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Old 13-09-2020, 08:16 AM
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The Mekon (John Briggs)
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Two difficult doubles

A half decent night yesterday prompted me to set up my 132CFF. I do not use this scope much as it is easier to bring out the 106AT and the views are 90% as good. But observing earlier in the week had drawn my attention to a couple of stars in Sagittarius and Scorpio. In the 106 I suspected both of these stars to be resolvable, but the smaller scope was just not getting there.

HWE 48 (Correction HWE43) is less than a degree south of M69. I found I could detect the faint companion in the CFF at 225x (4mm Delite)and noted it to be to the south.
Checking Stelle Doppie this morning showed Mag 5.4, 9.8 @3.4" PA 185.

HWE 86 is a just over a degree south of the Bug Nebula NGC 6302.
I thought this was more difficult but still managed to resolve the fainter companion close by at 225x. SD has 6.9, 9.0 @ 2.6" for HWE 86.

These doubles are tough as both magnitude differences (delta M) are greater than the separation in seconds.
Perhaps some of our other keen observers Steve (Tinderbox) or TropoBob might like to try?
Or am I the only one doing nutty stuff like chasing obscure double stars?

Last edited by The Mekon; 15-09-2020 at 06:59 AM.
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Old 13-09-2020, 08:32 PM
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Tinderboxsky (Steve)
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Two interesting double stars. Thanks for your report John.

No, you are not the only one still "doing nutty stuff like chasing obscure double stars”. I am still in the zone, but have been out of action for a while whilst we complete a long and drawn out move from Tinderbox to Kingston. It has been all about downsizing from acreage to be closer to services etc. I still cannot believe how much stuff I had accumulated in 26 years at Tinderbox. Condensing my workshop and moving lathes, milling machines and the like has been epic.

Whilst closer to Hobart, the night sky at Kingston is not as bad as I had feared. Kingston is south of Hobart, so the views to the high southern skies are still quite acceptable. Not pristine though. I hope to have telescopes and a small portable observatory set up next month. Then I’ll be back under the double stars!

Steve.
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Old 14-09-2020, 06:29 AM
gaseous (Patrick)
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Originally Posted by The Mekon View Post
A half decent night yesterday prompted me to set up my 132CFF. I do not use this scope much as it is easier to bring out the 106AT and the views are 90% as good. But observing earlier in the week had drawn my attention to a couple of stars in Sagittarius and Scorpio. In the 106 I suspected both of these stars to be resolvable, but the smaller scope was just not getting there.

HWE 48 is less than a degree south of M69. I found I could detect the faint companion in the CFF at 225x (4mm Delite)and noted it to be to the south.
Checking Stelle Doppie this morning showed Mag 5.4, 9.8 @3.4" PA 185.

HWE 86 is a just over a degree south of the Bug Nebula NGC 6302.
I thought this was more difficult but still managed to resolve the fainter companion close by at 225x. SD has 6.9, 9.0 @ 2.6" for HWE 86.

These doubles are tough as both magnitude differences (delta M) are greater than the separation in seconds.
Perhaps some of our other keen observers Steve (Tinderbox) or TropoBob might like to try?
Or am I the only one doing nutty stuff like chasing obscure double stars?

Thanks for those John. I tried both last night with my 8" dob under Bortle 5 skies. With a Baader zoom at 150x, there was no chance. At 255x with an ES 4.7mm, they were definitely split, but still quite challenging. I actually found HWE 86 the easier of the pair to split.
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Old 14-09-2020, 06:07 PM
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The Mekon (John Briggs)
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Steve and Patrick, thanks for the feedback. Steve I hope you get settled soon back into doubles, and Patrick your 8" must be a good one to tackle these stars - I have seen too many 8" reflectors that perform very poorly on double stars.
One thing you may have noticed is that these doubles are nearby to a well known deep sky object. I seem to collect a lot of these, and if you look hard there are quite a few, some even in the same field!
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Old 14-09-2020, 06:50 PM
gaseous (Patrick)
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Steve and Patrick, thanks for the feedback. Steve I hope you get settled soon back into doubles, and Patrick your 8" must be a good one to tackle these stars - I have seen too many 8" reflectors that perform very poorly on double stars.
One thing you may have noticed is that these doubles are nearby to a well known deep sky object. I seem to collect a lot of these, and if you look hard there are quite a few, some even in the same field!
Cheers John. I'm a bit confused now- you mentioned HWE48 as being about a degree south of M69, but that's not where I found it. HWE 43 is about a degree south of M69, but 48 is quite some distance away (and at mag 10 for both stars which may explain why it was such a challenge!).
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Old 14-09-2020, 07:48 PM
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The Mekon (John Briggs)
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Cheers John. I'm a bit confused now- you mentioned HWE48 as being about a degree south of M69, but that's not where I found it. HWE 43 is about a degree south of M69, but 48 is quite some distance away (and at mag 10 for both stars which may explain why it was such a challenge!).
Sorry Patrick - stupid typo meant to be HWE 43
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Old 14-09-2020, 07:56 PM
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Hi John,

Thanks for your interesting report.

Must admit I haven't seen the pair in Sagittarius, but here are my notes on HWE 86 in Scorpius with my old 25cm back in 1997:

HWE 86 Double star Scorpius
25cm x181: Difficult to pick out at low power, tight-ish with a magnitudes difference of 1.5 mags. Fairly close, probably just under 2" in PA150. As Hartung mentions, there is a group of fainter stars that seem to encircle it.

Best,

L.
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