Faint stars between the double double

[YKSE]

The doube double itself has been one of the summer objects both for testing sky conditions and scope cooling. I've not paid much attetnsion to the faint stars between the pair untill I came across this intriguing description here:

http://stargazerslounge.com/topic/196574-the-double-double/#entry2064818

Taking 120ED out last night to have a first look for these fainties, only the E star was easily seen in finder EP for 22.5x. Putting in Mark III zoom, working up the mags slowly, at around 10mm, there appeared to be some more faint fussies in averted vision. Switching forwards and backwards among BCO10mm and the Zooms, the F, G and K were spotted steadily in  averted vision, with K star brightest and at moments as a clear dot, and G was faintest of the three. quite interesting as K should be faintest by its mag 13, about the threadhold for 120ED.

[acey]

Well done - great stuff. F and G are John Herschel's "debelissima" pair, which Webb considered an "excellent test" for a 4" scope in "very fine air". William Herschel discovered all stars down to G with his 18.7" scope; Dawes discovered the others down to K, and I believe he saw all of them with a 3.8" refractor.

Great to see note being taken again of this forgotten challenge, which was as popular with 19th century observers as spotting the faint stars in the Trapezium in the Orion Nebula.

[jetstream]

Good going Yong. I looked with my 10" last night and saw E,F,G through a fogged up secondary. Next time the 90mm and 120mm will get a crack at them.

[jetstream]

Well done - great stuff. F and G are John Herschel's "debelissima" pair, which Webb considered an "excellent test" for a 4" scope in "very fine air". William Herschel discovered all stars down to G with his 18.7" scope; Dawes discovered the others down to K, and I believe he saw all of them with a 3.8" refractor.

Great to see note being taken again of this forgotten challenge, which was as popular with 19th century observers as spotting the faint stars in the Trapezium in the Orion Nebula.

 Acey, thanks for bringing this info up in your thread, I had never heard of checking these stars before. What an interesting read.

[John]

Very interesting

I'm aware of having seen some of these but I've not really observed them, if you know what I mean !

I'll take much more interest in them next time I'm out.

[alan potts]

I will pick up on this one too if the dam clouds will let me. I think the odd thing with the Double Double is you look at it transfixed trying to split it at say X70 and tend to ignore the other stars, lesson leant and consider myself told off, I will pay more attention in future.

Alan.

[Qualia]

Great report, Yong. Like John and Alan, I have the impression that these stars have been seen but not really observed. Next time I'm out, I'll have a peek and let you know how I get along. Thanks for picking up on this and putting it out   

[YKSE]

Had another look on Thursday with C8, the increased aperture made some difference, at virtually the same darkness (SQM 18.8), but worse seeing (the double double flickled more), even H and Y could be spotted momentarily in averted vision.

Last night when out in darkside for some DSO hunting, I took the chance to check again, SQM 20.9 means 1.4 magnitude difference to backyard. K, F and G were steadily seen, Y, H and T were seen in averted vision. T were most difficult because of  apporximity to one pair, needed to find the right magnification to get the controlled size of flare from the pair.

[Stu]

Tried this one last night with the Vixen. E was easy, as usual, but F and G also nicely visible. I guess my skies were around SQM 18.5 at the time. They got down to Mag 5 NELM later on so possibly a bit better then.

Will try with the 12" at some point soon. Nice challenge :-)

Sent from my iPhone using Tapatalk