Well, I've been wondering what's the "best" filter for viewing the bluish NPH (north polar hood) on Mars shown in my images and various other finer images here and on the web. Well tonight after an average seeing (Antoniadi IV-III), capturing bouncy Mars images with my 5-inch NP127 Light Cup, I spent some time laying out most of my filters and going through them ;-).
Here's what I found out. Remember I don't have every filter on the planet to try with (anyone want to send me a complete Wratten set ;-)?). The result may not work well for light buckets ;-). I used my 2-4mm Nagler zoom @3mm (200x). CM was around 229.
* No filter - too bright, too much glare, can't make out where the NPH ends or what color (seems white), NPH "region" is brighter than the martian plain.
* ND 96 - cut down nicely on the glare but dims everything else too, NPH grayish.
* #80A blue - whitish NPH
* #38 dark blue - very dark blue everywhere, NPH takes on very dark blue :-(
* Baader Moon & Skyglow - very nice pale bluish NPH, show largest area of the NPH and clear delinearation than my other filters and its boundary seem to closely match what I saw on the capture screen. Best filter for NPH :waytogo:.
* Baader Moon & Skyglow + #8 yellow (simulate Contrast Booster ;-)) - turned NPH mildly yellowish white.
* #12 yellow - everything looks yellow, NPH brighter and lighter yellow than martian plain
* Tele Vue Mars Type B - some part of NPH can be made out, but much smaller in size than Baader filter, lighter orange than the martian plain.
* #21 orange - NPH not seen at all
Please share your experience viewing the NPH. Maybe there're other filters that work even better on the NPH (and I don't mean those that are "out-of-print" ;-) but those that we can buy today ;-)). Thanks in advance.
The NPH looks much larger to me than it was in 2003. It may be because the NPR is tilted more toward us this apparition. If you want to see it, now is a good time.
Ron B[ee]
Here's what I found out. Remember I don't have every filter on the planet to try with (anyone want to send me a complete Wratten set ;-)?). The result may not work well for light buckets ;-). I used my 2-4mm Nagler zoom @3mm (200x). CM was around 229.
* No filter - too bright, too much glare, can't make out where the NPH ends or what color (seems white), NPH "region" is brighter than the martian plain.
* ND 96 - cut down nicely on the glare but dims everything else too, NPH grayish.
* #80A blue - whitish NPH
* #38 dark blue - very dark blue everywhere, NPH takes on very dark blue :-(
* Baader Moon & Skyglow - very nice pale bluish NPH, show largest area of the NPH and clear delinearation than my other filters and its boundary seem to closely match what I saw on the capture screen. Best filter for NPH :waytogo:.
* Baader Moon & Skyglow + #8 yellow (simulate Contrast Booster ;-)) - turned NPH mildly yellowish white.
* #12 yellow - everything looks yellow, NPH brighter and lighter yellow than martian plain
* Tele Vue Mars Type B - some part of NPH can be made out, but much smaller in size than Baader filter, lighter orange than the martian plain.
* #21 orange - NPH not seen at all
Please share your experience viewing the NPH. Maybe there're other filters that work even better on the NPH (and I don't mean those that are "out-of-print" ;-) but those that we can buy today ;-)). Thanks in advance.
The NPH looks much larger to me than it was in 2003. It may be because the NPR is tilted more toward us this apparition. If you want to see it, now is a good time.
Ron B[ee]
