Kemble’s Cascade

[AlcorAlly]

Refractor 3" f7.5 + binoviewer
Two views combined at ~40x which gave about ~3.6 degrees total FOV. Drawn across two nights last week.

I really enjoyed observing and drawing this asterism.
Kemble's  description captures it perfectly:

“A beautiful cascade of faint stars tumbling from the northwest down to the open cluster NGC 1502.” 

 

[josefk]

That’s very nice @AlcorAlly - I like glow around the open cluster. 

[Lurcher]

nicely done and annotated.!!

[JeremyS]

That is splendid @AlcorAlly 👍🏻👍🏻👍🏻
Which binoviewers are you using with your FC 76DCU? And are you using a GPC to reach focus?

Edited May 5 by JeremyS

[AlcorAlly]

8 hours ago, JeremyS said:

Which binoviewers are you using with your FC 76DCU? And are you using a GPC to reach focus?

Thank you Jeremy. It’s MaxBright II with 1.7 GPC, which just about reaches focus with 2-3 mm to spare. I feel the GPC gives slightly less than 1.7x magnification increase, 1.6 perhaps? 

[Pete Presland]

A fine sketch, some nice star colours in there if memory serves me correctly. I have not viewed this for a while, it would be nice to revisit this gem again . 

[Stu]

1 hour ago, AlcorAlly said:

Thank you Jeremy. It’s MaxBright II with 1.7 GPC, which just about reaches focus with 2-3 mm to spare. I feel the GPC gives slightly less than 1.7x magnification increase, 1.6 perhaps? 

Lovely sketch Ally, it’s a really nice asterism, especially in a wide field of view.

I think I’ve read that the x1.7 gives more like x1.5, although I’ve never tried to measure it.

Out of interest, is there a shorter fitting available between binoviewer and focuser as the Clicklock takes up a fair bit of optical path?

[AlcorAlly]

2 hours ago, Stu said:

Out of interest, is there a shorter fitting available between binoviewer and focuser as the Clicklock takes up a fair bit of optical path?

This is the shortest one I found by looking at @MalcolmM's helpful photographs. Takahashi's own 2 inch adapter seems to have longer optical path. Baader ultra short clamp would be nice but it's not compatible with M56i Tak thread.

But this combination gives about ~1.8° which is not too bad at all. 15mm more would have to be saved somewhere to use the 1.25 GPC...

Edited May 6 by AlcorAlly

[AlcorAlly]

@Stu There's this part on an Italian website, but I think it's for feather touch focusers only. 

https://www.adrianololli.com/articolo.asp?ID=5119

Nice video too: