Herschel Open Clusters and Planetary Nebula

[josefk]

Fantastic (and breakthrough) session for me last night in Northamptonshire. Early evening rain had left behind lovely clear skies and without aa moon it was fabulously dark. Managing condensation was important all night, I made it till 01:00 before finally losing my eyepieces to condensation.

Notional targets: Jupiter (aiming to bank it in case it is cloudy for opposition next weekend) and September Herschel targets. In the event the dark skies were so nice I diverted to Planetary Nebula and Bright Nebula at high angles and with a new UHC filter and gave Jupiter (in fact all the planets) a miss as they were glaring and shimmering in what i think was still quite a damp atmosphere at lower angles.

Steve O'Meara's "Herschel 400 Observing Guide" schedules the H400 for the year in multiple nightly (and seasonal) sessions. I cheat and transfer them to Sky Safari as a list for the month. September has 19 targets and i'm now only missing 5. One of which (The North America Nebula) i won't be able to observe with my current kit even though i did try (and failed) again last night. NGC 6823 (H VI-18), NGC 6830 (H VII-9), and NGC 6885 (H VIII-20) are three pretty Open Clusters in Vulpecula. All were nice and easy (with push to) and aesthetic targets early in the evening. NGC 6885 is quite near M27 the Dumbell Nebula and i thought i would take a quick look as i have a new UHC filter to try out. 

WOW. M27 was unreal - i've never seen it so big and i thought the filter had just paid for itself there and then (80x, 2.4mm exit pupil, UHC). In the event it wasn't only the new filter. I tried without and it was also bigger than i recall previously. I §don't think i've looked at M27 without a moon in the sky and the darker skies were clearly contributing enormously. I cycled through 80x/2.4mm exit pupil with and without UHC and 140x/1.3mm exit pupil with and without UHC and 200x/0.9mm exit pupil without UHC. All brought something to the observation though 80x with UHC and 140x without UHC were the best tools. If i'm honest i still didn't see the "hour glass" brightness within the oval as it appears in photographs and good sketches but i did see more variation and contrasted brightness differences across it than i've seen before. Superb.

Encouraged by M27 i moved round to The Eastern and Western Veil as these have been frustratingly missed for ages. I was ecstatic to see the Eastern Veil part (NGC 6995) using 2.4mm exit pupil and the UHC and see tendril like detail within it even. Fantastic. My widest TFOV is 1 degree so i was scrolling around the arc of it for the observation.  i could detect but couldn't really "see" the Western Veil part and couldn't detect either without UHC filter in place even while being parked in exactly the right spot.

New success with M27 and NGC 6995 encouraged me to take a look at NGC 6826 (H IV-73) the Blinking Nebula and NGC 7008; Planetary Nebula in Cygnus. The Blinking Nebula is funny. It blinked for me last night fully off/on with 80x/2.4mm pupil/UHC and blinked leaving behind the central star at 140x/1.3mm exit pupil. It didn't blink at all at 200x. The highest magnification was least satisfying. NGC 7008 was the other way round. Blinking on and off at higher magnification but not at lower ones. NGC 7008 is a lower magnitude PN than NGC 6826.

Three slightly harder targets (for me) finished the session;

NGC 6905 (H IV-16) the Blue Flash Nebula (not blue and no flash) no discernible shape or features but it is small and pretty dim.

NGC 6934 (H I-103) and NGC 7006 (I-52). These are also Caldwells and are small and dim Globular Clusters in Delphinus. For me in my scope these are hard to describe as Globular Clusters. No contrast to their edges and no resolvable stars. NGC 7006 in particular very hard to describe as a GC and i'm not sure i would have been able to see this at all on a brighter night.

Other than a sweep across the planets at the very end these targets finished the session. Id been taking great care to keep my eyepieces covered and where possible a little bit warm throughout the session but i finally lost the battle to condensation and that was the end of that. The scope itself though it wasn't dewed on the mirrors was absolutely running with water!

Cheers all.

[PeterW]

Maybe antifog spray could help. We had a breezy that seemed to keep the dampness at bay.

Peter

[josefk]

25 minutes ago, PeterW said:

Maybe antifog spray could help. We had a breezy that seemed to keep the dampness at bay.

Peter

Thanks for the tip Peter. I'm thinking of two strategies going forward - adding a very mildly heated pad in the bottom of my eypeicee case and hooking the case up to a dew controller or adding a slot in my eyepiece case for a hand warmer arrangement (i need to have a think about these two). The other is having a hand held fan of some sort to blow air across them in between use or in-between views while being used. I'm not sure this will work just blowing air at ambient temperature over them so may need to do an experiment one cloudy night. 🙂 Cheers

[PeterW]

Be careful where your breath goes as it will rise up, maybe deliberately blowing sideways will keep the warm moisture from rising into the eyepiece when viewing. Keeping eyepieces in your pocket  can help too.

Peter