jetstream Posted August 23, 2016 Share Posted August 23, 2016 Target- NAN area,transparency 4/5, darkness 21.7 mag/arc sec and using the VX10/Lumicon OIII/21E/30ES 82. Dark adaptation took about 10 minutes and the first observation of the Veil confirmed the sky conditions. The North American nebula complex has been very rewarding so far giving up many features this early season. Tonight the mini Gulf and Great Lake(s) showed well and some billowing structure shone up through the Gulf area to the other side of the neb. A delicate smattering of stars identified as NGC 6997. Using rolling averted vision made many of these stars pop in and out of view for a dazzling spectacle of this cluster. The dark nebs just off the mini Gulf also gave a great presentation as did SH2-119. My prize however was LBN 365, a nice faint target in the region and just south and over a bit from Xi Cygni. I caught a glimpse of a shadow in this area and went back to it repeatedly to confirm it for the evening. Actually I consider this a VG catch for the night! Gerry Link to comment Share on other sites More sharing options...
Pig Posted August 23, 2016 Share Posted August 23, 2016 Nice one Gerry it seems you are bagging some difficult targets. Link to comment Share on other sites More sharing options...
Stu Posted August 23, 2016 Share Posted August 23, 2016 Great stuff Gerry. I'll have a look at SkySafari to see where all these objects are later on today. Really nice report. Link to comment Share on other sites More sharing options...
John Posted August 23, 2016 Share Posted August 23, 2016 It's lovely to read about these sessions in the Canadian deep sky Gerry The stuff you are seeing and describing so well is generally just hinted at from here on a dark night I find but still enjoyable. Link to comment Share on other sites More sharing options...
Mark at Beaufort Posted August 23, 2016 Share Posted August 23, 2016 Excellent report and observing session Gerry. I checked out SH2-119 in my Interstellarum and I noticed that it recommends a H.beta filter. However, observing LBN365 is an excellent plus. I think we need an observing trip to Ontario. Link to comment Share on other sites More sharing options...
jetstream Posted August 23, 2016 Author Share Posted August 23, 2016 Thanks Mark, I think that some of these nebs must emit more than one line- my OIII works well on a lot of objects including these. There is a very good chance many people have seen these objects and not realized it- they surround the NAN and can appear just as shades. For example- SH2-119's edge is easily seen but it is also easy to get buried in the nebula itself. A large TFOV is a big asset. A friend asked for a marked image...I borrowed Olly's unparalleled image of the NAN area, the detail is incredible. LBN 365 showed as roughly circular in the eyepiece and the area viewed is marked in brackets on the image. The detatched patches ( not LBN 365) off the tip of the Gulf are underlined and with an arrow and these showed very well last night. While images are a great resource for identifying things many times what is seen visually looks different than the same area in an image as we may only see limited parts of things. I would imagine there are parts of the UK with similar skies, maybe a bit worse transparency as I'm at 1100ft. I had about an hour of true darkness last night before the moon erupted off the horizon killing the DSO , I'm sure glad I maximized the time out there. Link to comment Share on other sites More sharing options...
Mark at Beaufort Posted August 23, 2016 Share Posted August 23, 2016 Thanks Gerry that is really helpful. I agree with you that it would be useful to have a good TFOV to observe this area. I have a 30mm EP which is 70 degree but I think I might treat myself to an ES 30mm 82 which will give me a bit more area. I know it will increase my exit pupil but I might pick up some fainter detail of this type of object using a H.Beta or O-III filter. Link to comment Share on other sites More sharing options...
YKSE Posted August 23, 2016 Share Posted August 23, 2016 Really nice one, Gerry Weather looks like improving towards the end of this week, I might got a chance to give a shot one it too. Link to comment Share on other sites More sharing options...
jetstream Posted August 24, 2016 Author Share Posted August 24, 2016 4 hours ago, Mark at Beaufort said: Thanks Gerry that is really helpful. I agree with you that it would be useful to have a good TFOV to observe this area. I have a 30mm EP which is 70 degree but I think I might treat myself to an ES 30mm 82 which will give me a bit more area. I know it will increase my exit pupil but I might pick up some fainter detail of this type of object using a H.Beta or O-III filter. Your welcome Mark. I have been doing some exit pupil tests on my eyes using Bartels suggestion- this is quoted from his site in reference to his 6" f2.8. So far I can see the mirror clips in the 32mm TV plossl @ f4.8 giving an exit pupil of about 6.7mm. I think I have a bit more but have no other eyepiece to use for the test yet, a 34mm would be a good next try. It may be also worth pursuing using an eyepiece that allow your eye to be the limiting factor, but "just" ie for myself using 7mm exit pupil. There is also another concept that is interesting- the concept that your eye "accepts" a certain focal ratio- this is very very interesting and one that I'm just learning. The 30mm ES 82 is VG for nebula with filters at the appropriate exit pupil, the eye lens is recessed though and this bothers some people I think. Sorry to ramble. From Bartels site: "How to test for exit pupil without ruining dark adaption and causing the pupil to shrink? I test by slightly defocusing the star image so that it forms a disc. Since I can see the mirror's edge, I know that my eye's pupil is not truncating the mirror's aperture. However, I must place my eye exactly at the correct location centered and above the eyepiece (the rubber eyeguard helps). Consequently I also use the 17mm Ethos with its 3+ degree field of view at slightly higher power where my eye doesn't need to stay exactly centered. The 21mm Ethos eyepiece with this scope gives an exit pupil of 6.4mm. My eye opens to this size. But what would be the consequences if my exit pupil were smaller? If my eye opened only to 6mm then that's equivalent to stopping down the aperture to 5.6 inches, or a drop of about 10% illumination. This sounds significant. But the eye works logarithmically which means that the loss expressed in the eye's unit of measurement is 0.1 magnitude. And keep in mind that both the object and the sky background are equally affected, leaving the ratio between the two or the contrast the same. I've not been able to observe this difference or find anyone else who can in a blind experiment. Aperture is an important consideration since it is the primary expense (unless you make the mirror yourself) and sets the overall size and weight of the telescope. But field of view is equally important. Try considering field of view first. With this approach you determine the aperture based on the lowest power eyepiece in combination with your eye's exit pupil, giving the widest possible field of view. This makes the eye the limitation, not aperture, not field of view. That's as good as it gets. " Link to comment Share on other sites More sharing options...
PeterW Posted August 24, 2016 Share Posted August 24, 2016 Very handy image to use to confirm things. I have done sh119, but this shows quite bright in the image.. As you mark, there are other bits of nebulosity about too. cheers peter Link to comment Share on other sites More sharing options...
jetstream Posted August 25, 2016 Author Share Posted August 25, 2016 Another look tonight in 21.8 mag skies off the MW (21.55 on) and with excellent trans. I'm pretty sure this is the roundish area seen of LBN 365. It is not far at all from SH2-119 in the EP and this one (119) looks like it might curve around a bit towards LBN 365. This area is not tremendously difficult to see and definitely worth a look. Link to comment Share on other sites More sharing options...
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