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Rosette visually MkII


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Last night our puppy "Neek" woke us up at 3am growling and barking "really lots".. today we went to the point and saw a single set of timberwolf tracks, about 30 yds from the house-good catch Neek!

Im trying to train him to observe with me and I thought tonite would be a good session- until he started the growling and barking at the window as I prepared 😲 So I left him in the house and headed up to the ridge and seacan myself, believe me I was all ears out there.

@domstar is working out the details to observe the Rosette nebula and I figured I better "walk the talk" with respect to the opinions I'm giving. A steady -33c  set in and with great skies. I wanted to emulate a bit brighter sky situation so I set up with the sliver moon still up but low. Transparency was vg.

My 90mmSV Raptor is a great little scope that has seen hundreds of adventures around the area- I know this scope well.A 42mm LVW and Nikon 17/14 HW were on deck as well as an Astronomik OIII (wide, older one,vg) and the new tight, high trans TV OIII.

Under these vg but lightish conditions- very very faint MW, the 42mm/Astronomik OIII were enlisted for the first try- and success! The 6mm exit pupil and this OIII revealed the nebulosity and the Raptor framed it beautifully. Wide OIII worked? Ok time for the TV OIII, my best of three OIII's. This very tight high transmission filter gave an immediate contrast "pop" to the Rosette! A very noticeable difference.

Ok over to M42 for a break, off with the filter. A really small M42 presented itself, nothing like it should be... in goes the 14mm HW and bam! the bright core and draped wings were excellent - but- the lower loop-why is it sub par?

Off with the EIC in with the 17mm HW- whoa-a perfect bright view of M42 and its lower loop. A great sight. On goes the OIII and the lower loop was there but patchy and very faint.

By this time the moon lowered and I explored the area more- the 42 LVW/TV OIII revealed the Meissa nebula-its huge even for this 4.2 deg TFOV combo, larger than this. Not bad for a 90mm scope though?

Back to the Rosette- the 17mm HW, no filter showed the liquid grey glow of the Rosette nicely-so OK the OII will help right? This 2.4mm exit pupil combo killed the Rosette...

Anyway this was my mini adventure for the day and Im glad to have had it, the sky here is superb right now.

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6 hours ago, jetstream said:

Under these vg but lightish conditions- very very faint MW, the 42mm/Astronomik OIII were enlisted for the first try- and success! The 6mm exit pupil and this OIII revealed the nebulosity and the Raptor framed it beautifully. Wide OIII worked? Ok time for the TV OIII, my best of three OIII's. This very tight high transmission filter gave an immediate contrast "pop" to the Rosette! A very noticeable difference.

Did the Televue OIII make the difference, extra red spectrum filtered over the usual Astronomik ?

Edited by Deadlake
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Excellent report again and made me jealous that for the next week or so the forecast in uk is rubbish! Nice to read how your OIII has performed, can't wait for mine to arrive.

4 hours ago, jetstream said:

Back to the Rosette- the 17mm HW, no filter showed the liquid grey glow of the Rosette nicely-so OK the OII will help right? This 2.4mm exit pupil combo killed the Rosette...

 

could you explain why the short exit pupil had such an effect please (as you know i am a newbie so any info is very useful).

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Great report Gerry! I've been off the page for a while, the weather here...well you've probably heard about our snowfall. I think I've seen stars momentarily one night since my last observing report Jan19th.

We 'only' managed -23C at Braemar, not far from some of my fav viewing areas, though I haven't been for ages with lockdown and weather. 

Tomorrow night might be ok until midnight, but the moon is setting around then but might drag the 12" out and blow the dust off.

It was looking and feeling arctic here until yesterday, temps rising dramatically along the coast, perhaps 8 or 9C soon.

I love M42 now with the OIII filter, if you've used GIS, it's like turning different overlays on/off when I use different filters. A lot going on in that one.

Edited by Ships and Stars
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Great stuff Gerry, really nice to read your reports. Unfortunately I have no chance of the Rosette from Home; SQM 19 at best, need to wait for lock down to ease, and read your reports as compensation, so keep them coming! 👍

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7 hours ago, Deadlake said:

Did the Televue OIII make the difference, extra red spectrum filtered over the usual Astronomik ?

I think the difference is in the bandwidth, the TV is tight and the old Astronomik a bit wider. I would presume a new Astronomik to perform the same.

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6 hours ago, Kon said:

could you explain why the short exit pupil had such an effect please

The size of the light disk that hits your eye is called the exit pupil and this illuminates your eye. The size of this disk matters IMHO for a variety of things. Eventhough my eye opens well over 6mm, almost 7mm I find for me the trade off of a smaller 5mmish exit pupil and therefore increased image scale (mag) works extremely well (filter use).In talks with a bunch of "us" this seems to be a commonly liked place to be on large diffuse nebula.

The range revealed from conversation is 4mm for lighter skies to 5mm ish for any sky. In theory the UHC which allows more light through can use a smaller exit pupil (more mag). I generally don't do this- if the object is bright enough for this ie the "Swan", the filter comes off for better views.

On the other hand if you shrink the exit pupil and therefore increase mag and drop eye illumination these filters don't work well- not enough light hitting your eye- these filters espc a proper OIII really limit the total light through to your eyes.

To start try a 5m ish exit pupil +/- a little bit with an OIII IMHO.

On planetary neb this doesn't apply- throw everything you have at them, I regularly go over 350x with my 24" with a 1.5m exit pupil/OIII on small ones.

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1 hour ago, Ships and Stars said:

I've been off the page for a while, the weather here...well you've probably heard about our snowfall.

Great to hear from you!

Get the snowshoes out and report when clear! 😀

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51 minutes ago, Stu said:

Great stuff Gerry, really nice to read your reports

Thanks Stu! it was sure good to get the Raptor out, the views through the refractor were excellent, its been a while since I used it. Refractors do offer a purity of view and last night M42 showed extremely bright with the Nikon HW, this eyepiece on some things has no rival IMHO. On the Swan in the 24" the views are jaw dropping and photographic like.

Eagerly waiting your reports Stu!

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Excellent report Gerry; Polar Vortex, Timber wolfs, The Rosette Nebula what a mix, stimulating read and 'Neek' is growing accustomed to your environment well. Could be the closest many of us get to the Rosette this season, travel restrictions, now we are into the 'great thaw', perhaps @Ships and Starsmay get a shot at it.

However it is good to reminiscence on past occasions, such as a report from not sure when 'I hastily refitted an OIII and swung the scope around to observe the Rosette NGC 2237, the immenseness of nebula cloud enveloping around open cluster NGC 2244 was a fine sight until the curtain of cloud finally closed.' That was with my TV-85.

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6 hours ago, jetstream said:

The size of the light disk that hits your eye is called the exit pupil and this illuminates your eye. The size of this disk matters IMHO for a variety of things. Eventhough my eye opens well over 6mm, almost 7mm I find for me the trade off of a smaller 5mmish exit pupil and therefore increased image scale (mag) works extremely well (filter use).In talks with a bunch of "us" this seems to be a commonly liked place to be on large diffuse nebula.

The range revealed from conversation is 4mm for lighter skies to 5mm ish for any sky. In theory the UHC which allows more light through can use a smaller exit pupil (more mag). I generally don't do this- if the object is bright enough for this ie the "Swan", the filter comes off for better views.

On the other hand if you shrink the exit pupil and therefore increase mag and drop eye illumination these filters don't work well- not enough light hitting your eye- these filters espc a proper OIII really limit the total light through to your eyes.

To start try a 5m ish exit pupil +/- a little bit with an OIII IMHO.

On planetary neb this doesn't apply- throw everything you have at them, I regularly go over 350x with my 24" with a 1.5m exit pupil/OIII on small ones.

Thank you for this detailed explanation, I really appreciate it! I will take these into account next time i observe DSOs.

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