[sac-forum] Re: Ultraviolet Venus Filter to Lend?
- From: "Gene A. Lucas" <geneluca@xxxxxxxxxxxxx>
- To: sac-forum@xxxxxxxxxxxxx
- Date: Mon, 27 Feb 2012 19:09:53 -0700
Hi Tom,
Can't telll for sure if the U Band photometric filter will do quite the
same as the modern "U-Venus" filter.... I found bandpass specs for a
number of filters, in re: effectiveness for planetary work...
Like Jeff, I declined to purchase a U band filter for my Meade DSI CCD.
I have a very old one, from an Optex SSP-2 photometer (an antique!)
....But the filter looks cloudy, like it may have deteriorated... I
understand the glass used for the U Band filters is unstable....
I will see if I can dig up those bandpass plots for you...
Let me know when you would like to get together to "pass" that U-Venus
filter over to you....
Cheers,
Gene L.
On 2/27/2012 17:36, Jeff wrote:
Hi Tom,
I have a photometric U band filter that came with a set. Since the CCD
is not sensitive in that band it has been of no us. You are welcome to
it. I suspect on a bright object like Venus with a time exposure it
would produce an image.
Let me know if you are interested.
Jeff
Hopkins Phoenix Observatory
(*187283)*
Counting Photons
Phoenix, Arizona USA
www.hposoft.com/Astro/astro.html <http://www.hposoft.com/Astro/astro.html>
International Epsilon Aurigae Campaign
http://www.hposoft.com/Campaign09.html
On Feb 27, 2012, at 5:32 PM, Tom Polakis wrote:
Hi all,
I was recently surprised to see some cloud detail in my image of
Venus taken through a blue filter. As expected, the red and green
filters showed no detail. The filter of choice for Venus is an
ultraviolet-pass filter. This are sometimes referred to as "U"
filters or sort of cleverly," U-Venus" filters. They are priced very
high, as shown below, and Venus only presents enough size and enough
of its cloud tops for a few months around 50% illumination, which is
right now. Being cheap, I wondered if anybody might have a U filter
just sitting in their case that I could borrow for a month or so to
try my hand at Venus imaging.
Let me know if you have one that's not in use, and I'd love to try it
out. Again, this is a UV "pass" filter, and not a UV "cut" filter.
Thanks.
Tom
================
Here's one from Baader that I think only exists in 2" size, and is
priced at an outrageous $269.
http://www.highpointscientific.com/product/BAD-FUV-2/Baader-Planetarium-U-Filter-2-FUV-2.html?meta=GBASE&metacpg=BAD-FUV-2&utm_source=gbase&utm_medium=CPC&utm_content=&utm_campaign=BAD-FUV-2
<http://www.highpointscientific.com/product/BAD-FUV-2/Baader-Planetarium-U-Filter-2-FUV-2.html?meta=GBASE&metacpg=BAD-FUV-2&utm_source=gbase&utm_medium=CPC&utm_content=&utm_campaign=BAD-FUV-2>
...or this one, in 1 1/4" and priced at a mere $140.
http://www.optcorp.com/product.aspx?pid=12738&src=goog
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