Hello, I’m trying to get my new DSLR system going and having hard time finding reasonable priced 2" (48mm threads) V filters. Everywhere online these days are specialized narrowband and nebular filters aimed at the “pretty picture” enthusiasts. I did find a Chroma filter but they asking over $600 each!
If anyone has a spare 2" V filter I would be willing to pay a reasonable price + shipping. Thanks!
Mike
LMK
Mike,
Does your DSLR camera have a monochrome sensor?
No, it is a Canon full color CMOS APS-C 12 Mp.
Why do you need V filter for DSLR? Use only green pixels and report your estimations as TG (tri-color-green). Just check before stars shooting camera IR sensivity, because some DSLRs can see IR in blue and geen pixels (for example, old Canon 500D). UV/IR cut filters help to solve it.
If you steel need V filter, chech Baader Planetarium V filters de
Ok I was thinking to use the monochrome mode with the V filter, but on further study it appears that mode in the 450D is not true monochrome, so I guess like most do, I will just use the TG channel to approximate V. I’m pretty sure that the old 450D also has IR leak in the green, so maybe I need to change this post to reflect that I need a 2" “clear” or luminance cut filter?
I’m not sure about 450D. My friend tested his 400D and it doesn’t see IR. You can try to take image of working remote control for TV etc, because it sends signals by blinking the IR LED.
“Clear” filters pass IR, they usually blocks only UV, when “Luminance” filters pass red light till 700nm only. If you are going to shoot with your camera only via photolenses, there are many сhinese filters that fit into the thread in front of the lens. Their price is about $10-$50 on Aliexpress. Different models pass 370-670nm or 400-700nm.
Sadly, my tv remote is a cheap chinese one and it has a lot of red leak, lol. But reading online it says the 450D has an IR cut filter inside which people remove for such usage. So, pending a better way to test it, I will assume it does not sense much IR.
Now that I will likely just use the green channel rather than mono mode and V, which intro software (preferably free) would you recommend for easy TG extraction and photometry?
ASTAP can do both ASTAP, Astrometric Stacking Program
Ok, if you don’t have any other remote controls, you can test on miras. They mostly radiate in red and IR. If your photometry in green channel for them gives much higher estimations when from other observers, you will need additional IR cut filter.
If you don’t going to observe red variable stars (miras, SR*, L* etc types), in this case you don’t have to worry about it at all. 
Ok, I suppose I can just buy a cheap IR filter (R-72) on ebay Anyways thanks for the ASTAP link, that looks like quite a comprehensive package! As a beginner, what do you think of IRIS or Muniwin or AstroimageJ by comparison for ease of use?
I tried IRIS and Muniwin last time many-many years ago. That’s why I don’t know what they can do now in the last versions. I use only ASTAP now. It can do many things automatically which I need to do manually in other software. For example, it finds all variables which have AUID in AAVSO database, it also finds AAVSO comparison stars on image and gets their magnitudes from local files database or directly from AAVSO API. So, ASTAP saves my time.