Quel filtre pour la PL sur un C9,25 ?

[BBBenj]

Coucou !

 

Voilà, mon C9,25 et moi, nous déprimons sous le ciel de de Marseille. Et peu d'occasions de sortir pour le moment. Je devrais donc avoir accès à un magnifique toit d'immeuble, me rejetant l'éclairage direct très loin.

 

Voilà la situation.

 

Maintenant, j'ai déjà fait quelques recherches et il y a des tendances qui se dégagent. Je précise que je n'ai que des oculaires en 1,25", ça simplifie ! Et pas de photo avant longtemps

 

Il y aurait donc en lice, principalement, le Lumicon Deep Sky (65 € dans les PA) et l'Astronomik CLS (45 € dans les PA)...

 

Des avis pour, d'autres contre...

 

Pour Marseille et forte PL.

 

Merci de vos réponses (euh... je précise que le budget...)

[ghim31]

J'ai un cls et il donne une teinte verdâtre je crois. Tellement que je ne l'ai sorti qu'une fois pour l'essayer...

Et il est donné pour être le tout meilleur.

 

Edit: je ne remets pas en cause l'efficacité de ce filtre, juste que je n'aime pas la teinte qu'il donne.

[ghim31]

Test cls par Christian Buil.

Vas à la partie 2,en milieu de page.

[BBBenj]

Coucou !

 

Broad-Band "Light-Pollution" Filters

The broad-band "Light-pollution Reduction (LPR) filters are designed to improve the visibility of a variety of Deep-Sky objects by blocking out the common Mercury vapor, Sodium, and some other emission lines from man-made or natural sources which contribute to light pollution, while letting through a broad range of other more useful wavelengths. Since the eye is mainly a "contrast detector", this selective screening out of some of the background skyglow increases the contrast and helps Deep-sky objects stand out more noticably. While these broad-band filters do not eliminate the effects of light pollution or make the objects brighter, in many cases, these filters can improve the visibility of some deep-sky objects to at least some degree. The greatest improvement in the overall view is often found with emission nebulae, but broadband filters can also give a slight contrast boost to some reflection nebulae and a few of the larger more diffuse galaxies. In addition, larger versions of these broadband filters which fit over camera lenses can be somewhat useful for photography of wide star fields when some skyglow is present.

Some available broad-band filters are the Lumicon Deep-Sky, the Meade Series 4000 Broadband, the Celestron LPR, the Thousand Oaks Type 1, and the Orion SkyGlow. The Lumicon Deep-Sky can offer a noticable boost in contrast and visibility of the fainter outer detail in emisson nebulae over non-filtered views for objects like the Orion Nebula (M42), the Lagoon Nebula (M8), the Merope Nebula, the Trifid (M20), and a number of others. However, the improvement is not as noticable on star clusters or galaxies. I have found that using the filter on larger and more diffuse galaxies like M33, M81, M101, NGC 253 and NGC 2403 in my 10 inch when weak skyglow is present will help boost the visibility of the detail, but the effect is fairly mild. On star clusters, there is even less of an effect, since some of their emission falls in the portions of the spectrum blocked by these filters. In that case it may be better to use slightly higher power on some of the smaller objects to dilute the light pollution effect a bit. Since some light is blocked by the filters, there can be times when a few objects may even look fainter from a dark sky site when using a broad-band filter than without one. Severe levels of light pollution may also be too much for the broad-band filters to handle effectively, so you still want to find as dark an observing site as you can. The Lumicon Deep-Sky filter has an additional bonus, as it does work fairly well as a blue filter for observing Jupiter and for bringing out the white clouds and polar caps of Mars. In summary, the broad band "light pollution" filter can be useful in compensating for some light pollution, but may not be the most impressive filter intended for deep-sky use.

[BBBenj]

Coucou !

 

Et il y a l'IDAS-LPS... Mais à 145 € neuf et pas d'occasions...

[BBBenj]

Coucou !

 

Pas beaucoup de gens concernés par la PL, on dirait...

 

J'ai continué mes recherches dans la Quête Du Filtre Parfait.

 

Et j'ai trouvé cet article extrêmement intéressant sur les filtres en général et les filtres PL en particulier :

http://sites.google.com/site/profondeursduciel/31

Bravo à son auteur...

 

Je commence à y voir un peu plus clair !

[BBBenj]

Coucou !

 

J'affine de plus en plus mon choix...

 

http://www.koenvangorp.be/deepsky/filters.html

 

Il semblerait que l'IDAS-LPS sort du lot...

 

D'autres avis ?