John

Solid cloud a light drizzle here so definitely no magnitude comparisons going on here tonight

It's supposed to clear from around 1 am so I might get a chance then, if I feel like waiting up.

You can get thin foam foam sheets in hobby retailers that would probably have enough stiffness to make a suitable shield for a 150mm aperture.

I needed to keep the top end weight down on my dob as well because of balance so I'm pleased that my half moon shield (which is an Astro Engineering one) weighs very little.

Cloudy here tonight so I doubt I'll get a peek

8 minutes ago, Louis D said:

I forgot to add this thought of mine on uniformed individuals like my kids:  It should scare us informed voters that many, if not most, voters are completely uninformed or worse, misinformed, on most topics, and yet they choose our representatives via their votes.

Good point. Must find a way to stop the uninformed having a vote

5 minutes ago, johninderby said:

Hmmm..........at this rate will it become a requirement for all SGL members to own an AZ100. 😁😁😁

Well they are cheaper than a Tak !

3 minutes ago, Macavity said:

Aside from not too difficult (DOT-like!) 3C273, the "Hubble Deep Field".
- Or rather the "faintest" and (in this case) not too attractive an image? 🥳
Most of effort was in finding (multi-step EEVA star hopping) the thing...

I observed 3C 273 a couple of nights back:

https://stargazerslounge.com/topic/374487-from-near-to-very-far-quasar-3c-273/

I did also managed to observe the outburst of the blazar CTA-102 that @Owmuchonomy mentions here:

https://stargazerslounge.com/topic/374482-whats-the-furthest-away-thing-youve-imaged/?do=findComment&comment=4061446

That latter one is the most distant object that I've observed.

I have used the Baader fluid and their micro fibre cloth to clean eyepieces for the past decade with no issues at all. I use a hurricane blower to puff anything loose from the lens surface before using the fluid and only apply it via the cloth as per Baader's instructions. The fluid is applied to the cloth as a fine spray in a small patch and then using the cloth gently onto the glass so there should be no excess to get between lenses etc.

That is what has worked for me. I don't use the fluid very often. Most often all I need is a few puffs with the blower, with the lens held upside down to ensure that any debris falls away from the glass.

I use something similar on my 12 inch dobsonian. Its one of the half moon shaped ones to stop light getting onto the top of the secondary and inner end of the focuser. I've found it very effective. My light issues are from one general direction. For more all around problems a tube shape would be good.

I'm no imager (really !) but I did actually manage to snap a bit of the Hadley Rille using my ancient mobile phone over the eyepiece with my 12 inch dob last year. It's not much to look at but I was quite pleased with it. I've got a better phone now so maybe I should have another go ?:

39 minutes ago, johninderby said:

The Skytee II alt-az mount is a great choice although a bit heavier duty than would be needed for your scope but would allow fitting a bigger scope later on. 

https://www.firstlightoptics.com/alt-azimuth-astronomy-mounts/skywatcher-skytee-2-alt-azimuth-mount.html

That would be my suggestion as well

12 minutes ago, Nik271 said:

... there seems to be a bit of turbulence tonight.

I felt that as well.

I've had some short cloud gaps so I've had some nice but rather brief views of the moon including the lovely valley @Stu has pictured.

Rather solid cloud cover now though so I suspect that's it for tonight

27 minutes ago, paulastro said:

You were right John, had a good 45 mts before the cloud came in 🙂.

I'm getting short breaks in otherwise solid cloud here. A few minutes observing then a wait for the next gap. Better than nothing though.

Looking mixed here but I've popped a scope out in case I get a clear patch. Schroter's Valley is one of my favourites as well

While doing that I watched a very bright ISS pass over, which was nice

Schroter's Valley should look lovely tonight - if it stays clear 

Great report and photos Paul 

The views of the moon were very special last night.

28 minutes ago, bendiddley said:

Great stuff. It's not for my scope though, I'm just interested in the subject and wanted to find out more. By the way you say exit pupil is affected by the scope too, I thought it was just the eyepiece that affected this, how does the scope affect exit pupil?

Exit pupil is eyepiece focal length divided by focal ratio of scope.

2 minutes ago, bendiddley said:

Thanks. Is this the same for a 32mm plossl too ie. need much slower optics, what's the baseline for this? Or can faster scopes benefit from these as well, say f5?

I have not used all the Omni plossls but I have used quite a lot of similar quality ones. Optically they perform similarly across the the range of focal lengths. In the shorter focal lengths (10mm and less) the eye relief starts to get pretty tight.

In the central area of the field of view they will be fine in an F/5 scope but the optical correction may well suffer a bit in the outer parts of the field of view. There is not a sudden focal ratio cut off where an eyepiece simply won't perform, it is a gradual thing.

By correction I mean distortions to star images, mostly caused by the optical issue astigmatism which causes stars to take on an elongated "seagull" shape towards the outer parts of the field of view. At F/5 coma can also be an issue in newtonians but that is usually generated by the primary mirror of the scope.

This article gives more information:

http://umich.edu/~lowbrows/reflections/2007/dscobel.27.html

6 minutes ago, bendiddley said:

Thanks, but I'm wanting to know how it fairs on slower telescopes. I am curious. I have an f5 and know it wouldn't suit that. Celestron says it suits f6 and higher, just wondering how it fairs for slower scope and how slow it needs to be.

The slower the scope, the better the correction at the edges of the field of view will be. I presume that Celestron feel that F/6 is where the correction will be tolerable for most observers but it is still not likely to be perfect. In the centre of the field of view eyepieces generally perform pretty well regardless of scope focal ratio.

At F/10 and slower these plossls will be pretty much sharp right across the field of view.

If you have not already purchased the 40mm I would urge you to consider the 32mm instead.

Looking at your scopes, a 32mm eyepiece will show pretty much as wide a true field of view and have a more effective exit pupil (the diameter of the bundle of light that exits the eye lens of the eyepiece). The optical quality of the 32mm will be the same as the 40mm.

33 minutes ago, globular said:

Thanks John.
My skies cleared around 11pm and, like for you, the seeing was amazing but transparency poor.
Had a lovely session with the moon - picking out many of the features mentions in your threads of the last few nights.

Excellent

7 hours ago, globular said:

Cloudy here currently but I'm hopeful for later....

Will Hesiodus A still be viewable then?

Sorry, I missed the question. The answer is yes. Hope it stayed clear for you.

After a rather excited and lengthy session of lunar observing tonight, I wanted to chill out and observe something very different before packing my 12 inch dobsonian away for the night.

The seeing tonight was spectacular but the transparency was rather milky and the bright moon in the sky added to this to make the conditions far from suitable for hunting faint deep sky targets. But I fancied looking at something "deep" anyway.

The "bowl" of Virgo was well presented and I remembered that within that area lies the brightest quasar in the sky which is known as 3C 273. When I say brightest, it is still a magnitude 12.9 object but it is a point source so I hoped that would help it to cut through the milky background sky and be faintly visible.

Quasar 3C 273 certainly qualifies as a deep sky object as it lies at an immense distance of 2.443 Billion light years from us

I used the finder charts in this 2019 Astronomy Now article by Ade Ashford to star hop to the right part of Virgo and the narrow field finder chart to nail which of the faint stars was the actually the quasar:

https://astronomynow.com/2019/03/07/seek-out-3c-273-the-brightest-optical-quasar-in-the-spring-sky/

Under a transparent sky my 12 inch dob can get down to magnitude 14.7 point sources but under tonights sky magnitude 13 was pretty challenging and it took some time to allow my eye to get accustomed to picking out the dimmest stars in the field of view. 

But eventually I narrowed a faint suspect star down and used the detailed finder chart towards the bottom of the linked article to be sure, matching the alignment of my suspect with the brighter star patterns nearby.

So there was the faint speck of light, at the edge of visibility tonight, comprised of photons that have traveled for billions of years to get to my eye. Just another faint star-like point but knowing what it was, made it a bit special 

Quite a contrast to the bright lunar features that I had been exploring earlier this evening.

I think there are 3 other quasars that could be within the reach of my scope, especially under darker skies. I'll have a go at those when I feel like "going deep" again

5 minutes ago, Littleguy80 said:

Out with the 10” Dob tonight. Started with the Nova and M52. Got the concentric rings in Hesiodus A. Gassendi looks stunning. Great thread btw!

Thanks Neil - glad you have the views as well

I'm probably sounding like an overgrown kid in this thread

It's nice to get a bit excited by the sky again though

7 minutes ago, Sunshine said:

This is a beautifully detailed image, I wish I was there to see too! it's not every day that conditions are as good as you describe.

Quite rare for the conditions to be this good, I agree. We have had some good seeing lately here though, for a change. Not so good transparency though but with a bright moon in the sky, faint DSO's are not on the menu anyway.