chiltonstar

I'd agree with Andrew S - clear when scrolling the page, or indeed if I move my head from side to side and look at it.

Chris

Some interesting comments on seeing; I notice with mine (ZWO on 180 Mak) that where the poor seeing is of the sparkly, scintillating variety (you know what I mean) it appears to make no difference, but the slow swimming pool type that often appears if the sight line is over a hot road or roof or whatever, the ADC does appear to improve the view significantly.

Chris

I was getting flashes from Marlow direction - a good way from Oxford. I had the live lightning map app running on my laptop outside to see how far away the lightning effect could be seen. 

Here, I thought the Perseids were a bit underwhelming, although there was 50% cloud.

Chris

3 hours ago, John said:

Nice image anyway Chris

Here you go:

 

Wouldn't I need three for the tripod feet? After all, I'm 182 cm so it's not me that needs elevating....

Chris

My first attempt at Saturn this year; 1000/6000 frames with 180 Mak/ADC/AS120 colour camera. Image processed in Autostakkert/Registax. Oh for a bit of elevation!

Chris

My pennyworth.....it's horses and courses really. My first scope, mainly for planetary and doubles, was a 102mm f13 (Vixen objective) achro refractor. It still gives excellent views of doubles, but it is only 102mm aperture which limits resolution and of course limiting magnitude - there are many doubles of interest with faint secondaries. It is also long and unwieldy.

I then added a 127 Mak, which IMO is a truly excellent scope for the price, and enabled me to get to tighter doubles and fainter secondaries. To get lower, I then bought a 180 Mak which has enough aperture to reach many of the fainter doubles and (an important point) it is reasonably compact. Big newtonians and refractors may give excellent views, but they aren't that compact or convenient to use! For me personally, I have another issue as I live next to fields with wheat, barley and huge amounts of dust on occasions (eg yesterday) That makes open tube designs like newts or classical cassegrains less practical.

Chris

I've just had a good session too. Jupiter was just visible through thin cloud, the shadow was clear but intermittent and then miraculously, the cloud cleared leaving a haze and the seeing improved. The shadow was sharp and stable and in the position indicated in SkySafari; Europa itself suddenly came into view as a lighter disk slightly higher on the belt than in SS I believe, and the GRS slightly earlier than the SS position. A glorious sight!

Chris

Despite their current low altitude, I got a real treat last night with Saturn and Jupiter at their glorious best, despite the intense moonlight! Using my 180 Mak with ADC, Vixen SLV 15 mm, Baader Ortho 6 and 10mm and a 7.2 to 21.5mm zoom EPs, I had almost Hubble-like views for a few minutes as the seeing improved after a bank of cloud. Best magnification for J and S was about x245 and up to x300 once or twice.

The GRS and surrounding area was clear and sharp and a beautiful pale rose colour, and the belts full of intricate detail. The colour contrast between Callisto and Ganymede was particularly striking as the two moons were close together (23:30).

Nearby Saturn was textbook, with a very clear and sharp Cassini, banding on the disk, ring-on-planet and planet-on-ring shadows, a hint of the inner dark ring, and 4 or 5 moons readily visible. 

I tried taking the ADC off briefly (re recent post about the benefits or not) but there was little doubt that the visible detail was significantly better with the ADC, particularly on features such as the GRS. 

Chris

3 hours ago, Stu said:

Nice one, thanks Chris. 23.30 looks like it should be excellent if clear. Europa should be potentially visible against the limb darkening. Must finish off my 8” f8 for these planets plus Mars of course!

Yes,  defo one for the 8 inch f8. It would be interesting to see how @John's baby makling performs on it, and maybe the classical cassegrain? 

Chris

Monday evening 3rd August at about 23:30, at an altitude of about 16 degrees (from Oxford).

At the moment, the weather is uncertain so we may be lucky and have a clear patch or two.

Chris

7 hours ago, John said:

Got the split of Epsilon Lyrae with a Celestron 90mm mak-cassegrain at 90x tonight. Lower and the slightly wider pair stayed split but the closer pair became heavily notched but not quite split.

These little scopes are a lot of fun !

 

Small can be fun! I used my ED80 on my Vixen Porta2 to split it at x110; the easier pair split at x80, but it needed more for the more difficult unequal pair. I then moved the mount and scope into a nearby field to have my first look of the season at Mars as it rose. No detail, but always a thrill.

Chris

Just now, Merlin66 said:

Obviously a 100mm aperture, under good seeing, and good eyesight, are capable of resolving this double double.

 

Yes, with good seeing it is of course an easy pair of pairs to split with my 102mm f13 frac.

Chris

12 minutes ago, Merlin66 said:

A thin black thread separation is the “minimum “

Takes time, this is not a 30 second challenge.

Good practice to train your eye. It’s a bit like running....everyone can run, but few have the dedication to run properly. Takes practice and rigor and some dedication.

The more you look......the more you see.

 

But of course, you can't beat the limits set by aperture and resolving power. 

Chris

I can usually split them (180 Mak) at around x108. Worth noting that "split" is quite difficult to define, and what many of us see as split might not be to others.

There is a formula which allows you to calculate minimum magnification: for a person with excellent acuity and with stars of equal magnitude, it is about 130/separation, or about 200/separation for many of us. Assuming somewhere between the two, Epsilon Lyrae would need about  x72 magnification.

Chris

8 hours ago, A McEwan said:

Astroboot often have things like this up for grabs (and lots of other useful little bits n bobs that you didn't know you needed until you see them....)

https://www.astroboot.co.uk/AstroBoot

Ant

I browse this occasionally - I'll have another look.

Chris

As an alternative, I believe some suppliers stock extra tall pillar mounts.

Chris

7 hours ago, Philip R said:

Apologies for the confusion @chiltonstar

I have just re-read your post and now realised you are wanting a 'solid' end cap.

Many thanks, yes - it needs to be rigid like the original (ABS?) cap on the scope so I can drill it and mount a couple of brackets.

Chris

9 hours ago, DaveL59 said:

might have been me Mark as I did get one for the TAL-M a while back. I think they're also referred to as a bearing end cap and are solid. The nitrile helps it grip the tube well too.

Only thing I'd ask Chris - out of curiosity, what are you thinking to mount using an end cap?

For an objective prism system for spectroscopy, ditto some large gratings I have.

Again, thanks to all for the answers.

Chris

Many thanks, I'll try these two suggestions. Vinyl looks a bit soft perhaps, I really need something harder like ABS perhaps.

Chris

Anyone know where I can get spare scope front caps from??

I particularly need one for an SW 127 Mak, od 150mm, id 144 mm in order to mount some optical kit.

Many thanks,

Chris

10 minutes ago, markse68 said:

You probably need better quality optics or you lack experience in your observing or you should have been using a smaller scope.

I agree with Michael (fate187); looking at Ganymede at the moment without the ADC  (180 Mak, 10mm and 6mm Baader orthos) I can't see the dark patterns I would expect to see under better conditions as the disk is blurred vertically by the AD. With the ADC, Ganymede becomes a disk once again with detail. Maybe I'm more aware of AD than some because I have very good colour vision apparently (according to the workplace optician I went to when using high power lasers in the lab) but ppoor steroscopicity. Use of a smaller aperture refractor will of course reduce the amount of AD in line with theory, but of course will also reduce the amount of available resolution - no way around the laws of physics here I'm afraid. I see using an ADC as maximising the amount of resolution potentially available with more aperture.

Chris

Lovely little scope - I borrowed one last year for a holiday in Darkest Cornwall, and it was very impressive. I certainly could hardly bear to hand it back!

Chris

24 minutes ago, DaveHKent said:

Cheers. Macro is not that important. I was mainly wondering why many of the lenses I was looking at were described as macro and does that make them unsuitable for astro.

The macro description you quote is another way of saying close-focussing so they should work for astro, but it is worth looking at test reviews to see how far you need to stop it down to get best performance. I have a 28mm Nikon lens that is close focussing (not described as macro though) and does a good job for wide field imaging.

Chris

An additional point: you mention "macro of bugs around the garden" - generally short-focus macro lenses are not good for this because you need to get so close to the insect that you frighten them off (most people tend you use macro lenses around 100mm fl for insects).

Chris

Good that some club groups have managed to assemble! Lovel report.

Chris