H130 on polaris

[jetstream]

More playing around with the Heritage 130, this time on Polaris and with different eyepieces. The 3-6 NZ showed the split but upping the mag past 5mm had us going backwards for some reason. The 12.5mm orthos (Tak, Circle T) gave an excellent split and the 3, 18mm (BCO,Tak, UO VT) orthos did well too with a tie between the Tak and old UO VT for first place and the mag is dropping...so far 36x-not bad. Back into the house for the 25mm TV plossl and the 25mm Super plossl. The 25mmTV did an excellent job giving a nice clean tight split at 26x! The 25mm Super plossl failed the split. As a last try the 24ES 68 was inserted and yes it did split polaris but not as good as the 25mm TV plossl.

I wonder if there is an exit pupil sweet spot for high mag (relatively) splitting? less than 1mm didn't work for me that great tonight. That low 26x split made me smile and I wonder how low of mag others split Polaris, with this scope or others?

[Littleguy80]

In the SkyWatcher 130M, I often got nice splits on wider doubles, including Polaris, using the ES68 24mm at 38x. It was also good for bringing through colour with doubles like Albireo. 

[Stu]

Pretty sure I’ve split Polaris with the 24mm Pan in the Tak, x30, but not easy.

I definitely think there is a maximum or optimum minimum exit pupil below which things get harder. I think this varies with the target magnitude and the conditions.

The trapezium E&F stars are one example of this, it is a case of finding the right mag to see them, not just throwing max mag at it.

I also remember some years back observing Saturn under quite decent conditions. In the Doctor 12.5mm ie x59 I could see five of the moons, but at higher power the fainter ones just disappeared.

I suspect it is almost as complex as understanding faint nebula visibility!

[jetstream]

5 hours ago, Stu said:

I suspect it is almost as complex as understanding faint nebula visibility!

Thanks Stu , I hope to get into some doubles and faint star observing- I need to get more experience..

[CraigT82]

Neil English wrote s good blog post on observing doubles with the H130... he really rated it as a star splitter, part in thanks to the single stalk up front (He also pimped up his one with hilux coatings and a smaller secondary).