my own money back.

It's clear tonight, so, despite the just past Full Moon, I'm off out to my
backyard  observatory to play!

Roger

-----Original Message-----
From: astronomers-bounces at hamiltonrasc.ca
[mailto:astronomers-bounces at hamiltonrasc.ca] On Behalf Of Roger Hill
Sent: Sunday, July 01, 2012 6:15 PM
To: astronomers at hamiltonrasc.ca
Subject: RE: RASC Hamilton Getting a DSLR modified...

Hi, Mark...

The factory default filter that Canon uses for it's regular cameras results
in a spectral response that is an odd shape.  The filter is veryu good at
blocking out UV, but letting blue through.  It has a very sharp dividing
line betrween them.  The other end of the spectrum is not as good.

At the red end, the response gradually tails off, which results in only a
20% respose at the Hydrogen Alpha line.  This is not good!

The Astrodon filter is a visible light only filter (until about 1200
nanometers, but by then, the CMOS chip is extremely insensitive, so it
dowsn't matter).  This filter has a very sharp cut off not only at the UV
end, but also at the IR end, as well.

At 390nm, the filter is essentially opaque, rising to 99% passthrough at
400nm.  It remains at 98-99% transparency until 700nm and is back to opaque
at about 710nm.

I certainly hope it works with lenses...I have a 300mm f/4 SMC Takumar I
recently took apart and put back together to allow it to focus at, and
beyond, infinity. 

Roger


-----Original Message-----
From: astronomers-bounces at hamiltonrasc.ca on behalf of Mark Kaye
Sent: Fri 29/06/2012 9:36 AM
To: astronomers at hamiltonrasc.ca
Subject: Re: RASC Hamilton Getting a DSLR modified...
 
At 22:35 6/28/2012, you wrote:

>He also offers a choice of two different replacement filters.  One is 
>made by Baader and the other by Astrodon.  These filters allow you to 
>use the camera for normal daytime use, as long as you use a custom 
>white balance.  The Astrodon filter is $30 more expensive, but Astrodon

>has a superb reputation for producing the highest quality filters for 
>astronomical use.  So, despite my predilection for choosing the less 
>expensive items, I went with the Astrodon filter.

    I own a Baader IR/UV blocking filter.  It is completely clear to the
unaided eye, but I know it blocks IR as I have a web cam that is not chip
filtered for IR and with some lenses, it washes out completely due to IR,
but when I put the Baader filter in front, it works normally.
Some webcams filter the chip and let the lens be unfiltered, while others
filter the lens and leave the chip unfiltered.  That makes some cameras
unsuitable for using with IR illumination, if the chip is filtered.
    Does the Astrodon filter IR?  I cannot use my refractor for CCD work
unless I filter out IR and UV.  While the scope is beauty focusing visible
light, it quickly goes into out of focus once you get outside of the visible
range, especially at the red end and makes the scope very hard to focus.  I
suspect that unless IR is filtered, most lens systems will not give sharp
images.  Of course, mirrors are not affected by this, but Schmidts and Maks
are.

>After two days of no updates, and with visions of modified cameras 
>being lost, this evening, it showed up in Miami!  Apparently, though, 
>it's normal for the US Postal Service to send things hundreds of miles 
>out of the way.

    You have to love express service.  I bought a base for my C11 and had it
shipped express because I wanted it by the end of the week when I was
travelling down here to install it.  It did not arrive in the "guaranteed"
delivery time or two days later, for that matter.  It arrived sometime
during the week I was away and because I was not at home to get the package,
I then had to go to the post office to get it.
The express mailing rate was more expensive than the part and while they
guarantee delivery, it is an empty guarantee.  They only guarantee that I
will get it, on what ever time frame they wish, despite the huge extra bucks
they charge.  I got the parcel, so what do they care?  The one advantage of
the postal service is that there is not a bondage fee to pay for storing the
item at the border while they delay your shipment.
    Good luck with your package.  Since the company that shall not be named
believes Canada is in the southern hemisphere, maybe it is a myth for all of
California and your package is in Miami because that is about as far south
as you can get before shipping it to the nether regions.
Just what you wanted to hear...

    Clear skies!
                MK

The Observatory by the Lake
http://www3.sympatico.ca/mark.kaye/index.htm  


_______________________________________________
astronomers mailing list
astronomers at hamiltonrasc.ca
http://hamiltonrasc.ca/mailman/listinfo/astronomers_hamiltonrasc.ca