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#1 agmakr

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Posted 20 September 2013 - 02:16 PM

Hello,

i am in search of photometric filters (starting with V)
and so far i have found these suppliers:

-Astrodon, at $175 each
-Custom Scientific, at $150 which always seem -backordered/waiting list
-Baader, which i sell in Europe for about $200

So my only option seems Astrodon, or am i missing something?

Thanks,
Angelos

#2 Ed Wiley

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Posted 20 September 2013 - 08:44 PM

Nope, not a thing so far as I know. Sometimes, but not often, used photometric filters appear for sale. If you find a older Schuler V made sure it is clear and not fogged. You can fix a fogged one with a bit of cleaning, but if fogged there should be a discount and you will have to hunt around for the correct cleaning method. I opted for a ST-402ME with its little photometric (BVIC) filter wheel. Works great on my F4 8" Schmidt-Newtonian. I suspect the FOV would be very limiting in an SCT.

Ed

#3 agmakr

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Posted 21 September 2013 - 08:25 AM

Thanks for your time Ed,

does anyone know a dealer in US for the Baader photometric filters, apart from Astrodon (which sells them as a set)?

Thansk,
Angelos

#4 btieman

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Posted 21 September 2013 - 11:08 AM

doeas anyone know a dealer in US for the Baader photometric filters, apart from Astrodon (which sells them as a set)?


I purchased mine as a set from Astrodon but they do list them singly as well.

#5 groz

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Posted 24 September 2013 - 12:33 PM

we have two sets here. I snagged one new set (BVRI) on a vendor blowout posted on Astromart. A few months later, another set came up (BVR), which we bought for my wifes telescope. I got both sets for sub $200.

Patience is a virtue they say, and, if shopping for astro gear, not in a hurry, combine patience with Astromart and CN classifieds, what you want will show up, at a price that makes you happy.

It worked for us.

#6 agmakr

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Posted 24 September 2013 - 04:24 PM

Hi groz,

the fact is that i'm not in a hurry as the weather where i live will be rainy from October till May.
So there is not much to lose in winter.

I check classifieds of several sites daily, until something good comes up.

Angelos

#7 Ed Wiley

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Posted 24 September 2013 - 05:09 PM

BTW Angelos, many variable observers only have a "V" and have been reporting results for years. So don't think you need the entire set to get started, or even "finished" for that matter.

Ed

#8 btieman

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Posted 28 September 2013 - 06:49 AM

Hi groz,

the fact is that i'm not in a hurry as the weather where i live will be rainy from October till May.
So there is not much to lose in winter.

I check classifieds of several sites daily, until something good comes up.

Angelos


Angelo's, not sure your price range, but this deal looks pretty good...

http://www.astromart...ified_id=832823

#9 agmakr

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Posted 29 September 2013 - 04:05 PM

Hi Brian,

i have noticed the ad some days ago, but i was reluctant to
contact the seller as i know that these filters are discontinued from Astrodon.
I think it would be better to get the latest Photometric filters.

But this might be a good chance to discuss the reasons these filters where discontinued.

Angelos

#10 btieman

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Posted 30 September 2013 - 09:36 PM

But this might be a good chance to discuss the reasons these filters where discontinued.

Angelos


My understanding is the biggest issue is the glass is no longer being made. A minor cross concern is that the Sloan survey was done in different bands. Even so, uBVRI will be in use for a long time...there's a lot of history in those bands.

As far as newer filters, I've yet to see the AAVSO release a new comp star database for the new filter bands. They may have done it...they've been working in that direction...but I'm no longer a member and variable stars aren't really my thing at the moment. I wouldn't go with a band other than uBVRI until a usable comp star database is released.

I think there are replacement options for uBVRI that are interference filters as opposed to colored glass. They have much higher transmission, but the color profile might not be quite the same. The negative to interference filters is reflections can be more problematic and they're a little harder to clean since scratching the coatings is easier than straight glass.

But do take all of that with a grain of salt...I'm not much of an expert on photometric filters so maybe someone more in the know will jump in and correct my inaccuracies :p

#11 agmakr

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Posted 01 October 2013 - 02:31 AM

Your detailed answers are always welcomed Brian!

Thanks,
Angelos






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