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jetstream

A 3.5" frac, great skies, good EP'S NO HH...BUT :)

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I had to try...the 90mmAPO on the HH and it did not show it lol! But I was only half dark adapted....I must work on this.

What it did show was M42's lower loop! :grin: and the Flame neb very well :grin: and OK the Monkey head too :grin: , wait a minute the Pacman was chewing away tonight in plain view too!!

Back to the Flame as this is a HH test. I confirmed again the keeping Alnitak out of the FOV is a huge benefit to observing this object. The winner tonight was the 18 BCO, unfiltered. It gave up a bright flame neb and with a few little "ruffles" in the tank tracks,

I tried the 32TV/Hb to no avail on the HH.

My skies were 21.8 mag,excellent transparency and I lost Cass buried in the stars lol! I had to walk to a different vantage point to find it :shocked::smiley: Bottom line the sky was excellent.

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Grrrrr. Got to emigrate. Rubbish UK sky.....

Wow. Good effort. Your 3.5" under your sky outdoes my 10" under my best sky!! I'll have a crack at the Flame with my 3.5" APO. Not expecting much though.

I always enjoy a good dar sky observing report.

Thanks

Paul

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Sounds awesome Gerry. I've read that Matthew has seen the Flame very nicely in his 105mm so your sky must have been amazing to get a good view in the 90!

Clear sky here finally this morning, wonder if it will last until tonight?

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Nice experiment and report Gerry :smiley:

That 3.5" is a catch for those large fuzzies, isn't? Looks like the whole Bernard's loop is within reach.

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Great report Gerry - very motivating too, when we get some clear skies over here :smiley:

I agree that the 18mm BCO is a super deep sky eyepiece. I may get it and the 10mm just for this purpose.

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Really interesting Gerry, I would like to trial my small frac with an exchange of filters on a few large nebula from a dark sky sometime - 21.8 mag is something else! Currently all we have to look forward to over here is the arrival of storm Desmond - trying to get my roof fixed after the last storm cannot get hold of a roofer for love or money, buckets at the ready.

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Sigh, I think the only solution is a four thousand foot long classic refractor to poke above the cloudtops. Do we have a sky? :grin:

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Very informative report! I would be curious to see the flame nebula! 

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Well done, your skies seem pretty magic. M42 is all billowy and curves round and in on itself... Is this what you mean? If you can see ic434 you are doing well...HH is a tiny we thing, need to familiarise yourself where the little notch should be.

Cheers

Peter

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This sketch shows the lower loop as I call it, my 10" shows more extensively than this. I barely made out the hook in the wing with the 90mm, but using rolling averted vision had brief glimpses of it. The Flame was easy, but a narrow FOV helps me quite a bit. Yes the skies here can be pretty good, thankfully.

Is this how you see M42 with the intensifier?

post-30641-0-55740700-1449354015.jpg

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I have never seen the flame even with my 16" dob.

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I have never seen the flame even with my 16" dob.

My guess is that the sky conditions have the final say here.

The advantage of 16" over 3.5" is the bigger image size at the same exit pupil size(for the same brigthtness), the flame is quite large, 30'x30', i.e. as large as the Moon, a 3.5" at 13x should deliver max brightness, and still have the Flame in big enough size for our eyes to recognize.

Acey's "What is a dark site"
explananation of figure 18 in the linked article:
"It is interesting to make general comparative predictions
of instrument performance. Fig. 18 shows threshold curves
for a single user (p = 7 mm, F = 2) at two sites, one light
polluted (µsky = 20 mag arcsec-2, naked-eye limit 5.5 mag),
the other dark (µsky = 21.5 mag arcsec-2, 6.0 mag). The
instruments are 10 × 50 binoculars and a 6-inch refractor
(D = 150 mm) at the dark site, and a 16-inch reflector with
25 per cent central obstruction (D = 393 mm) at the lightpolluted
one, with assumed transmittances 85, 95 and 75
per cent respectively. Both telescopes have exit pupil 3mm.
Data are also plotted for the 16 Messier galaxies in the Virgo
Cluster (Steinicke 2014a), subject to the usual caveats regarding
isophotal limit and non-uniformity, but providing a
reasonably homogeneous sample for illustrative purposes. It
can be seen that for any target larger than 1 arcmin2
the 16-inch is outperformed by the smaller telescope at the darker
site: light pollution renders it ineffective for viewing galaxies.
Binoculars outperform the 6-inch for very large, low surface-brightness objects; however the 6-inch will show  numerous
smaller targets. Since the effect of varying the field factor F
is to move all the curves up or down equally, this qualitative
result will remain the same for individuals whose naked-eye
limit is higher or lower than the chosen figure."
Difference in our eyes can have some impact too, compare someone with max dilated pupil 7mm  to a 5mm one, the former will see 96% brighter image when he can use max exit pupil under right sky.

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YKSE - is your link going to the right place?

The artical sounds facinating.

Paul

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Yep, 80mm handheld you get a billowy puffy structure that closes in on itself. Got a similar view of part of it in a 20" a number of years back. Need enough focal length to get the image scale to get the detail. Will have to try my 8" when the pesky clouds finally go away.

Cheers

Peter

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Yep, 80mm handheld you get a billowy puffy structure that closes in on itself. Got a similar view of part of it in a 20" a number of years back. Need enough focal length to get the image scale to get the detail. Will have to try my 8" when the pesky clouds finally go away.

Cheers

Peter

Sounds good Peter :smiley: I'm still watching your set up type, very very interesting...

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Great stuff, Jetstream! Weve got nothing but High winds and plenty of cloud to observe. Like many others I'm looking for a decent session soon :)

I didn't realize the Flame was so big and might need to retry for this again. Is this an UHC or O-III target? Thanks for the tip on Alnitak.

Edit: you stated unfiltered in 18 BCO, so question answered!

Edited by Special K
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Tried and failed for the M42 loop with my 10" last night. The view looked very like the above sketch except without the loop. The Flame was the merest single smudge with no detail, so I guess that the seeing at 25° Wasn't the greatest.

Paul

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Tried and failed for the M42 loop with my 10" last night. The view looked very like the above sketch except without the loop. The Flame was the merest single smudge with no detail, so I guess that the seeing at 25° Wasn't the greatest.

Paul

Congrats for seeing part of the Flame Paul! :smiley:  under good skies it looks like tank tracks and under excellent skies like a set of Stonehenge stones kind of.

The lower loop responds to certain types of eyepieces...what one did you use? and which one for the Flame?

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Congrats for seeing part of the Flame Paul! :smiley:  under good skies it looks like tank tracks and under excellent skies like a set of Stonehenge stones kind of.

The lower loop responds to certain types of eyepieces...what one did you use? and which one for the Flame?

I can often make out the extended flame with the three main dark dust(?) lanes making it look a bit like errrr a Flame... On wed morning I could only make out the very brightest section. I used a17.3mm Delos (unfiltered). I often use a 18mm BCO which, although it doesn't go quite so deep as the Delos, has a much reduced FOV to keep the bright stars out of shot.

Re, the M42 loop. I tried 24mm ES 82°, Delos 17.3 & 12mm. All with / without UHC.

Given the poor showing of the Flame, I wasn't expecting much loop action! I shall persevere.

Any tips greatfully recieved.

Paul

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Very nice eyepiece selection Paul, perfect for this. Interesting that the Delos goes deeper than the BCO, have you tried on faint galaxies too? I barlow the 18BCO to 9mm with great luck, just a squeak more mag than the 10BCO. Anyway, I'm rambling..... :grin:

We must see the Flame similarly from your description, except for one thing- I always see both "track" sections of the neb, if the neb is visible, one never shows without the other to my eyes, the top segment does though. That 17.3mm Delos is perfect for this with Ethos contrast on the nebs, nice equipment Paul. Under my best skies the Flame shows segmented and is a very interesting object.

You are right on the money with the loop too! Your 24mm ES 82 is perfect for showing this! Under my skies the UHC does not benefit the loop for some reason, it shows best unfiltered, so far at least. I see the loop with my 30ES,21E,18ES etc- you will see this soon. AND.......

If the Flame shows segments and you see the loop- you WILL see the HH, for sure- with the right eyepiece and Hb (possibly UHC too). It will be easier with a 25mm TV plossl/Hb to see the HH, espc with your 10" scopes wide FOV.

Under those condition IC434 will stand out in the FOV with an Hb-really helps to keep Alnitak out of sight though.

How long do you dark adapt Paul? do you have any lights around you even at a distance when observing?

Edited by jetstream

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Hmm. Interesting. I will try the BCO comparison on a couple of faint fuzzies.

The Flame doesn't jump out at me and even on the best nights it takes a while to start getting the structure. I am very lucky in having a bad garden which backs onto fields. The two streetlights in the village are about 1/2 a mile away. So dark adaption can get pretty good.

I'll keep looking for that loop.

Paul

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