chiltonstar

3 hours ago, PeterW said:

Was pleasantly surprised last night when testing out different 5-7mm ep options and went over to Plato and managed to get see some fleeting white dots (when I could flick the floaters away from the centre of my field of view)! 
knowing where to look for some domes/rilles etc is good, but there’s always more subtle and small stuff to see.

Peter

Floaters ........ I think mine came with the bus pass!

Chris

50 minutes ago, Stu said:

I found them a little more obvious last night than the previous night for some reason. Seeing was similar so I guess I was illumination.

Any idea in best phase for seeing as dark pits, 9 days ish?

This is Monday evening at 23:00 - the bright part is about 50% of the pits (leading to them appearing as whitish blotches if the seeing isn't 100++%. I think the day before, Sunday evening, would have given the best view IMO?? I'm not sure exactly what number of days that would have been.

Chris

11 hours ago, John said:

 

Illumination when they show as pits with tiny ramparts is the most helpful. It's harder to spot more than "the big four" under more direct illumination, when they appear as bright spots on the dark floor of Plato.

 

Good point John. Interestingly, I've found that when they appear visually as bright spots (eg last night), they still image as pits although less defined than when the contrast is higher. The image shows 5+ pits, but I could only see 4 or 5 whitish patches.

Chris

I like the seating Stu! How do you raise and lower the height to keep your eye at the right level?

The Moon last night was cracking, wasn't it? I had my 180 Mak and little ED80 out, and the seeing was good enough (just) to see the Plato craterlets amongst other delights!

Let's hope the early summer continues a bit longer!

Chris

What an interesting post! Fascinating to know what goes on inside, but I'm not sure I am ready to take mine apart yet!

Chris

Ouch! Hope you get it sorted Stu. Can OOUK supply a new tube, maybe out of Dural or something less dentable than steel?

Chris

Very impressive! Rather better than those of us at 52 N can manage!

Chris

Lovely scope - I still have something very similar, but my mount is tattier through 20+ years use.

Interesting that you've got the head set as alt-az rather than equatorial.

Chris

6 hours ago, Stu said:

Thanks John. It was very close to your sketch the seeing settled, although at times it looked like  a picture of spaghetti drawn by a 2 year old!! 🤣.

I have no idea if I’ve been seeing this before but not recognising it, although I’m fairly sure I haven’t (In a 4” I mean). Even though conditions were not that good, it was consistently in the right place and quite obvious.

It was very interesting to refer to my description in the 8” under good conditions and see the difference ie the 8” was very much resolving the two disks, vs the kind of elongated secondary in the smaller scope.

Either my kit or my observing has got better over the years, likely both as I’m definitely seeing these targets better now than a few years ago when I first started observing tighter doubles.

I have both my 180 Mak and a small frac - ED80 - on my mount at the same time. This way, I get the beauty of a frac view,  even if the Airy disks are huge, and the resolution of the Mak. It helps to see the split as well.

Chris

37 minutes ago, Stu said:

Thanks Chris. Not sure if you saw but I did catch it a while back in the 8”. It was a night of much better seeing, and the view was quite different to last night. In the 8”, I got two round airy disks, whereas last might the secondary was very much like John’s sketch, ie elongated around the diffraction ring. I’m surprised and pleased to have got it in the Vixen, it does show it is a very capable scope. The additional focal length over the FC100DC is useful as it gives me x300 with the Nag Zoom vs x246, a useful increase.

 

Yes, I'd forgotten Stu. Must be one of the effects of extended home incarceration!

Chris

8 hours ago, Stu said:

Just managed Zeta Herc in the FL102S. Very pleased with that! It was coming and going in the seeing, but I had a few minutes when it was excellent and appeared just in the right place, quite similar to John’s sketch. I was using a nag zoom at 3mm, so x300.

The seeing is not fantastic and when I tried in the 8” it was a mess, no chance at all so it seems it does need better seeing in the larger scopes.

Good to see you've joined the Zeta Her club Stu! It is a tricky little pair though for the smaller scope because of the secondary falling on the diff ring. Might be worth trying again with the 8" on a night when the seeing is good??

Chris

With excellent transparency and U Maj high in the sky, I had another look at M97 (The Owl nebula) last night, using my 180 Mak with a 2" 38mm Panavision EP. For the first time, I could just make out "the eyes" of the owl - normally for me it is a nearly formless blob with no detail visible. A tribute to the conditions, and the fact that U Maj was well away from the north, as I have a lot of LP (streetlamps + gigawatt security lights) to the north of me.

Nearby M108 was as beautiful as ever, with a lot of granular detail visible along the core - some of which was twinkling like resolved stars in a glob.

Then across the sky and on to Markarian's Chain; the conditions made finding M84 and M86 easier, and with the near perfect conditions, the whole sequence was visible, even less bright galaxies I don't think I've spotted before. Who says Maks aren't deep sky scopes....

Roll on more clear and transparent evenings!

Chris

Nice report John. I've found with my scopes the Limiting Magnitudes calculated using www.cruxis.com are much closer to my own visual limits than some of the textbook values, giving me quite often four Uranian moons for example, rather than the three that some LM values would suggest.

Chris

A very nice sketch John - far better than I can manage.

After a few nights of excellent seeing here, tonight was "unremarkable" although the transparency was pretty good.

Chris

3 hours ago, F15Rules said:

Come on, Chris, man up!!😂😀

Long tubes are great! I owned a Vixen F13 Pulsar altaz some years ago..and IMO the quality of the double star images these long old fracs serve up are hard to beat..proper observing for oldies like me!😊

Dave

Man up?  it's "gender neutral internally fortify" these days!

I love the view through my 102mm f13, but not the practical aspects, which is why I mainly went to Maks about 10 years ago. Lying on my back on wet grass at 0 degrees at 70+ years of age is best avoided.

My 180 Mak gives "nearly a refractor view", but is compact and fairly easy to mount. With insulation to lick the cooling issues, it is ready to go in just a few minutes and the larger aperture gets me down to 0.7 arcsec separation doubles, and a much lower limiting magnitude than the 102mm could ever manage. However, the view through a 102mm frac is exquisite!

Chris

18 hours ago, mikeDnight said:

Does the Sky Tee have a counterweight arm Chris?  If so you could construct a Hargreaves Strut extending from behind the lens cell to the end of the counter arm, which should add some stability to the 4" F13.  Ive a real soft spot for the Vixen 102mm F13.  I had one for years and loved it! 

There is a counterweight arm - in the past, I have used a couple of elasticated cords to stabilise the scope a bit.

For nostalgia's sake, I had the scope out last night (excellent+ seeing) and looked at Izar with it for the first time in maybe 20 years, with the 9mm Ortho. Well resolved, although at x145 or so the colours were slightly muted. With a 6mm ortho (x220), the pair were still sharp but now with the full magnificent gold and slatey-blue colours. I had a hunt around for some old favourites including Epsilon Lyrae (textbook pattern with sharp, stable diff rings) , Delta Cygni (resolved), Lambda Cygni (not resolved) and Beta Cygni. Izar at its current altitude is a bit of a neck-twister though!

Chris

13 hours ago, John said:

I had a choice of 64x, 133x or 200x Stu. Simple Huygenian type - 2 elements in 2 groups !

Mind you, F/13.3 fracs are not too fussy.

A cloud free night, a stable mount and a modern eyepiece / diagonal and the results may well be different

Edit: my earlier post should have read thin cloud cover rather than tin cloud cover. Doh ! 

I'm tempted to try my old f13 Vixen 102mm out with a vintage 9mm ortho I have - might give a nice view of the pair. The scope performs gloriously on doubles, just the inconvenience of the length which means I have to have the tripod at maximum height, and use extenders on the SkyTee alt-az knobs. It's a bit susceptible to wind also (bit like the horses in the field next to my house at night!).

Chris

Great report Stu - I love the enthusiasm! The last two nights here have been excellent for seeing so I've been wandering round old favourites (DD, Vega, Zeta Her, Delta Cyg included) with my 180 Mak on one side and my little Mak on the other side of the mount, just to compare the two. For 127 (119) mm the small Mak really does perform well sometimes.

Chris

1 hour ago, Don Pensack said:

and it's a rare eyepiece that doesn't have some chromatic aberration in the outer field.

Maybe, although I am a little spoilt by using Orthos which have less in my experience.

Chris

Just a comment. I have a 15mm SLV which I bought (partly on advice from @John) for my Mak 180, mainly for planetary viewing as it gives about x190 - ideal for me usually for Saturn and Jupiter.

I have not seen any obvious reflections with it although I've not used it for Venus (a cheaper well-known planetary EP I have does have objectionable reflections from the brighter planets, and gives visibly less detail). The SLV gives superb detail in the centre of the field and a wonderful colour rendition, showing the warm peach colours of Saturn very well. Eye relief is good and it is nearly parfocal with some orthos I use. The only optical failing I've found is slight CA in the outer part of the field - very obvious if a double star is allowed to drift across the field. A small failing though.

Chris

Last night's shadows - always a treat to watch them move across the floor! Mak 180, AS1220 MC, 1000 frames from 6000, processed in PIPP, Autostakkert/PS.

Chris

1 hour ago, Stu said:

Of course you are right Chris, but it is curious when such a tiny scope can appear to outperform larger ones when trying to split some of these double stars. I understand that resolution has a big impact, but have always found that larger scopes have not necessarily performed as well as they theoretically should on these targets. Looking back at your Aberrator image, I actually think the view in the 65mm was a combination of the 60mm and 100mm. The secondary star was positioned on the 1st diffraction ring as in the 60mm example, however the star tightness was much more like the 100mm, with clear separation between the two stars.

I guess I just enjoy viewing these doubles more through smaller scopes than larger ones; I enjoy the Double Double way more in my Tak than in any larger aperture compound or reflecting scope. Just personal preference I guess?

Whatever turns you on, as they say! The Aberrator images vary of course according to brightness (and mag), turn up the intensity and you appear to expand the stars somewhat - I think this is roughly what happens sometimes when you use a larger scope. However, I don't think you can beat the Dawes limit with a smaller scope!?

Chris

On 26/04/2020 at 09:50, John said:

Great report Stu !

I have a rather old copy of the Broadhurst Clarkson and Fuller catalogue (bookalogue as they called it) which dates to around the time that the little Tal 65 became available over there. Dudley Fuller says in there that he rarely recommends scopes of less than 3 inches aperture but he was delighted to make an exception for the Tal Alkor becuse it has exquisite optical quality, excellent design and is over-engineered in a way that you just don't find in the average scope of this aperture.

Your experiences confirm Dudley's views I think

But presumably, despite the excellent optical quality, they are not able to beat the laws of diffraction though? 65mm is 65mm........

Chris

9 hours ago, Stu said:

They really are amazingly capable little scopes John, and the eyepiece/Barlow system is simple and easy to use. I much prefer it on a regular mount although I do have the original.

5 minutes ago, Scosmico said:

Hi

Does anyone know where I can find star charts down to mag 15?

Sky safari is not that good with faint stars around deep sky objects. 

Same around pluto. 

I have been taking advantage of recent great transparency and was galaxy hunting for many nights in a row. 

Many thanks

Have you tried Cartes du Ciel?

Chris