Jump to content

sgl_imaging_challenge_banner_31.thumb.jpg.b7a41d6a0fa4e315f57ea3e240acf140.jpg

Venus, filters and seeing


Recommended Posts

I had a few minutes to grab a bit of observing time this evening so I decided to try out my new #47 violet filter on Venus. Through my variable polarising filter attached to the 9.7mm on my 8" f10 LX200 Venus was a boiling mass and not a very promising target at all. I then removed the polariser and put on the #47 violet filter and suddenly all was calm(ish). The difference was remarkable (hence my remarks!).

Has anyone else noted this effect with a #47 violet filter?

With the violet filter I could just make out what appeared to be an area of darkening near the terminator.

Link to post
Share on other sites

Hi Michael,

Your observation is interesting. A few weeks ago i noted shading at the terminator of venus whilst observing in twilight to lessen the irridation effect .

If you check out the Sketching section on Cloudynights.com you will see a set of drawings by Sol robbins which you'll find interesting.

I'm looking forward to observing venus with my newly acquired Tak FS 128 apo, using the very same violet filter as soon as possible.

Regards

Mike

Link to post
Share on other sites

i tend to use the 47 when observing Venus. I sometimes think I see some cloud features but then that might be the old averted imagination at work. It's def the best filter for Venus, apart from anything else it stops the glare.

Link to post
Share on other sites

There's an old saying re details on Venus: "If you think you see them, you don't". The composition of the atmosphere of Venus causes it to reflect light almost entirely in the ultraviolet. I can see, (and have) how you may think you see details, and a #47 violet filter may help, but I find it interesting that people here confirm what others may be imagining they see. I believe myself to be a very experienced and careful observer, and try as I might, I've never seen two things: the horsehead nebula and details on Venus, and I've tried through instruments ranging from small refractors to large, professional instruments of various configurations, including the 24" Clarke at Lowell and the .9 m SARA telescope on Kitt Peak. True, I didn't have a violet filter, but I doubt it'd make a difference.

No offense intended.

Link to post
Share on other sites

I believe myself to be a very experienced and careful observer, and try as I might, I've never seen two things: the horsehead nebula and details on Venus, and I've tried through instruments ranging from small refractors to large, professional instruments of various configurations, including the 24" Clarke at Lowell and the .9 m SARA telescope on Kitt Peak.

TBH, I can't understand why you've never been able to see the Horsehead... my friend Jeremy (in Flagstaff AZ) has bagged it using a 6" Newtonian.

Link to post
Share on other sites

I believe myself to be a very experienced and careful observer, and try as I might, I've never seen two things: the horsehead nebula and details on Venus, and I've tried through instruments ranging from small refractors to large, professional instruments of various configurations, including the 24" Clarke at Lowell and the .9 m SARA telescope on Kitt Peak.

TBH, I can't understand why you've never been able to see the Horsehead... my friend Jeremy (in Flagstaff AZ) has bagged it using a 6" Newtonian.

I often hear from folks that claim to have seen the HH, (Barnard 33 and IC 434). When pressed, they almost always discover they've actually seen the Flame Nebula, (Ngc 2024). 2024 is east of Alnitak, HH is south. And it's not just me. It's the operator of the respective scope as well. We can all recognize the field stars, but none see the actual nebula. I tried it once again Saturday night with the 20". Freshly cleaned mirror, meticulously collimated, nebula filters in hand, (I suppose it would have been better to put them on the EP's, er, uh), rock solid seeing, transparency an 8 of 10. No luck.

But maybe it's me. I'm just sayin'...

Here's a link that shows both:

http://www.randybrewer.net/images/FSQ-Images/HorseHead.jpg

Link to post
Share on other sites
I often hear from folks that claim to have seen the HH, (Barnard 33 and IC 434). When pressed, they almost always discover they've actually seen the Flame Nebula, (Ngc 2024).

When pressed though, perhaps they begin doubting what they know they saw. :grin: It'd be a shame to make someone second-guess their sighting just because you yourself have never seen the target, even though you have superior equipment at your disposal.

Makes me wonder... if Stephen James O'Meara didn't have the fame and solid reputation he has, would anyone have suggested to him that he was mistaken when he visually saw the spokes in Saturn's B Ring before the Voyager 1 spacecraft imaged them? :(

That being said, I certainly agree some Amateurs might make an honest mistake and think they've seen the Horsehead when it was actually the Flame. But I know Jeremy and he's much too meticulous to do that. Besides, the proof is in the sketch.. that's definitely not the Flame. :)

Link to post
Share on other sites

When pressed though, perhaps they begin doubting what they know they saw. :(

When I say, "pressed", I simply mean I ask "Which direction did you move from Alnitak when you made this observation?" It's not like I interrogate them. I could believe someone could photograph this object with a 6" Newt, given an excellent mount etc, but I refuse to believe they could actually see it with one. It's flat impossible, just from a resolution aspect. A 6" is simply incapable of resolving it sufficiently for the eye to detect. Go ahead and suggest it's me, but it's not just me. Have you been observing from Arizona? Anywhere? If I can't see it through a 22" Newt with excellet optics from Kitt Peak, I doubt an observation from, well, anywhere, with a 6".

Sorry.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.