Venus Filters for poor people?

[Rihard]

Hello people,

I would like to buy a decent but not too much expensive filter to see some details on Venus. I know the Astrodon ones do the job perfectly, however they are way out of my budget. I'm thinking to something for less then £50.

Would a simple purple or violet filter, or a combination of violet and others (like the ones sold by TS at about 15 euros) do the job, and give some contrast / show some details on Venus? I will need this mainly for webcam imaging.

Thank you for your advise folks.

[riklaunim]

To use violet #47 visual filter for imaging you need also Schott BG39, which you can get from here: Schott Shortpass Filters UQG Optics from Stock, Order Online (the 25 mm dia version). And note that most of the UV is cut out by color sensors so the performance may be limited.

[Rihard]

To use violet #47 visual filter for imaging you need also Schott BG39, which you can get from here: Schott Shortpass Filters UQG Optics from Stock, Order Online (the 25 mm dia version). And note that most of the UV is cut out by color sensors so the performance may be limited.

Thanks a lot riklaunim; that's what I needed

If I set a camera to shot in B/W, would that make any difference or I actually need a B/W sensor?

Or that only causes sensor to record (and thus cut off the UV) in color and then the output converted to a B/W palette or something like that?

[riklaunim]

Color sensor can't do images like mono sensor as it has bayer filters on each pixel. Probably blue pixels will catch most of that UV signal but how much that depends on the bayer filter specs - and for webcam CMOS sensors there isn't any data available. Friend of mine did got one Venus clouds image with a MS Lifecam.

Here is a comparison for a Aptina/Micron CMOS found in QHY5v and alike cameras. For Venus 350-370 nm and 418 nm are those most interesting:

[Rihard]

riklaunim thank you for the detailed information. I'll try to get a mono in the future… and some filters any valuable cheap mono camera?

[riklaunim]

Cheapest, while still good for an entry-level mono are: DMK22 (DMK 21 maybe too), Point Grey Firefly 0.3 or QHY5v. Those are equipped with a Micron/Aptina CMOS sensor. QHY5v would be easiest to get, but DMK and Firefly are supported by better software (FireCapture, industrial IC.Capture for DMK). Their sensors differ slightly and some may be more UV-sensitive than others. I need to check if they differ greatly, but for BG39/#47 it shouldn't be a big problem (for Astrodon UVenus yes).

Going up in the price there are lunar CMOS cameras: QHY5, ASI130. They don't like bad seeing (rolling shutter), but still can do some planetary and lunary images. (ASI wins with software again).

Even more up we have better "lunar" cameras: Point Grey Chameleon, or maybe even IDS 1240LE. Chameleon has better software support, but IDS cam can be faster for planets.

At the top: DMK21AU618.